Convert System.Security.Cryptography.Native to C (#30376)

* Rename extension .cpp to .c

* Convert System.Security.Cryptography.Native to C

* Address feedback comments

63 files changed, 1640 insertions, 1578 deletions

diff --git a/src/Native/Unix/Common/pal_utilities.h b/src/Native/Unix/Common/pal_utilities.h
index 21f73923d0..ff12d33af5 100644
--- a/src/Native/Unix/Common/pal_utilities.h
+++ b/src/Native/Unix/Common/pal_utilities.h
@@ -14,6 +14,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <unistd.h>
+#include <limits.h>
 
 #ifdef __cplusplus
 #include <limits>
@@ -187,3 +188,21 @@ static inline bool CheckInterrupted(TInt result)
 }
 
 #endif // __cplusplus
+
+inline static uint32_t Int32ToUint32(int32_t value)
+{
+    assert(value >= 0);
+    return (uint32_t)value;
+}
+
+inline static size_t Int32ToSizeT(int32_t value)
+{
+    assert(value >= 0);
+    return (size_t)value;
+}
+
+inline static int32_t Uint32ToInt32(uint32_t value)
+{
+    assert(value <= INT_MAX);
+    return (int32_t)value;
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/CMakeLists.txt b/src/Native/Unix/System.Security.Cryptography.Native/CMakeLists.txt
index 352f456d07..e829db0c58 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/CMakeLists.txt
+++ b/src/Native/Unix/System.Security.Cryptography.Native/CMakeLists.txt
@@ -16,32 +16,32 @@ find_package(OpenSSL REQUIRED)
 include_directories(SYSTEM ${OPENSSL_INCLUDE_DIR})
 
 set(NATIVECRYPTO_SOURCES
-    openssl.cpp
-    pal_asn1.cpp
-    pal_asn1_print.cpp
-    pal_bignum.cpp
-    pal_bio.cpp
-    pal_dsa.cpp
-    pal_ecdsa.cpp
-    pal_ecc_import_export.cpp
-    pal_eckey.cpp
-    pal_err.cpp
-    pal_evp.cpp
-    pal_evp_pkey.cpp
-    pal_evp_pkey_dsa.cpp
-    pal_evp_pkey_ecdh.cpp
-    pal_evp_pkey_eckey.cpp
-    pal_evp_pkey_rsa.cpp
-    pal_evp_cipher.cpp
-    pal_hmac.cpp
-    pal_pkcs12.cpp
-    pal_pkcs7.cpp
-    pal_rsa.cpp
-    pal_ssl.cpp
-    pal_x509.cpp
-    pal_x509_name.cpp
-    pal_x509_root.cpp
-    pal_x509ext.cpp
+    openssl.c
+    pal_asn1.c
+    pal_asn1_print.c
+    pal_bignum.c
+    pal_bio.c
+    pal_dsa.c
+    pal_ecdsa.c
+    pal_ecc_import_export.c
+    pal_eckey.c
+    pal_err.c
+    pal_evp.c
+    pal_evp_pkey.c
+    pal_evp_pkey_dsa.c
+    pal_evp_pkey_ecdh.c
+    pal_evp_pkey_eckey.c
+    pal_evp_pkey_rsa.c
+    pal_evp_cipher.c
+    pal_hmac.c
+    pal_pkcs12.c
+    pal_pkcs7.c
+    pal_rsa.c
+    pal_ssl.c
+    pal_x509.c
+    pal_x509_name.c
+    pal_x509_root.c
+    pal_x509ext.c
 )
 
 if (FEATURE_DISTRO_AGNOSTIC_SSL)
@@ -50,7 +50,7 @@ if (FEATURE_DISTRO_AGNOSTIC_SSL)
     endif()
 
     list(APPEND NATIVECRYPTO_SOURCES
-        opensslshim.cpp
+        opensslshim.c
     )
     add_definitions(-DFEATURE_DISTRO_AGNOSTIC_SSL)
 endif()
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/openssl.cpp b/src/Native/Unix/System.Security.Cryptography.Native/openssl.c
index f424932055..dde8297e2e 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/openssl.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/openssl.c
@@ -15,7 +15,6 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
-#include <memory>
 
 // See X509NameType.SimpleName
 #define NAME_TYPE_SIMPLE 0
@@ -67,7 +66,7 @@ Return values:
 1: Data was copied
 Any negative value: The input buffer size was reported as insufficient. A buffer of size ABS(return) is required.
 */
-extern "C" int32_t CryptoNative_GetX509Thumbprint(X509* x509, uint8_t* pBuf, int32_t cBuf)
+int32_t CryptoNative_GetX509Thumbprint(X509* x509, uint8_t* pBuf, int32_t cBuf)
 {
     if (!x509)
     {
@@ -98,7 +97,7 @@ Return values:
 NULL if the validity cannot be determined, a pointer to the ASN1_TIME structure for the NotBefore value
 otherwise.
 */
-extern "C" ASN1_TIME* CryptoNative_GetX509NotBefore(X509* x509)
+ASN1_TIME* CryptoNative_GetX509NotBefore(X509* x509)
 {
     if (x509 && x509->cert_info && x509->cert_info->validity)
     {
@@ -119,7 +118,7 @@ Return values:
 NULL if the validity cannot be determined, a pointer to the ASN1_TIME structure for the NotAfter value
 otherwise.
 */
-extern "C" ASN1_TIME* CryptoNative_GetX509NotAfter(X509* x509)
+ASN1_TIME* CryptoNative_GetX509NotAfter(X509* x509)
 {
     if (x509 && x509->cert_info && x509->cert_info->validity)
     {
@@ -140,7 +139,7 @@ Return values:
 NULL if the validity cannot be determined, a pointer to the ASN1_TIME structure for the NextUpdate value
 otherwise.
 */
-extern "C" ASN1_TIME* CryptoNative_GetX509CrlNextUpdate(X509_CRL* crl)
+ASN1_TIME* CryptoNative_GetX509CrlNextUpdate(X509_CRL* crl)
 {
     if (crl)
     {
@@ -164,12 +163,12 @@ The encoded value of the version, otherwise:
   1: X509v2
   2: X509v3
 */
-extern "C" int32_t CryptoNative_GetX509Version(X509* x509)
+int32_t CryptoNative_GetX509Version(X509* x509)
 {
     if (x509 && x509->cert_info)
     {
         long ver = ASN1_INTEGER_get(x509->cert_info->version);
-        return static_cast<int32_t>(ver);
+        return (int32_t)ver;
     }
 
     return -1;
@@ -186,7 +185,7 @@ Return values:
 NULL if the algorithm cannot be determined, otherwise a pointer to the OpenSSL ASN1_OBJECT structure
 describing the object type.
 */
-extern "C" ASN1_OBJECT* CryptoNative_GetX509PublicKeyAlgorithm(X509* x509)
+ASN1_OBJECT* CryptoNative_GetX509PublicKeyAlgorithm(X509* x509)
 {
     if (x509 && x509->cert_info && x509->cert_info->key && x509->cert_info->key->algor)
     {
@@ -207,7 +206,7 @@ Return values:
 NULL if the algorithm cannot be determined, otherwise a pointer to the OpenSSL ASN1_OBJECT structure
 describing the object type.
 */
-extern "C" ASN1_OBJECT* CryptoNative_GetX509SignatureAlgorithm(X509* x509)
+ASN1_OBJECT* CryptoNative_GetX509SignatureAlgorithm(X509* x509)
 {
     if (x509 && x509->sig_alg && x509->sig_alg->algorithm)
     {
@@ -229,7 +228,7 @@ Return values:
 1: Data was copied
 Any negative value: The input buffer size was reported as insufficient. A buffer of size ABS(return) is required.
 */
-extern "C" int32_t CryptoNative_GetX509PublicKeyParameterBytes(X509* x509, uint8_t* pBuf, int32_t cBuf)
+int32_t CryptoNative_GetX509PublicKeyParameterBytes(X509* x509, uint8_t* pBuf, int32_t cBuf)
 {
     if (!x509 || !x509->cert_info || !x509->cert_info->key || !x509->cert_info->key->algor)
     {
@@ -274,7 +273,7 @@ Return values:
 NULL if the public key cannot be determined, a pointer to the ASN1_BIT_STRING structure representing
 the public key.
 */
-extern "C" ASN1_BIT_STRING* CryptoNative_GetX509PublicKeyBytes(X509* x509)
+ASN1_BIT_STRING* CryptoNative_GetX509PublicKeyBytes(X509* x509)
 {
     if (x509 && x509->cert_info && x509->cert_info->key)
     {
@@ -317,7 +316,7 @@ Remarks:
 
  So this function will really work on all of them.
 */
-extern "C" int32_t CryptoNative_GetAsn1StringBytes(ASN1_STRING* asn1, uint8_t* pBuf, int32_t cBuf)
+int32_t CryptoNative_GetAsn1StringBytes(ASN1_STRING* asn1, uint8_t* pBuf, int32_t cBuf)
 {
     if (!asn1 || cBuf < 0)
     {
@@ -336,7 +335,7 @@ extern "C" int32_t CryptoNative_GetAsn1StringBytes(ASN1_STRING* asn1, uint8_t* p
         return -length;
     }
 
-    memcpy_s(pBuf, UnsignedCast(cBuf), asn1->data, UnsignedCast(length));
+    memcpy_s(pBuf, Int32ToSizeT(cBuf), asn1->data, Int32ToSizeT(length));
     return 1;
 }
 
@@ -352,7 +351,7 @@ Return values:
 1: Data was copied
 Any negative value: The input buffer size was reported as insufficient. A buffer of size ABS(return) is required.
 */
-extern "C" int32_t CryptoNative_GetX509NameRawBytes(X509_NAME* x509Name, uint8_t* pBuf, int32_t cBuf)
+int32_t CryptoNative_GetX509NameRawBytes(X509_NAME* x509Name, uint8_t* pBuf, int32_t cBuf)
 {
     if (!x509Name || !x509Name->bytes || cBuf < 0)
     {
@@ -374,7 +373,7 @@ extern "C" int32_t CryptoNative_GetX509NameRawBytes(X509_NAME* x509Name, uint8_t
         return 0;
     }
 
-    int length = static_cast<int>(x509Name->bytes->length);
+    int length = (int)(x509Name->bytes->length);
 
     if (length < 0)
     {
@@ -387,7 +386,7 @@ extern "C" int32_t CryptoNative_GetX509NameRawBytes(X509_NAME* x509Name, uint8_t
         return -length;
     }
 
-    memcpy_s(pBuf, UnsignedCast(cBuf), x509Name->bytes->data, UnsignedCast(length));
+    memcpy_s(pBuf, Int32ToSizeT(cBuf), x509Name->bytes->data, Int32ToSizeT(length));
     return 1;
 }
 
@@ -402,7 +401,7 @@ Return values:
 0 if the field count cannot be determined, or the count of OIDs present in the EKU.
 Note that 0 does not always indicate an error, merely that GetX509EkuField should not be called.
 */
-extern "C" int32_t CryptoNative_GetX509EkuFieldCount(EXTENDED_KEY_USAGE* eku)
+int32_t CryptoNative_GetX509EkuFieldCount(EXTENDED_KEY_USAGE* eku)
 {
     return sk_ASN1_OBJECT_num(eku);
 }
@@ -418,7 +417,7 @@ Return values:
 NULL if eku is NULL or loc is out of bounds, otherwise a pointer to the ASN1_OBJECT structure encoding
 that particular OID.
 */
-extern "C" ASN1_OBJECT* CryptoNative_GetX509EkuField(EXTENDED_KEY_USAGE* eku, int32_t loc)
+ASN1_OBJECT* CryptoNative_GetX509EkuField(EXTENDED_KEY_USAGE* eku, int32_t loc)
 {
     return sk_ASN1_OBJECT_value(eku, loc);
 }
@@ -434,7 +433,7 @@ Return values:
 NULL if the certificate is invalid or no name information could be found, otherwise a pointer to a
 memory-backed BIO structure which contains the answer to the GetNameInfo query
 */
-extern "C" BIO* CryptoNative_GetX509NameInfo(X509* x509, int32_t nameType, int32_t forIssuer)
+BIO* CryptoNative_GetX509NameInfo(X509* x509, int32_t nameType, int32_t forIssuer)
 {
     static const char szOidUpn[] = "1.3.6.1.4.1.311.20.2.3";
 
@@ -564,7 +563,7 @@ extern "C" BIO* CryptoNative_GetX509NameInfo(X509* x509, int32_t nameType, int32
                 break;
         }
 
-        STACK_OF(GENERAL_NAME)* altNames = static_cast<STACK_OF(GENERAL_NAME)*>(
+        STACK_OF(GENERAL_NAME)* altNames = (STACK_OF(GENERAL_NAME)*)(
             X509_get_ext_d2i(x509, forIssuer ? NID_issuer_alt_name : NID_subject_alt_name, NULL, NULL));
 
         if (altNames)
@@ -730,7 +729,7 @@ static int CheckX509HostnameMatch(ASN1_STRING* candidate, const char* hostname,
         }
 
         // Great, candidateStr is just candidate->data!
-        candidateStr = reinterpret_cast<char*>(candidate->data);
+        candidateStr = (char*)(candidate->data);
 
         // First, verify that the string is alphanumeric, plus hyphens or periods and maybe starting with an asterisk.
         for (i = 0; i < candidate->length; ++i)
@@ -750,7 +749,7 @@ static int CheckX509HostnameMatch(ASN1_STRING* candidate, const char* hostname,
                 return 0;
             }
 
-            return !memcmp(candidateStr, hostname, static_cast<size_t>(cchHostname));
+            return !memcmp(candidateStr, hostname, (size_t)cchHostname);
         }
 
         for (i = 0; i < cchHostname; ++i)
@@ -783,7 +782,7 @@ static int CheckX509HostnameMatch(ASN1_STRING* candidate, const char* hostname,
                 return 0;
             }
 
-            return !memcmp(candidateStr + 1, hostname + hostnameFirstDot, static_cast<size_t>(matchLength));
+            return !memcmp(candidateStr + 1, hostname + hostnameFirstDot, (size_t)matchLength);
         }
     }
 
@@ -794,7 +793,7 @@ static int CheckX509HostnameMatch(ASN1_STRING* candidate, const char* hostname,
         return 0;
     }
 
-    return !memcmp(candidate->data, hostname, static_cast<size_t>(cchHostname));
+    return !memcmp(candidate->data, hostname, (size_t)cchHostname);
 }
 
 /*
@@ -809,7 +808,7 @@ Return values:
 0 if the hostname is not a match
 Any negative number indicates an error in the arguments.
 */
-extern "C" int32_t CryptoNative_CheckX509Hostname(X509* x509, const char* hostname, int32_t cchHostname)
+int32_t CryptoNative_CheckX509Hostname(X509* x509, const char* hostname, int32_t cchHostname)
 {
     if (!x509)
         return -2;
@@ -820,7 +819,7 @@ extern "C" int32_t CryptoNative_CheckX509Hostname(X509* x509, const char* hostna
 
     int subjectNid = NID_commonName;
     int sanGenType = GEN_DNS;
-    GENERAL_NAMES* san = static_cast<GENERAL_NAMES*>(
+    GENERAL_NAMES* san = (GENERAL_NAMES*)(
         X509_get_ext_d2i(x509, NID_subject_alt_name, NULL, NULL));
     char readSubject = 1;
     int success = 0;
@@ -893,7 +892,7 @@ Return values:
 0 if the hostname is not a match
 Any negative number indicates an error in the arguments.
 */
-extern "C" int32_t CryptoNative_CheckX509IpAddress(
+int32_t CryptoNative_CheckX509IpAddress(
     X509* x509, const uint8_t* addressBytes, int32_t addressBytesLen, const char* hostname, int32_t cchHostname)
 {
     if (!x509)
@@ -909,7 +908,7 @@ extern "C" int32_t CryptoNative_CheckX509IpAddress(
 
     int subjectNid = NID_commonName;
     int sanGenType = GEN_IPADD;
-    GENERAL_NAMES* san = static_cast<GENERAL_NAMES*>(X509_get_ext_d2i(x509, NID_subject_alt_name, NULL, NULL));
+    GENERAL_NAMES* san = (GENERAL_NAMES*)(X509_get_ext_d2i(x509, NID_subject_alt_name, NULL, NULL));
     int success = 0;
 
     if (san)
@@ -934,7 +933,7 @@ extern "C" int32_t CryptoNative_CheckX509IpAddress(
                 continue;
             }
 
-            if (!memcmp(addressBytes, ipAddr->data, static_cast<size_t>(addressBytesLen)))
+            if (!memcmp(addressBytes, ipAddr->data, (size_t)addressBytesLen))
             {
                 success = 1;
                 break;
@@ -981,7 +980,7 @@ Return values:
 0 if the field count cannot be determined, or the count of certificates in STACK_OF(X509)
 Note that 0 does not always indicate an error, merely that GetX509StackField should not be called.
 */
-extern "C" int32_t CryptoNative_GetX509StackFieldCount(STACK_OF(X509) * stack)
+int32_t CryptoNative_GetX509StackFieldCount(STACK_OF(X509) * stack)
 {
     return sk_X509_num(stack);
 }
@@ -997,7 +996,7 @@ Return values:
 NULL if stack is NULL or loc is out of bounds, otherwise a pointer to the X509 structure encoding
 that particular element.
 */
-extern "C" X509* CryptoNative_GetX509StackField(STACK_OF(X509) * stack, int loc)
+X509* CryptoNative_GetX509StackField(STACK_OF(X509) * stack, int loc)
 {
     return sk_X509_value(stack, loc);
 }
@@ -1009,7 +1008,7 @@ RecursiveFreeX509Stack
 Used by System.Security.Cryptography.X509Certificates' OpenSslX509ChainProcessor to free a stack
 when done with it.
 */
-extern "C" void CryptoNative_RecursiveFreeX509Stack(STACK_OF(X509) * stack)
+void CryptoNative_RecursiveFreeX509Stack(STACK_OF(X509) * stack)
 {
     sk_X509_pop_free(stack, X509_free);
 }
@@ -1025,7 +1024,7 @@ Return values:
 0 if ctx is NULL, if ctx has no X509_VERIFY_PARAM, or the date inputs don't produce a valid time_t;
 1 on success.
 */
-extern "C" int32_t CryptoNative_SetX509ChainVerifyTime(X509_STORE_CTX* ctx,
+int32_t CryptoNative_SetX509ChainVerifyTime(X509_STORE_CTX* ctx,
                                                    int32_t year,
                                                    int32_t month,
                                                    int32_t day,
@@ -1041,7 +1040,7 @@ extern "C" int32_t CryptoNative_SetX509ChainVerifyTime(X509_STORE_CTX* ctx,
 
     time_t verifyTime = MakeTimeT(year, month, day, hour, minute, second, isDst);
 
-    if (verifyTime == static_cast<time_t>(-1))
+    if (verifyTime == (time_t)-1)
     {
         return 0;
     }
@@ -1068,7 +1067,7 @@ Return values:
 If bio containns a valid DER-encoded X509 object, a pointer to that X509 structure that was deserialized,
 otherwise NULL.
 */
-extern "C" X509* CryptoNative_ReadX509AsDerFromBio(BIO* bio)
+X509* CryptoNative_ReadX509AsDerFromBio(BIO* bio)
 {
     return d2i_X509_bio(bio, NULL);
 }
@@ -1088,7 +1087,7 @@ behavior on non-file, non-null BIO objects.
 See also:
 OpenSSL's BIO_tell
 */
-extern "C" int32_t CryptoNative_BioTell(BIO* bio)
+int32_t CryptoNative_BioTell(BIO* bio)
 {
     if (!bio)
     {
@@ -1115,7 +1114,7 @@ otherwise unspecified
 See also:
 OpenSSL's BIO_seek
 */
-extern "C" int32_t CryptoNative_BioSeek(BIO* bio, int32_t ofs)
+int32_t CryptoNative_BioSeek(BIO* bio, int32_t ofs)
 {
     if (!bio)
     {
@@ -1135,7 +1134,7 @@ of X509* to OpenSSL.
 Return values:
 A STACK_OF(X509*) with no comparator.
 */
-extern "C" STACK_OF(X509) * CryptoNative_NewX509Stack()
+STACK_OF(X509) * CryptoNative_NewX509Stack()
 {
     return sk_X509_new_null();
 }
@@ -1151,7 +1150,7 @@ Return values:
 1 on success
 0 on a NULL stack, or an error within sk_X509_push
 */
-extern "C" int32_t CryptoNative_PushX509StackField(STACK_OF(X509) * stack, X509* x509)
+int32_t CryptoNative_PushX509StackField(STACK_OF(X509) * stack, X509* x509)
 {
     if (!stack)
     {
@@ -1172,7 +1171,7 @@ Returns a bool to managed code.
 1 for success
 0 for failure
 */
-extern "C" int32_t CryptoNative_GetRandomBytes(uint8_t* buf, int32_t num)
+int32_t CryptoNative_GetRandomBytes(uint8_t* buf, int32_t num)
 {
     int ret = RAND_bytes(buf, num);
 
@@ -1192,7 +1191,7 @@ Return values:
 -1 indicates OpenSSL signalled an error, CryptographicException should be raised.
 -2 indicates an error in the input arguments
 */
-extern "C" int32_t CryptoNative_LookupFriendlyNameByOid(const char* oidValue, const char** friendlyName)
+int32_t CryptoNative_LookupFriendlyNameByOid(const char* oidValue, const char** friendlyName)
 {
     ASN1_OBJECT* oid;
     int nid;
@@ -1246,7 +1245,7 @@ extern "C" int32_t CryptoNative_LookupFriendlyNameByOid(const char* oidValue, co
 static pthread_mutex_t g_initLock = PTHREAD_MUTEX_INITIALIZER;
 
 // Set of locks initialized for OpenSSL
-static pthread_mutex_t* g_locks = nullptr;
+static pthread_mutex_t* g_locks = NULL;
 
 /*
 Function:
@@ -1307,7 +1306,7 @@ Return values:
 0 on success
 non-zero on failure
 */
-extern "C" int32_t CryptoNative_EnsureOpenSslInitialized()
+int32_t CryptoNative_EnsureOpenSslInitialized()
 {
     int ret = 0;
     int numLocks = 0;
@@ -1316,7 +1315,7 @@ extern "C" int32_t CryptoNative_EnsureOpenSslInitialized()
 
     pthread_mutex_lock(&g_initLock);
 
-    if (g_locks != nullptr)
+    if (g_locks != NULL)
     {
         // Already initialized; nothing more to do.
         goto done;
@@ -1332,8 +1331,15 @@ extern "C" int32_t CryptoNative_EnsureOpenSslInitialized()
     }
 
     // Create the locks array
-    g_locks = new (std::nothrow) pthread_mutex_t[numLocks];
-    if (g_locks == nullptr)
+    size_t allocationSize = 0;
+    if (!multiply_s(sizeof(pthread_mutex_t), (size_t)numLocks, &allocationSize))
+    {
+        ret = 2;
+        goto done;
+    }
+
+    g_locks = (pthread_mutex_t*)malloc(allocationSize);
+    if (g_locks == NULL)
     {
         ret = 2;
         goto done;
@@ -1376,13 +1382,13 @@ done:
     if (ret != 0)
     {
         // Cleanup on failure
-        if (g_locks != nullptr)
+        if (g_locks != NULL)
         {
             for (int i = locksInitialized - 1; i >= 0; i--)
             {
                 pthread_mutex_destroy(&g_locks[i]); // ignore failures
             }
-            delete[] g_locks;
+            free(g_locks);
             g_locks = NULL;
         }
     }
@@ -1401,7 +1407,7 @@ Return values:
 Textual description of the version on success.
 "not available" string on failure.
 */
-extern "C" char* CryptoNative_SSLEayVersion()
+char* CryptoNative_SSLEayVersion()
 {
     return strdup(SSLeay_version(SSLEAY_VERSION));
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/openssl.h b/src/Native/Unix/System.Security.Cryptography.Native/openssl.h
index 7da64ca04e..2a0a2562b6 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/openssl.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/openssl.h
@@ -5,65 +5,66 @@
 
 #pragma once
 
+#include "pal_compiler.h"
 #include <openssl/x509.h>
 #include <openssl/x509v3.h>
 
-extern "C" int32_t CryptoNative_GetX509Thumbprint(X509* x509, uint8_t* pBuf, int32_t cBuf);
+DLLEXPORT int32_t CryptoNative_GetX509Thumbprint(X509* x509, uint8_t* pBuf, int32_t cBuf);
 
-extern "C" ASN1_TIME* CryptoNative_GetX509NotBefore(X509* x509);
+DLLEXPORT ASN1_TIME* CryptoNative_GetX509NotBefore(X509* x509);
 
-extern "C" ASN1_TIME* CryptoNative_GetX509NotAfter(X509* x509);
+DLLEXPORT ASN1_TIME* CryptoNative_GetX509NotAfter(X509* x509);
 
-extern "C" ASN1_TIME* CryptoNative_GetX509CrlNextUpdate(X509_CRL* crl);
+DLLEXPORT ASN1_TIME* CryptoNative_GetX509CrlNextUpdate(X509_CRL* crl);
 
-extern "C" int32_t CryptoNative_GetX509Version(X509* x509);
+DLLEXPORT int32_t CryptoNative_GetX509Version(X509* x509);
 
-extern "C" ASN1_OBJECT* CryptoNative_GetX509PublicKeyAlgorithm(X509* x509);
+DLLEXPORT ASN1_OBJECT* CryptoNative_GetX509PublicKeyAlgorithm(X509* x509);
 
-extern "C" ASN1_OBJECT* CryptoNative_GetX509SignatureAlgorithm(X509* x509);
+DLLEXPORT ASN1_OBJECT* CryptoNative_GetX509SignatureAlgorithm(X509* x509);
 
-extern "C" int32_t CryptoNative_GetX509PublicKeyParameterBytes(X509* x509, uint8_t* pBuf, int32_t cBuf);
+DLLEXPORT int32_t CryptoNative_GetX509PublicKeyParameterBytes(X509* x509, uint8_t* pBuf, int32_t cBuf);
 
-extern "C" ASN1_BIT_STRING* CryptoNative_GetX509PublicKeyBytes(X509* x509);
+DLLEXPORT ASN1_BIT_STRING* CryptoNative_GetX509PublicKeyBytes(X509* x509);
 
-extern "C" int32_t CryptoNative_GetAsn1StringBytes(ASN1_STRING* asn1, uint8_t* pBuf, int32_t cBuf);
+DLLEXPORT int32_t CryptoNative_GetAsn1StringBytes(ASN1_STRING* asn1, uint8_t* pBuf, int32_t cBuf);
 
-extern "C" int32_t CryptoNative_GetX509NameRawBytes(X509_NAME* x509Name, uint8_t* pBuf, int32_t cBuf);
+DLLEXPORT int32_t CryptoNative_GetX509NameRawBytes(X509_NAME* x509Name, uint8_t* pBuf, int32_t cBuf);
 
-extern "C" int32_t CryptoNative_GetX509EkuFieldCount(EXTENDED_KEY_USAGE* eku);
+DLLEXPORT int32_t CryptoNative_GetX509EkuFieldCount(EXTENDED_KEY_USAGE* eku);
 
-extern "C" ASN1_OBJECT* CryptoNative_GetX509EkuField(EXTENDED_KEY_USAGE* eku, int32_t loc);
+DLLEXPORT ASN1_OBJECT* CryptoNative_GetX509EkuField(EXTENDED_KEY_USAGE* eku, int32_t loc);
 
-extern "C" BIO* CryptoNative_GetX509NameInfo(X509* x509, int32_t nameType, int32_t forIssuer);
+DLLEXPORT BIO* CryptoNative_GetX509NameInfo(X509* x509, int32_t nameType, int32_t forIssuer);
 
-extern "C" int32_t CryptoNative_CheckX509Hostname(X509* x509, const char* hostname, int32_t cchHostname);
+DLLEXPORT int32_t CryptoNative_CheckX509Hostname(X509* x509, const char* hostname, int32_t cchHostname);
 
-extern "C" int32_t CryptoNative_CheckX509IpAddress(
+DLLEXPORT int32_t CryptoNative_CheckX509IpAddress(
     X509* x509, const uint8_t* addressBytes, int32_t addressBytesLen, const char* hostname, int32_t cchHostname);
 
-extern "C" int32_t CryptoNative_GetX509StackFieldCount(STACK_OF(X509) * stack);
+DLLEXPORT int32_t CryptoNative_GetX509StackFieldCount(STACK_OF(X509) * stack);
 
-extern "C" X509* CryptoNative_GetX509StackField(STACK_OF(X509) * stack, int loc);
+DLLEXPORT X509* CryptoNative_GetX509StackField(STACK_OF(X509) * stack, int loc);
 
-extern "C" void CryptoNative_RecursiveFreeX509Stack(STACK_OF(X509) * stack);
+DLLEXPORT void CryptoNative_RecursiveFreeX509Stack(STACK_OF(X509) * stack);
 
-extern "C" int32_t CryptoNative_SetX509ChainVerifyTime(
+DLLEXPORT int32_t CryptoNative_SetX509ChainVerifyTime(
     X509_STORE_CTX* ctx, int32_t year, int32_t month, int32_t day, int32_t hour, int32_t minute, int32_t second, int32_t isDst);
 
-extern "C" X509* CryptoNative_ReadX509AsDerFromBio(BIO* bio);
+DLLEXPORT X509* CryptoNative_ReadX509AsDerFromBio(BIO* bio);
 
-extern "C" int32_t CryptoNative_BioTell(BIO* bio);
+DLLEXPORT int32_t CryptoNative_BioTell(BIO* bio);
 
-extern "C" int32_t CryptoNative_BioSeek(BIO* bio, int32_t ofs);
+DLLEXPORT int32_t CryptoNative_BioSeek(BIO* bio, int32_t ofs);
 
-extern "C" STACK_OF(X509) * CryptoNative_NewX509Stack(void);
+DLLEXPORT STACK_OF(X509) * CryptoNative_NewX509Stack(void);
 
-extern "C" int32_t CryptoNative_PushX509StackField(STACK_OF(X509) * stack, X509* x509);
+DLLEXPORT int32_t CryptoNative_PushX509StackField(STACK_OF(X509) * stack, X509* x509);
 
-extern "C" int32_t CryptoNative_GetRandomBytes(uint8_t* buf, int32_t num);
+DLLEXPORT int32_t CryptoNative_GetRandomBytes(uint8_t* buf, int32_t num);
 
-extern "C" int32_t CryptoNative_LookupFriendlyNameByOid(const char* oidValue, const char** friendlyName);
+DLLEXPORT int32_t CryptoNative_LookupFriendlyNameByOid(const char* oidValue, const char** friendlyName);
 
-extern "C" int32_t CryptoNative_EnsureOpenSslInitialized(void);
+DLLEXPORT int32_t CryptoNative_EnsureOpenSslInitialized(void);
 
-extern "C" char* CryptoNative_SSLEayVersion(void);
+DLLEXPORT char* CryptoNative_SSLEayVersion(void);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.cpp b/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.c
index 9e5b676eb7..66807866de 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.c
@@ -5,19 +5,20 @@
 
 #include <dlfcn.h>
 #include <stdio.h>
+#include <stdbool.h>
 
 #include "opensslshim.h"
 
 // Define pointers to all the used ICU functions
-#define PER_FUNCTION_BLOCK(fn, isRequired) decltype(fn) fn##_ptr;
+#define PER_FUNCTION_BLOCK(fn, isRequired) __typeof(fn) fn##_ptr;
 FOR_ALL_OPENSSL_FUNCTIONS
 #undef PER_FUNCTION_BLOCK
 
 // x.x.x, considering the max number of decimal digits for each component
-static const int MaxVersionStringLength = 32;
+#define MaxVersionStringLength 32
 #define SONAME_BASE "libssl.so."
 
-static void* libssl = nullptr;
+static void* libssl = NULL;
 
 static bool OpenLibrary()
 {
@@ -27,7 +28,7 @@ static bool OpenLibrary()
     // like 1.0.0, 1.0.2 etc.
     char* versionOverride = getenv("CLR_OPENSSL_VERSION_OVERRIDE");
 
-    if ((versionOverride != nullptr) && strnlen(versionOverride, MaxVersionStringLength + 1) <= MaxVersionStringLength)
+    if ((versionOverride != NULL) && strnlen(versionOverride, MaxVersionStringLength + 1) <= MaxVersionStringLength)
     {
         char soName[sizeof(SONAME_BASE) + MaxVersionStringLength] = SONAME_BASE;
 
@@ -35,7 +36,7 @@ static bool OpenLibrary()
         libssl = dlopen(soName, RTLD_LAZY);
     }
 
-    if (libssl == nullptr)
+    if (libssl == NULL)
     {
         // Debian 9 has dropped support for SSLv3 and so they have bumped their soname. Let's try it
         // before trying the version 1.0.0 to make it less probable that some of our other dependencies 
@@ -43,19 +44,19 @@ static bool OpenLibrary()
         libssl = dlopen("libssl.so.1.0.2", RTLD_LAZY);
     }
 
-    if (libssl == nullptr)
+    if (libssl == NULL)
     {
         // Now try the default versioned so naming as described in the OpenSSL doc
         libssl = dlopen("libssl.so.1.0.0", RTLD_LAZY);
     }
 
-    if (libssl == nullptr)
+    if (libssl == NULL)
     {
         // Fedora derived distros use different naming for the version 1.0.0
         libssl = dlopen("libssl.so.10", RTLD_LAZY);
     }
 
-    return libssl != nullptr;
+    return libssl != NULL;
 }
 
 __attribute__((constructor))
@@ -69,7 +70,7 @@ static void InitializeOpenSSLShim()
 
     // Get pointers to all the ICU functions that are needed
 #define PER_FUNCTION_BLOCK(fn, isRequired) \
-    fn##_ptr = reinterpret_cast<decltype(fn)>(dlsym(libssl, #fn)); \
+    fn##_ptr = (__typeof(fn))(dlsym(libssl, #fn)); \
     if ((fn##_ptr) == NULL && isRequired) { fprintf(stderr, "Cannot get required symbol " #fn " from libssl\n"); abort(); }
 
     FOR_ALL_OPENSSL_FUNCTIONS
@@ -79,7 +80,7 @@ static void InitializeOpenSSLShim()
 __attribute__((destructor))
 static void ShutdownOpenSSLShim()
 {
-    if (libssl != nullptr)
+    if (libssl != NULL)
     {
         dlclose(libssl);
     }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h b/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
index afb2559d12..a844178e57 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
@@ -65,7 +65,7 @@ void SSL_CTX_set_alpn_select_cb(SSL_CTX* ctx, int (*cb) (SSL *ssl,
 void SSL_get0_alpn_selected(const SSL* ssl, const unsigned char** protocol, unsigned int* len);
 #endif
 
-#define API_EXISTS(fn) (fn != nullptr)
+#define API_EXISTS(fn) (fn != NULL)
 
 // List of all functions from the libssl that are used in the System.Security.Cryptography.Native.
 // Forgetting to add a function here results in build failure with message reporting the function
@@ -365,7 +365,7 @@ void SSL_get0_alpn_selected(const SSL* ssl, const unsigned char** protocol, unsi
     PER_FUNCTION_BLOCK(EC_POINT_set_affine_coordinates_GF2m, false) \
     
 // Declare pointers to all the used OpenSSL functions
-#define PER_FUNCTION_BLOCK(fn, isRequired) extern decltype(fn)* fn##_ptr;
+#define PER_FUNCTION_BLOCK(fn, isRequired) extern __typeof(fn)* fn##_ptr;
 FOR_ALL_OPENSSL_FUNCTIONS
 #undef PER_FUNCTION_BLOCK
 
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.c
new file mode 100644
index 0000000000..8a3f2b5798
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.c
@@ -0,0 +1,110 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_asn1.h"
+#include <stdlib.h>
+#include <stdbool.h>
+
+c_static_assert(PAL_NID_undef == NID_undef);
+c_static_assert(PAL_NID_X9_62_prime256v1 == NID_X9_62_prime256v1);
+c_static_assert(PAL_NID_secp224r1 == NID_secp224r1);
+c_static_assert(PAL_NID_secp384r1 == NID_secp384r1);
+c_static_assert(PAL_NID_secp521r1 == NID_secp521r1);
+
+const ASN1_OBJECT* CryptoNative_ObjTxt2Obj(const char* s)
+{
+    return OBJ_txt2obj(s, true);
+}
+
+int32_t CryptoNative_ObjObj2Txt(char* buf, int32_t buf_len, const ASN1_OBJECT* a)
+{
+    return OBJ_obj2txt(buf, buf_len, a, true);
+}
+
+const ASN1_OBJECT* CryptoNative_GetObjectDefinitionByName(const char* friendlyName)
+{
+    int nid = OBJ_ln2nid(friendlyName);
+
+    if (nid == NID_undef)
+    {
+        nid = OBJ_sn2nid(friendlyName);
+    }
+
+    if (nid == NID_undef)
+    {
+        return NULL;
+    }
+
+    return OBJ_nid2obj(nid);
+}
+
+int32_t CryptoNative_ObjSn2Nid(const char* sn)
+{
+    return OBJ_sn2nid(sn);
+}
+
+ASN1_OBJECT* CryptoNative_ObjNid2Obj(int32_t nid)
+{
+    return OBJ_nid2obj(nid);
+}
+
+void CryptoNative_Asn1ObjectFree(ASN1_OBJECT* a)
+{
+    ASN1_OBJECT_free(a);
+}
+
+ASN1_BIT_STRING* CryptoNative_DecodeAsn1BitString(const uint8_t* buf, int32_t len)
+{
+    if (!buf || !len)
+    {
+        return NULL;
+    }
+
+    return d2i_ASN1_BIT_STRING(NULL, &buf, len);
+}
+
+void CryptoNative_Asn1BitStringFree(ASN1_STRING* a)
+{
+    ASN1_BIT_STRING_free(a);
+}
+
+ASN1_OCTET_STRING* CryptoNative_DecodeAsn1OctetString(const uint8_t* buf, int32_t len)
+{
+    if (!buf || !len)
+    {
+        return NULL;
+    }
+
+    return d2i_ASN1_OCTET_STRING(NULL, &buf, len);
+}
+
+ASN1_OCTET_STRING* CryptoNative_Asn1OctetStringNew()
+{
+    return ASN1_OCTET_STRING_new();
+}
+
+int32_t CryptoNative_Asn1OctetStringSet(ASN1_OCTET_STRING* s, const uint8_t* data, int32_t len)
+{
+    return ASN1_OCTET_STRING_set(s, data, len);
+}
+
+void CryptoNative_Asn1OctetStringFree(ASN1_STRING* a)
+{
+    ASN1_OCTET_STRING_free(a);
+}
+
+void CryptoNative_Asn1StringFree(ASN1_STRING* a)
+{
+    ASN1_STRING_free(a);
+}
+
+int32_t CryptoNative_GetAsn1IntegerDerSize(ASN1_INTEGER* i)
+{
+    return i2d_ASN1_INTEGER(i, NULL);
+}
+
+int32_t CryptoNative_EncodeAsn1Integer(ASN1_INTEGER* i, uint8_t* buf)
+{
+    return i2d_ASN1_INTEGER(i, &buf);
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.cpp
deleted file mode 100644
index 5429592e57..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.cpp
+++ /dev/null
@@ -1,108 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_asn1.h"
-
-static_assert(PAL_NID_undef == NID_undef, "");
-static_assert(PAL_NID_X9_62_prime256v1 == NID_X9_62_prime256v1, "");
-static_assert(PAL_NID_secp224r1 == NID_secp224r1, "");
-static_assert(PAL_NID_secp384r1 == NID_secp384r1, "");
-static_assert(PAL_NID_secp521r1 == NID_secp521r1, "");
-
-extern "C" const ASN1_OBJECT* CryptoNative_ObjTxt2Obj(const char* s)
-{
-    return OBJ_txt2obj(s, true);
-}
-
-extern "C" int32_t CryptoNative_ObjObj2Txt(char* buf, int32_t buf_len, const ASN1_OBJECT* a)
-{
-    return OBJ_obj2txt(buf, buf_len, a, true);
-}
-
-extern "C" const ASN1_OBJECT* CryptoNative_GetObjectDefinitionByName(const char* friendlyName)
-{
-    int nid = OBJ_ln2nid(friendlyName);
-
-    if (nid == NID_undef)
-    {
-        nid = OBJ_sn2nid(friendlyName);
-    }
-
-    if (nid == NID_undef)
-    {
-        return nullptr;
-    }
-
-    return OBJ_nid2obj(nid);
-}
-
-extern "C" int32_t CryptoNative_ObjSn2Nid(const char* sn)
-{
-    return OBJ_sn2nid(sn);
-}
-
-extern "C" ASN1_OBJECT* CryptoNative_ObjNid2Obj(int32_t nid)
-{
-    return OBJ_nid2obj(nid);
-}
-
-extern "C" void CryptoNative_Asn1ObjectFree(ASN1_OBJECT* a)
-{
-    ASN1_OBJECT_free(a);
-}
-
-extern "C" ASN1_BIT_STRING* CryptoNative_DecodeAsn1BitString(const uint8_t* buf, int32_t len)
-{
-    if (!buf || !len)
-    {
-        return nullptr;
-    }
-
-    return d2i_ASN1_BIT_STRING(nullptr, &buf, len);
-}
-
-extern "C" void CryptoNative_Asn1BitStringFree(ASN1_STRING* a)
-{
-    ASN1_BIT_STRING_free(a);
-}
-
-extern "C" ASN1_OCTET_STRING* CryptoNative_DecodeAsn1OctetString(const uint8_t* buf, int32_t len)
-{
-    if (!buf || !len)
-    {
-        return nullptr;
-    }
-
-    return d2i_ASN1_OCTET_STRING(nullptr, &buf, len);
-}
-
-extern "C" ASN1_OCTET_STRING* CryptoNative_Asn1OctetStringNew()
-{
-    return ASN1_OCTET_STRING_new();
-}
-
-extern "C" int32_t CryptoNative_Asn1OctetStringSet(ASN1_OCTET_STRING* s, const uint8_t* data, int32_t len)
-{
-    return ASN1_OCTET_STRING_set(s, data, len);
-}
-
-extern "C" void CryptoNative_Asn1OctetStringFree(ASN1_STRING* a)
-{
-    ASN1_OCTET_STRING_free(a);
-}
-
-extern "C" void CryptoNative_Asn1StringFree(ASN1_STRING* a)
-{
-    ASN1_STRING_free(a);
-}
-
-extern "C" int32_t CryptoNative_GetAsn1IntegerDerSize(ASN1_INTEGER* i)
-{
-    return i2d_ASN1_INTEGER(i, nullptr);
-}
-
-extern "C" int32_t CryptoNative_EncodeAsn1Integer(ASN1_INTEGER* i, uint8_t* buf)
-{
-    return i2d_ASN1_INTEGER(i, &buf);
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.h
index 6ec1795d25..852a735c3d 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -20,79 +21,79 @@ enum SupportedAlgorithmNids
 /*
 Direct shim to OBJ_txt2obj.
 */
-extern "C" const ASN1_OBJECT* CryptoNative_ObjTxt2Obj(const char* s);
+DLLEXPORT const ASN1_OBJECT* CryptoNative_ObjTxt2Obj(const char* s);
 
 /*
 Direct shim to OBJ_obj2txt.
 */
-extern "C" int32_t CryptoNative_ObjObj2Txt(char* buf, int32_t buf_len, const ASN1_OBJECT* a);
+DLLEXPORT int32_t CryptoNative_ObjObj2Txt(char* buf, int32_t buf_len, const ASN1_OBJECT* a);
 
 /*
 Retrieves the ASN1_OBJECT for the specified friendly name.
 
 Can return nullptr if there isn't a corresponding shared object.
 */
-extern "C" const ASN1_OBJECT* CryptoNative_GetObjectDefinitionByName(const char* friendlyName);
+DLLEXPORT const ASN1_OBJECT* CryptoNative_GetObjectDefinitionByName(const char* friendlyName);
 
 /*
 Direct shim to OBJ_sn2nid.
 */
-extern "C" int32_t CryptoNative_ObjSn2Nid(const char* sn);
+DLLEXPORT int32_t CryptoNative_ObjSn2Nid(const char* sn);
 
 /*
 Direct shim to OBJ_nid2obj.
 */
-extern "C" ASN1_OBJECT* CryptoNative_ObjNid2Obj(int32_t nid);
+DLLEXPORT ASN1_OBJECT* CryptoNative_ObjNid2Obj(int32_t nid);
 
 /*
 Direct shim to ASN1_OBJECT_free.
 */
-extern "C" void CryptoNative_Asn1ObjectFree(ASN1_OBJECT* a);
+DLLEXPORT void CryptoNative_Asn1ObjectFree(ASN1_OBJECT* a);
 
 /*
 Shims the d2i_ASN1_BIT_STRING method and makes it easier to invoke from managed code.
 */
-extern "C" ASN1_BIT_STRING* CryptoNative_DecodeAsn1BitString(const uint8_t* buf, int32_t len);
+DLLEXPORT ASN1_BIT_STRING* CryptoNative_DecodeAsn1BitString(const uint8_t* buf, int32_t len);
 
 /*
 Direct shim to ASN1_BIT_STRING_free.
 */
-extern "C" void CryptoNative_Asn1BitStringFree(ASN1_STRING* a);
+DLLEXPORT void CryptoNative_Asn1BitStringFree(ASN1_STRING* a);
 
 /*
 Shims the d2i_ASN1_OCTET_STRING method and makes it easier to invoke from managed code.
 */
-extern "C" ASN1_OCTET_STRING* CryptoNative_DecodeAsn1OctetString(const uint8_t* buf, int32_t len);
+DLLEXPORT ASN1_OCTET_STRING* CryptoNative_DecodeAsn1OctetString(const uint8_t* buf, int32_t len);
 
 /*
 Direct shim to ASN1_OCTET_STRING_new.
 */
-extern "C" ASN1_OCTET_STRING* CryptoNative_Asn1OctetStringNew();
+DLLEXPORT ASN1_OCTET_STRING* CryptoNative_Asn1OctetStringNew(void);
 
 /*
 Direct shim to ASN1_OCTET_STRING_set.
 */
-extern "C" int32_t CryptoNative_Asn1OctetStringSet(ASN1_OCTET_STRING* s, const uint8_t* data, int32_t len);
+DLLEXPORT int32_t CryptoNative_Asn1OctetStringSet(ASN1_OCTET_STRING* s, const uint8_t* data, int32_t len);
 
 /*
 Direct shim to ASN1_OCTET_STRING_free.
 */
-extern "C" void CryptoNative_Asn1OctetStringFree(ASN1_STRING* a);
+DLLEXPORT void CryptoNative_Asn1OctetStringFree(ASN1_STRING* a);
 
 /*
 Direct shim to ASN1_STRING_free.
 */
-extern "C" void CryptoNative_Asn1StringFree(ASN1_STRING* a);
+DLLEXPORT void CryptoNative_Asn1StringFree(ASN1_STRING* a);
 
 /*
 Returns the number of bytes it will take to convert
 the ASN1_INTEGER to a DER format.
 */
-extern "C" int32_t CryptoNative_GetAsn1IntegerDerSize(ASN1_INTEGER* i);
+DLLEXPORT int32_t CryptoNative_GetAsn1IntegerDerSize(ASN1_INTEGER* i);
 
 /*
 Shims the i2d_ASN1_INTEGER method.
 
 Returns the number of bytes written to buf.
 */
-extern "C" int32_t CryptoNative_EncodeAsn1Integer(ASN1_INTEGER* i, uint8_t* buf);
+DLLEXPORT int32_t CryptoNative_EncodeAsn1Integer(ASN1_INTEGER* i, uint8_t* buf);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.c
new file mode 100644
index 0000000000..aca41d839d
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.c
@@ -0,0 +1,40 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_asn1_print.h"
+
+c_static_assert(PAL_B_ASN1_NUMERICSTRING == B_ASN1_NUMERICSTRING);
+c_static_assert(PAL_B_ASN1_PRINTABLESTRING == B_ASN1_PRINTABLESTRING);
+c_static_assert(PAL_B_ASN1_T61STRING == B_ASN1_T61STRING);
+c_static_assert(PAL_B_ASN1_VIDEOTEXSTRING == B_ASN1_VIDEOTEXSTRING);
+c_static_assert(PAL_B_ASN1_IA5STRING == B_ASN1_IA5STRING);
+c_static_assert(PAL_B_ASN1_GRAPHICSTRING == B_ASN1_GRAPHICSTRING);
+c_static_assert(PAL_B_ASN1_VISIBLESTRING == B_ASN1_VISIBLESTRING);
+c_static_assert(PAL_B_ASN1_GENERALSTRING == B_ASN1_GENERALSTRING);
+c_static_assert(PAL_B_ASN1_UNIVERSALSTRING == B_ASN1_UNIVERSALSTRING);
+c_static_assert(PAL_B_ASN1_OCTET_STRING == B_ASN1_OCTET_STRING);
+c_static_assert(PAL_B_ASN1_BIT_STRING == B_ASN1_BIT_STRING);
+c_static_assert(PAL_B_ASN1_BMPSTRING == B_ASN1_BMPSTRING);
+c_static_assert(PAL_B_ASN1_UNKNOWN == B_ASN1_UNKNOWN);
+c_static_assert(PAL_B_ASN1_UTF8STRING == B_ASN1_UTF8STRING);
+c_static_assert(PAL_B_ASN1_UTCTIME == B_ASN1_UTCTIME);
+c_static_assert(PAL_B_ASN1_GENERALIZEDTIME == B_ASN1_GENERALIZEDTIME);
+c_static_assert(PAL_B_ASN1_SEQUENCE == B_ASN1_SEQUENCE);
+
+c_static_assert(PAL_ASN1_STRFLGS_UTF8_CONVERT == ASN1_STRFLGS_UTF8_CONVERT);
+
+ASN1_STRING* CryptoNative_DecodeAsn1TypeBytes(const uint8_t* buf, int32_t len, Asn1StringTypeFlags type)
+{
+    if (!buf || !len)
+    {
+        return NULL;
+    }
+
+    return d2i_ASN1_type_bytes(NULL, &buf, len, type);
+}
+
+int32_t CryptoNative_Asn1StringPrintEx(BIO* out, ASN1_STRING* str, Asn1StringPrintFlags flags)
+{
+    return ASN1_STRING_print_ex(out, str, flags);
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.cpp
deleted file mode 100644
index ffbfef980d..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.cpp
+++ /dev/null
@@ -1,40 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_asn1_print.h"
-
-static_assert(PAL_B_ASN1_NUMERICSTRING == B_ASN1_NUMERICSTRING, "");
-static_assert(PAL_B_ASN1_PRINTABLESTRING == B_ASN1_PRINTABLESTRING, "");
-static_assert(PAL_B_ASN1_T61STRING == B_ASN1_T61STRING, "");
-static_assert(PAL_B_ASN1_VIDEOTEXSTRING == B_ASN1_VIDEOTEXSTRING, "");
-static_assert(PAL_B_ASN1_IA5STRING == B_ASN1_IA5STRING, "");
-static_assert(PAL_B_ASN1_GRAPHICSTRING == B_ASN1_GRAPHICSTRING, "");
-static_assert(PAL_B_ASN1_VISIBLESTRING == B_ASN1_VISIBLESTRING, "");
-static_assert(PAL_B_ASN1_GENERALSTRING == B_ASN1_GENERALSTRING, "");
-static_assert(PAL_B_ASN1_UNIVERSALSTRING == B_ASN1_UNIVERSALSTRING, "");
-static_assert(PAL_B_ASN1_OCTET_STRING == B_ASN1_OCTET_STRING, "");
-static_assert(PAL_B_ASN1_BIT_STRING == B_ASN1_BIT_STRING, "");
-static_assert(PAL_B_ASN1_BMPSTRING == B_ASN1_BMPSTRING, "");
-static_assert(PAL_B_ASN1_UNKNOWN == B_ASN1_UNKNOWN, "");
-static_assert(PAL_B_ASN1_UTF8STRING == B_ASN1_UTF8STRING, "");
-static_assert(PAL_B_ASN1_UTCTIME == B_ASN1_UTCTIME, "");
-static_assert(PAL_B_ASN1_GENERALIZEDTIME == B_ASN1_GENERALIZEDTIME, "");
-static_assert(PAL_B_ASN1_SEQUENCE == B_ASN1_SEQUENCE, "");
-
-static_assert(PAL_ASN1_STRFLGS_UTF8_CONVERT == ASN1_STRFLGS_UTF8_CONVERT, "");
-
-extern "C" ASN1_STRING* CryptoNative_DecodeAsn1TypeBytes(const uint8_t* buf, int32_t len, Asn1StringTypeFlags type)
-{
-    if (!buf || !len)
-    {
-        return nullptr;
-    }
-
-    return d2i_ASN1_type_bytes(nullptr, &buf, len, type);
-}
-
-extern "C" int32_t CryptoNative_Asn1StringPrintEx(BIO* out, ASN1_STRING* str, Asn1StringPrintFlags flags)
-{
-    return ASN1_STRING_print_ex(out, str, flags);
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.h
index 982506e420..78c092da65 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_asn1_print.h
@@ -3,12 +3,13 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
 Flags for the 'type' parameter of CryptoNative_DecodeAsn1TypeBytes.
 */
-enum Asn1StringTypeFlags : int32_t
+typedef enum
 {
     PAL_B_ASN1_NUMERICSTRING = 0x0001,
     PAL_B_ASN1_PRINTABLESTRING = 0x0002,
@@ -27,22 +28,22 @@ enum Asn1StringTypeFlags : int32_t
     PAL_B_ASN1_UTCTIME = 0x4000,
     PAL_B_ASN1_GENERALIZEDTIME = 0x8000,
     PAL_B_ASN1_SEQUENCE = 0x10000,
-};
+} Asn1StringTypeFlags;
 
 /*
 Flags for the 'flags' parameter of CryptoNative_Asn1StringPrintEx.
 */
-enum Asn1StringPrintFlags : uint64_t
+typedef enum
 {
     PAL_ASN1_STRFLGS_UTF8_CONVERT = 0x10,
-};
+} Asn1StringPrintFlags;
 
 /*
 Shims the d2i_ASN1_type_bytes method and makes it easier to invoke from managed code.
 */
-extern "C" ASN1_STRING* CryptoNative_DecodeAsn1TypeBytes(const uint8_t* buf, int32_t len, Asn1StringTypeFlags type);
+DLLEXPORT ASN1_STRING* CryptoNative_DecodeAsn1TypeBytes(const uint8_t* buf, int32_t len, Asn1StringTypeFlags type);
 
 /*
 Direct shim to ASN1_STRING_print_ex.
 */
-extern "C" int32_t CryptoNative_Asn1StringPrintEx(BIO* out, ASN1_STRING* str, Asn1StringPrintFlags flags);
+DLLEXPORT int32_t CryptoNative_Asn1StringPrintEx(BIO* out, ASN1_STRING* str, Asn1StringPrintFlags flags);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.c
index bb133d2b62..d9f7453a3c 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.c
@@ -4,25 +4,25 @@
 
 #include "pal_bignum.h"
 
-extern "C" void CryptoNative_BigNumDestroy(BIGNUM* a)
+void CryptoNative_BigNumDestroy(BIGNUM* a)
 {
-    if (a != nullptr)
+    if (a != NULL)
     {
         BN_clear_free(a);
     }
 }
 
-extern "C" BIGNUM* CryptoNative_BigNumFromBinary(const uint8_t* s, int32_t len)
+BIGNUM* CryptoNative_BigNumFromBinary(const uint8_t* s, int32_t len)
 {
     if (!s || !len)
     {
-        return nullptr;
+        return NULL;
     }
 
-    return BN_bin2bn(s, len, nullptr);
+    return BN_bin2bn(s, len, NULL);
 }
 
-extern "C" int32_t CryptoNative_BigNumToBinary(const BIGNUM* a, uint8_t* to)
+int32_t CryptoNative_BigNumToBinary(const BIGNUM* a, uint8_t* to)
 {
     if (!a || !to)
     {
@@ -32,7 +32,7 @@ extern "C" int32_t CryptoNative_BigNumToBinary(const BIGNUM* a, uint8_t* to)
     return BN_bn2bin(a, to);
 }
 
-extern "C" int32_t CryptoNative_GetBigNumBytes(const BIGNUM* a)
+int32_t CryptoNative_GetBigNumBytes(const BIGNUM* a)
 {
     if (!a)
     {
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.h
index 19919c8141..79da9b89fb 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_bignum.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -15,19 +16,19 @@ No-op if a is null.
 The given BIGNUM pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_BigNumDestroy(BIGNUM* a);
+DLLEXPORT void CryptoNative_BigNumDestroy(BIGNUM* a);
 
 /*
 Shims the BN_bin2bn method.
 */
-extern "C" BIGNUM* CryptoNative_BigNumFromBinary(const uint8_t* s, int32_t len);
+DLLEXPORT BIGNUM* CryptoNative_BigNumFromBinary(const uint8_t* s, int32_t len);
 
 /*
 Shims the BN_bn2bin method.
 */
-extern "C" int32_t CryptoNative_BigNumToBinary(const BIGNUM* a, uint8_t* to);
+DLLEXPORT int32_t CryptoNative_BigNumToBinary(const BIGNUM* a, uint8_t* to);
 
 /*
 Returns the number of bytes needed to export a BIGNUM.
 */
-extern "C" int32_t CryptoNative_GetBigNumBytes(const BIGNUM* a);
+DLLEXPORT int32_t CryptoNative_GetBigNumBytes(const BIGNUM* a);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.c
index b4009d5c40..0e55e62966 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.c
@@ -6,49 +6,49 @@
 
 #include <assert.h>
 
-extern "C" BIO* CryptoNative_CreateMemoryBio()
+BIO* CryptoNative_CreateMemoryBio()
 {
     return BIO_new(BIO_s_mem());
 }
 
-extern "C" BIO* CryptoNative_BioNewFile(const char* filename, const char* mode)
+BIO* CryptoNative_BioNewFile(const char* filename, const char* mode)
 {
     return BIO_new_file(filename, mode);
 }
 
-extern "C" int32_t CryptoNative_BioDestroy(BIO* a)
+int32_t CryptoNative_BioDestroy(BIO* a)
 {
     return BIO_free(a);
 }
 
-extern "C" int32_t CryptoNative_BioGets(BIO* b, char* buf, int32_t size)
+int32_t CryptoNative_BioGets(BIO* b, char* buf, int32_t size)
 {
     return BIO_gets(b, buf, size);
 }
 
-extern "C" int32_t CryptoNative_BioRead(BIO* b, void* buf, int32_t len)
+int32_t CryptoNative_BioRead(BIO* b, void* buf, int32_t len)
 {
     return BIO_read(b, buf, len);
 }
 
-extern "C" int32_t CryptoNative_BioWrite(BIO* b, const void* buf, int32_t len)
+int32_t CryptoNative_BioWrite(BIO* b, const void* buf, int32_t len)
 {
     return BIO_write(b, buf, len);
 }
 
-extern "C" int32_t CryptoNative_GetMemoryBioSize(BIO* bio)
+int32_t CryptoNative_GetMemoryBioSize(BIO* bio)
 {
-    long ret = BIO_get_mem_data(bio, nullptr);
+    long ret = BIO_get_mem_data(bio, NULL);
 
     // BIO_get_mem_data returns the memory size, which will always be
     // an int32.
     assert(ret <= INT32_MAX);
-    return static_cast<int32_t>(ret);
+    return (int32_t)ret;
 }
 
-extern "C" int32_t CryptoNative_BioCtrlPending(BIO* bio)
+int32_t CryptoNative_BioCtrlPending(BIO* bio)
 {
     size_t result = BIO_ctrl_pending(bio);
     assert(result <= INT32_MAX);
-    return static_cast<int32_t>(result);
+    return (int32_t)result;
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.h
index 6897dc1403..21a1989095 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_bio.h
@@ -3,17 +3,18 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
 Creates a new memory-backed BIO instance.
 */
-extern "C" BIO* CryptoNative_CreateMemoryBio();
+DLLEXPORT BIO* CryptoNative_CreateMemoryBio(void);
 
 /*
 Direct shim to BIO_new_file.
 */
-extern "C" BIO* CryptoNative_BioNewFile(const char* filename, const char* mode);
+DLLEXPORT BIO* CryptoNative_BioNewFile(const char* filename, const char* mode);
 
 /*
 Cleans up and deletes a BIO instance.
@@ -24,33 +25,33 @@ Implemented by:
 No-op if a is null.
 The given BIO pointer is invalid after this call.
 */
-extern "C" int32_t CryptoNative_BioDestroy(BIO* a);
+DLLEXPORT int32_t CryptoNative_BioDestroy(BIO* a);
 
 /*
 Direct shim to BIO_gets.
 */
-extern "C" int32_t CryptoNative_BioGets(BIO* b, char* buf, int32_t size);
+DLLEXPORT int32_t CryptoNative_BioGets(BIO* b, char* buf, int32_t size);
 
 /*
 Direct shim to BIO_read.
 */
-extern "C" int32_t CryptoNative_BioRead(BIO* b, void* buf, int32_t len);
+DLLEXPORT int32_t CryptoNative_BioRead(BIO* b, void* buf, int32_t len);
 
 /*
 Direct shim to BIO_write.
 */
-extern "C" int32_t CryptoNative_BioWrite(BIO* b, const void* buf, int32_t len);
+DLLEXPORT int32_t CryptoNative_BioWrite(BIO* b, const void* buf, int32_t len);
 
 /*
 Gets the size of data available in the BIO.
 
 Shims the BIO_get_mem_data method.
 */
-extern "C" int32_t CryptoNative_GetMemoryBioSize(BIO* bio);
+DLLEXPORT int32_t CryptoNative_GetMemoryBioSize(BIO* bio);
 
 /*
 Shims the BIO_ctrl_pending method.
 
 Returns the number of pending characters in the BIOs read and write buffers.
 */
-extern "C" int32_t CryptoNative_BioCtrlPending(BIO* bio);
+DLLEXPORT int32_t CryptoNative_BioCtrlPending(BIO* bio);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.c
index af9ce59d64..54ef433857 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.c
@@ -5,20 +5,20 @@
 #include "pal_dsa.h"
 #include "pal_utilities.h"
 
-extern "C" int32_t CryptoNative_DsaUpRef(DSA* dsa)
+int32_t CryptoNative_DsaUpRef(DSA* dsa)
 {
     return DSA_up_ref(dsa);
 }
 
-extern "C" void CryptoNative_DsaDestroy(DSA* dsa)
+void CryptoNative_DsaDestroy(DSA* dsa)
 {
-    if (dsa != nullptr)
+    if (dsa != NULL)
     {
         DSA_free(dsa);
     }
 }
 
-extern "C" int32_t CryptoNative_DsaGenerateKey(DSA** dsa, int32_t bits)
+int32_t CryptoNative_DsaGenerateKey(DSA** dsa, int32_t bits)
 {
     *dsa = DSA_new();
     if (!dsa)
@@ -27,47 +27,47 @@ extern "C" int32_t CryptoNative_DsaGenerateKey(DSA** dsa, int32_t bits)
         return 0;
     }
 
-    if (!DSA_generate_parameters_ex(*dsa, bits, nullptr, 0, nullptr, nullptr, nullptr) ||
+    if (!DSA_generate_parameters_ex(*dsa, bits, NULL, 0, NULL, NULL, NULL) ||
         !DSA_generate_key(*dsa))
     {
         DSA_free(*dsa);
-        *dsa = nullptr;
+        *dsa = NULL;
         return 0;
     }
 
     return 1;
 }
 
-extern "C" int32_t CryptoNative_DsaSizeSignature(DSA* dsa)
+int32_t CryptoNative_DsaSizeSignature(DSA* dsa)
 {
     return DSA_size(dsa);
 }
 
-extern "C" int32_t CryptoNative_DsaSizeP(DSA* dsa)
+int32_t CryptoNative_DsaSizeP(DSA* dsa)
 {
     return BN_num_bytes(dsa->p);
 }
 
-extern "C" int32_t CryptoNative_DsaSizeQ(DSA* dsa)
+int32_t CryptoNative_DsaSizeQ(DSA* dsa)
 {
     return BN_num_bytes(dsa->q);
 }
 
-extern "C" int32_t CryptoNative_DsaSign(
+int32_t CryptoNative_DsaSign(
     DSA* dsa,
     const uint8_t* hash,
     int32_t hashLength,
     uint8_t* refsignature,
     int32_t* outSignatureLength)
 {
-    if (outSignatureLength == nullptr || dsa == nullptr)
+    if (outSignatureLength == NULL || dsa == NULL)
     {
         assert(false);
         return 0;
     }
 
     // DSA_OpenSSL() returns a shared pointer, no need to free/cache.
-    if (dsa->meth == DSA_OpenSSL() && dsa->priv_key == nullptr)
+    if (dsa->meth == DSA_OpenSSL() && dsa->priv_key == NULL)
     {
         *outSignatureLength = 0;
         ERR_PUT_error(ERR_LIB_DSA, DSA_F_DSA_DO_SIGN, DSA_R_MISSING_PARAMETERS, __FILE__, __LINE__);
@@ -83,11 +83,11 @@ extern "C" int32_t CryptoNative_DsaSign(
     }
 
     assert(unsignedSigLen <= INT32_MAX);
-    *outSignatureLength = static_cast<int32_t>(unsignedSigLen);
+    *outSignatureLength = (int32_t)unsignedSigLen;
     return 1;
 }
 
-extern "C" int32_t CryptoNative_DsaVerify(
+int32_t CryptoNative_DsaVerify(
     DSA* dsa,
     const uint8_t* hash,
     int32_t hashLength,
@@ -109,7 +109,7 @@ extern "C" int32_t CryptoNative_DsaVerify(
     return 1;
 }
 
-extern "C" int32_t CryptoNative_GetDsaParameters(
+int32_t CryptoNative_GetDsaParameters(
     const DSA* dsa,
     BIGNUM** p, int32_t* pLength,
     BIGNUM** q, int32_t* qLength,
@@ -122,11 +122,11 @@ extern "C" int32_t CryptoNative_GetDsaParameters(
         assert(false);
 
         // since these parameters are 'out' parameters in managed code, ensure they are initialized
-        if (p) *p = nullptr; if (pLength) *pLength = 0;
-        if (q) *q = nullptr; if (qLength) *qLength = 0;
-        if (g) *g = nullptr; if (gLength) *gLength = 0;
-        if (y) *y = nullptr; if (yLength) *yLength = 0;
-        if (x) *x = nullptr; if (xLength) *xLength = 0;
+        if (p) *p = NULL; if (pLength) *pLength = 0;
+        if (q) *q = NULL; if (qLength) *qLength = 0;
+        if (g) *g = NULL; if (gLength) *gLength = 0;
+        if (y) *y = NULL; if (yLength) *yLength = 0;
+        if (x) *x = NULL; if (xLength) *xLength = 0;
         return 0;
     }
     
@@ -137,34 +137,34 @@ extern "C" int32_t CryptoNative_GetDsaParameters(
 
     // dsa->priv_key is optional
     *x = dsa->priv_key;
-    *xLength = (*x == nullptr) ? 0 : BN_num_bytes(*x);
+    *xLength = (*x == NULL) ? 0 : BN_num_bytes(*x);
 
     return 1;
 }
 
 static int32_t SetDsaParameter(BIGNUM** dsaFieldAddress, uint8_t* buffer, int32_t bufferLength)
 {
-    assert(dsaFieldAddress != nullptr);
+    assert(dsaFieldAddress != NULL);
     if (dsaFieldAddress)
     {
         if (!buffer || !bufferLength)
         {
-            *dsaFieldAddress = nullptr;
+            *dsaFieldAddress = NULL;
             return 1;
         }
         else
         {
-            BIGNUM* bigNum = BN_bin2bn(buffer, bufferLength, nullptr);
+            BIGNUM* bigNum = BN_bin2bn(buffer, bufferLength, NULL);
             *dsaFieldAddress = bigNum;
 
-            return bigNum != nullptr;
+            return bigNum != NULL;
         }
     }
 
     return 0;
 }
 
-extern "C" int32_t CryptoNative_DsaKeyCreateByExplicitParameters(
+int32_t CryptoNative_DsaKeyCreateByExplicitParameters(
     DSA** outDsa,
     uint8_t* p,
     int32_t pLength,
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.h
index ede7065992..2e60536ae0 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_dsa.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -10,14 +11,14 @@ Shims the DSA_new method.
 
 Returns the new DSA instance.
 */
-extern "C" DSA* CryptoNative_DsaCreate();
+DLLEXPORT DSA* CryptoNative_DsaCreate(void);
 
 /*
 Shims the DSA_up_ref method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_DsaUpRef(DSA* dsa);
+DLLEXPORT int32_t CryptoNative_DsaUpRef(DSA* dsa);
 
 /*
 Cleans up and deletes a DSA instance.
@@ -28,38 +29,38 @@ No-op if dsa is null.
 The given DSA pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_DsaDestroy(DSA* dsa);
+DLLEXPORT void CryptoNative_DsaDestroy(DSA* dsa);
 
 /*
 Shims the DSA_generate_key_ex method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_DsaGenerateKey(DSA** dsa, int32_t bits);
+DLLEXPORT int32_t CryptoNative_DsaGenerateKey(DSA** dsa, int32_t bits);
 
 /*
 Shims the DSA_size method.
 
 Returns the size of the ASN.1 encoded signature.
 */
-extern "C" int32_t CryptoNative_DsaSizeSignature(DSA* dsa);
+DLLEXPORT int32_t CryptoNative_DsaSizeSignature(DSA* dsa);
 
 /*
 Returns the size of the p parameter in bytes.
 */
-extern "C" int32_t CryptoNative_DsaSizeP(DSA* dsa);
+DLLEXPORT int32_t CryptoNative_DsaSizeP(DSA* dsa);
 
 /*
 Returns the size of the q parameter in bytes.
 */
-extern "C" int32_t CryptoNative_DsaSizeQ(DSA* dsa);
+DLLEXPORT int32_t CryptoNative_DsaSizeQ(DSA* dsa);
 
 /*
 Shims the DSA_sign method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_DsaSign(
     DSA* dsa,
     const uint8_t* hash,
@@ -72,7 +73,7 @@ Shims the DSA_verify method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_DsaVerify(
     DSA* dsa,
     const uint8_t* hash,
@@ -85,7 +86,7 @@ Gets all the parameters from the DSA instance.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_GetDsaParameters(
+DLLEXPORT int32_t CryptoNative_GetDsaParameters(
     const DSA* dsa,
     BIGNUM** p, int32_t* pLength,
     BIGNUM** q, int32_t* qLength,
@@ -96,7 +97,7 @@ extern "C" int32_t CryptoNative_GetDsaParameters(
 /*
 Sets all the parameters on the DSA instance.
 */
-extern "C" int32_t CryptoNative_DsaKeyCreateByExplicitParameters(
+DLLEXPORT int32_t CryptoNative_DsaKeyCreateByExplicitParameters(
     DSA** dsa,
     uint8_t* p,
     int32_t pLength,
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.c
index 59ab434881..f605e698ed 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.c
@@ -8,48 +8,48 @@
 static ECCurveType MethodToCurveType(EC_METHOD* method)
 {
     if (method == EC_GFp_mont_method())
-        return ECCurveType::PrimeMontgomery;
+        return PrimeMontgomery;
 
     int fieldType = EC_METHOD_get_field_type(method);
 
     if (fieldType == NID_X9_62_characteristic_two_field)
-        return ECCurveType::Characteristic2;
+        return Characteristic2;
 
     if (fieldType == NID_X9_62_prime_field)
-        return ECCurveType::PrimeShortWeierstrass;
+        return PrimeShortWeierstrass;
 
-    return ECCurveType::Unspecified;
+    return Unspecified;
 }
 
 static const EC_METHOD* CurveTypeToMethod(ECCurveType curveType)
 {
-    if (curveType == ECCurveType::PrimeShortWeierstrass)
+    if (curveType == PrimeShortWeierstrass)
         return EC_GFp_simple_method();
 
-    if (curveType == ECCurveType::PrimeMontgomery)
+    if (curveType == PrimeMontgomery)
         return EC_GFp_mont_method();
 
 #if HAVE_OPENSSL_EC2M
-    if (API_EXISTS(EC_GF2m_simple_method) && (curveType == ECCurveType::Characteristic2))
+    if (API_EXISTS(EC_GF2m_simple_method) && (curveType == Characteristic2))
         return EC_GF2m_simple_method();
 #endif
 
-    return nullptr; //Edwards and others
+    return NULL; //Edwards and others
 }
 
-extern "C" ECCurveType CryptoNative_EcKeyGetCurveType(
+ECCurveType CryptoNative_EcKeyGetCurveType(
     const EC_KEY* key)
 {
     const EC_GROUP* group = EC_KEY_get0_group(key);
-    if (!group) return ECCurveType::Unspecified;
+    if (!group) return Unspecified;
 
     const EC_METHOD* method = EC_GROUP_method_of(group);
-    if (!method) return ECCurveType::Unspecified;
+    if (!method) return Unspecified;
 
-    return MethodToCurveType(const_cast<EC_METHOD*>(method));
+    return MethodToCurveType(method);
 }
 
-extern "C" int32_t CryptoNative_GetECKeyParameters(
+int32_t CryptoNative_GetECKeyParameters(
     const EC_KEY* key,
     int32_t includePrivate,
     BIGNUM** qx, int32_t* cbQx,
@@ -65,22 +65,22 @@ extern "C" int32_t CryptoNative_GetECKeyParameters(
         assert(false);
 
         // Since these parameters are 'out' parameters in managed code, ensure they are initialized
-        if (qx) *qx = nullptr; if (cbQx) *cbQx = 0;
-        if (qy) *qy = nullptr; if (cbQy) *cbQy = 0;
-        if (d)  *d  = nullptr; if (cbD) *cbD = 0;
+        if (qx) *qx = NULL; if (cbQx) *cbQx = 0;
+        if (qy) *qy = NULL; if (cbQy) *cbQy = 0;
+        if (d)  *d  = NULL; if (cbD) *cbD = 0;
 
         return 0;
     }
 
     // Get the public key and curve
     int rc = 0;
-    BIGNUM *xBn = nullptr;
-    BIGNUM *yBn = nullptr;
+    BIGNUM *xBn = NULL;
+    BIGNUM *yBn = NULL;
 
     ECCurveType curveType = CryptoNative_EcKeyGetCurveType(key);
     const EC_POINT* Q = EC_KEY_get0_public_key(key);
     const EC_GROUP* group = EC_KEY_get0_group(key);
-    if (curveType == ECCurveType::Unspecified || !Q || !group) 
+    if (curveType == Unspecified || !Q || !group) 
         goto error;
 
     // Extract qx and qy
@@ -90,15 +90,15 @@ extern "C" int32_t CryptoNative_GetECKeyParameters(
         goto error;
 
 #if HAVE_OPENSSL_EC2M
-    if (API_EXISTS(EC_POINT_get_affine_coordinates_GF2m) && (curveType == ECCurveType::Characteristic2))
+    if (API_EXISTS(EC_POINT_get_affine_coordinates_GF2m) && (curveType == Characteristic2))
     {
-        if (!EC_POINT_get_affine_coordinates_GF2m(group, Q, xBn, yBn, nullptr)) 
+        if (!EC_POINT_get_affine_coordinates_GF2m(group, Q, xBn, yBn, NULL)) 
             goto error;
     }
     else
 #endif
     {
-        if (!EC_POINT_get_affine_coordinates_GFp(group, Q, xBn, yBn, nullptr)) 
+        if (!EC_POINT_get_affine_coordinates_GFp(group, Q, xBn, yBn, NULL)) 
             goto error;
     }
 
@@ -109,9 +109,9 @@ extern "C" int32_t CryptoNative_GetECKeyParameters(
     if (includePrivate)
     {
         const BIGNUM* const_bignum_privateKey = EC_KEY_get0_private_key(key);
-        if (const_bignum_privateKey != nullptr)
+        if (const_bignum_privateKey != NULL)
         {
-            *d = const_cast<BIGNUM*>(const_bignum_privateKey);
+            *d = const_bignum_privateKey;
             *cbD = BN_num_bytes(*d);
         }
         else
@@ -123,7 +123,7 @@ extern "C" int32_t CryptoNative_GetECKeyParameters(
     else
     {
         if (d)
-            *d = nullptr;
+            *d = NULL;
 
         if (cbD)
             *cbD = 0;
@@ -135,14 +135,14 @@ extern "C" int32_t CryptoNative_GetECKeyParameters(
 error:
     *cbQx = *cbQy = 0;
     *qx = *qy = 0;
-    if (d) *d = nullptr;
+    if (d) *d = NULL;
     if (cbD) *cbD = 0;
     if (xBn) BN_free(xBn);
     if (yBn) BN_free(yBn);
     return rc;
 }
 
-extern "C" int32_t CryptoNative_GetECCurveParameters(
+int32_t CryptoNative_GetECCurveParameters(
     const EC_KEY* key,
     int32_t includePrivate,
     ECCurveType* curveType,
@@ -174,29 +174,29 @@ extern "C" int32_t CryptoNative_GetECCurveParameters(
         assert(false);
 
         // Since these parameters are 'out' parameters in managed code, ensure they are initialized
-        if (p) *p = nullptr; if (cbP) *cbP = 0;
-        if (a) *a = nullptr; if (cbA) *cbA = 0;
-        if (b) *b = nullptr; if (cbB) *cbB = 0;
-        if (gx) *gx = nullptr; if (cbGx) *cbGx = 0;
-        if (gy) *gy = nullptr; if (cbGy) *cbGy = 0;
-        if (order) *order = nullptr; if (cbOrder) *cbOrder = 0;
-        if (cofactor) *cofactor = nullptr; if (cbCofactor) *cbCofactor = 0;
-        if (seed) *seed = nullptr; if (cbSeed) *cbSeed = 0;
+        if (p) *p = NULL; if (cbP) *cbP = 0;
+        if (a) *a = NULL; if (cbA) *cbA = 0;
+        if (b) *b = NULL; if (cbB) *cbB = 0;
+        if (gx) *gx = NULL; if (cbGx) *cbGx = 0;
+        if (gy) *gy = NULL; if (cbGy) *cbGy = 0;
+        if (order) *order = NULL; if (cbOrder) *cbOrder = 0;
+        if (cofactor) *cofactor = NULL; if (cbCofactor) *cbCofactor = 0;
+        if (seed) *seed = NULL; if (cbSeed) *cbSeed = 0;
 
         return 0;
     }
 
-    EC_GROUP* group = nullptr;
-    EC_POINT* G = nullptr;
-    EC_METHOD* curveMethod = nullptr;
-    BIGNUM* xBn = nullptr;
-    BIGNUM* yBn = nullptr;
-    BIGNUM* pBn = nullptr;
-    BIGNUM* aBn = nullptr;
-    BIGNUM* bBn = nullptr;
-    BIGNUM* orderBn = nullptr;
-    BIGNUM* cofactorBn = nullptr;
-    BIGNUM* seedBn = nullptr;
+    EC_GROUP* group = NULL;
+    EC_POINT* G = NULL;
+    EC_METHOD* curveMethod = NULL;
+    BIGNUM* xBn = NULL;
+    BIGNUM* yBn = NULL;
+    BIGNUM* pBn = NULL;
+    BIGNUM* aBn = NULL;
+    BIGNUM* bBn = NULL;
+    BIGNUM* orderBn = NULL;
+    BIGNUM* cofactorBn = NULL;
+    BIGNUM* seedBn = NULL;
 
     // Exit if CryptoNative_GetECKeyParameters failed
     if (rc != 1) 
@@ -213,38 +213,38 @@ extern "C" int32_t CryptoNative_GetECCurveParameters(
     if (!xBn || !yBn || !pBn || !aBn || !bBn || !orderBn || !cofactorBn)
         goto error;
 
-    group = const_cast<EC_GROUP*>(EC_KEY_get0_group(key)); // curve
+    group = EC_KEY_get0_group(key); // curve
     if (!group) 
         goto error;
 
-    curveMethod = const_cast<EC_METHOD*>(EC_GROUP_method_of(group));
+    curveMethod = EC_GROUP_method_of(group);
     if (!curveMethod) 
         goto error;
 
     *curveType = MethodToCurveType(curveMethod);
-    if (*curveType == ECCurveType::Unspecified) 
+    if (*curveType == Unspecified) 
         goto error;
 
     // Extract p, a, b
 #if HAVE_OPENSSL_EC2M
-    if (API_EXISTS(EC_GROUP_get_curve_GF2m) && (*curveType == ECCurveType::Characteristic2))
+    if (API_EXISTS(EC_GROUP_get_curve_GF2m) && (*curveType == Characteristic2))
     {
         // pBn represents the binary polynomial
-        if (!EC_GROUP_get_curve_GF2m(group, pBn, aBn, bBn, nullptr)) 
+        if (!EC_GROUP_get_curve_GF2m(group, pBn, aBn, bBn, NULL)) 
             goto error;
     }
     else
 #endif
     {
         // pBn represents the prime
-        if (!EC_GROUP_get_curve_GFp(group, pBn, aBn, bBn, nullptr))
+        if (!EC_GROUP_get_curve_GFp(group, pBn, aBn, bBn, NULL))
             goto error;
     }
 
     // Extract gx and gy
-    G = const_cast<EC_POINT*>(EC_GROUP_get0_generator(group));
+    G = EC_GROUP_get0_generator(group);
 #if HAVE_OPENSSL_EC2M
-    if (API_EXISTS(EC_POINT_get_affine_coordinates_GF2m) && (*curveType == ECCurveType::Characteristic2))
+    if (API_EXISTS(EC_POINT_get_affine_coordinates_GF2m) && (*curveType == Characteristic2))
     {
         if (!EC_POINT_get_affine_coordinates_GF2m(group, G, xBn, yBn, NULL)) 
             goto error;
@@ -257,18 +257,18 @@ extern "C" int32_t CryptoNative_GetECCurveParameters(
     }
 
     // Extract order (n)
-    if (!EC_GROUP_get_order(group, orderBn, nullptr))
+    if (!EC_GROUP_get_order(group, orderBn, NULL))
         goto error;
 
     // Extract cofactor (h)
-    if (!EC_GROUP_get_cofactor(group, cofactorBn, nullptr))
+    if (!EC_GROUP_get_cofactor(group, cofactorBn, NULL))
         goto error;
 
     // Extract seed (optional)
     if (EC_GROUP_get0_seed(group))
     {
         seedBn = BN_bin2bn(EC_GROUP_get0_seed(group), 
-            static_cast<int>(EC_GROUP_get_seed_len(group)), NULL);
+            (int)EC_GROUP_get_seed_len(group), NULL);
         
         *seed = seedBn;
         *cbSeed = BN_num_bytes(seedBn);
@@ -282,7 +282,7 @@ extern "C" int32_t CryptoNative_GetECCurveParameters(
     }
     else
     {
-        *seed = nullptr;
+        *seed = NULL;
         *cbSeed = 0;
     }
 
@@ -301,14 +301,14 @@ extern "C" int32_t CryptoNative_GetECCurveParameters(
 error:
     // Clear out variables from CryptoNative_GetECKeyParameters
     *cbQx = *cbQy = 0;
-    *qx = *qy = nullptr;
-    if (d) *d = nullptr;
+    *qx = *qy = NULL;
+    if (d) *d = NULL;
     if (cbD) *cbD = 0;
 
     // Clear our out variables
-    *curveType = ECCurveType::Unspecified;
+    *curveType = Unspecified;
     *cbP = *cbA = *cbB = *cbGx = *cbGy = *cbOrder = *cbCofactor = *cbSeed = 0;
-    *p = *a = *b = *gx = *gy = *order = *cofactor = *seed = nullptr;
+    *p = *a = *b = *gx = *gy = *order = *cofactor = *seed = NULL;
 
     if (xBn) BN_free(xBn);
     if (yBn) BN_free(yBn);
@@ -323,7 +323,7 @@ exit:
     return rc;
 }
 
-extern "C" int32_t CryptoNative_EcKeyCreateByKeyParameters(EC_KEY** key, const char* oid, uint8_t* qx, int32_t qxLength, uint8_t* qy, int32_t qyLength, uint8_t* d, int32_t dLength)
+int32_t CryptoNative_EcKeyCreateByKeyParameters(EC_KEY** key, const char* oid, uint8_t* qx, int32_t qxLength, uint8_t* qy, int32_t qyLength, uint8_t* d, int32_t dLength)
 {
     if (!key || !oid)
     {
@@ -331,7 +331,7 @@ extern "C" int32_t CryptoNative_EcKeyCreateByKeyParameters(EC_KEY** key, const c
         return 0;
     }
 
-    *key = nullptr;
+    *key = NULL;
 
     // oid can be friendly name or value
     int nid = OBJ_txt2nid(oid);
@@ -342,15 +342,15 @@ extern "C" int32_t CryptoNative_EcKeyCreateByKeyParameters(EC_KEY** key, const c
     if (!(*key))
         return -1;
 
-    BIGNUM* dBn = nullptr;
-    BIGNUM* qxBn = nullptr;
-    BIGNUM* qyBn = nullptr;
+    BIGNUM* dBn = NULL;
+    BIGNUM* qxBn = NULL;
+    BIGNUM* qyBn = NULL;
 
     // If key values specified, use them, otherwise a key will be generated later
     if (qx && qy)
     {
-        qxBn = BN_bin2bn(qx, qxLength, nullptr);
-        qyBn = BN_bin2bn(qy, qyLength, nullptr);
+        qxBn = BN_bin2bn(qx, qxLength, NULL);
+        qyBn = BN_bin2bn(qy, qyLength, NULL);
         if (!qxBn || !qyBn)
             goto error;
 
@@ -360,7 +360,7 @@ extern "C" int32_t CryptoNative_EcKeyCreateByKeyParameters(EC_KEY** key, const c
         // Set private key (optional)
         if (d && dLength > 0)
         {
-            dBn = BN_bin2bn(d, dLength, nullptr);
+            dBn = BN_bin2bn(d, dLength, NULL);
             if (!dBn)
                 goto error;
 
@@ -383,12 +383,12 @@ error:
     if (*key)
     {
         EC_KEY_free(*key);
-        *key = nullptr;
+        *key = NULL;
     }
     return 0;
 }
 
-extern "C" EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
+EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
     ECCurveType curveType,
     uint8_t* qx, int32_t qxLength,
     uint8_t* qy, int32_t qyLength,
@@ -409,75 +409,75 @@ extern "C" EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
         return 0;
     }
 
-    EC_KEY* key = nullptr;
-    EC_POINT* G = nullptr;
+    EC_KEY* key = NULL;
+    EC_POINT* G = NULL;
 
-    BIGNUM* qxBn = nullptr;
-    BIGNUM* qyBn = nullptr;
-    BIGNUM* dBn = nullptr;
-    BIGNUM* pBn = nullptr; // p = either the char2 polynomial or the prime
-    BIGNUM* aBn = nullptr;
-    BIGNUM* bBn = nullptr;
-    BIGNUM* gxBn = nullptr;
-    BIGNUM* gyBn = nullptr;
-    BIGNUM* orderBn = nullptr;
-    BIGNUM* cofactorBn = nullptr;
+    BIGNUM* qxBn = NULL;
+    BIGNUM* qyBn = NULL;
+    BIGNUM* dBn = NULL;
+    BIGNUM* pBn = NULL; // p = either the char2 polynomial or the prime
+    BIGNUM* aBn = NULL;
+    BIGNUM* bBn = NULL;
+    BIGNUM* gxBn = NULL;
+    BIGNUM* gyBn = NULL;
+    BIGNUM* orderBn = NULL;
+    BIGNUM* cofactorBn = NULL;
 
     // Create the group. Explicitly specify the curve type because using EC_GROUP_new_curve_GFp
     // will default to montgomery curve
     const EC_METHOD* curveMethod = CurveTypeToMethod(curveType);
-    if (!curveMethod) return nullptr;
+    if (!curveMethod) return NULL;
 
     EC_GROUP* group = EC_GROUP_new(curveMethod);
-    if (!group) return nullptr;
+    if (!group) return NULL;
 
-    pBn = BN_bin2bn(p, pLength, nullptr);
+    pBn = BN_bin2bn(p, pLength, NULL);
     // At this point we should use 'goto error' since we allocated memory
-    aBn = BN_bin2bn(a, aLength, nullptr);
-    bBn = BN_bin2bn(b, bLength, nullptr);
+    aBn = BN_bin2bn(a, aLength, NULL);
+    bBn = BN_bin2bn(b, bLength, NULL);
 
 #if HAVE_OPENSSL_EC2M
-    if (API_EXISTS(EC_GROUP_set_curve_GF2m) && (curveType == ECCurveType::Characteristic2))
+    if (API_EXISTS(EC_GROUP_set_curve_GF2m) && (curveType == Characteristic2))
     {
-        if (!EC_GROUP_set_curve_GF2m(group, pBn, aBn, bBn, nullptr)) 
+        if (!EC_GROUP_set_curve_GF2m(group, pBn, aBn, bBn, NULL)) 
             goto error;
     }
     else
 #endif
     {
-        if (!EC_GROUP_set_curve_GFp(group, pBn, aBn, bBn, nullptr))    
+        if (!EC_GROUP_set_curve_GFp(group, pBn, aBn, bBn, NULL))    
             goto error;
     }
 
     // Set generator, order and cofactor
     G = EC_POINT_new(group);
-    gxBn = BN_bin2bn(gx, gxLength, nullptr);
-    gyBn = BN_bin2bn(gy, gyLength, nullptr);
+    gxBn = BN_bin2bn(gx, gxLength, NULL);
+    gyBn = BN_bin2bn(gy, gyLength, NULL);
 
 #if HAVE_OPENSSL_EC2M
-    if (API_EXISTS(EC_POINT_set_affine_coordinates_GF2m) && (curveType == ECCurveType::Characteristic2))
+    if (API_EXISTS(EC_POINT_set_affine_coordinates_GF2m) && (curveType == Characteristic2))
     {
-        EC_POINT_set_affine_coordinates_GF2m(group, G, gxBn, gyBn, nullptr);
+        EC_POINT_set_affine_coordinates_GF2m(group, G, gxBn, gyBn, NULL);
     }
     else
 #endif
     {
-        EC_POINT_set_affine_coordinates_GFp(group, G, gxBn, gyBn, nullptr);
+        EC_POINT_set_affine_coordinates_GFp(group, G, gxBn, gyBn, NULL);
     }
 
-    orderBn = BN_bin2bn(order, orderLength, nullptr);
-    cofactorBn = BN_bin2bn(cofactor, cofactorLength, nullptr);
+    orderBn = BN_bin2bn(order, orderLength, NULL);
+    cofactorBn = BN_bin2bn(cofactor, cofactorLength, NULL);
     EC_GROUP_set_generator(group, G, orderBn, cofactorBn);
 
     // Set seed (optional)
     if (seed && seedLength > 0)
     {
-        if (!EC_GROUP_set_seed(group, seed, static_cast<size_t>(seedLength)))
+        if (!EC_GROUP_set_seed(group, seed, (size_t)seedLength))
             goto error;
     }
 
     // Validate group
-    if (!EC_GROUP_check(group, nullptr))
+    if (!EC_GROUP_check(group, NULL))
         goto error;
 
     // Create key
@@ -491,8 +491,8 @@ extern "C" EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
     // Set the public and private key values
     if (qx && qy)
     {
-        qxBn = BN_bin2bn(qx, qxLength, nullptr);
-        qyBn = BN_bin2bn(qy, qyLength, nullptr);
+        qxBn = BN_bin2bn(qx, qxLength, NULL);
+        qyBn = BN_bin2bn(qy, qyLength, NULL);
         if (!qxBn || !qyBn)
             goto error;
 
@@ -502,7 +502,7 @@ extern "C" EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
         // Set private key (optional)
         if (d && dLength)
         {
-            dBn = BN_bin2bn(d, dLength, nullptr);
+            dBn = BN_bin2bn(d, dLength, NULL);
             if (!dBn)
                 goto error;
 
@@ -532,5 +532,5 @@ error:
     if (G) EC_POINT_free(G);
     if (group) EC_GROUP_free(group);
     if (key) EC_KEY_free(key);
-    return nullptr;
+    return NULL;
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.h
index b138a080e6..f6fc6e0065 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecc_import_export.h
@@ -3,9 +3,11 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
-typedef enum : int32_t {
+typedef enum
+{
     Unspecified = 0,
     PrimeShortWeierstrass = 1,
     PrimeTwistedEdwards = 2,
@@ -17,13 +19,13 @@ typedef enum : int32_t {
 /*
 Returns the ECCurveType given the key.
 */
-extern "C" ECCurveType CryptoNative_EcKeyGetCurveType(
+DLLEXPORT ECCurveType CryptoNative_EcKeyGetCurveType(
     const EC_KEY* key);
 
 /*
 Returns the ECC key parameters.
 */
-extern "C" int32_t CryptoNative_GetECKeyParameters(
+DLLEXPORT int32_t CryptoNative_GetECKeyParameters(
     const EC_KEY* key,
     int32_t includePrivate,
     BIGNUM** qx, int32_t* cbQx,
@@ -33,7 +35,7 @@ extern "C" int32_t CryptoNative_GetECKeyParameters(
 /*
 Returns the ECC key and curve parameters.
 */
-extern "C" int32_t CryptoNative_GetECCurveParameters(
+DLLEXPORT int32_t CryptoNative_GetECCurveParameters(
     const EC_KEY* key,
     int32_t includePrivate,
     ECCurveType* curveType,
@@ -53,7 +55,7 @@ extern "C" int32_t CryptoNative_GetECCurveParameters(
 Creates the new EC_KEY instance using the curve oid (friendly name or value) and public key parameters.
 Returns 1 upon success, -1 if oid was not found, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EcKeyCreateByKeyParameters(
+DLLEXPORT int32_t CryptoNative_EcKeyCreateByKeyParameters(
     EC_KEY** key,
     const char* oid,
     uint8_t* qx, int32_t qxLength, 
@@ -63,7 +65,7 @@ extern "C" int32_t CryptoNative_EcKeyCreateByKeyParameters(
 /*
 Returns the new EC_KEY instance using the explicit parameters.
 */
-extern "C" EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
+DLLEXPORT EC_KEY* CryptoNative_EcKeyCreateByExplicitParameters(
     ECCurveType curveType,
     uint8_t* qx, int32_t qxLength,
     uint8_t* qy, int32_t qyLength,
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.c
index 1e61f09f9a..27889bbf90 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.c
@@ -5,7 +5,7 @@
 #include "pal_ecdsa.h"
 #include "pal_utilities.h"
 
-extern "C" int32_t
+int32_t
 CryptoNative_EcDsaSign(const uint8_t* dgst, int32_t dgstlen, uint8_t* sig, int32_t* siglen, EC_KEY* key)
 {
     if (!siglen)
@@ -13,19 +13,19 @@ CryptoNative_EcDsaSign(const uint8_t* dgst, int32_t dgstlen, uint8_t* sig, int32
         return 0;
     }
 
-    unsigned int unsignedSigLength = UnsignedCast(*siglen);
+    unsigned int unsignedSigLength = Int32ToUint32(*siglen);
     int ret = ECDSA_sign(0, dgst, dgstlen, sig, &unsignedSigLength, key);
-    *siglen = SignedCast(unsignedSigLength);
+    *siglen = Uint32ToInt32(unsignedSigLength);
     return ret;
 }
 
-extern "C" int32_t
+int32_t
 CryptoNative_EcDsaVerify(const uint8_t* dgst, int32_t dgstlen, const uint8_t* sig, int32_t siglen, EC_KEY* key)
 {
     return ECDSA_verify(0, dgst, dgstlen, sig, siglen, key);
 }
 
-extern "C" int32_t CryptoNative_EcDsaSize(const EC_KEY* key)
+int32_t CryptoNative_EcDsaSize(const EC_KEY* key)
 {
     return ECDSA_size(key);
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.h
index 13ed17bb29..ccc47c9568 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_ecdsa.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -10,7 +11,7 @@ Shims the ECDSA_sign method.
 
 Returns 1 on success, otherwise 0.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_EcDsaSign(const uint8_t* dgst, int32_t dgstlen, uint8_t* sig, int32_t* siglen, EC_KEY* key);
 
 /*
@@ -18,7 +19,7 @@ Shims the ECDSA_verify method.
 
 Returns 1 for a correct signature, 0 for an incorrect signature, -1 on error.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_EcDsaVerify(const uint8_t* dgst, int32_t dgstlen, const uint8_t* sig, int32_t siglen, EC_KEY* key);
 
 /*
@@ -26,4 +27,4 @@ Shims the ECDSA_size method.
 
 Returns the maximum length of a DER encoded ECDSA signature created with this key.
 */
-extern "C" int32_t CryptoNative_EcDsaSize(const EC_KEY* key);
+DLLEXPORT int32_t CryptoNative_EcDsaSize(const EC_KEY* key);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.c
index 9a5a2a3662..77b598e333 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.c
@@ -6,25 +6,25 @@
 
 #include <assert.h>
 
-extern "C" void CryptoNative_EcKeyDestroy(EC_KEY* r)
+void CryptoNative_EcKeyDestroy(EC_KEY* r)
 {
     EC_KEY_free(r);
 }
 
 // For backwards compatibility
-extern "C" EC_KEY* CryptoNative_EcKeyCreateByCurveName(int32_t nid)
+EC_KEY* CryptoNative_EcKeyCreateByCurveName(int32_t nid)
 {
     return EC_KEY_new_by_curve_name(nid);
 }
 
-extern "C" EC_KEY* CryptoNative_EcKeyCreateByOid(const char* oid)
+EC_KEY* CryptoNative_EcKeyCreateByOid(const char* oid)
 {
     // oid can be friendly name or value
     int nid = OBJ_txt2nid(oid);
     return CryptoNative_EcKeyCreateByCurveName(nid);
 }
 
-extern "C" int32_t CryptoNative_EcKeyGenerateKey(EC_KEY* eckey)
+int32_t CryptoNative_EcKeyGenerateKey(EC_KEY* eckey)
 {
     if (!EC_KEY_generate_key(eckey))
         return 0;
@@ -32,12 +32,12 @@ extern "C" int32_t CryptoNative_EcKeyGenerateKey(EC_KEY* eckey)
     return EC_KEY_check_key(eckey);
 }
 
-extern "C" int32_t CryptoNative_EcKeyUpRef(EC_KEY* r)
+int32_t CryptoNative_EcKeyUpRef(EC_KEY* r)
 {
     return EC_KEY_up_ref(r);
 }
 
-extern "C" int32_t CryptoNative_EcKeyGetSize(const EC_KEY* key, int32_t* keySize)
+int32_t CryptoNative_EcKeyGetSize(const EC_KEY* key, int32_t* keySize)
 {
     if (!keySize)
         return 0;
@@ -57,15 +57,15 @@ extern "C" int32_t CryptoNative_EcKeyGetSize(const EC_KEY* key, int32_t* keySize
 }
 
 // For backwards compatibility
-extern "C" int32_t CryptoNative_EcKeyGetCurveName(const EC_KEY* key)
+int32_t CryptoNative_EcKeyGetCurveName(const EC_KEY* key)
 {
-    if (key == nullptr)
+    if (key == NULL)
     {
         return NID_undef;
     }
 
     const EC_GROUP* group = EC_KEY_get0_group(key);
-    if (group == nullptr)
+    if (group == NULL)
     {
         return NID_undef;
     }
@@ -73,7 +73,7 @@ extern "C" int32_t CryptoNative_EcKeyGetCurveName(const EC_KEY* key)
     return EC_GROUP_get_curve_name(group);
 }
 
-extern "C" int32_t CryptoNative_EcKeyGetCurveName2(const EC_KEY* key, int32_t* nidName)
+int32_t CryptoNative_EcKeyGetCurveName2(const EC_KEY* key, int32_t* nidName)
 {
     if (!nidName)
         return 0;
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.h
index 4f180c9007..a590d356f6 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_eckey.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -14,51 +15,51 @@ No-op if r is null.
 The given EC_KEY pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_EcKeyDestroy(EC_KEY* r);
+DLLEXPORT void CryptoNative_EcKeyDestroy(EC_KEY* r);
 
 /*
 Shims the EC_KEY_new_by_curve_name method.
 
 Returns the new EC_KEY instance.
 */
-extern "C" EC_KEY* CryptoNative_EcKeyCreateByCurveName(int32_t nid);
+DLLEXPORT EC_KEY* CryptoNative_EcKeyCreateByCurveName(int32_t nid);
 
 /*
 Shims the EC_KEY_new_by_curve_name method.
 
 Returns the new EC_KEY instance.
 */
-extern "C" EC_KEY* CryptoNative_EcKeyCreateByOid(const char* oid);
+DLLEXPORT EC_KEY* CryptoNative_EcKeyCreateByOid(const char* oid);
 
 /*
 Shims the EC_KEY_generate_key method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EcKeyGenerateKey(EC_KEY* eckey);
+DLLEXPORT int32_t CryptoNative_EcKeyGenerateKey(EC_KEY* eckey);
 
 /*
 Shims the EC_KEY_up_ref method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EcKeyUpRef(EC_KEY* r);
+DLLEXPORT int32_t CryptoNative_EcKeyUpRef(EC_KEY* r);
 
 /*
 Gets the key size in bits for the specified EC_KEY.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EcKeyGetSize(const EC_KEY* key, int32_t* keySize);
+DLLEXPORT int32_t CryptoNative_EcKeyGetSize(const EC_KEY* key, int32_t* keySize);
 
 /*
 Gets the NID of the curve name as an oid value for the specified EC_KEY.
 */
-extern "C" int32_t CryptoNative_EcKeyGetCurveName(const EC_KEY* key);
+DLLEXPORT int32_t CryptoNative_EcKeyGetCurveName(const EC_KEY* key);
 
 /*
 Gets the NID of the curve name as an oid value for the specified EC_KEY.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EcKeyGetCurveName2(const EC_KEY* key, int32_t* nidName);
+DLLEXPORT int32_t CryptoNative_EcKeyGetCurveName2(const EC_KEY* key, int32_t* nidName);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_err.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_err.c
new file mode 100644
index 0000000000..b8f9ed6a44
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_err.c
@@ -0,0 +1,48 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_err.h"
+#include "pal_utilities.h"
+
+void CryptoNative_ErrClearError()
+{
+    ERR_clear_error();
+}
+
+uint64_t CryptoNative_ErrGetError()
+{
+    return ERR_get_error();
+}
+
+uint64_t CryptoNative_ErrGetErrorAlloc(int32_t* isAllocFailure)
+{
+    unsigned long err = ERR_get_error();
+
+    if (isAllocFailure)
+    {
+        *isAllocFailure = ERR_GET_REASON(err) == ERR_R_MALLOC_FAILURE;
+    }
+
+    return err;
+}
+
+uint64_t CryptoNative_ErrPeekError()
+{
+    return ERR_peek_error();
+}
+
+uint64_t CryptoNative_ErrPeekLastError()
+{
+    return ERR_peek_last_error();
+}
+
+const char* CryptoNative_ErrReasonErrorString(uint64_t error)
+{
+    return ERR_reason_error_string((unsigned long)error);
+}
+
+void CryptoNative_ErrErrorStringN(uint64_t e, char* buf, int32_t len)
+{
+    ERR_error_string_n((unsigned long)e, buf, Int32ToSizeT(len));
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_err.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_err.cpp
deleted file mode 100644
index 80997a8380..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_err.cpp
+++ /dev/null
@@ -1,48 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_err.h"
-#include "pal_utilities.h"
-
-extern "C" void CryptoNative_ErrClearError()
-{
-    ERR_clear_error();
-}
-
-extern "C" uint64_t CryptoNative_ErrGetError()
-{
-    return ERR_get_error();
-}
-
-extern "C" uint64_t CryptoNative_ErrGetErrorAlloc(int32_t* isAllocFailure)
-{
-    unsigned long err = ERR_get_error();
-
-    if (isAllocFailure)
-    {
-        *isAllocFailure = ERR_GET_REASON(err) == ERR_R_MALLOC_FAILURE;
-    }
-
-    return err;
-}
-
-extern "C" uint64_t CryptoNative_ErrPeekError()
-{
-    return ERR_peek_error();
-}
-
-extern "C" uint64_t CryptoNative_ErrPeekLastError()
-{
-    return ERR_peek_last_error();
-}
-
-extern "C" const char* CryptoNative_ErrReasonErrorString(uint64_t error)
-{
-    return ERR_reason_error_string(static_cast<unsigned long>(error));
-}
-
-extern "C" void CryptoNative_ErrErrorStringN(uint64_t e, char* buf, int32_t len)
-{
-    ERR_error_string_n(static_cast<unsigned long>(e), buf, UnsignedCast(len));
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_err.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_err.h
index 4da05604f4..eaa4c93898 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_err.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_err.h
@@ -2,37 +2,38 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#include "pal_compiler.h"
 #include <stdint.h>
 #include "opensslshim.h"
 
 /*
 Shims the ERR_clear_error method.
 */
-extern "C" void CryptoNative_ErrClearError();
+DLLEXPORT void CryptoNative_ErrClearError(void);
 
 /*
 Shims the ERR_get_error method.
 */
-extern "C" uint64_t CryptoNative_ErrGetError();
+DLLEXPORT uint64_t CryptoNative_ErrGetError(void);
 
 /*
 Shim to ERR_get_error which also returns whether the error
 was caused by an allocation failure.
 */
-extern "C" uint64_t CryptoNative_ErrGetErrorAlloc(int32_t* isAllocFailure);
+DLLEXPORT uint64_t CryptoNative_ErrGetErrorAlloc(int32_t* isAllocFailure);
 
-extern "C" uint64_t CryptoNative_ErrPeekError(void);
+DLLEXPORT uint64_t CryptoNative_ErrPeekError(void);
 
-extern "C" uint64_t CryptoNative_ErrPeekLastError(void);
+DLLEXPORT uint64_t CryptoNative_ErrPeekLastError(void);
 
 /*
 Shims the ERR_reason_error_string method.
 
 Returns the string for the specified error.
 */
-extern "C" const char* CryptoNative_ErrReasonErrorString(uint64_t error);
+DLLEXPORT const char* CryptoNative_ErrReasonErrorString(uint64_t error);
 
 /*
 Direct shim to ERR_error_string_n.
 */
-extern "C" void CryptoNative_ErrErrorStringN(uint64_t e, char* buf, int32_t len);
+DLLEXPORT void CryptoNative_ErrErrorStringN(uint64_t e, char* buf, int32_t len);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.c
new file mode 100644
index 0000000000..f475c41a55
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.c
@@ -0,0 +1,93 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_evp.h"
+
+#include <assert.h>
+
+#define SUCCESS 1
+
+EVP_MD_CTX* CryptoNative_EvpMdCtxCreate(const EVP_MD* type)
+{
+    EVP_MD_CTX* ctx = EVP_MD_CTX_create();
+    if (ctx == NULL)
+    {
+        // Allocation failed
+        return NULL;
+    }
+
+    int ret = EVP_DigestInit_ex(ctx, type, NULL);
+    if (!ret)
+    {
+        EVP_MD_CTX_destroy(ctx);
+        return NULL;
+    }
+
+    return ctx;
+}
+
+void CryptoNative_EvpMdCtxDestroy(EVP_MD_CTX* ctx)
+{
+    if (ctx != NULL)
+    {
+        EVP_MD_CTX_destroy(ctx);
+    }
+}
+
+int32_t CryptoNative_EvpDigestReset(EVP_MD_CTX* ctx, const EVP_MD* type)
+{
+    return EVP_DigestInit_ex(ctx, type, NULL);
+}
+
+int32_t CryptoNative_EvpDigestUpdate(EVP_MD_CTX* ctx, const void* d, size_t cnt)
+{
+    return EVP_DigestUpdate(ctx, d, cnt);
+}
+
+int32_t CryptoNative_EvpDigestFinalEx(EVP_MD_CTX* ctx, uint8_t* md, uint32_t* s)
+{
+    unsigned int size;
+    int32_t ret = EVP_DigestFinal_ex(ctx, md, &size);
+    if (ret == SUCCESS)
+    {
+        *s = size;
+    }
+
+    return ret;
+}
+
+int32_t CryptoNative_EvpMdSize(const EVP_MD* md)
+{
+    return EVP_MD_size(md);
+}
+
+const EVP_MD* CryptoNative_EvpMd5()
+{
+    return EVP_md5();
+}
+
+const EVP_MD* CryptoNative_EvpSha1()
+{
+    return EVP_sha1();
+}
+
+const EVP_MD* CryptoNative_EvpSha256()
+{
+    return EVP_sha256();
+}
+
+const EVP_MD* CryptoNative_EvpSha384()
+{
+    return EVP_sha384();
+}
+
+const EVP_MD* CryptoNative_EvpSha512()
+{
+    return EVP_sha512();
+}
+
+int32_t CryptoNative_GetMaxMdSize()
+{
+    return EVP_MAX_MD_SIZE;
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.cpp
deleted file mode 100644
index 1fbadce9af..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.cpp
+++ /dev/null
@@ -1,93 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_evp.h"
-
-#include <assert.h>
-
-#define SUCCESS 1
-
-extern "C" EVP_MD_CTX* CryptoNative_EvpMdCtxCreate(const EVP_MD* type)
-{
-    EVP_MD_CTX* ctx = EVP_MD_CTX_create();
-    if (ctx == nullptr)
-    {
-        // Allocation failed
-        return nullptr;
-    }
-
-    int ret = EVP_DigestInit_ex(ctx, type, nullptr);
-    if (!ret)
-    {
-        EVP_MD_CTX_destroy(ctx);
-        return nullptr;
-    }
-
-    return ctx;
-}
-
-extern "C" void CryptoNative_EvpMdCtxDestroy(EVP_MD_CTX* ctx)
-{
-    if (ctx != nullptr)
-    {
-        EVP_MD_CTX_destroy(ctx);
-    }
-}
-
-extern "C" int32_t CryptoNative_EvpDigestReset(EVP_MD_CTX* ctx, const EVP_MD* type)
-{
-    return EVP_DigestInit_ex(ctx, type, nullptr);
-}
-
-extern "C" int32_t CryptoNative_EvpDigestUpdate(EVP_MD_CTX* ctx, const void* d, size_t cnt)
-{
-    return EVP_DigestUpdate(ctx, d, cnt);
-}
-
-extern "C" int32_t CryptoNative_EvpDigestFinalEx(EVP_MD_CTX* ctx, uint8_t* md, uint32_t* s)
-{
-    unsigned int size;
-    int32_t ret = EVP_DigestFinal_ex(ctx, md, &size);
-    if (ret == SUCCESS)
-    {
-        *s = size;
-    }
-
-    return ret;
-}
-
-extern "C" int32_t CryptoNative_EvpMdSize(const EVP_MD* md)
-{
-    return EVP_MD_size(md);
-}
-
-extern "C" const EVP_MD* CryptoNative_EvpMd5()
-{
-    return EVP_md5();
-}
-
-extern "C" const EVP_MD* CryptoNative_EvpSha1()
-{
-    return EVP_sha1();
-}
-
-extern "C" const EVP_MD* CryptoNative_EvpSha256()
-{
-    return EVP_sha256();
-}
-
-extern "C" const EVP_MD* CryptoNative_EvpSha384()
-{
-    return EVP_sha384();
-}
-
-extern "C" const EVP_MD* CryptoNative_EvpSha512()
-{
-    return EVP_sha512();
-}
-
-extern "C" int32_t CryptoNative_GetMaxMdSize()
-{
-    return EVP_MAX_MD_SIZE;
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.h
index 1e0dc4a141..b0d7f9b61b 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp.h
@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#include "pal_compiler.h"
 #include <stdint.h>
 #include "opensslshim.h"
 
@@ -14,7 +15,7 @@ Implemented by:
 
 Returns new EVP_MD_CTX on success, nullptr on failure.
 */
-extern "C" EVP_MD_CTX* CryptoNative_EvpMdCtxCreate(const EVP_MD* type);
+DLLEXPORT EVP_MD_CTX* CryptoNative_EvpMdCtxCreate(const EVP_MD* type);
 
 /*
 Cleans up and deletes an EVP_MD_CTX instance created by EvpMdCtxCreate.
@@ -26,12 +27,12 @@ No-op if ctx is null.
 The given EVP_MD_CTX pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_EvpMdCtxDestroy(EVP_MD_CTX* ctx);
+DLLEXPORT void CryptoNative_EvpMdCtxDestroy(EVP_MD_CTX* ctx);
 
 /*
 Resets an EVP_MD_CTX instance for a new computation.
 */
-extern "C" int32_t CryptoNative_EvpDigestReset(EVP_MD_CTX* ctx, const EVP_MD* type);
+DLLEXPORT int32_t CryptoNative_EvpDigestReset(EVP_MD_CTX* ctx, const EVP_MD* type);
 
 /*
 Function:
@@ -39,7 +40,7 @@ EvpDigestUpdate
 
 Direct shim to EVP_DigestUpdate.
 */
-extern "C" int32_t CryptoNative_EvpDigestUpdate(EVP_MD_CTX* ctx, const void* d, size_t cnt);
+DLLEXPORT int32_t CryptoNative_EvpDigestUpdate(EVP_MD_CTX* ctx, const void* d, size_t cnt);
 
 /*
 Function:
@@ -47,7 +48,7 @@ EvpDigestFinalEx
 
 Direct shim to EVP_DigestFinal_ex.
 */
-extern "C" int32_t CryptoNative_EvpDigestFinalEx(EVP_MD_CTX* ctx, uint8_t* md, uint32_t* s);
+DLLEXPORT int32_t CryptoNative_EvpDigestFinalEx(EVP_MD_CTX* ctx, uint8_t* md, uint32_t* s);
 
 /*
 Function:
@@ -55,7 +56,7 @@ EvpMdSize
 
 Direct shim to EVP_MD_size.
 */
-extern "C" int32_t CryptoNative_EvpMdSize(const EVP_MD* md);
+DLLEXPORT int32_t CryptoNative_EvpMdSize(const EVP_MD* md);
 
 /*
 Function:
@@ -63,7 +64,7 @@ EvpMd5
 
 Direct shim to EVP_md5.
 */
-extern "C" const EVP_MD* CryptoNative_EvpMd5();
+DLLEXPORT const EVP_MD* CryptoNative_EvpMd5(void);
 
 /*
 Function:
@@ -71,7 +72,7 @@ EvpSha1
 
 Direct shim to EVP_sha1.
 */
-extern "C" const EVP_MD* CryptoNative_EvpSha1();
+DLLEXPORT const EVP_MD* CryptoNative_EvpSha1(void);
 
 /*
 Function:
@@ -79,7 +80,7 @@ EvpSha256
 
 Direct shim to EVP_sha256.
 */
-extern "C" const EVP_MD* CryptoNative_EvpSha256();
+DLLEXPORT const EVP_MD* CryptoNative_EvpSha256(void);
 
 /*
 Function:
@@ -87,7 +88,7 @@ EvpSha384
 
 Direct shim to EVP_sha384.
 */
-extern "C" const EVP_MD* CryptoNative_EvpSha384();
+DLLEXPORT const EVP_MD* CryptoNative_EvpSha384(void);
 
 /*
 Function:
@@ -95,7 +96,7 @@ EvpSha512
 
 Direct shim to EVP_sha512.
 */
-extern "C" const EVP_MD* CryptoNative_EvpSha512();
+DLLEXPORT const EVP_MD* CryptoNative_EvpSha512(void);
 
 /*
 Function:
@@ -103,4 +104,4 @@ GetMaxMdSize
 
 Returns the maxium bytes for a message digest.
 */
-extern "C" int32_t CryptoNative_GetMaxMdSize();
+DLLEXPORT int32_t CryptoNative_GetMaxMdSize(void);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.c
index 1f2e80e114..58a7ce13c9 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.c
@@ -5,76 +5,79 @@
 #include "pal_evp_cipher.h"
 
 #include <assert.h>
-#include <memory>
 
 #define SUCCESS 1
 #define KEEP_CURRENT_DIRECTION -1
 
-extern "C" EVP_CIPHER_CTX*
+EVP_CIPHER_CTX*
 CryptoNative_EvpCipherCreate(const EVP_CIPHER* type, uint8_t* key, unsigned char* iv, int32_t enc)
 {
     return CryptoNative_EvpCipherCreate2(type, key, 0, 0, iv, enc);
 }
 
-extern "C" EVP_CIPHER_CTX*
+EVP_CIPHER_CTX*
 CryptoNative_EvpCipherCreate2(const EVP_CIPHER* type, uint8_t* key, int32_t keyLength, int32_t effectiveKeyLength, unsigned char* iv, int32_t enc)
 {
-    std::unique_ptr<EVP_CIPHER_CTX> ctx(new (std::nothrow) EVP_CIPHER_CTX);
-    if (ctx == nullptr)
+    EVP_CIPHER_CTX* ctx = (EVP_CIPHER_CTX*)malloc(sizeof(EVP_CIPHER_CTX));
+    if (ctx == NULL)
     {
         // Allocation failed
-        return nullptr;
+        return NULL;
     }
 
-    EVP_CIPHER_CTX_init(ctx.get());
+    EVP_CIPHER_CTX_init(ctx);
 
     // Perform partial initialization so we can set the key lengths
-    int ret = EVP_CipherInit_ex(ctx.get(), type, nullptr, nullptr, nullptr, 0);
+    int ret = EVP_CipherInit_ex(ctx, type, NULL, NULL, NULL, 0);
     if (!ret)
     {
-        return nullptr;
+        free(ctx);
+        return NULL;
     }
 
     if (keyLength > 0)
     {
         // Necessary when the default key size is different than current
-        ret = EVP_CIPHER_CTX_set_key_length(ctx.get(), keyLength / 8);
+        ret = EVP_CIPHER_CTX_set_key_length(ctx, keyLength / 8);
         if (!ret)
         {
-            return nullptr;
+            free(ctx);
+            return NULL;
         }
     }
 
     if (effectiveKeyLength > 0)
     {
         // Necessary for RC2
-        ret = EVP_CIPHER_CTX_ctrl(ctx.get(), EVP_CTRL_SET_RC2_KEY_BITS, effectiveKeyLength, nullptr);
+        ret = EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC2_KEY_BITS, effectiveKeyLength, NULL);
         if (ret <= 0)
         {
-            return nullptr;
+            free(ctx);
+            return NULL;
         }
     }
 
     // Perform final initialization specifying the remaining arguments
-    ret = EVP_CipherInit_ex(ctx.get(), nullptr, nullptr, key, iv, enc);
+    ret = EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, enc);
     if (!ret)
     {
-        return nullptr;
+        free(ctx);
+        return NULL;
     }
 
-    return ctx.release();
+    return ctx;
 }
 
-extern "C" void CryptoNative_EvpCipherDestroy(EVP_CIPHER_CTX* ctx)
+void CryptoNative_EvpCipherDestroy(EVP_CIPHER_CTX* ctx)
 {
-    if (ctx != nullptr)
+    if (ctx != NULL)
     {
         EVP_CIPHER_CTX_cleanup(ctx);
-        delete ctx;
+        free(ctx);
     }
 }
 
-extern "C" int32_t CryptoNative_EvpCipherReset(EVP_CIPHER_CTX* ctx)
+int32_t CryptoNative_EvpCipherReset(EVP_CIPHER_CTX* ctx)
 {
     // EVP_CipherInit_ex with all nulls preserves the algorithm, resets the IV,
     // and maintains the key.
@@ -85,15 +88,15 @@ extern "C" int32_t CryptoNative_EvpCipherReset(EVP_CIPHER_CTX* ctx)
     // But since we have a different object returned for CreateEncryptor
     // and CreateDecryptor we don't need to worry about that.
 
-    return EVP_CipherInit_ex(ctx, nullptr, nullptr, nullptr, nullptr, KEEP_CURRENT_DIRECTION);
+    return EVP_CipherInit_ex(ctx, NULL, NULL, NULL, NULL, KEEP_CURRENT_DIRECTION);
 }
 
-extern "C" int32_t CryptoNative_EvpCipherCtxSetPadding(EVP_CIPHER_CTX* x, int32_t padding)
+int32_t CryptoNative_EvpCipherCtxSetPadding(EVP_CIPHER_CTX* x, int32_t padding)
 {
     return EVP_CIPHER_CTX_set_padding(x, padding);
 }
 
-extern "C" int32_t
+int32_t
 CryptoNative_EvpCipherUpdate(EVP_CIPHER_CTX* ctx, uint8_t* out, int32_t* outl, unsigned char* in, int32_t inl)
 {
     int outLength;
@@ -106,7 +109,7 @@ CryptoNative_EvpCipherUpdate(EVP_CIPHER_CTX* ctx, uint8_t* out, int32_t* outl, u
     return ret;
 }
 
-extern "C" int32_t CryptoNative_EvpCipherFinalEx(EVP_CIPHER_CTX* ctx, uint8_t* outm, int32_t* outl)
+int32_t CryptoNative_EvpCipherFinalEx(EVP_CIPHER_CTX* ctx, uint8_t* outm, int32_t* outl)
 {
     int outLength;
     int32_t ret = EVP_CipherFinal_ex(ctx, outm, &outLength);
@@ -118,62 +121,62 @@ extern "C" int32_t CryptoNative_EvpCipherFinalEx(EVP_CIPHER_CTX* ctx, uint8_t* o
     return ret;
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes128Ecb()
+const EVP_CIPHER* CryptoNative_EvpAes128Ecb()
 {
     return EVP_aes_128_ecb();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes128Cbc()
+const EVP_CIPHER* CryptoNative_EvpAes128Cbc()
 {
     return EVP_aes_128_cbc();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes192Ecb()
+const EVP_CIPHER* CryptoNative_EvpAes192Ecb()
 {
     return EVP_aes_192_ecb();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes192Cbc()
+const EVP_CIPHER* CryptoNative_EvpAes192Cbc()
 {
     return EVP_aes_192_cbc();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes256Ecb()
+const EVP_CIPHER* CryptoNative_EvpAes256Ecb()
 {
     return EVP_aes_256_ecb();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes256Cbc()
+const EVP_CIPHER* CryptoNative_EvpAes256Cbc()
 {
     return EVP_aes_256_cbc();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpDesEcb()
+const EVP_CIPHER* CryptoNative_EvpDesEcb()
 {
     return EVP_des_ecb();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpDesCbc()
+const EVP_CIPHER* CryptoNative_EvpDesCbc()
 {
     return EVP_des_cbc();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpDes3Ecb()
+const EVP_CIPHER* CryptoNative_EvpDes3Ecb()
 {
     return EVP_des_ede3();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpDes3Cbc()
+const EVP_CIPHER* CryptoNative_EvpDes3Cbc()
 {
     return EVP_des_ede3_cbc();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpRC2Ecb()
+const EVP_CIPHER* CryptoNative_EvpRC2Ecb()
 {
     return EVP_rc2_ecb();
 }
 
-extern "C" const EVP_CIPHER* CryptoNative_EvpRC2Cbc()
+const EVP_CIPHER* CryptoNative_EvpRC2Cbc()
 {
     return EVP_rc2_cbc();
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.h
index fb3a6c750e..f95ea8f898 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_cipher.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -15,10 +16,10 @@ Implemented by:
 
 Returns new EVP_CIPHER_CTX on success, nullptr on failure.
 */
-extern "C" EVP_CIPHER_CTX*
+DLLEXPORT EVP_CIPHER_CTX*
 CryptoNative_EvpCipherCreate(const EVP_CIPHER* type, uint8_t* key, unsigned char* iv, int32_t enc);
 
-extern "C" EVP_CIPHER_CTX*
+DLLEXPORT EVP_CIPHER_CTX*
 CryptoNative_EvpCipherCreate2(const EVP_CIPHER* type, uint8_t* key, int32_t keyLength, int32_t effectiveKeyLength, unsigned char* iv, int32_t enc);
 /*
 Cleans up and deletes an EVP_CIPHER_CTX instance created by EvpCipherCreate.
@@ -31,7 +32,7 @@ No-op if ctx is null.
 The given EVP_CIPHER_CTX pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_EvpCipherDestroy(EVP_CIPHER_CTX* ctx);
+DLLEXPORT void CryptoNative_EvpCipherDestroy(EVP_CIPHER_CTX* ctx);
 
 /*
 Function:
@@ -39,7 +40,7 @@ EvpCipherReset
 
 Resets an EVP_CIPHER_CTX instance for a new computation.
 */
-extern "C" int32_t CryptoNative_EvpCipherReset(EVP_CIPHER_CTX* ctx);
+DLLEXPORT int32_t CryptoNative_EvpCipherReset(EVP_CIPHER_CTX* ctx);
 
 /*
 Function:
@@ -47,7 +48,7 @@ EvpCipherCtxSetPadding
 
 Direct shim to EVP_CIPHER_CTX_set_padding.
 */
-extern "C" int32_t CryptoNative_EvpCipherCtxSetPadding(EVP_CIPHER_CTX* x, int32_t padding);
+DLLEXPORT int32_t CryptoNative_EvpCipherCtxSetPadding(EVP_CIPHER_CTX* x, int32_t padding);
 
 /*
 Function:
@@ -55,7 +56,7 @@ EvpCipherUpdate
 
 Direct shim to EVP_CipherUpdate.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_EvpCipherUpdate(EVP_CIPHER_CTX* ctx, uint8_t* out, int32_t* outl, unsigned char* in, int32_t inl);
 
 /*
@@ -64,7 +65,7 @@ EvpCipherFinalEx
 
 Direct shim to EVP_CipherFinal_ex.
 */
-extern "C" int32_t CryptoNative_EvpCipherFinalEx(EVP_CIPHER_CTX* ctx, uint8_t* outm, int32_t* outl);
+DLLEXPORT int32_t CryptoNative_EvpCipherFinalEx(EVP_CIPHER_CTX* ctx, uint8_t* outm, int32_t* outl);
 
 /*
 Function:
@@ -72,7 +73,7 @@ EvpAes128Ecb
 
 Direct shim to EVP_aes_128_ecb.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes128Ecb();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpAes128Ecb(void);
 
 /*
 Function:
@@ -80,7 +81,7 @@ EvpAes128Cbc
 
 Direct shim to EVP_aes_128_cbc.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes128Cbc();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpAes128Cbc(void);
 
 /*
 Function:
@@ -88,7 +89,7 @@ EvpAes192Ecb
 
 Direct shim to EVP_aes_192_ecb.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes192Ecb();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpAes192Ecb(void);
 
 /*
 Function:
@@ -96,7 +97,7 @@ EvpAes192Cbc
 
 Direct shim to EVP_aes_192_cbc.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes192Cbc();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpAes192Cbc(void);
 
 /*
 Function:
@@ -104,7 +105,7 @@ EvpAes256Ecb
 
 Direct shim to EVP_aes_256_ecb.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes256Ecb();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpAes256Ecb(void);
 
 /*
 Function:
@@ -112,7 +113,7 @@ EvpAes256Cbc
 
 Direct shim to EVP_aes_256_cbc.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpAes256Cbc();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpAes256Cbc(void);
 
 /*
 Function:
@@ -120,7 +121,7 @@ EvpDes3Ecb
 
 Direct shim to EVP_des_ede3.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpDes3Ecb();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpDes3Ecb(void);
 
 /*
 Function:
@@ -128,7 +129,7 @@ EvpDes3Cbc
 
 Direct shim to EVP_des_ede3_cbc.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpDes3Cbc();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpDes3Cbc(void);
 
 /*
 Function:
@@ -136,7 +137,7 @@ EvpDesEcb
 
 Direct shim to EVP_des_ecb.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpDesEcb();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpDesEcb(void);
 
 /*
 Function:
@@ -144,7 +145,7 @@ EvpDesCbc
 
 Direct shim to EVP_des_ede_cbc.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpDesCbc();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpDesCbc(void);
 
 /*
 Function:
@@ -152,7 +153,7 @@ EvpRC2Ecb
 
 Direct shim to EVP_rc2_ecb.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpRC2Ecb();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpRC2Ecb(void);
 
 /*
 Function:
@@ -160,4 +161,4 @@ EvpRC2Cbc
 
 Direct shim to EVP_des_rc2_cbc.
 */
-extern "C" const EVP_CIPHER* CryptoNative_EvpRC2Cbc();
+DLLEXPORT const EVP_CIPHER* CryptoNative_EvpRC2Cbc(void);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.c
index 384030740e..02e8524d96 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.c
@@ -4,20 +4,20 @@
 
 #include "pal_evp_pkey.h"
 
-extern "C" EVP_PKEY* CryptoNative_EvpPkeyCreate()
+EVP_PKEY* CryptoNative_EvpPkeyCreate()
 {
     return EVP_PKEY_new();
 }
 
-extern "C" void CryptoNative_EvpPkeyDestroy(EVP_PKEY* pkey)
+void CryptoNative_EvpPkeyDestroy(EVP_PKEY* pkey)
 {
-    if (pkey != nullptr)
+    if (pkey != NULL)
     {
         EVP_PKEY_free(pkey);
     }
 }
 
-extern "C" int32_t CryptoNative_UpRefEvpPkey(EVP_PKEY* pkey)
+int32_t CryptoNative_UpRefEvpPkey(EVP_PKEY* pkey)
 {
     if (!pkey)
     {
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.h
index 1449fda5b4..7baf997d8d 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -10,7 +11,7 @@ Shims the EVP_PKEY_new method.
 
 Returns the new EVP_PKEY instance.
 */
-extern "C" EVP_PKEY* CryptoNative_EvpPkeyCreate();
+DLLEXPORT EVP_PKEY* CryptoNative_EvpPkeyCreate(void);
 
 /*
 Cleans up and deletes a EVP_PKEY instance.
@@ -21,7 +22,7 @@ No-op if pkey is null.
 The given EVP_PKEY pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_EvpPkeyDestroy(EVP_PKEY* pkey);
+DLLEXPORT void CryptoNative_EvpPkeyDestroy(EVP_PKEY* pkey);
 
 /*
 Used by System.Security.Cryptography.X509Certificates' OpenSslX509CertificateReader when
@@ -30,4 +31,4 @@ duplicating a private key context as part of duplicating the Pal object.
 Returns the number (as of this call) of references to the EVP_PKEY. Anything less than
 2 is an error, because the key is already in the process of being freed.
 */
-extern "C" int32_t CryptoNative_UpRefEvpPkey(EVP_PKEY* pkey);
+DLLEXPORT int32_t CryptoNative_UpRefEvpPkey(EVP_PKEY* pkey);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.c
index 797d21d045..e67642d419 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.c
@@ -4,12 +4,12 @@
 
 #include "pal_evp_pkey_dsa.h"
 
-extern "C" DSA* CryptoNative_EvpPkeyGetDsa(EVP_PKEY* pkey)
+DSA* CryptoNative_EvpPkeyGetDsa(EVP_PKEY* pkey)
 {
     return EVP_PKEY_get1_DSA(pkey);
 }
 
-extern "C" int32_t CryptoNative_EvpPkeySetDsa(EVP_PKEY* pkey, DSA* dsa)
+int32_t CryptoNative_EvpPkeySetDsa(EVP_PKEY* pkey, DSA* dsa)
 {
     return EVP_PKEY_set1_DSA(pkey, dsa);
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.h
index 79835d27ec..7ea1743809 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_dsa.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -10,7 +11,7 @@ Shims the EVP_PKEY_get1_DSA method.
 
 Returns the DSA instance for the EVP_PKEY.
 */
-extern "C" DSA* CryptoNative_EvpPkeyGetDsa(EVP_PKEY* pkey);
+DLLEXPORT DSA* CryptoNative_EvpPkeyGetDsa(EVP_PKEY* pkey);
 
 /*
 Shims the EVP_PKEY_set1_DSA method to set the DSA
@@ -18,4 +19,4 @@ instance on the EVP_KEY.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EvpPkeySetDsa(EVP_PKEY* pkey, DSA* dsa);
+DLLEXPORT int32_t CryptoNative_EvpPkeySetDsa(EVP_PKEY* pkey, DSA* dsa);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.c
index 1b696096b2..0fd53380fa 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.c
@@ -4,22 +4,22 @@
 
 #include "pal_evp_pkey_ecdh.h"
 
-extern "C" EVP_PKEY_CTX* CryptoNative_EvpPKeyCtxCreate(EVP_PKEY* pkey, EVP_PKEY* peerkey, uint32_t* secretLength)
+EVP_PKEY_CTX* CryptoNative_EvpPKeyCtxCreate(EVP_PKEY* pkey, EVP_PKEY* peerkey, uint32_t* secretLength)
 {
-    if (secretLength != nullptr)
+    if (secretLength != NULL)
         *secretLength = 0;
 
-    if (pkey == nullptr || peerkey == nullptr || secretLength == nullptr)
+    if (pkey == NULL || peerkey == NULL || secretLength == NULL)
     {
-        return nullptr;
+        return NULL;
     }
 
     /* Create the context for the shared secret derivation */
     EVP_PKEY_CTX* ctx = EVP_PKEY_CTX_new(pkey, NULL);
 
-    if (ctx == nullptr)
+    if (ctx == NULL)
     {
-        return nullptr;
+        return NULL;
     }
 
     size_t tmpLength = 0;
@@ -29,19 +29,19 @@ extern "C" EVP_PKEY_CTX* CryptoNative_EvpPKeyCtxCreate(EVP_PKEY* pkey, EVP_PKEY*
         1 != EVP_PKEY_derive(ctx, NULL, &tmpLength))
     {
         EVP_PKEY_CTX_free(ctx);
-        return nullptr;
+        return NULL;
     }
 
     *secretLength = (uint32_t)tmpLength;
     return ctx;
 }
 
-extern "C" int32_t CryptoNative_EvpPKeyDeriveSecretAgreement(uint8_t* secret, uint32_t secretLength, EVP_PKEY_CTX* ctx)
+int32_t CryptoNative_EvpPKeyDeriveSecretAgreement(uint8_t* secret, uint32_t secretLength, EVP_PKEY_CTX* ctx)
 {
     size_t tmpSize = (size_t)secretLength;
     int ret = 0;
 
-    if (secret != nullptr && ctx != nullptr)
+    if (secret != NULL && ctx != NULL)
     {
         ret = EVP_PKEY_derive(ctx, secret, &tmpSize);
 
@@ -55,9 +55,9 @@ extern "C" int32_t CryptoNative_EvpPKeyDeriveSecretAgreement(uint8_t* secret, ui
     return ret;
 }
 
-extern "C" void CryptoNative_EvpPKeyCtxDestroy(EVP_PKEY_CTX* ctx)
+void CryptoNative_EvpPKeyCtxDestroy(EVP_PKEY_CTX* ctx)
 {
-    if (ctx != nullptr)
+    if (ctx != NULL)
     {
         EVP_PKEY_CTX_free(ctx);
     }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.h
index 59052a15ab..e97f4e2603 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_ecdh.h
@@ -2,11 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#include "opensslshim.h"
 #include "pal_types.h"
+#include "pal_compiler.h"
+#include "opensslshim.h"
 
-extern "C" EVP_PKEY_CTX* CryptoNative_EvpPKeyCtxCreate(EVP_PKEY* pkey, EVP_PKEY* peerkey, uint32_t* secretLength);
+DLLEXPORT EVP_PKEY_CTX* CryptoNative_EvpPKeyCtxCreate(EVP_PKEY* pkey, EVP_PKEY* peerkey, uint32_t* secretLength);
 
-extern "C" int32_t CryptoNative_EvpPKeyDeriveSecretAgreement(uint8_t* secret, uint32_t secretLength, EVP_PKEY_CTX* ctx);
+DLLEXPORT int32_t CryptoNative_EvpPKeyDeriveSecretAgreement(uint8_t* secret, uint32_t secretLength, EVP_PKEY_CTX* ctx);
 
-extern "C" void CryptoNative_EvpPKeyCtxDestroy(EVP_PKEY_CTX* ctx);
+DLLEXPORT void CryptoNative_EvpPKeyCtxDestroy(EVP_PKEY_CTX* ctx);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.c
index 1c792514e6..305734212e 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.c
@@ -4,12 +4,12 @@
 
 #include "pal_evp_pkey_eckey.h"
 
-extern "C" EC_KEY* CryptoNative_EvpPkeyGetEcKey(EVP_PKEY* pkey)
+EC_KEY* CryptoNative_EvpPkeyGetEcKey(EVP_PKEY* pkey)
 {
     return EVP_PKEY_get1_EC_KEY(pkey);
 }
 
-extern "C" int32_t CryptoNative_EvpPkeySetEcKey(EVP_PKEY* pkey, EC_KEY* key)
+int32_t CryptoNative_EvpPkeySetEcKey(EVP_PKEY* pkey, EC_KEY* key)
 {
     return EVP_PKEY_set1_EC_KEY(pkey, key);
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.h
index 0b71546cf8..fbeea59bff 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_eckey.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -10,7 +11,7 @@ Shims the EVP_PKEY_get1_EC_KEY method.
 
 Returns the EC_KEY instance for the EVP_PKEY.
 */
-extern "C" EC_KEY* CryptoNative_EvpPkeyGetEcKey(EVP_PKEY* pkey);
+DLLEXPORT EC_KEY* CryptoNative_EvpPkeyGetEcKey(EVP_PKEY* pkey);
 
 /*
 Shims the EVP_PKEY_set1_EC_KEY method to set the EC_KEY
@@ -18,4 +19,4 @@ instance on the EVP_KEY.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EvpPkeySetEcKey(EVP_PKEY* pkey, EC_KEY* key);
+DLLEXPORT int32_t CryptoNative_EvpPkeySetEcKey(EVP_PKEY* pkey, EC_KEY* key);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.c
index c36a830722..e8d961dbd2 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.c
@@ -4,12 +4,12 @@
 
 #include "pal_evp_pkey_rsa.h"
 
-extern "C" RSA* CryptoNative_EvpPkeyGetRsa(EVP_PKEY* pkey)
+RSA* CryptoNative_EvpPkeyGetRsa(EVP_PKEY* pkey)
 {
     return EVP_PKEY_get1_RSA(pkey);
 }
 
-extern "C" int32_t CryptoNative_EvpPkeySetRsa(EVP_PKEY* pkey, RSA* rsa)
+int32_t CryptoNative_EvpPkeySetRsa(EVP_PKEY* pkey, RSA* rsa)
 {
     return EVP_PKEY_set1_RSA(pkey, rsa);
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.h
index 3200a6180e..d8ff369670 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -10,7 +11,7 @@ Shims the EVP_PKEY_get1_RSA method.
 
 Returns the RSA instance for the EVP_PKEY.
 */
-extern "C" RSA* CryptoNative_EvpPkeyGetRsa(EVP_PKEY* pkey);
+DLLEXPORT RSA* CryptoNative_EvpPkeyGetRsa(EVP_PKEY* pkey);
 
 /*
 Shims the EVP_PKEY_set1_RSA method to set the RSA
@@ -18,4 +19,4 @@ instance on the EVP_KEY.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_EvpPkeySetRsa(EVP_PKEY* pkey, RSA* rsa);
+DLLEXPORT int32_t CryptoNative_EvpPkeySetRsa(EVP_PKEY* pkey, RSA* rsa);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.c
new file mode 100644
index 0000000000..783850ee6b
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.c
@@ -0,0 +1,88 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_config.h"
+#include "pal_utilities.h"
+#include "pal_hmac.h"
+
+#include <assert.h>
+
+HMAC_CTX* CryptoNative_HmacCreate(const uint8_t* key, int32_t keyLen, const EVP_MD* md)
+{
+    assert(key != NULL || keyLen == 0);
+    assert(keyLen >= 0);
+    assert(md != NULL);
+
+    HMAC_CTX* ctx = (HMAC_CTX*)malloc(sizeof(HMAC_CTX));
+    if (ctx == NULL)
+    {
+        // Allocation failed
+        return NULL;
+    }
+
+    // NOTE: We can't pass NULL as empty key since HMAC_Init_ex will interpret
+    // that as request to reuse the "existing" key.
+    uint8_t _;
+    if (keyLen == 0)
+        key = &_;
+
+    HMAC_CTX_init(ctx);
+    int ret = HMAC_Init_ex(ctx, key, keyLen, md, NULL);
+
+    if (!ret)
+    {
+        free(ctx);
+        return NULL;
+    }
+
+    return ctx;
+}
+
+void CryptoNative_HmacDestroy(HMAC_CTX* ctx)
+{
+    if (ctx != NULL)
+    {
+        HMAC_CTX_cleanup(ctx);
+        free(ctx);
+    }
+}
+
+int32_t CryptoNative_HmacReset(HMAC_CTX* ctx)
+{
+    assert(ctx != NULL);
+
+    return HMAC_Init_ex(ctx, NULL, 0, NULL, NULL);
+}
+
+int32_t CryptoNative_HmacUpdate(HMAC_CTX* ctx, const uint8_t* data, int32_t len)
+{
+    assert(ctx != NULL);
+    assert(data != NULL || len == 0);
+    assert(len >= 0);
+
+    if (len < 0)
+    {
+        return 0;
+    }
+
+    return HMAC_Update(ctx, data, Int32ToSizeT(len));
+}
+
+int32_t CryptoNative_HmacFinal(HMAC_CTX* ctx, uint8_t* md, int32_t* len)
+{
+    assert(ctx != NULL);
+    assert(len != NULL);
+    assert(md != NULL || *len == 0);
+    assert(*len >= 0);
+
+    if (len == NULL || *len < 0)
+    {
+        return 0;
+    }
+
+    unsigned int unsignedLen = Int32ToUint32(*len);
+    int ret = HMAC_Final(ctx, md, &unsignedLen);
+    *len = Uint32ToInt32(unsignedLen);
+    return ret;
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.cpp
deleted file mode 100644
index 10eef6809c..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.cpp
+++ /dev/null
@@ -1,88 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_config.h"
-#include "pal_utilities.h"
-#include "pal_hmac.h"
-
-#include <assert.h>
-#include <memory>
-
-extern "C" HMAC_CTX* CryptoNative_HmacCreate(const uint8_t* key, int32_t keyLen, const EVP_MD* md)
-{
-    assert(key != nullptr || keyLen == 0);
-    assert(keyLen >= 0);
-    assert(md != nullptr);
-
-    std::unique_ptr<HMAC_CTX> ctx(new (std::nothrow) HMAC_CTX);
-    if (ctx == nullptr)
-    {
-        // Allocation failed
-        return nullptr;
-    }
-
-    // NOTE: We can't pass nullptr as empty key since HMAC_Init_ex will interpret
-    // that as request to reuse the "existing" key.
-    uint8_t _;
-    if (keyLen == 0)
-        key = &_;
-
-    HMAC_CTX_init(ctx.get());
-    int ret = HMAC_Init_ex(ctx.get(), key, keyLen, md, nullptr);
-
-    if (!ret)
-    {
-        return nullptr;
-    }
-
-    return ctx.release();
-}
-
-extern "C" void CryptoNative_HmacDestroy(HMAC_CTX* ctx)
-{
-    if (ctx != nullptr)
-    {
-        HMAC_CTX_cleanup(ctx);
-        delete ctx;
-    }
-}
-
-extern "C" int32_t CryptoNative_HmacReset(HMAC_CTX* ctx)
-{
-    assert(ctx != nullptr);
-
-    return HMAC_Init_ex(ctx, nullptr, 0, nullptr, nullptr);
-}
-
-extern "C" int32_t CryptoNative_HmacUpdate(HMAC_CTX* ctx, const uint8_t* data, int32_t len)
-{
-    assert(ctx != nullptr);
-    assert(data != nullptr || len == 0);
-    assert(len >= 0);
-
-    if (len < 0)
-    {
-        return 0;
-    }
-
-    return HMAC_Update(ctx, data, UnsignedCast(len));
-}
-
-extern "C" int32_t CryptoNative_HmacFinal(HMAC_CTX* ctx, uint8_t* md, int32_t* len)
-{
-    assert(ctx != nullptr);
-    assert(len != nullptr);
-    assert(md != nullptr || *len == 0);
-    assert(*len >= 0);
-
-    if (len == nullptr || *len < 0)
-    {
-        return 0;
-    }
-
-    unsigned int unsignedLen = UnsignedCast(*len);
-    int ret = HMAC_Final(ctx, md, &unsignedLen);
-    *len = SignedCast(unsignedLen);
-    return ret;
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.h
index 131e148c00..72862b8b9c 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_hmac.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 // The shim API here is slightly less than 1:1 with underlying API so that:
@@ -24,7 +25,7 @@ typedef struct env_md_st EVP_MD;
  *
  * Returns new HMAC_CTX on success, nullptr on failure.
  */
-extern "C" HMAC_CTX* CryptoNative_HmacCreate(const uint8_t* key, int32_t keyLen, const EVP_MD* md);
+DLLEXPORT HMAC_CTX* CryptoNative_HmacCreate(const uint8_t* key, int32_t keyLen, const EVP_MD* md);
 
 /**
  * Cleans up and deletes an HMAC_CTX instance created by HmacCreate.
@@ -37,14 +38,14 @@ extern "C" HMAC_CTX* CryptoNative_HmacCreate(const uint8_t* key, int32_t keyLen,
  * The given HMAC_CTX pointer is invalid after this call.
  * Always succeeds.
  */
-extern "C" void CryptoNative_HmacDestroy(HMAC_CTX* ctx);
+DLLEXPORT void CryptoNative_HmacDestroy(HMAC_CTX* ctx);
 
 /**
  * Resets an HMAC_CTX instance for a new computation, preserving the key and EVP_MD.
  *
  * Implemented by passing all null/0 values but ctx to HMAC_Init_ex.
 */
-extern "C" int32_t CryptoNative_HmacReset(HMAC_CTX* ctx);
+DLLEXPORT int32_t CryptoNative_HmacReset(HMAC_CTX* ctx);
 
 /**
  * Appends data to the computation.
@@ -53,7 +54,7 @@ extern "C" int32_t CryptoNative_HmacReset(HMAC_CTX* ctx);
  *
  * Returns 1 for success or 0 for failure. (Always succeeds on platforms where HMAC_Update returns void.)
  */
-extern "C" int32_t CryptoNative_HmacUpdate(HMAC_CTX* ctx, const uint8_t* data, int32_t len);
+DLLEXPORT int32_t CryptoNative_HmacUpdate(HMAC_CTX* ctx, const uint8_t* data, int32_t len);
 
 /**
  * Finalizes the computation and obtains the result.
@@ -62,4 +63,4 @@ extern "C" int32_t CryptoNative_HmacUpdate(HMAC_CTX* ctx, const uint8_t* data, i
  *
  * Returns 1 for success or 0 for failure. (Always succeeds on platforms where HMAC_Update returns void.)
  */
-extern "C" int32_t CryptoNative_HmacFinal(HMAC_CTX* ctx, uint8_t* md, int32_t* len);
+DLLEXPORT int32_t CryptoNative_HmacFinal(HMAC_CTX* ctx, uint8_t* md, int32_t* len);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.c
index 7e48813e03..ea88390191 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.c
@@ -4,46 +4,46 @@
 
 #include "pal_pkcs12.h"
 
-extern "C" PKCS12* CryptoNative_DecodePkcs12(const uint8_t* buf, int32_t len)
+PKCS12* CryptoNative_DecodePkcs12(const uint8_t* buf, int32_t len)
 {
     if (!buf || !len)
     {
-        return nullptr;
+        return NULL;
     }
 
-    return d2i_PKCS12(nullptr, &buf, len);
+    return d2i_PKCS12(NULL, &buf, len);
 }
 
-extern "C" PKCS12* CryptoNative_DecodePkcs12FromBio(BIO* bio)
+PKCS12* CryptoNative_DecodePkcs12FromBio(BIO* bio)
 {
-    return d2i_PKCS12_bio(bio, nullptr);
+    return d2i_PKCS12_bio(bio, NULL);
 }
 
-extern "C" void CryptoNative_Pkcs12Destroy(PKCS12* p12)
+void CryptoNative_Pkcs12Destroy(PKCS12* p12)
 {
-    if (p12 != nullptr)
+    if (p12 != NULL)
     {
         PKCS12_free(p12);
     }
 }
 
-extern "C" PKCS12* CryptoNative_Pkcs12Create(char* pass, EVP_PKEY* pkey, X509* cert, X509Stack* ca)
+PKCS12* CryptoNative_Pkcs12Create(char* pass, EVP_PKEY* pkey, X509* cert, X509Stack* ca)
 {
     return PKCS12_create(
-        pass, nullptr, pkey, cert, ca, NID_undef, NID_undef, PKCS12_DEFAULT_ITER, PKCS12_DEFAULT_ITER, 0);
+        pass, NULL, pkey, cert, ca, NID_undef, NID_undef, PKCS12_DEFAULT_ITER, PKCS12_DEFAULT_ITER, 0);
 }
 
-extern "C" int32_t CryptoNative_GetPkcs12DerSize(PKCS12* p12)
+int32_t CryptoNative_GetPkcs12DerSize(PKCS12* p12)
 {
-    return i2d_PKCS12(p12, nullptr);
+    return i2d_PKCS12(p12, NULL);
 }
 
-extern "C" int32_t CryptoNative_EncodePkcs12(PKCS12* p12, uint8_t* buf)
+int32_t CryptoNative_EncodePkcs12(PKCS12* p12, uint8_t* buf)
 {
     return i2d_PKCS12(p12, &buf);
 }
 
-extern "C" int32_t CryptoNative_Pkcs12Parse(PKCS12* p12, const char* pass, EVP_PKEY** pkey, X509** cert, X509Stack** ca)
+int32_t CryptoNative_Pkcs12Parse(PKCS12* p12, const char* pass, EVP_PKEY** pkey, X509** cert, X509Stack** ca)
 {
     int32_t ret = PKCS12_parse(p12, pass, pkey, cert, ca);
 
@@ -60,8 +60,8 @@ extern "C" int32_t CryptoNative_Pkcs12Parse(PKCS12* p12, const char* pass, EVP_P
         // placed in.
         // If those handles make it back into managed code they will crash 
         // the coreclr when Disposed.
-        *pkey = nullptr;
-        *cert = nullptr;
+        *pkey = NULL;
+        *cert = NULL;
     }
 
     return ret;
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.h
index 9b9960a1a7..b3eb1fce14 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs12.h
@@ -3,19 +3,20 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_crypto_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
 Shims the d2i_PKCS12 method and makes it easier to invoke from managed code.
 */
-extern "C" PKCS12* CryptoNative_DecodePkcs12(const uint8_t* buf, int32_t len);
+DLLEXPORT PKCS12* CryptoNative_DecodePkcs12(const uint8_t* buf, int32_t len);
 
 /*
 Shims the d2i_PKCS12_bio method.
 
 Returns the new PKCS12 instance.
 */
-extern "C" PKCS12* CryptoNative_DecodePkcs12FromBio(BIO* bio);
+DLLEXPORT PKCS12* CryptoNative_DecodePkcs12FromBio(BIO* bio);
 
 /*
 Cleans up and deletes a PKCS12 instance.
@@ -26,32 +27,32 @@ No-op if p12 is null.
 The given PKCS12 pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_Pkcs12Destroy(PKCS12* p12);
+DLLEXPORT void CryptoNative_Pkcs12Destroy(PKCS12* p12);
 
 /*
 Shims the PKCS12_create method.
 
 Returns the new PKCS12 instance.
 */
-extern "C" PKCS12* CryptoNative_Pkcs12Create(char* pass, EVP_PKEY* pkey, X509* cert, X509Stack* ca);
+DLLEXPORT PKCS12* CryptoNative_Pkcs12Create(char* pass, EVP_PKEY* pkey, X509* cert, X509Stack* ca);
 
 /*
 Returns the number of bytes it will take to convert
 the PKCS12 to a DER format.
 */
-extern "C" int32_t CryptoNative_GetPkcs12DerSize(PKCS12* p12);
+DLLEXPORT int32_t CryptoNative_GetPkcs12DerSize(PKCS12* p12);
 
 /*
 Shims the i2d_PKCS12 method.
 
 Returns the number of bytes written to buf.
 */
-extern "C" int32_t CryptoNative_EncodePkcs12(PKCS12* p12, uint8_t* buf);
+DLLEXPORT int32_t CryptoNative_EncodePkcs12(PKCS12* p12, uint8_t* buf);
 
 /*
 Shims the PKCS12_parse method.
 
 Returns 1 on success, otherwise 0.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_Pkcs12Parse(PKCS12* p12, const char* pass, EVP_PKEY** pkey, X509** cert, X509Stack** ca);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.c
index 718d6ccfb4..09c72ed1af 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.c
@@ -4,53 +4,53 @@
 
 #include "pal_pkcs7.h"
 
-extern "C" PKCS7* CryptoNative_PemReadBioPkcs7(BIO* bp)
+PKCS7* CryptoNative_PemReadBioPkcs7(BIO* bp)
 {
-    return PEM_read_bio_PKCS7(bp, nullptr, nullptr, nullptr);
+    return PEM_read_bio_PKCS7(bp, NULL, NULL, NULL);
 }
 
-extern "C" PKCS7* CryptoNative_DecodePkcs7(const uint8_t* buf, int32_t len)
+PKCS7* CryptoNative_DecodePkcs7(const uint8_t* buf, int32_t len)
 {
     if (!buf || !len)
     {
-        return nullptr;
+        return NULL;
     }
 
-    return d2i_PKCS7(nullptr, &buf, len);
+    return d2i_PKCS7(NULL, &buf, len);
 }
 
-extern "C" PKCS7* CryptoNative_D2IPkcs7Bio(BIO* bp)
+PKCS7* CryptoNative_D2IPkcs7Bio(BIO* bp)
 {
-    return d2i_PKCS7_bio(bp, nullptr);
+    return d2i_PKCS7_bio(bp, NULL);
 }
 
-extern "C" PKCS7* CryptoNative_Pkcs7CreateSigned()
+PKCS7* CryptoNative_Pkcs7CreateSigned()
 {
     PKCS7* pkcs7 = PKCS7_new();
 
-    if (pkcs7 == nullptr)
+    if (pkcs7 == NULL)
     {
-        return nullptr;
+        return NULL;
     }
 
     if (!PKCS7_set_type(pkcs7, NID_pkcs7_signed) || !PKCS7_content_new(pkcs7, NID_pkcs7_data))
     {
         PKCS7_free(pkcs7);
-        return nullptr;
+        return NULL;
     }
 
     return pkcs7;
 }
 
-extern "C" void CryptoNative_Pkcs7Destroy(PKCS7* p7)
+void CryptoNative_Pkcs7Destroy(PKCS7* p7)
 {
-    if (p7 != nullptr)
+    if (p7 != NULL)
     {
         PKCS7_free(p7);
     }
 }
 
-extern "C" int32_t CryptoNative_GetPkcs7Certificates(PKCS7* p7, X509Stack** certs)
+int32_t CryptoNative_GetPkcs7Certificates(PKCS7* p7, X509Stack** certs)
 {
     if (!p7 || !certs)
     {
@@ -70,9 +70,9 @@ extern "C" int32_t CryptoNative_GetPkcs7Certificates(PKCS7* p7, X509Stack** cert
     return 0;
 }
 
-extern "C" int32_t CryptoNative_Pkcs7AddCertificate(PKCS7* p7, X509* x509)
+int32_t CryptoNative_Pkcs7AddCertificate(PKCS7* p7, X509* x509)
 {
-    if (p7 == nullptr || x509 == nullptr)
+    if (p7 == NULL || x509 == NULL)
     {
         return 0;
     }
@@ -80,12 +80,12 @@ extern "C" int32_t CryptoNative_Pkcs7AddCertificate(PKCS7* p7, X509* x509)
     return PKCS7_add_certificate(p7, x509);
 }
 
-extern "C" int32_t CryptoNative_GetPkcs7DerSize(PKCS7* p7)
+int32_t CryptoNative_GetPkcs7DerSize(PKCS7* p7)
 {
-    return i2d_PKCS7(p7, nullptr);
+    return i2d_PKCS7(p7, NULL);
 }
 
-extern "C" int32_t CryptoNative_EncodePkcs7(PKCS7* p7, uint8_t* buf)
+int32_t CryptoNative_EncodePkcs7(PKCS7* p7, uint8_t* buf)
 {
     return i2d_PKCS7(p7, &buf);
 }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.h
index e7921c1be4..59f0914a0d 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_pkcs7.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_crypto_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -12,12 +13,12 @@ Direct shim to PEM_read_bio_PKCS7.
 
 Returns the new PKCS7 instance.
 */
-extern "C" PKCS7* CryptoNative_PemReadBioPkcs7(BIO* bp);
+DLLEXPORT PKCS7* CryptoNative_PemReadBioPkcs7(BIO* bp);
 
 /*
 Shims the d2i_PKCS7 method and makes it easier to invoke from managed code.
 */
-extern "C" PKCS7* CryptoNative_DecodePkcs7(const uint8_t* buf, int32_t len);
+DLLEXPORT PKCS7* CryptoNative_DecodePkcs7(const uint8_t* buf, int32_t len);
 
 /*
 Reads a PKCS7 instance in DER format from a BIO.
@@ -26,7 +27,7 @@ Direct shim to d2i_PKCS7_bio.
 
 Returns the new PKCS7 instance.
 */
-extern "C" PKCS7* CryptoNative_D2IPkcs7Bio(BIO* bp);
+DLLEXPORT PKCS7* CryptoNative_D2IPkcs7Bio(BIO* bp);
 
 /*
 Create a new PKCS7 instance and prepare it to be a signed PKCS7
@@ -34,7 +35,7 @@ with a data payload.
 
 Returns the new PKCS7 instance.
 */
-extern "C" PKCS7* CryptoNative_Pkcs7CreateSigned();
+DLLEXPORT PKCS7* CryptoNative_Pkcs7CreateSigned(void);
 
 /*
 Cleans up and deletes a PKCS7 instance.
@@ -45,7 +46,7 @@ No-op if p7 is null.
 The given PKCS7 pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_Pkcs7Destroy(PKCS7* p7);
+DLLEXPORT void CryptoNative_Pkcs7Destroy(PKCS7* p7);
 
 /*
 Function:
@@ -59,22 +60,22 @@ Return values:
 1 when the file format is understood, and *certs is assigned to the
 certificate contents of the structure.
 */
-extern "C" int32_t CryptoNative_GetPkcs7Certificates(PKCS7* p7, X509Stack** certs);
+DLLEXPORT int32_t CryptoNative_GetPkcs7Certificates(PKCS7* p7, X509Stack** certs);
 
 /*
 Shims the PKCS7_add_certificate function and makes it easier to invoke from managed code.
 */
-extern "C" int32_t CryptoNative_Pkcs7AddCertificate(PKCS7* p7, X509* x509);
+DLLEXPORT int32_t CryptoNative_Pkcs7AddCertificate(PKCS7* p7, X509* x509);
 
 /*
 Returns the number of bytes it will take to convert
 the PKCS7 to a DER format.
 */
-extern "C" int32_t CryptoNative_GetPkcs7DerSize(PKCS7* p7);
+DLLEXPORT int32_t CryptoNative_GetPkcs7DerSize(PKCS7* p7);
 
 /*
 Shims the i2d_PKCS7 method.
 
 Returns the number of bytes written to buf.
 */
-extern "C" int32_t CryptoNative_EncodePkcs7(PKCS7* p7, uint8_t* buf);
+DLLEXPORT int32_t CryptoNative_EncodePkcs7(PKCS7* p7, uint8_t* buf);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.c
index 9ad896aa72..1f2fad46f4 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.c
@@ -5,32 +5,32 @@
 #include "pal_rsa.h"
 #include "pal_utilities.h"
 
-extern "C" RSA* CryptoNative_RsaCreate()
+RSA* CryptoNative_RsaCreate()
 {
     return RSA_new();
 }
 
-extern "C" int32_t CryptoNative_RsaUpRef(RSA* rsa)
+int32_t CryptoNative_RsaUpRef(RSA* rsa)
 {
     return RSA_up_ref(rsa);
 }
 
-extern "C" void CryptoNative_RsaDestroy(RSA* rsa)
+void CryptoNative_RsaDestroy(RSA* rsa)
 {
-    if (rsa != nullptr)
+    if (rsa != NULL)
     {
         RSA_free(rsa);
     }
 }
 
-extern "C" RSA* CryptoNative_DecodeRsaPublicKey(const uint8_t* buf, int32_t len)
+RSA* CryptoNative_DecodeRsaPublicKey(const uint8_t* buf, int32_t len)
 {
     if (!buf || !len)
     {
-        return nullptr;
+        return NULL;
     }
 
-    return d2i_RSAPublicKey(nullptr, &buf, len);
+    return d2i_RSAPublicKey(NULL, &buf, len);
 }
 
 static int GetOpenSslPadding(RsaPadding padding)
@@ -50,7 +50,7 @@ static int GetOpenSslPadding(RsaPadding padding)
 
 static int HasNoPrivateKey(RSA* rsa)
 {
-    if (rsa == nullptr)
+    if (rsa == NULL)
         return 1;
 
     // Shared pointer, don't free.
@@ -72,23 +72,23 @@ static int HasNoPrivateKey(RSA* rsa)
 
     // The module is documented as accepting either d or the full set of CRT parameters (p, q, dp, dq, qInv)
     // So if we see d, we're good. Otherwise, if any of the rest are missing, we're public-only.
-    if (rsa->d != nullptr)
+    if (rsa->d != NULL)
         return 0;
 
-    if (rsa->p == nullptr || rsa->q == nullptr || rsa->dmp1 == nullptr || rsa->dmq1 == nullptr || rsa->iqmp == nullptr)
+    if (rsa->p == NULL || rsa->q == NULL || rsa->dmp1 == NULL || rsa->dmq1 == NULL || rsa->iqmp == NULL)
         return 1;
 
     return 0;
 }
 
-extern "C" int32_t
+int32_t
 CryptoNative_RsaPublicEncrypt(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa, RsaPadding padding)
 {
     int openSslPadding = GetOpenSslPadding(padding);
     return RSA_public_encrypt(flen, from, to, rsa, openSslPadding);
 }
 
-extern "C" int32_t
+int32_t
 CryptoNative_RsaPrivateDecrypt(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa, RsaPadding padding)
 {
     if (HasNoPrivateKey(rsa))
@@ -101,7 +101,7 @@ CryptoNative_RsaPrivateDecrypt(int32_t flen, const uint8_t* from, uint8_t* to, R
     return RSA_private_decrypt(flen, from, to, rsa, openSslPadding);
 }
 
-extern "C" int32_t CryptoNative_RsaSignPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa)
+int32_t CryptoNative_RsaSignPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa)
 {
     if (HasNoPrivateKey(rsa))
     {
@@ -112,25 +112,25 @@ extern "C" int32_t CryptoNative_RsaSignPrimitive(int32_t flen, const uint8_t* fr
     return RSA_private_encrypt(flen, from, to, rsa, RSA_NO_PADDING);
 }
 
-extern "C" int32_t CryptoNative_RsaVerificationPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa)
+int32_t CryptoNative_RsaVerificationPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa)
 {
     return RSA_public_decrypt(flen, from, to, rsa, RSA_NO_PADDING);
 }
 
-extern "C" int32_t CryptoNative_RsaSize(RSA* rsa)
+int32_t CryptoNative_RsaSize(RSA* rsa)
 {
     return RSA_size(rsa);
 }
 
-extern "C" int32_t CryptoNative_RsaGenerateKeyEx(RSA* rsa, int32_t bits, BIGNUM* e)
+int32_t CryptoNative_RsaGenerateKeyEx(RSA* rsa, int32_t bits, BIGNUM* e)
 {
-    return RSA_generate_key_ex(rsa, bits, e, nullptr);
+    return RSA_generate_key_ex(rsa, bits, e, NULL);
 }
 
-extern "C" int32_t
+int32_t
 CryptoNative_RsaSign(int32_t type, const uint8_t* m, int32_t mlen, uint8_t* sigret, int32_t* siglen, RSA* rsa)
 {
-    if (siglen == nullptr)
+    if (siglen == NULL)
     {
         assert(false);
         return 0;
@@ -149,26 +149,26 @@ CryptoNative_RsaSign(int32_t type, const uint8_t* m, int32_t mlen, uint8_t* sigr
 
     // If the digest itself isn't known then RSA_R_UNKNOWN_ALGORITHM_TYPE will get reported, but
     // we have to check that the digest size matches what we expect.
-    if (digest != nullptr && mlen != EVP_MD_size(digest))
+    if (digest != NULL && mlen != EVP_MD_size(digest))
     {
         ERR_PUT_error(ERR_LIB_RSA, RSA_F_RSA_SIGN, RSA_R_INVALID_MESSAGE_LENGTH, __FILE__, __LINE__);
         return 0;
     }
 
     unsigned int unsignedSigLen = 0;
-    int32_t ret = RSA_sign(type, m, UnsignedCast(mlen), sigret, &unsignedSigLen, rsa);
+    int32_t ret = RSA_sign(type, m, Int32ToUint32(mlen), sigret, &unsignedSigLen, rsa);
     assert(unsignedSigLen <= INT32_MAX);
-    *siglen = static_cast<int32_t>(unsignedSigLen);
+    *siglen = (int32_t)unsignedSigLen;
     return ret;
 }
 
-extern "C" int32_t
+int32_t
 CryptoNative_RsaVerify(int32_t type, const uint8_t* m, int32_t mlen, uint8_t* sigbuf, int32_t siglen, RSA* rsa)
 {
-    return RSA_verify(type, m, UnsignedCast(mlen), sigbuf, UnsignedCast(siglen), rsa);
+    return RSA_verify(type, m, Int32ToUint32(mlen), sigbuf, Int32ToUint32(siglen), rsa);
 }
 
-extern "C" int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
+int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
                                                  BIGNUM** n,
                                                  BIGNUM** e,
                                                  BIGNUM** d,
@@ -184,21 +184,21 @@ extern "C" int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
 
         // since these parameters are 'out' parameters in managed code, ensure they are initialized
         if (n)
-            *n = nullptr;
+            *n = NULL;
         if (e)
-            *e = nullptr;
+            *e = NULL;
         if (d)
-            *d = nullptr;
+            *d = NULL;
         if (p)
-            *p = nullptr;
+            *p = NULL;
         if (dmp1)
-            *dmp1 = nullptr;
+            *dmp1 = NULL;
         if (q)
-            *q = nullptr;
+            *q = NULL;
         if (dmq1)
-            *dmq1 = nullptr;
+            *dmq1 = NULL;
         if (iqmp)
-            *iqmp = nullptr;
+            *iqmp = NULL;
 
         return 0;
     }
@@ -217,27 +217,27 @@ extern "C" int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
 
 static int32_t SetRsaParameter(BIGNUM** rsaFieldAddress, uint8_t* buffer, int32_t bufferLength)
 {
-    assert(rsaFieldAddress != nullptr);
+    assert(rsaFieldAddress != NULL);
     if (rsaFieldAddress)
     {
         if (!buffer || !bufferLength)
         {
-            *rsaFieldAddress = nullptr;
+            *rsaFieldAddress = NULL;
             return 1;
         }
         else
         {
-            BIGNUM* bigNum = BN_bin2bn(buffer, bufferLength, nullptr);
+            BIGNUM* bigNum = BN_bin2bn(buffer, bufferLength, NULL);
             *rsaFieldAddress = bigNum;
 
-            return bigNum != nullptr;
+            return bigNum != NULL;
         }
     }
 
     return 0;
 }
 
-extern "C" int32_t CryptoNative_SetRsaParameters(RSA* rsa,
+int32_t CryptoNative_SetRsaParameters(RSA* rsa,
                                               uint8_t* n,
                                               int32_t nLength,
                                               uint8_t* e,
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.h
index c4a2737ced..83a0e01569 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_rsa.h
@@ -2,33 +2,34 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#include "opensslshim.h"
 #include "pal_types.h"
+#include "pal_compiler.h"
+#include "opensslshim.h"
 
 /*
 Padding options for RsaPublicEncrypt and RsaPrivateDecrypt.
 These values should be kept in sync with Interop.Crypto.RsaPadding.
 */
-enum RsaPadding : int32_t
+typedef enum
 {
     Pkcs1 = 0,
     OaepSHA1 = 1,
     NoPadding = 2,
-};
+} RsaPadding;
 
 /*
 Shims the RSA_new method.
 
 Returns the new RSA instance.
 */
-extern "C" RSA* CryptoNative_RsaCreate();
+DLLEXPORT RSA* CryptoNative_RsaCreate(void);
 
 /*
 Shims the RSA_up_ref method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_RsaUpRef(RSA* rsa);
+DLLEXPORT int32_t CryptoNative_RsaUpRef(RSA* rsa);
 
 /*
 Cleans up and deletes a RSA instance.
@@ -39,19 +40,19 @@ No-op if rsa is null.
 The given RSA pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_RsaDestroy(RSA* rsa);
+DLLEXPORT void CryptoNative_RsaDestroy(RSA* rsa);
 
 /*
 Shims the d2i_RSAPublicKey method and makes it easier to invoke from managed code.
 */
-extern "C" RSA* CryptoNative_DecodeRsaPublicKey(const uint8_t* buf, int32_t len);
+DLLEXPORT RSA* CryptoNative_DecodeRsaPublicKey(const uint8_t* buf, int32_t len);
 
 /*
 Shims the RSA_public_encrypt method.
 
 Returns the size of the signature, or -1 on error.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_RsaPublicEncrypt(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa, RsaPadding padding);
 
 /*
@@ -59,7 +60,7 @@ Shims the RSA_private_decrypt method.
 
 Returns the size of the signature, or -1 on error.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_RsaPrivateDecrypt(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa, RsaPadding padding);
 
 /*
@@ -68,7 +69,7 @@ Shims RSA_private_encrypt with a fixed value of RSA_NO_PADDING.
 Requires that the input be the size of the key.
 Returns the number of bytes written (which should be flen), or -1 on error.
 */
-extern "C" int32_t CryptoNative_RsaSignPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa);
+DLLEXPORT int32_t CryptoNative_RsaSignPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa);
 
 /*
 Shims RSA_public_decrypt with a fixed value of RSA_NO_PADDING.
@@ -76,28 +77,28 @@ Shims RSA_public_decrypt with a fixed value of RSA_NO_PADDING.
 Requires that the input be the size of the key.
 Returns the number of bytes written (which should be flen), or -1 on error.
 */
-extern "C" int32_t CryptoNative_RsaVerificationPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa);
+DLLEXPORT int32_t CryptoNative_RsaVerificationPrimitive(int32_t flen, const uint8_t* from, uint8_t* to, RSA* rsa);
 
 /*
 Shims the RSA_size method.
 
 Returns the RSA modulus size in bytes.
 */
-extern "C" int32_t CryptoNative_RsaSize(RSA* rsa);
+DLLEXPORT int32_t CryptoNative_RsaSize(RSA* rsa);
 
 /*
 Shims the RSA_generate_key_ex method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_RsaGenerateKeyEx(RSA* rsa, int32_t bits, BIGNUM* e);
+DLLEXPORT int32_t CryptoNative_RsaGenerateKeyEx(RSA* rsa, int32_t bits, BIGNUM* e);
 
 /*
 Shims the RSA_sign method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_RsaSign(int32_t type, const uint8_t* m, int32_t mlen, uint8_t* sigret, int32_t* siglen, RSA* rsa);
 
 /*
@@ -105,7 +106,7 @@ Shims the RSA_verify method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t
+DLLEXPORT int32_t
 CryptoNative_RsaVerify(int32_t type, const uint8_t* m, int32_t mlen, uint8_t* sigbuf, int32_t siglen, RSA* rsa);
 
 /*
@@ -113,7 +114,7 @@ Gets all the parameters from the RSA instance.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
+DLLEXPORT int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
                                                  BIGNUM** n,
                                                  BIGNUM** e,
                                                  BIGNUM** d,
@@ -126,7 +127,7 @@ extern "C" int32_t CryptoNative_GetRsaParameters(const RSA* rsa,
 /*
 Sets all the parameters on the RSA instance.
 */
-extern "C" int32_t CryptoNative_SetRsaParameters(RSA* rsa,
+DLLEXPORT int32_t CryptoNative_SetRsaParameters(RSA* rsa,
                                               uint8_t* n,
                                               int32_t nLength,
                                               uint8_t* e,
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.c
index f93cdf3ced..c09661c9ec 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.c
@@ -6,35 +6,36 @@
 
 #include <assert.h>
 #include <string.h>
+#include <stdbool.h>
 
-static_assert(PAL_SSL_ERROR_NONE == SSL_ERROR_NONE, "");
-static_assert(PAL_SSL_ERROR_SSL == SSL_ERROR_SSL, "");
-static_assert(PAL_SSL_ERROR_WANT_READ == SSL_ERROR_WANT_READ, "");
-static_assert(PAL_SSL_ERROR_WANT_WRITE == SSL_ERROR_WANT_WRITE, "");
-static_assert(PAL_SSL_ERROR_SYSCALL == SSL_ERROR_SYSCALL, "");
-static_assert(PAL_SSL_ERROR_ZERO_RETURN == SSL_ERROR_ZERO_RETURN, "");
+c_static_assert(PAL_SSL_ERROR_NONE == SSL_ERROR_NONE);
+c_static_assert(PAL_SSL_ERROR_SSL == SSL_ERROR_SSL);
+c_static_assert(PAL_SSL_ERROR_WANT_READ == SSL_ERROR_WANT_READ);
+c_static_assert(PAL_SSL_ERROR_WANT_WRITE == SSL_ERROR_WANT_WRITE);
+c_static_assert(PAL_SSL_ERROR_SYSCALL == SSL_ERROR_SYSCALL);
+c_static_assert(PAL_SSL_ERROR_ZERO_RETURN == SSL_ERROR_ZERO_RETURN);
 
-extern "C" int32_t CryptoNative_EnsureOpenSslInitialized();
+int32_t CryptoNative_EnsureOpenSslInitialized(void);
 
-extern "C" void CryptoNative_EnsureLibSslInitialized()
+void CryptoNative_EnsureLibSslInitialized()
 {
     CryptoNative_EnsureOpenSslInitialized();
     SSL_library_init();
     SSL_load_error_strings();
 }
 
-extern "C" const SSL_METHOD* CryptoNative_SslV2_3Method()
+const SSL_METHOD* CryptoNative_SslV2_3Method()
 {
     const SSL_METHOD* method = SSLv23_method();
-    assert(method != nullptr);
+    assert(method != NULL);
     return method;
 }
 
-extern "C" SSL_CTX* CryptoNative_SslCtxCreate(SSL_METHOD* method)
+SSL_CTX* CryptoNative_SslCtxCreate(SSL_METHOD* method)
 {
     SSL_CTX* ctx = SSL_CTX_new(method);
 
-    if (ctx != nullptr)
+    if (ctx != NULL)
     {
         // As of OpenSSL 1.1.0, compression is disabled by default. In case an older build
         // is used, ensure it's disabled.
@@ -56,7 +57,7 @@ static long TrySetECDHNamedCurve(SSL_CTX* ctx)
 	result = SSL_CTX_set_ecdh_auto(ctx, 1);
 #else
 	EC_KEY *ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
-	if (ecdh != nullptr)
+	if (ecdh != NULL)
 	{
 		result = SSL_CTX_set_tmp_ecdh(ctx, ecdh);
 		EC_KEY_free(ecdh);
@@ -66,7 +67,7 @@ static long TrySetECDHNamedCurve(SSL_CTX* ctx)
 	return result;
 }
 
-extern "C" void CryptoNative_SetProtocolOptions(SSL_CTX* ctx, SslProtocols protocols)
+void CryptoNative_SetProtocolOptions(SSL_CTX* ctx, SslProtocols protocols)
 {
     // protocols may be 0, meaning system default, in which case let OpenSSL do what OpenSSL wants.
     if (protocols == 0)
@@ -108,12 +109,12 @@ extern "C" void CryptoNative_SetProtocolOptions(SSL_CTX* ctx, SslProtocols proto
     }
 }
 
-extern "C" SSL* CryptoNative_SslCreate(SSL_CTX* ctx)
+SSL* CryptoNative_SslCreate(SSL_CTX* ctx)
 {
     return SSL_new(ctx);
 }
 
-extern "C" int32_t CryptoNative_SslGetError(SSL* ssl, int32_t ret)
+int32_t CryptoNative_SslGetError(SSL* ssl, int32_t ret)
 {
     // This pops off "old" errors left by other operations
     // until the first error is equal to the last one, 
@@ -128,7 +129,7 @@ extern "C" int32_t CryptoNative_SslGetError(SSL* ssl, int32_t ret)
     return SSL_get_error(ssl, ret);
 }
 
-extern "C" void CryptoNative_SslDestroy(SSL* ssl)
+void CryptoNative_SslDestroy(SSL* ssl)
 {
     if (ssl)
     {
@@ -136,7 +137,7 @@ extern "C" void CryptoNative_SslDestroy(SSL* ssl)
     }
 }
 
-extern "C" void CryptoNative_SslCtxDestroy(SSL_CTX* ctx)
+void CryptoNative_SslCtxDestroy(SSL_CTX* ctx)
 {
     if (ctx)
     {
@@ -144,36 +145,36 @@ extern "C" void CryptoNative_SslCtxDestroy(SSL_CTX* ctx)
     }
 }
 
-extern "C" void CryptoNative_SslSetConnectState(SSL* ssl)
+void CryptoNative_SslSetConnectState(SSL* ssl)
 {
     SSL_set_connect_state(ssl);
 }
 
-extern "C" void CryptoNative_SslSetAcceptState(SSL* ssl)
+void CryptoNative_SslSetAcceptState(SSL* ssl)
 {
     SSL_set_accept_state(ssl);
 }
 
-extern "C" const char* CryptoNative_SslGetVersion(SSL* ssl)
+const char* CryptoNative_SslGetVersion(SSL* ssl)
 {
     return SSL_get_version(ssl);
 }
 
-extern "C" int32_t CryptoNative_SslGetFinished(SSL* ssl, void* buf, int32_t count)
+int32_t CryptoNative_SslGetFinished(SSL* ssl, void* buf, int32_t count)
 {
-    size_t result = SSL_get_finished(ssl, buf, size_t(count));
+    size_t result = SSL_get_finished(ssl, buf, (size_t)count);
     assert(result <= INT32_MAX);
-    return static_cast<int32_t>(result);
+    return (int32_t)result;
 }
 
-extern "C" int32_t CryptoNative_SslGetPeerFinished(SSL* ssl, void* buf, int32_t count)
+int32_t CryptoNative_SslGetPeerFinished(SSL* ssl, void* buf, int32_t count)
 {
-    size_t result = SSL_get_peer_finished(ssl, buf, size_t(count));
+    size_t result = SSL_get_peer_finished(ssl, buf, (size_t)count);
     assert(result <= INT32_MAX);
-    return static_cast<int32_t>(result);
+    return (int32_t)result;
 }
 
-extern "C" int32_t CryptoNative_SslSessionReused(SSL* ssl)
+int32_t CryptoNative_SslSessionReused(SSL* ssl)
 {
     return SSL_session_reused(ssl) == 1;
 }
@@ -191,115 +192,115 @@ static bool StringSpanEquals(const char* lhs, const char* rhs, size_t lhsLength)
 static CipherAlgorithmType MapCipherAlgorithmType(const char* encryption, size_t encryptionLength)
 {
     if (StringSpanEquals(encryption, "DES(56)", encryptionLength))
-        return CipherAlgorithmType::Des;
+        return Des;
     if (StringSpanEquals(encryption, "3DES(168)", encryptionLength))
-        return CipherAlgorithmType::TripleDes;
+        return TripleDes;
     if (StringSpanEquals(encryption, "RC4(128)", encryptionLength))
-        return CipherAlgorithmType::Rc4;
+        return Rc4;
     if (StringSpanEquals(encryption, "RC2(128)", encryptionLength))
-        return CipherAlgorithmType::Rc2;
+        return Rc2;
     if (StringSpanEquals(encryption, "None", encryptionLength))
-        return CipherAlgorithmType::Null;
+        return Null;
     if (StringSpanEquals(encryption, "IDEA(128)", encryptionLength))
-        return CipherAlgorithmType::SSL_IDEA;
+        return SSL_IDEA;
     if (StringSpanEquals(encryption, "SEED(128)", encryptionLength))
-        return CipherAlgorithmType::SSL_SEED;
+        return SSL_SEED;
     if (StringSpanEquals(encryption, "AES(128)", encryptionLength))
-        return CipherAlgorithmType::Aes128;
+        return Aes128;
     if (StringSpanEquals(encryption, "AES(256)", encryptionLength))
-        return CipherAlgorithmType::Aes256;
+        return Aes256;
     if (StringSpanEquals(encryption, "Camellia(128)", encryptionLength))
-        return CipherAlgorithmType::SSL_CAMELLIA128;
+        return SSL_CAMELLIA128;
     if (StringSpanEquals(encryption, "Camellia(256)", encryptionLength))
-        return CipherAlgorithmType::SSL_CAMELLIA256;
+        return SSL_CAMELLIA256;
     if (StringSpanEquals(encryption, "GOST89(256)", encryptionLength))
-        return CipherAlgorithmType::SSL_eGOST2814789CNT;
+        return SSL_eGOST2814789CNT;
     if (StringSpanEquals(encryption, "AESGCM(128)", encryptionLength))
-        return CipherAlgorithmType::Aes128;
+        return Aes128;
     if (StringSpanEquals(encryption, "AESGCM(256)", encryptionLength))
-        return CipherAlgorithmType::Aes256;
+        return Aes256;
 
-    return CipherAlgorithmType::None;
+    return CipherAlgorithmType_None;
 }
 
 static ExchangeAlgorithmType MapExchangeAlgorithmType(const char* keyExchange, size_t keyExchangeLength)
 {
     if (StringSpanEquals(keyExchange, "RSA", keyExchangeLength))
-        return ExchangeAlgorithmType::RsaKeyX;
+        return RsaKeyX;
     if (StringSpanEquals(keyExchange, "DH/RSA", keyExchangeLength))
-        return ExchangeAlgorithmType::DiffieHellman;
+        return DiffieHellman;
     if (StringSpanEquals(keyExchange, "DH/DSS", keyExchangeLength))
-        return ExchangeAlgorithmType::DiffieHellman;
+        return DiffieHellman;
     if (StringSpanEquals(keyExchange, "DH", keyExchangeLength))
-        return ExchangeAlgorithmType::DiffieHellman;
+        return DiffieHellman;
     if (StringSpanEquals(keyExchange, "KRB5", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_kKRB5;
+        return SSL_kKRB5;
     if (StringSpanEquals(keyExchange, "ECDH", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_ECDHE;
+        return SSL_ECDHE;
     if (StringSpanEquals(keyExchange, "ECDH/RSA", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_ECDH;
+        return SSL_ECDH;
     if (StringSpanEquals(keyExchange, "ECDH/ECDSA", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_ECDSA;
+        return SSL_ECDSA;
     if (StringSpanEquals(keyExchange, "PSK", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_kPSK;
+        return SSL_kPSK;
     if (StringSpanEquals(keyExchange, "GOST", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_kGOST;
+        return SSL_kGOST;
     if (StringSpanEquals(keyExchange, "SRP", keyExchangeLength))
-        return ExchangeAlgorithmType::SSL_kSRP;
+        return SSL_kSRP;
 
-    return ExchangeAlgorithmType::None;
+    return ExchangeAlgorithmType_None;
 }
 
 static void GetHashAlgorithmTypeAndSize(const char* mac,
                                         size_t macLength,
-                                        HashAlgorithmType& dataHashAlg,
-                                        DataHashSize& hashKeySize)
+                                        HashAlgorithmType* dataHashAlg,
+                                        DataHashSize* hashKeySize)
 {
     if (StringSpanEquals(mac, "MD5", macLength))
     {
-        dataHashAlg = HashAlgorithmType::Md5;
-        hashKeySize = DataHashSize::MD5_HashKeySize;
+        *dataHashAlg = Md5;
+        *hashKeySize = MD5_HashKeySize;
         return;
     }
     if (StringSpanEquals(mac, "SHA1", macLength))
     {
-        dataHashAlg = HashAlgorithmType::Sha1;
-        hashKeySize = DataHashSize::SHA1_HashKeySize;
+        *dataHashAlg = Sha1;
+        *hashKeySize = SHA1_HashKeySize;
         return;
     }
     if (StringSpanEquals(mac, "GOST94", macLength))
     {
-        dataHashAlg = HashAlgorithmType::SSL_GOST94;
-        hashKeySize = DataHashSize::GOST_HashKeySize;
+        *dataHashAlg = SSL_GOST94;
+        *hashKeySize = GOST_HashKeySize;
         return;
     }
     if (StringSpanEquals(mac, "GOST89", macLength))
     {
-        dataHashAlg = HashAlgorithmType::SSL_GOST89;
-        hashKeySize = DataHashSize::GOST_HashKeySize;
+        *dataHashAlg = SSL_GOST89;
+        *hashKeySize = GOST_HashKeySize;
         return;
     }
     if (StringSpanEquals(mac, "SHA256", macLength))
     {
-        dataHashAlg = HashAlgorithmType::SSL_SHA256;
-        hashKeySize = DataHashSize::SHA256_HashKeySize;
+        *dataHashAlg = SSL_SHA256;
+        *hashKeySize = SHA256_HashKeySize;
         return;
     }
     if (StringSpanEquals(mac, "SHA384", macLength))
     {
-        dataHashAlg = HashAlgorithmType::SSL_SHA384;
-        hashKeySize = DataHashSize::SHA384_HashKeySize;
+        *dataHashAlg = SSL_SHA384;
+        *hashKeySize = SHA384_HashKeySize;
         return;
     }
     if (StringSpanEquals(mac, "AEAD", macLength))
     {
-        dataHashAlg = HashAlgorithmType::SSL_AEAD;
-        hashKeySize = DataHashSize::Default;
+        *dataHashAlg = SSL_AEAD;
+        *hashKeySize = Default;
         return;
     }
 
-    dataHashAlg = HashAlgorithmType::None;
-    hashKeySize = DataHashSize::Default;
+    *dataHashAlg = HashAlgorithmType_None;
+    *hashKeySize = Default;
 }
 
 /*
@@ -309,11 +310,11 @@ Given a keyName string like "Enc=XXX", parses the description string and returns
 Returns a value indicating whether the pattern starting with keyName was found in description.
 */
 static bool GetDescriptionValue(
-    const char* description, const char* keyName, size_t keyNameLength, const char** value, size_t& valueLength)
+    const char* description, const char* keyName, size_t keyNameLength, const char** value, size_t* valueLength)
 {
     // search for keyName in description
     const char* keyNameStart = strstr(description, keyName);
-    if (keyNameStart != nullptr)
+    if (keyNameStart != NULL)
     {
         // set valueStart to the beginning of the value
         const char* valueStart = keyNameStart + keyNameLength;
@@ -326,55 +327,56 @@ static bool GetDescriptionValue(
         }
 
         *value = valueStart;
-        valueLength = index;
+        *valueLength = index;
         return true;
     }
 
     return false;
 }
 
+#define descriptionLength 256
+
 /*
 Parses the Kx, Enc, and Mac values out of the SSL_CIPHER_description and
 maps the values to the corresponding .NET enum value.
 */
 static bool GetSslConnectionInfoFromDescription(const SSL_CIPHER* cipher,
-                                                CipherAlgorithmType& dataCipherAlg,
-                                                ExchangeAlgorithmType& keyExchangeAlg,
-                                                HashAlgorithmType& dataHashAlg,
-                                                DataHashSize& hashKeySize)
+                                                CipherAlgorithmType* dataCipherAlg,
+                                                ExchangeAlgorithmType* keyExchangeAlg,
+                                                HashAlgorithmType* dataHashAlg,
+                                                DataHashSize* hashKeySize)
 {
-    const int descriptionLength = 256;
-    char description[descriptionLength] = {};
+    char description[descriptionLength] = { 0 };
     SSL_CIPHER_description(cipher, description, descriptionLength - 1); // ensure description is NULL-terminated
 
     const char* keyExchange;
     size_t keyExchangeLength;
-    if (!GetDescriptionValue(description, "Kx=", 3, &keyExchange, keyExchangeLength))
+    if (!GetDescriptionValue(description, "Kx=", 3, &keyExchange, &keyExchangeLength))
     {
         return false;
     }
 
     const char* encryption;
     size_t encryptionLength;
-    if (!GetDescriptionValue(description, "Enc=", 4, &encryption, encryptionLength))
+    if (!GetDescriptionValue(description, "Enc=", 4, &encryption, &encryptionLength))
     {
         return false;
     }
 
     const char* mac;
     size_t macLength;
-    if (!GetDescriptionValue(description, "Mac=", 4, &mac, macLength))
+    if (!GetDescriptionValue(description, "Mac=", 4, &mac, &macLength))
     {
         return false;
     }
 
-    keyExchangeAlg = MapExchangeAlgorithmType(keyExchange, keyExchangeLength);
-    dataCipherAlg = MapCipherAlgorithmType(encryption, encryptionLength);
+    *keyExchangeAlg = MapExchangeAlgorithmType(keyExchange, keyExchangeLength);
+    *dataCipherAlg = MapCipherAlgorithmType(encryption, encryptionLength);
     GetHashAlgorithmTypeAndSize(mac, macLength, dataHashAlg, hashKeySize);
     return true;
 }
 
-extern "C" int32_t CryptoNative_GetSslConnectionInfo(SSL* ssl,
+int32_t CryptoNative_GetSslConnectionInfo(SSL* ssl,
                                                      CipherAlgorithmType* dataCipherAlg,
                                                      ExchangeAlgorithmType* keyExchangeAlg,
                                                      HashAlgorithmType* dataHashAlg,
@@ -395,7 +397,7 @@ extern "C" int32_t CryptoNative_GetSslConnectionInfo(SSL* ssl,
     }
 
     *dataKeySize = cipher->alg_bits;
-    if (GetSslConnectionInfoFromDescription(cipher, *dataCipherAlg, *keyExchangeAlg, *dataHashAlg, *hashKeySize))
+    if (GetSslConnectionInfoFromDescription(cipher, dataCipherAlg, keyExchangeAlg, dataHashAlg, hashKeySize))
     {
         return 1;
     }
@@ -404,104 +406,104 @@ err:
     assert(false);
 
     if (dataCipherAlg)
-        *dataCipherAlg = CipherAlgorithmType::None;
+        *dataCipherAlg = CipherAlgorithmType_None;
     if (keyExchangeAlg)
-        *keyExchangeAlg = ExchangeAlgorithmType::None;
+        *keyExchangeAlg = ExchangeAlgorithmType_None;
     if (dataHashAlg)
-        *dataHashAlg = HashAlgorithmType::None;
+        *dataHashAlg = HashAlgorithmType_None;
     if (dataKeySize)
         *dataKeySize = 0;
     if (hashKeySize)
-        *hashKeySize = DataHashSize::Default;
+        *hashKeySize = Default;
 
     return 0;
 }
 
-extern "C" int32_t CryptoNative_SslWrite(SSL* ssl, const void* buf, int32_t num)
+int32_t CryptoNative_SslWrite(SSL* ssl, const void* buf, int32_t num)
 {
     return SSL_write(ssl, buf, num);
 }
 
-extern "C" int32_t CryptoNative_SslRead(SSL* ssl, void* buf, int32_t num)
+int32_t CryptoNative_SslRead(SSL* ssl, void* buf, int32_t num)
 {
     return SSL_read(ssl, buf, num);
 }
 
-extern "C" int32_t CryptoNative_IsSslRenegotiatePending(SSL* ssl)
+int32_t CryptoNative_IsSslRenegotiatePending(SSL* ssl)
 {
     return SSL_renegotiate_pending(ssl) != 0;
 }
 
-extern "C" int32_t CryptoNative_SslShutdown(SSL* ssl)
+int32_t CryptoNative_SslShutdown(SSL* ssl)
 {
     ERR_clear_error();
     return SSL_shutdown(ssl);
 }
 
-extern "C" void CryptoNative_SslSetBio(SSL* ssl, BIO* rbio, BIO* wbio)
+void CryptoNative_SslSetBio(SSL* ssl, BIO* rbio, BIO* wbio)
 {
     SSL_set_bio(ssl, rbio, wbio);
 }
 
-extern "C" int32_t CryptoNative_SslDoHandshake(SSL* ssl)
+int32_t CryptoNative_SslDoHandshake(SSL* ssl)
 {
     ERR_clear_error();
     return SSL_do_handshake(ssl);
 }
 
-extern "C" int32_t CryptoNative_IsSslStateOK(SSL* ssl)
+int32_t CryptoNative_IsSslStateOK(SSL* ssl)
 {
     return SSL_state(ssl) == SSL_ST_OK;
 }
 
-extern "C" X509* CryptoNative_SslGetPeerCertificate(SSL* ssl)
+X509* CryptoNative_SslGetPeerCertificate(SSL* ssl)
 {
     return SSL_get_peer_certificate(ssl);
 }
 
-extern "C" X509Stack* CryptoNative_SslGetPeerCertChain(SSL* ssl)
+X509Stack* CryptoNative_SslGetPeerCertChain(SSL* ssl)
 {
     return SSL_get_peer_cert_chain(ssl);
 }
 
-extern "C" int32_t CryptoNative_SslCtxUseCertificate(SSL_CTX* ctx, X509* x)
+int32_t CryptoNative_SslCtxUseCertificate(SSL_CTX* ctx, X509* x)
 {
     return SSL_CTX_use_certificate(ctx, x);
 }
 
-extern "C" int32_t CryptoNative_SslCtxUsePrivateKey(SSL_CTX* ctx, EVP_PKEY* pkey)
+int32_t CryptoNative_SslCtxUsePrivateKey(SSL_CTX* ctx, EVP_PKEY* pkey)
 {
     return SSL_CTX_use_PrivateKey(ctx, pkey);
 }
 
-extern "C" int32_t CryptoNative_SslCtxCheckPrivateKey(SSL_CTX* ctx)
+int32_t CryptoNative_SslCtxCheckPrivateKey(SSL_CTX* ctx)
 {
     return SSL_CTX_check_private_key(ctx);
 }
 
-extern "C" void CryptoNative_SslCtxSetQuietShutdown(SSL_CTX* ctx)
+void CryptoNative_SslCtxSetQuietShutdown(SSL_CTX* ctx)
 {
     SSL_CTX_set_quiet_shutdown(ctx, 1);
 }
 
-extern "C" void CryptoNative_SslSetQuietShutdown(SSL* ssl, int mode)
+void CryptoNative_SslSetQuietShutdown(SSL* ssl, int mode)
 {
     SSL_set_quiet_shutdown(ssl, mode);
 }
 
-extern "C" X509NameStack* CryptoNative_SslGetClientCAList(SSL* ssl)
+X509NameStack* CryptoNative_SslGetClientCAList(SSL* ssl)
 {
     return SSL_get_client_CA_list(ssl);
 }
 
-extern "C" void CryptoNative_SslCtxSetVerify(SSL_CTX* ctx, SslCtxSetVerifyCallback callback)
+void CryptoNative_SslCtxSetVerify(SSL_CTX* ctx, SslCtxSetVerifyCallback callback)
 {
     int mode = SSL_VERIFY_PEER;
 
     SSL_CTX_set_verify(ctx, mode, callback);
 }
 
-extern "C" void
+void
 CryptoNative_SslCtxSetCertVerifyCallback(SSL_CTX* ctx, SslCtxSetCertVerifyCallbackCallback callback, void* arg)
 {
     SSL_CTX_set_cert_verify_callback(ctx, callback, arg);
@@ -514,36 +516,36 @@ CryptoNative_SslCtxSetCertVerifyCallback(SSL_CTX* ctx, SslCtxSetCertVerifyCallba
 #define SSL_TXT_AllIncludingNull SSL_TXT_ALL SSL_TXT_Separator SSL_TXT_eNULL
 #define SSL_TXT_NotAnon SSL_TXT_Separator SSL_TXT_Exclusion SSL_TXT_aNULL
 
-extern "C" int32_t CryptoNative_SetEncryptionPolicy(SSL_CTX* ctx, EncryptionPolicy policy)
+int32_t CryptoNative_SetEncryptionPolicy(SSL_CTX* ctx, EncryptionPolicy policy)
 {
-    const char* cipherString = nullptr;
+    const char* cipherString = NULL;
     switch (policy)
     {
-        case EncryptionPolicy::RequireEncryption:
+        case RequireEncryption:
             cipherString = SSL_TXT_ALL SSL_TXT_NotAnon;
             break;
 
-        case EncryptionPolicy::AllowNoEncryption:
+        case AllowNoEncryption:
             cipherString = SSL_TXT_AllIncludingNull;
             break;
 
-        case EncryptionPolicy::NoEncryption:
+        case NoEncryption:
             cipherString = SSL_TXT_eNULL;
             break;
     }
 
-    assert(cipherString != nullptr);
+    assert(cipherString != NULL);
 
     return SSL_CTX_set_cipher_list(ctx, cipherString);
 }
 
 
-extern "C" void CryptoNative_SslCtxSetClientCertCallback(SSL_CTX* ctx, SslClientCertCallback callback)
+void CryptoNative_SslCtxSetClientCertCallback(SSL_CTX* ctx, SslClientCertCallback callback)
 {
     SSL_CTX_set_client_cert_cb(ctx, callback);
 }
 
-extern "C" int32_t CryptoNative_SslAddExtraChainCert(SSL* ssl, X509* x509)
+int32_t CryptoNative_SslAddExtraChainCert(SSL* ssl, X509* x509)
 {
     if (!x509 || !ssl)
     {
@@ -559,7 +561,7 @@ extern "C" int32_t CryptoNative_SslAddExtraChainCert(SSL* ssl, X509* x509)
     return 0;
 }
 
-extern "C" void CryptoNative_SslCtxSetAlpnSelectCb(SSL_CTX* ctx, SslCtxSetAlpnCallback cb, void* arg)
+void CryptoNative_SslCtxSetAlpnSelectCb(SSL_CTX* ctx, SslCtxSetAlpnCallback cb, void* arg)
 {
 #if HAVE_OPENSSL_ALPN
     if (API_EXISTS(SSL_CTX_set_alpn_select_cb))
@@ -573,7 +575,7 @@ extern "C" void CryptoNative_SslCtxSetAlpnSelectCb(SSL_CTX* ctx, SslCtxSetAlpnCa
 #endif
 }
 
-extern "C" int32_t CryptoNative_SslCtxSetAlpnProtos(SSL_CTX* ctx, const uint8_t* protos, uint32_t protos_len)
+int32_t CryptoNative_SslCtxSetAlpnProtos(SSL_CTX* ctx, const uint8_t* protos, uint32_t protos_len)
 {
 #if HAVE_OPENSSL_ALPN
     if (API_EXISTS(SSL_CTX_set_alpn_protos))
@@ -591,7 +593,7 @@ extern "C" int32_t CryptoNative_SslCtxSetAlpnProtos(SSL_CTX* ctx, const uint8_t*
     }
 }
 
-extern "C" void CryptoNative_SslGet0AlpnSelected(SSL* ssl, const uint8_t** protocol, uint32_t* len)
+void CryptoNative_SslGet0AlpnSelected(SSL* ssl, const uint8_t** protocol, uint32_t* len)
 {
 #if HAVE_OPENSSL_ALPN
     if (API_EXISTS(SSL_get0_alpn_selected))
@@ -603,13 +605,13 @@ extern "C" void CryptoNative_SslGet0AlpnSelected(SSL* ssl, const uint8_t** proto
     (void)ssl;
 #endif
     {
-        *protocol = nullptr;
+        *protocol = NULL;
         *len = 0;
     }
 }
 
-extern "C" int32_t CryptoNative_SslSetTlsExtHostName(SSL* ssl, const uint8_t* name)
+int32_t CryptoNative_SslSetTlsExtHostName(SSL* ssl, uint8_t* name)
 {
-    return static_cast<int32_t>(SSL_set_tlsext_host_name(ssl, const_cast<unsigned char*>(name)));
+    return (int32_t)SSL_set_tlsext_host_name(ssl, name);
 }
 
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.h
index a5415a17d9..971018b686 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_ssl.h
@@ -3,12 +3,13 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_crypto_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
 These values should be kept in sync with System.Security.Authentication.SslProtocols.
 */
-enum SslProtocols : int32_t
+typedef enum
 {
     PAL_SSL_NONE = 0,
     PAL_SSL_SSL2 = 12,
@@ -16,24 +17,24 @@ enum SslProtocols : int32_t
     PAL_SSL_TLS = 192,
     PAL_SSL_TLS11 = 768,
     PAL_SSL_TLS12 = 3072
-};
+} SslProtocols;
 
 /*
 These values should be kept in sync with System.Net.Security.EncryptionPolicy.
 */
-enum class EncryptionPolicy : int32_t
+typedef enum
 {
     RequireEncryption = 0,
     AllowNoEncryption,
     NoEncryption
-};
+} EncryptionPolicy;
 
 /*
 These values should be kept in sync with System.Security.Authentication.CipherAlgorithmType.
 */
-enum class CipherAlgorithmType : int32_t
+typedef enum
 {
-    None = 0,
+    CipherAlgorithmType_None = 0,
     Null = 24576,
     Des = 26113,
     Rc2 = 26114,
@@ -50,14 +51,14 @@ enum class CipherAlgorithmType : int32_t
     SSL_CAMELLIA256 = 229382,
     SSL_eGOST2814789CNT = 229383,
     SSL_SEED = 229384,
-};
+} CipherAlgorithmType;
 
 /*
 These values should be kept in sync with System.Security.Authentication.ExchangeAlgorithmType.
 */
-enum class ExchangeAlgorithmType : int32_t
+typedef enum
 {
-    None,
+    ExchangeAlgorithmType_None,
     RsaSign = 9216,
     RsaKeyX = 41984,
     DiffieHellman = 43522,
@@ -70,14 +71,14 @@ enum class ExchangeAlgorithmType : int32_t
     SSL_kGOST = 229391,
     SSL_kSRP = 229392,
     SSL_kKRB5 = 229393,
-};
+} ExchangeAlgorithmType;
 
 /*
 These values should be kept in sync with System.Security.Authentication.HashAlgorithmType.
 */
-enum class HashAlgorithmType : int32_t
+typedef enum
 {
-    None = 0,
+    HashAlgorithmType_None = 0,
     Md5 = 32771,
     Sha1 = 32772,
 
@@ -87,9 +88,9 @@ enum class HashAlgorithmType : int32_t
     SSL_GOST94 = 229410,
     SSL_GOST89 = 229411,
     SSL_AEAD = 229412,
-};
+} HashAlgorithmType;
 
-enum class DataHashSize : int32_t
+typedef enum
 {
     MD5_HashKeySize = 8 * MD5_DIGEST_LENGTH,
     SHA1_HashKeySize = 8 * SHA_DIGEST_LENGTH,
@@ -97,9 +98,9 @@ enum class DataHashSize : int32_t
     SHA384_HashKeySize = 8 * SHA384_DIGEST_LENGTH,
     GOST_HashKeySize = 256,
     Default = 0,
-};
+} DataHashSize;
 
-enum SslErrorCode : int32_t
+enum SslErrorCode
 {
     PAL_SSL_ERROR_NONE = 0,
     PAL_SSL_ERROR_SSL = 1,
@@ -128,40 +129,40 @@ typedef int32_t (*SslCtxSetAlpnCallback)(SSL* ssl,
 /*
 Ensures that libssl is correctly initialized and ready to use.
 */
-extern "C" void CryptoNative_EnsureLibSslInitialized();
+DLLEXPORT void CryptoNative_EnsureLibSslInitialized(void);
 
 /*
 Shims the SSLv23_method method.
 
 Returns the requested SSL_METHOD.
 */
-extern "C" const SSL_METHOD* CryptoNative_SslV2_3Method();
+DLLEXPORT const SSL_METHOD* CryptoNative_SslV2_3Method(void);
 
 /*
 Shims the SSL_CTX_new method.
 
 Returns the new SSL_CTX instance.
 */
-extern "C" SSL_CTX* CryptoNative_SslCtxCreate(SSL_METHOD* method);
+DLLEXPORT SSL_CTX* CryptoNative_SslCtxCreate(SSL_METHOD* method);
 
 /*
 Sets the specified protocols in the SSL_CTX options.
 */
-extern "C" void CryptoNative_SetProtocolOptions(SSL_CTX* ctx, SslProtocols protocols);
+DLLEXPORT void CryptoNative_SetProtocolOptions(SSL_CTX* ctx, SslProtocols protocols);
 
 /*
 Shims the SSL_new method.
 
 Returns the new SSL instance.
 */
-extern "C" SSL* CryptoNative_SslCreate(SSL_CTX* ctx);
+DLLEXPORT SSL* CryptoNative_SslCreate(SSL_CTX* ctx);
 
 /*
 Shims the SSL_get_error method.
 
 Returns the error code for the specified result.
 */
-extern "C" int32_t CryptoNative_SslGetError(SSL* ssl, int32_t ret);
+DLLEXPORT int32_t CryptoNative_SslGetError(SSL* ssl, int32_t ret);
 
 /*
 Cleans up and deletes an SSL instance.
@@ -172,7 +173,7 @@ No-op if ssl is null.
 The given X509 SSL is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_SslDestroy(SSL* ssl);
+DLLEXPORT void CryptoNative_SslDestroy(SSL* ssl);
 
 /*
 Cleans up and deletes an SSL_CTX instance.
@@ -183,24 +184,24 @@ No-op if ctx is null.
 The given X509 SSL_CTX is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_SslCtxDestroy(SSL_CTX* ctx);
+DLLEXPORT void CryptoNative_SslCtxDestroy(SSL_CTX* ctx);
 
 /*
 Shims the SSL_set_connect_state method.
 */
-extern "C" void CryptoNative_SslSetConnectState(SSL* ssl);
+DLLEXPORT void CryptoNative_SslSetConnectState(SSL* ssl);
 
 /*
 Shims the SSL_set_accept_state method.
 */
-extern "C" void CryptoNative_SslSetAcceptState(SSL* ssl);
+DLLEXPORT void CryptoNative_SslSetAcceptState(SSL* ssl);
 
 /*
 Shims the SSL_get_version method.
 
 Returns the protocol version string for the SSL instance.
 */
-extern "C" const char* CryptoNative_SslGetVersion(SSL* ssl);
+DLLEXPORT const char* CryptoNative_SslGetVersion(SSL* ssl);
 
 /*
 Returns the connection information for the SSL instance.
@@ -208,7 +209,7 @@ Returns the connection information for the SSL instance.
 Returns 1 upon success, otherwise 0.
 */
 
-extern "C" int32_t CryptoNative_GetSslConnectionInfo(SSL* ssl,
+DLLEXPORT int32_t CryptoNative_GetSslConnectionInfo(SSL* ssl,
                                                      CipherAlgorithmType* dataCipherAlg,
                                                      ExchangeAlgorithmType* keyExchangeAlg,
                                                      HashAlgorithmType* dataHashAlg,
@@ -221,7 +222,7 @@ Shims the SSL_write method.
 Returns the positive number of bytes written when successful, 0 or a negative number
 when an error is encountered.
 */
-extern "C" int32_t CryptoNative_SslWrite(SSL* ssl, const void* buf, int32_t num);
+DLLEXPORT int32_t CryptoNative_SslWrite(SSL* ssl, const void* buf, int32_t num);
 
 /*
 Shims the SSL_read method.
@@ -229,14 +230,14 @@ Shims the SSL_read method.
 Returns the positive number of bytes read when successful, 0 or a negative number
 when an error is encountered.
 */
-extern "C" int32_t CryptoNative_SslRead(SSL* ssl, void* buf, int32_t num);
+DLLEXPORT int32_t CryptoNative_SslRead(SSL* ssl, void* buf, int32_t num);
 
 /*
 Shims the SSL_renegotiate_pending method.
 
 Returns 1 when negotiation is requested; 0 once a handshake has finished.
 */
-extern "C" int32_t CryptoNative_IsSslRenegotiatePending(SSL* ssl);
+DLLEXPORT int32_t CryptoNative_IsSslRenegotiatePending(SSL* ssl);
 
 /*
 Shims the SSL_shutdown method.
@@ -246,12 +247,12 @@ Returns:
 0 if the shutdown is not yet finished;
 <0 if the shutdown was not successful because a fatal error.
 */
-extern "C" int32_t CryptoNative_SslShutdown(SSL* ssl);
+DLLEXPORT int32_t CryptoNative_SslShutdown(SSL* ssl);
 
 /*
 Shims the SSL_set_bio method.
 */
-extern "C" void CryptoNative_SslSetBio(SSL* ssl, BIO* rbio, BIO* wbio);
+DLLEXPORT void CryptoNative_SslSetBio(SSL* ssl, BIO* rbio, BIO* wbio);
 
 /*
 Shims the SSL_do_handshake method.
@@ -262,104 +263,104 @@ Returns:
 and by the specifications of the TLS/SSL protocol;
 <0 if the handshake was not successful because of a fatal error.
 */
-extern "C" int32_t CryptoNative_SslDoHandshake(SSL* ssl);
+DLLEXPORT int32_t CryptoNative_SslDoHandshake(SSL* ssl);
 
 /*
 Gets a value indicating whether the SSL_state is SSL_ST_OK.
 
 Returns 1 if the state is OK, otherwise 0.
 */
-extern "C" int32_t CryptoNative_IsSslStateOK(SSL* ssl);
+DLLEXPORT int32_t CryptoNative_IsSslStateOK(SSL* ssl);
 
 /*
 Shims the SSL_get_peer_certificate method.
 
 Returns the certificate presented by the peer.
 */
-extern "C" X509* CryptoNative_SslGetPeerCertificate(SSL* ssl);
+DLLEXPORT X509* CryptoNative_SslGetPeerCertificate(SSL* ssl);
 
 /*
 Shims the SSL_get_peer_cert_chain method.
 
 Returns the certificate chain presented by the peer.
 */
-extern "C" X509Stack* CryptoNative_SslGetPeerCertChain(SSL* ssl);
+DLLEXPORT X509Stack* CryptoNative_SslGetPeerCertChain(SSL* ssl);
 
 /*
 Shims the SSL_CTX_use_certificate method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_SslCtxUseCertificate(SSL_CTX* ctx, X509* x);
+DLLEXPORT int32_t CryptoNative_SslCtxUseCertificate(SSL_CTX* ctx, X509* x);
 
 /*
 Shims the SSL_CTX_use_PrivateKey method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_SslCtxUsePrivateKey(SSL_CTX* ctx, EVP_PKEY* pkey);
+DLLEXPORT int32_t CryptoNative_SslCtxUsePrivateKey(SSL_CTX* ctx, EVP_PKEY* pkey);
 
 /*
 Shims the SSL_CTX_check_private_key method.
 
 Returns 1 upon success, otherwise 0.
 */
-extern "C" int32_t CryptoNative_SslCtxCheckPrivateKey(SSL_CTX* ctx);
+DLLEXPORT int32_t CryptoNative_SslCtxCheckPrivateKey(SSL_CTX* ctx);
 
 /*
 Shims the SSL_CTX_set_quiet_shutdown method.
 */
-extern "C" void CryptoNative_SslCtxSetQuietShutdown(SSL_CTX* ctx);
+DLLEXPORT void CryptoNative_SslCtxSetQuietShutdown(SSL_CTX* ctx);
 
 /*
 Shims the SSL_set_quiet_shutdown method.
 */
-extern "C" void CryptoNative_SslSetQuietShutdown(SSL* ctx, int mode);
+DLLEXPORT void CryptoNative_SslSetQuietShutdown(SSL* ctx, int mode);
 
 /*
 Shims the SSL_get_client_CA_list method.
 
 Returns the list of CA names explicity set.
 */
-extern "C" X509NameStack* CryptoNative_SslGetClientCAList(SSL* ssl);
+DLLEXPORT X509NameStack* CryptoNative_SslGetClientCAList(SSL* ssl);
 
 /*
 Shims the SSL_CTX_set_verify method.
 */
-extern "C" void CryptoNative_SslCtxSetVerify(SSL_CTX* ctx, SslCtxSetVerifyCallback callback);
+DLLEXPORT void CryptoNative_SslCtxSetVerify(SSL_CTX* ctx, SslCtxSetVerifyCallback callback);
 
 /*
 Shims the SSL_CTX_set_cert_verify_callback method.
 */
-extern "C" void
+DLLEXPORT void
 CryptoNative_SslCtxSetCertVerifyCallback(SSL_CTX* ctx, SslCtxSetCertVerifyCallbackCallback callback, void* arg);
 
 /*
 Sets the specified encryption policy on the SSL_CTX.
 Returns 1 if any cipher could be selected, and 0 if none were available.
 */
-extern "C" int32_t CryptoNative_SetEncryptionPolicy(SSL_CTX* ctx, EncryptionPolicy policy);
+DLLEXPORT int32_t CryptoNative_SetEncryptionPolicy(SSL_CTX* ctx, EncryptionPolicy policy);
 
 /*
 Shims the SSL_CTX_set_client_cert_cb method
 */
-extern "C" void CryptoNative_SslCtxSetClientCertCallback(SSL_CTX* ctx, SslClientCertCallback callback);
+DLLEXPORT void CryptoNative_SslCtxSetClientCertCallback(SSL_CTX* ctx, SslClientCertCallback callback);
 
 /*
 Shims the SSL_get_finished method.
 */
-extern "C" int32_t CryptoNative_SslGetFinished(SSL* ssl, void* buf, int32_t count);
+DLLEXPORT int32_t CryptoNative_SslGetFinished(SSL* ssl, void* buf, int32_t count);
 
 /*
 Shims the SSL_get_peer_finished method.
 */
-extern "C" int32_t CryptoNative_SslGetPeerFinished(SSL* ssl, void* buf, int32_t count);
+DLLEXPORT int32_t CryptoNative_SslGetPeerFinished(SSL* ssl, void* buf, int32_t count);
 
 /*
 Returns true/false based on if existing ssl session was re-used or not.
 Shims the SSL_session_reused macro.
 */
-extern "C" int32_t CryptoNative_SslSessionReused(SSL* ssl);
+DLLEXPORT int32_t CryptoNative_SslSessionReused(SSL* ssl);
 
 /*
 adds the given certificate to the extra chain certificates associated with ctx that is associated with the ssl.
@@ -367,26 +368,26 @@ adds the given certificate to the extra chain certificates associated with ctx t
 libssl frees the x509 object.
 Returns 1 if success and 0 in case of failure
 */
-extern "C" int32_t CryptoNative_SslAddExtraChainCert(SSL* ssl, X509* x509);
+DLLEXPORT int32_t CryptoNative_SslAddExtraChainCert(SSL* ssl, X509* x509);
 
 /*
 Shims the ssl_ctx_set_alpn_select_cb method.
 */
-extern "C" void CryptoNative_SslCtxSetAlpnSelectCb(SSL_CTX* ctx, SslCtxSetAlpnCallback cb, void *arg);
+DLLEXPORT void CryptoNative_SslCtxSetAlpnSelectCb(SSL_CTX* ctx, SslCtxSetAlpnCallback cb, void *arg);
 
 /*
 Shims the ssl_ctx_set_alpn_protos method.
 Returns 0 on success, non-zero on failure.
 */
-extern "C" int32_t CryptoNative_SslCtxSetAlpnProtos(SSL_CTX* ctx, const uint8_t* protos, uint32_t protos_len);
+DLLEXPORT int32_t CryptoNative_SslCtxSetAlpnProtos(SSL_CTX* ctx, const uint8_t* protos, uint32_t protos_len);
 
 /*
 Shims the ssl_get0_alpn_selected method.
 */
-extern "C" void CryptoNative_SslGet0AlpnSelected(SSL* ssl, const uint8_t** protocol, uint32_t* len);
+DLLEXPORT void CryptoNative_SslGet0AlpnSelected(SSL* ssl, const uint8_t** protocol, uint32_t* len);
 
 /*
 Shims the SSL_set_tlsext_host_name method.
 */
-extern "C" int32_t CryptoNative_SslSetTlsExtHostName(SSL* ssl, const uint8_t* name);
+DLLEXPORT int32_t CryptoNative_SslSetTlsExtHostName(SSL* ssl, uint8_t* name);
 
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.c
new file mode 100644
index 0000000000..67e2e2521e
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.c
@@ -0,0 +1,310 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_x509.h"
+
+#include <stdbool.h>
+#include <assert.h>
+
+c_static_assert(PAL_X509_V_OK == X509_V_OK);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_CRL == X509_V_ERR_UNABLE_TO_GET_CRL);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE == X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY == X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY);
+c_static_assert(PAL_X509_V_ERR_CERT_SIGNATURE_FAILURE == X509_V_ERR_CERT_SIGNATURE_FAILURE);
+c_static_assert(PAL_X509_V_ERR_CRL_SIGNATURE_FAILURE == X509_V_ERR_CRL_SIGNATURE_FAILURE);
+c_static_assert(PAL_X509_V_ERR_CERT_NOT_YET_VALID == X509_V_ERR_CERT_NOT_YET_VALID);
+c_static_assert(PAL_X509_V_ERR_CERT_HAS_EXPIRED == X509_V_ERR_CERT_HAS_EXPIRED);
+c_static_assert(PAL_X509_V_ERR_CRL_NOT_YET_VALID == X509_V_ERR_CRL_NOT_YET_VALID);
+c_static_assert(PAL_X509_V_ERR_CRL_HAS_EXPIRED == X509_V_ERR_CRL_HAS_EXPIRED);
+c_static_assert(PAL_X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD == X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD);
+c_static_assert(PAL_X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD == X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD);
+c_static_assert(PAL_X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD == X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD);
+c_static_assert(PAL_X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD == X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD);
+c_static_assert(PAL_X509_V_ERR_OUT_OF_MEM == X509_V_ERR_OUT_OF_MEM);
+c_static_assert(PAL_X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT);
+c_static_assert(PAL_X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE == X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE);
+c_static_assert(PAL_X509_V_ERR_CERT_CHAIN_TOO_LONG == X509_V_ERR_CERT_CHAIN_TOO_LONG);
+c_static_assert(PAL_X509_V_ERR_CERT_REVOKED == X509_V_ERR_CERT_REVOKED);
+c_static_assert(PAL_X509_V_ERR_INVALID_CA == X509_V_ERR_INVALID_CA);
+c_static_assert(PAL_X509_V_ERR_PATH_LENGTH_EXCEEDED == X509_V_ERR_PATH_LENGTH_EXCEEDED);
+c_static_assert(PAL_X509_V_ERR_INVALID_PURPOSE == X509_V_ERR_INVALID_PURPOSE);
+c_static_assert(PAL_X509_V_ERR_CERT_UNTRUSTED == X509_V_ERR_CERT_UNTRUSTED);
+c_static_assert(PAL_X509_V_ERR_CERT_REJECTED == X509_V_ERR_CERT_REJECTED);
+c_static_assert(PAL_X509_V_ERR_KEYUSAGE_NO_CERTSIGN == X509_V_ERR_KEYUSAGE_NO_CERTSIGN);
+c_static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER == X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER);
+c_static_assert(PAL_X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION == X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION);
+c_static_assert(PAL_X509_V_ERR_KEYUSAGE_NO_CRL_SIGN == X509_V_ERR_KEYUSAGE_NO_CRL_SIGN);
+c_static_assert(PAL_X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION == X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION);
+c_static_assert(PAL_X509_V_ERR_INVALID_NON_CA == X509_V_ERR_INVALID_NON_CA);
+c_static_assert(PAL_X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE == X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE);
+c_static_assert(PAL_X509_V_ERR_INVALID_EXTENSION == X509_V_ERR_INVALID_EXTENSION);
+c_static_assert(PAL_X509_V_ERR_INVALID_POLICY_EXTENSION == X509_V_ERR_INVALID_POLICY_EXTENSION);
+c_static_assert(PAL_X509_V_ERR_NO_EXPLICIT_POLICY == X509_V_ERR_NO_EXPLICIT_POLICY);
+
+EVP_PKEY* CryptoNative_GetX509EvpPublicKey(X509* x509)
+{
+    if (!x509)
+    {
+        return NULL;
+    }
+
+    // X509_get_X509_PUBKEY returns an interior pointer, so should not be freed
+    return X509_PUBKEY_get(X509_get_X509_PUBKEY(x509));
+}
+
+X509_CRL* CryptoNative_DecodeX509Crl(const uint8_t* buf, int32_t len)
+{
+    if (!buf || !len)
+    {
+        return NULL;
+    }
+
+    return d2i_X509_CRL(NULL, &buf, len);
+}
+
+X509* CryptoNative_DecodeX509(const uint8_t* buf, int32_t len)
+{
+    if (!buf || !len)
+    {
+        return NULL;
+    }
+
+    return d2i_X509(NULL, &buf, len);
+}
+
+int32_t CryptoNative_GetX509DerSize(X509* x)
+{
+    return i2d_X509(x, NULL);
+}
+
+int32_t CryptoNative_EncodeX509(X509* x, uint8_t* buf)
+{
+    return i2d_X509(x, &buf);
+}
+
+void CryptoNative_X509Destroy(X509* a)
+{
+    if (a != NULL)
+    {
+        X509_free(a);
+    }
+}
+
+X509* CryptoNative_X509Duplicate(X509* x509)
+{
+    return X509_dup(x509);
+}
+
+X509* CryptoNative_PemReadX509FromBio(BIO* bio)
+{
+    return PEM_read_bio_X509_AUX(bio, NULL, NULL, NULL);
+}
+
+ASN1_INTEGER* CryptoNative_X509GetSerialNumber(X509* x509)
+{
+    return X509_get_serialNumber(x509);
+}
+
+X509_NAME* CryptoNative_X509GetIssuerName(X509* x509)
+{
+    return X509_get_issuer_name(x509);
+}
+
+X509_NAME* CryptoNative_X509GetSubjectName(X509* x509)
+{
+    return X509_get_subject_name(x509);
+}
+
+int32_t CryptoNative_X509CheckPurpose(X509* x, int32_t id, int32_t ca)
+{
+    return X509_check_purpose(x, id, ca);
+}
+
+int32_t CryptoNative_X509CheckIssued(X509* issuer, X509* subject)
+{
+    return X509_check_issued(issuer, subject);
+}
+
+uint64_t CryptoNative_X509IssuerNameHash(X509* x)
+{
+    return X509_issuer_name_hash(x);
+}
+
+int32_t CryptoNative_X509GetExtCount(X509* x)
+{
+    return X509_get_ext_count(x);
+}
+
+X509_EXTENSION* CryptoNative_X509GetExt(X509* x, int32_t loc)
+{
+    return X509_get_ext(x, loc);
+}
+
+ASN1_OBJECT* CryptoNative_X509ExtensionGetOid(X509_EXTENSION* x)
+{
+    return X509_EXTENSION_get_object(x);
+}
+
+ASN1_OCTET_STRING* CryptoNative_X509ExtensionGetData(X509_EXTENSION* x)
+{
+    return X509_EXTENSION_get_data(x);
+}
+
+int32_t CryptoNative_X509ExtensionGetCritical(X509_EXTENSION* x)
+{
+    return X509_EXTENSION_get_critical(x);
+}
+
+X509_STORE* CryptoNative_X509StoreCreate()
+{
+    return X509_STORE_new();
+}
+
+void CryptoNative_X509StoreDestory(X509_STORE* v)
+{
+    if (v != NULL)
+    {
+        X509_STORE_free(v);
+    }
+}
+
+int32_t CryptoNative_X509StoreAddCert(X509_STORE* ctx, X509* x)
+{
+    return X509_STORE_add_cert(ctx, x);
+}
+
+int32_t CryptoNative_X509StoreAddCrl(X509_STORE* ctx, X509_CRL* x)
+{
+    return X509_STORE_add_crl(ctx, x);
+}
+
+int32_t CryptoNative_X509StoreSetRevocationFlag(X509_STORE* ctx, X509RevocationFlag revocationFlag)
+{
+    unsigned long verifyFlags = X509_V_FLAG_CRL_CHECK;
+
+    if (revocationFlag != EndCertificateOnly)
+    {
+        verifyFlags |= X509_V_FLAG_CRL_CHECK_ALL;
+    }
+
+    return X509_STORE_set_flags(ctx, verifyFlags);
+}
+
+X509_STORE_CTX* CryptoNative_X509StoreCtxCreate()
+{
+    return X509_STORE_CTX_new();
+}
+
+void CryptoNative_X509StoreCtxDestroy(X509_STORE_CTX* v)
+{
+    if (v != NULL)
+    {
+        X509_STORE_CTX_free(v);
+    }
+}
+
+int32_t CryptoNative_X509StoreCtxInit(X509_STORE_CTX* ctx, X509_STORE* store, X509* x509, X509Stack* extraStore)
+{
+    int32_t val = X509_STORE_CTX_init(ctx, store, x509, extraStore);
+
+    if (val != 0)
+    {
+        X509_STORE_CTX_set_flags(ctx, X509_V_FLAG_CHECK_SS_SIGNATURE);
+    }
+
+    return val;
+}
+
+int32_t CryptoNative_X509VerifyCert(X509_STORE_CTX* ctx)
+{
+    return X509_verify_cert(ctx);
+}
+
+X509Stack* CryptoNative_X509StoreCtxGetChain(X509_STORE_CTX* ctx)
+{
+    return X509_STORE_CTX_get1_chain(ctx);
+}
+
+X509Stack* CryptoNative_X509StoreCtxGetSharedUntrusted(X509_STORE_CTX* ctx)
+{
+    return ctx ? ctx->untrusted : NULL;
+}
+
+X509* CryptoNative_X509StoreCtxGetTargetCert(X509_STORE_CTX* ctx)
+{
+    return ctx ? ctx->cert : NULL;
+}
+
+X509VerifyStatusCode CryptoNative_X509StoreCtxGetError(X509_STORE_CTX* ctx)
+{
+    return (unsigned int)X509_STORE_CTX_get_error(ctx);
+}
+
+void CryptoNative_X509StoreCtxSetVerifyCallback(X509_STORE_CTX* ctx, X509StoreVerifyCallback callback)
+{
+    X509_STORE_CTX_set_verify_cb(ctx, callback);
+}
+
+int32_t CryptoNative_X509StoreCtxGetErrorDepth(X509_STORE_CTX* ctx)
+{
+    return X509_STORE_CTX_get_error_depth(ctx);
+}
+
+const char* CryptoNative_X509VerifyCertErrorString(X509VerifyStatusCode n)
+{
+    return X509_verify_cert_error_string(n);
+}
+
+void CryptoNative_X509CrlDestroy(X509_CRL* a)
+{
+    if (a != NULL)
+    {
+        X509_CRL_free(a);
+    }
+}
+
+int32_t CryptoNative_PemWriteBioX509Crl(BIO* bio, X509_CRL* crl)
+{
+    return PEM_write_bio_X509_CRL(bio, crl);
+}
+
+X509_CRL* CryptoNative_PemReadBioX509Crl(BIO* bio)
+{
+    return PEM_read_bio_X509_CRL(bio, NULL, NULL, NULL);
+}
+
+int32_t CryptoNative_GetX509SubjectPublicKeyInfoDerSize(X509* x509)
+{
+    if (!x509)
+    {
+        return 0;
+    }
+
+    // X509_get_X509_PUBKEY returns an interior pointer, so should not be freed
+    return i2d_X509_PUBKEY(X509_get_X509_PUBKEY(x509), NULL);
+}
+
+int32_t CryptoNative_EncodeX509SubjectPublicKeyInfo(X509* x509, uint8_t* buf)
+{
+    if (!x509)
+    {
+        return 0;
+    }
+
+    // X509_get_X509_PUBKEY returns an interior pointer, so should not be freed
+    return i2d_X509_PUBKEY(X509_get_X509_PUBKEY(x509), &buf);
+}
+
+X509* CryptoNative_X509UpRef(X509* x509)
+{
+    if (x509 != NULL)
+    {
+        CRYPTO_add(&x509->references, 1, CRYPTO_LOCK_X509);
+    }
+
+    return x509;
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp
deleted file mode 100644
index 3118c9aa2c..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.cpp
+++ /dev/null
@@ -1,309 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_x509.h"
-
-#include <assert.h>
-
-static_assert(PAL_X509_V_OK == X509_V_OK, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_CRL == X509_V_ERR_UNABLE_TO_GET_CRL, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE == X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY == X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY, "");
-static_assert(PAL_X509_V_ERR_CERT_SIGNATURE_FAILURE == X509_V_ERR_CERT_SIGNATURE_FAILURE, "");
-static_assert(PAL_X509_V_ERR_CRL_SIGNATURE_FAILURE == X509_V_ERR_CRL_SIGNATURE_FAILURE, "");
-static_assert(PAL_X509_V_ERR_CERT_NOT_YET_VALID == X509_V_ERR_CERT_NOT_YET_VALID, "");
-static_assert(PAL_X509_V_ERR_CERT_HAS_EXPIRED == X509_V_ERR_CERT_HAS_EXPIRED, "");
-static_assert(PAL_X509_V_ERR_CRL_NOT_YET_VALID == X509_V_ERR_CRL_NOT_YET_VALID, "");
-static_assert(PAL_X509_V_ERR_CRL_HAS_EXPIRED == X509_V_ERR_CRL_HAS_EXPIRED, "");
-static_assert(PAL_X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD == X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD, "");
-static_assert(PAL_X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD == X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD, "");
-static_assert(PAL_X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD == X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD, "");
-static_assert(PAL_X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD == X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD, "");
-static_assert(PAL_X509_V_ERR_OUT_OF_MEM == X509_V_ERR_OUT_OF_MEM, "");
-static_assert(PAL_X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT, "");
-static_assert(PAL_X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY == X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE == X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE, "");
-static_assert(PAL_X509_V_ERR_CERT_CHAIN_TOO_LONG == X509_V_ERR_CERT_CHAIN_TOO_LONG, "");
-static_assert(PAL_X509_V_ERR_CERT_REVOKED == X509_V_ERR_CERT_REVOKED, "");
-static_assert(PAL_X509_V_ERR_INVALID_CA == X509_V_ERR_INVALID_CA, "");
-static_assert(PAL_X509_V_ERR_PATH_LENGTH_EXCEEDED == X509_V_ERR_PATH_LENGTH_EXCEEDED, "");
-static_assert(PAL_X509_V_ERR_INVALID_PURPOSE == X509_V_ERR_INVALID_PURPOSE, "");
-static_assert(PAL_X509_V_ERR_CERT_UNTRUSTED == X509_V_ERR_CERT_UNTRUSTED, "");
-static_assert(PAL_X509_V_ERR_CERT_REJECTED == X509_V_ERR_CERT_REJECTED, "");
-static_assert(PAL_X509_V_ERR_KEYUSAGE_NO_CERTSIGN == X509_V_ERR_KEYUSAGE_NO_CERTSIGN, "");
-static_assert(PAL_X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER == X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER, "");
-static_assert(PAL_X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION == X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION, "");
-static_assert(PAL_X509_V_ERR_KEYUSAGE_NO_CRL_SIGN == X509_V_ERR_KEYUSAGE_NO_CRL_SIGN, "");
-static_assert(PAL_X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION == X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION, "");
-static_assert(PAL_X509_V_ERR_INVALID_NON_CA == X509_V_ERR_INVALID_NON_CA, "");
-static_assert(PAL_X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE == X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE, "");
-static_assert(PAL_X509_V_ERR_INVALID_EXTENSION == X509_V_ERR_INVALID_EXTENSION, "");
-static_assert(PAL_X509_V_ERR_INVALID_POLICY_EXTENSION == X509_V_ERR_INVALID_POLICY_EXTENSION, "");
-static_assert(PAL_X509_V_ERR_NO_EXPLICIT_POLICY == X509_V_ERR_NO_EXPLICIT_POLICY, "");
-
-extern "C" EVP_PKEY* CryptoNative_GetX509EvpPublicKey(X509* x509)
-{
-    if (!x509)
-    {
-        return nullptr;
-    }
-
-    // X509_get_X509_PUBKEY returns an interior pointer, so should not be freed
-    return X509_PUBKEY_get(X509_get_X509_PUBKEY(x509));
-}
-
-extern "C" X509_CRL* CryptoNative_DecodeX509Crl(const uint8_t* buf, int32_t len)
-{
-    if (!buf || !len)
-    {
-        return nullptr;
-    }
-
-    return d2i_X509_CRL(nullptr, &buf, len);
-}
-
-extern "C" X509* CryptoNative_DecodeX509(const uint8_t* buf, int32_t len)
-{
-    if (!buf || !len)
-    {
-        return nullptr;
-    }
-
-    return d2i_X509(nullptr, &buf, len);
-}
-
-extern "C" int32_t CryptoNative_GetX509DerSize(X509* x)
-{
-    return i2d_X509(x, nullptr);
-}
-
-extern "C" int32_t CryptoNative_EncodeX509(X509* x, uint8_t* buf)
-{
-    return i2d_X509(x, &buf);
-}
-
-extern "C" void CryptoNative_X509Destroy(X509* a)
-{
-    if (a != nullptr)
-    {
-        X509_free(a);
-    }
-}
-
-extern "C" X509* CryptoNative_X509Duplicate(X509* x509)
-{
-    return X509_dup(x509);
-}
-
-extern "C" X509* CryptoNative_PemReadX509FromBio(BIO* bio)
-{
-    return PEM_read_bio_X509_AUX(bio, nullptr, nullptr, nullptr);
-}
-
-extern "C" ASN1_INTEGER* CryptoNative_X509GetSerialNumber(X509* x509)
-{
-    return X509_get_serialNumber(x509);
-}
-
-extern "C" X509_NAME* CryptoNative_X509GetIssuerName(X509* x509)
-{
-    return X509_get_issuer_name(x509);
-}
-
-extern "C" X509_NAME* CryptoNative_X509GetSubjectName(X509* x509)
-{
-    return X509_get_subject_name(x509);
-}
-
-extern "C" int32_t CryptoNative_X509CheckPurpose(X509* x, int32_t id, int32_t ca)
-{
-    return X509_check_purpose(x, id, ca);
-}
-
-extern "C" int32_t CryptoNative_X509CheckIssued(X509* issuer, X509* subject)
-{
-    return X509_check_issued(issuer, subject);
-}
-
-extern "C" uint64_t CryptoNative_X509IssuerNameHash(X509* x)
-{
-    return X509_issuer_name_hash(x);
-}
-
-extern "C" int32_t CryptoNative_X509GetExtCount(X509* x)
-{
-    return X509_get_ext_count(x);
-}
-
-extern "C" X509_EXTENSION* CryptoNative_X509GetExt(X509* x, int32_t loc)
-{
-    return X509_get_ext(x, loc);
-}
-
-extern "C" ASN1_OBJECT* CryptoNative_X509ExtensionGetOid(X509_EXTENSION* x)
-{
-    return X509_EXTENSION_get_object(x);
-}
-
-extern "C" ASN1_OCTET_STRING* CryptoNative_X509ExtensionGetData(X509_EXTENSION* x)
-{
-    return X509_EXTENSION_get_data(x);
-}
-
-extern "C" int32_t CryptoNative_X509ExtensionGetCritical(X509_EXTENSION* x)
-{
-    return X509_EXTENSION_get_critical(x);
-}
-
-extern "C" X509_STORE* CryptoNative_X509StoreCreate()
-{
-    return X509_STORE_new();
-}
-
-extern "C" void CryptoNative_X509StoreDestory(X509_STORE* v)
-{
-    if (v != nullptr)
-    {
-        X509_STORE_free(v);
-    }
-}
-
-extern "C" int32_t CryptoNative_X509StoreAddCert(X509_STORE* ctx, X509* x)
-{
-    return X509_STORE_add_cert(ctx, x);
-}
-
-extern "C" int32_t CryptoNative_X509StoreAddCrl(X509_STORE* ctx, X509_CRL* x)
-{
-    return X509_STORE_add_crl(ctx, x);
-}
-
-extern "C" int32_t CryptoNative_X509StoreSetRevocationFlag(X509_STORE* ctx, X509RevocationFlag revocationFlag)
-{
-    unsigned long verifyFlags = X509_V_FLAG_CRL_CHECK;
-
-    if (revocationFlag != X509RevocationFlag::EndCertificateOnly)
-    {
-        verifyFlags |= X509_V_FLAG_CRL_CHECK_ALL;
-    }
-
-    return X509_STORE_set_flags(ctx, verifyFlags);
-}
-
-extern "C" X509_STORE_CTX* CryptoNative_X509StoreCtxCreate()
-{
-    return X509_STORE_CTX_new();
-}
-
-extern "C" void CryptoNative_X509StoreCtxDestroy(X509_STORE_CTX* v)
-{
-    if (v != nullptr)
-    {
-        X509_STORE_CTX_free(v);
-    }
-}
-
-extern "C" int32_t CryptoNative_X509StoreCtxInit(X509_STORE_CTX* ctx, X509_STORE* store, X509* x509, X509Stack* extraStore)
-{
-    int32_t val = X509_STORE_CTX_init(ctx, store, x509, extraStore);
-
-    if (val != 0)
-    {
-        X509_STORE_CTX_set_flags(ctx, X509_V_FLAG_CHECK_SS_SIGNATURE);
-    }
-
-    return val;
-}
-
-extern "C" int32_t CryptoNative_X509VerifyCert(X509_STORE_CTX* ctx)
-{
-    return X509_verify_cert(ctx);
-}
-
-extern "C" X509Stack* CryptoNative_X509StoreCtxGetChain(X509_STORE_CTX* ctx)
-{
-    return X509_STORE_CTX_get1_chain(ctx);
-}
-
-extern "C" X509Stack* CryptoNative_X509StoreCtxGetSharedUntrusted(X509_STORE_CTX* ctx)
-{
-    return ctx ? ctx->untrusted : nullptr;
-}
-
-extern "C" X509* CryptoNative_X509StoreCtxGetTargetCert(X509_STORE_CTX* ctx)
-{
-    return ctx ? ctx->cert : nullptr;
-}
-
-extern "C" X509VerifyStatusCode CryptoNative_X509StoreCtxGetError(X509_STORE_CTX* ctx)
-{
-    return static_cast<X509VerifyStatusCode>(X509_STORE_CTX_get_error(ctx));
-}
-
-extern "C" void CryptoNative_X509StoreCtxSetVerifyCallback(X509_STORE_CTX* ctx, X509StoreVerifyCallback callback)
-{
-    X509_STORE_CTX_set_verify_cb(ctx, callback);
-}
-
-extern "C" int32_t CryptoNative_X509StoreCtxGetErrorDepth(X509_STORE_CTX* ctx)
-{
-    return X509_STORE_CTX_get_error_depth(ctx);
-}
-
-extern "C" const char* CryptoNative_X509VerifyCertErrorString(X509VerifyStatusCode n)
-{
-    return X509_verify_cert_error_string(n);
-}
-
-extern "C" void CryptoNative_X509CrlDestroy(X509_CRL* a)
-{
-    if (a != nullptr)
-    {
-        X509_CRL_free(a);
-    }
-}
-
-extern "C" int32_t CryptoNative_PemWriteBioX509Crl(BIO* bio, X509_CRL* crl)
-{
-    return PEM_write_bio_X509_CRL(bio, crl);
-}
-
-extern "C" X509_CRL* CryptoNative_PemReadBioX509Crl(BIO* bio)
-{
-    return PEM_read_bio_X509_CRL(bio, nullptr, nullptr, nullptr);
-}
-
-extern "C" int32_t CryptoNative_GetX509SubjectPublicKeyInfoDerSize(X509* x509)
-{
-    if (!x509)
-    {
-        return 0;
-    }
-
-    // X509_get_X509_PUBKEY returns an interior pointer, so should not be freed
-    return i2d_X509_PUBKEY(X509_get_X509_PUBKEY(x509), nullptr);
-}
-
-extern "C" int32_t CryptoNative_EncodeX509SubjectPublicKeyInfo(X509* x509, uint8_t* buf)
-{
-    if (!x509)
-    {
-        return 0;
-    }
-
-    // X509_get_X509_PUBKEY returns an interior pointer, so should not be freed
-    return i2d_X509_PUBKEY(X509_get_X509_PUBKEY(x509), &buf);
-}
-
-extern "C" X509* CryptoNative_X509UpRef(X509* x509)
-{
-    if (x509 != nullptr)
-    {
-        CRYPTO_add(&x509->references, 1, CRYPTO_LOCK_X509);
-    }
-
-    return x509;
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.h
index d182de6569..79a03da7d3 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509.h
@@ -3,24 +3,25 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_crypto_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
 These values should be kept in sync with System.Security.Cryptography.X509Certificates.X509RevocationFlag.
 */
-enum X509RevocationFlag : int32_t
+typedef enum
 {
     EndCertificateOnly = 0,
     EntireChain = 1,
     ExcludeRoot = 2,
-};
+} X509RevocationFlag;
 
 /*
 The error codes used when verifying X509 certificate chains.
 
 These values should be kept in sync with Interop.Crypto.X509VerifyStatusCode.
 */
-enum X509VerifyStatusCode : int32_t
+typedef enum
 {
     PAL_X509_V_OK = 0,
     PAL_X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT = 2,
@@ -59,7 +60,7 @@ enum X509VerifyStatusCode : int32_t
     PAL_X509_V_ERR_INVALID_EXTENSION = 41,
     PAL_X509_V_ERR_INVALID_POLICY_EXTENSION = 42,
     PAL_X509_V_ERR_NO_EXPLICIT_POLICY = 43,
-};
+} X509VerifyStatusCode;
 
 typedef int32_t (*X509StoreVerifyCallback)(int32_t, X509_STORE_CTX*);
 
@@ -69,30 +70,30 @@ GetX509EvpPublicKey
 
 Returns a EVP_PKEY* equivalent to the public key of the certificate.
 */
-extern "C" EVP_PKEY* CryptoNative_GetX509EvpPublicKey(X509* x509);
+DLLEXPORT EVP_PKEY* CryptoNative_GetX509EvpPublicKey(X509* x509);
 
 /*
 Shims the d2i_X509_CRL method and makes it easier to invoke from managed code.
 */
-extern "C" X509_CRL* CryptoNative_DecodeX509Crl(const uint8_t* buf, int32_t len);
+DLLEXPORT X509_CRL* CryptoNative_DecodeX509Crl(const uint8_t* buf, int32_t len);
 
 /*
 Shims the d2i_X509 method and makes it easier to invoke from managed code.
 */
-extern "C" X509* CryptoNative_DecodeX509(const uint8_t* buf, int32_t len);
+DLLEXPORT X509* CryptoNative_DecodeX509(const uint8_t* buf, int32_t len);
 
 /*
 Returns the number of bytes it will take to convert
 the X509 to a DER format.
 */
-extern "C" int32_t CryptoNative_GetX509DerSize(X509* x);
+DLLEXPORT int32_t CryptoNative_GetX509DerSize(X509* x);
 
 /*
 Shims the i2d_X509 method.
 
 Returns the number of bytes written to buf.
 */
-extern "C" int32_t CryptoNative_EncodeX509(X509* x, uint8_t* buf);
+DLLEXPORT int32_t CryptoNative_EncodeX509(X509* x, uint8_t* buf);
 
 /*
 Cleans up and deletes an X509 instance.
@@ -103,196 +104,196 @@ No-op if a is null.
 The given X509 pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_X509Destroy(X509* a);
+DLLEXPORT void CryptoNative_X509Destroy(X509* a);
 
 /*
 Shims the X509_dup method.
 
 Returns the duplicated X509 instance.
 */
-extern "C" X509* CryptoNative_X509Duplicate(X509* x509);
+DLLEXPORT X509* CryptoNative_X509Duplicate(X509* x509);
 
 /*
 Shims the PEM_read_bio_X509_AUX method.
 
 Returns the read X509 instance.
 */
-extern "C" X509* CryptoNative_PemReadX509FromBio(BIO* bio);
+DLLEXPORT X509* CryptoNative_PemReadX509FromBio(BIO* bio);
 
 /*
 Shims the X509_get_serialNumber method.
 
 Returns the ASN1_INTEGER for the serial number.
 */
-extern "C" ASN1_INTEGER* CryptoNative_X509GetSerialNumber(X509* x509);
+DLLEXPORT ASN1_INTEGER* CryptoNative_X509GetSerialNumber(X509* x509);
 
 /*
 Shims the X509_get_issuer_name method.
 
 Returns the ASN1_INTEGER for the issuer name.
 */
-extern "C" X509_NAME* CryptoNative_X509GetIssuerName(X509* x509);
+DLLEXPORT X509_NAME* CryptoNative_X509GetIssuerName(X509* x509);
 
 /*
 Shims the X509_get_subject_name method.
 
 Returns the X509_NAME for the subject name.
 */
-extern "C" X509_NAME* CryptoNative_X509GetSubjectName(X509* x509);
+DLLEXPORT X509_NAME* CryptoNative_X509GetSubjectName(X509* x509);
 
 /*
 Shims the X509_check_purpose method.
 */
-extern "C" int32_t CryptoNative_X509CheckPurpose(X509* x, int32_t id, int32_t ca);
+DLLEXPORT int32_t CryptoNative_X509CheckPurpose(X509* x, int32_t id, int32_t ca);
 
 /*
 Shims the X509_check_issued method.
 */
-extern "C" int32_t CryptoNative_X509CheckIssued(X509* issuer, X509* subject);
+DLLEXPORT int32_t CryptoNative_X509CheckIssued(X509* issuer, X509* subject);
 
 /*
 Shims the X509_issuer_name_hash method.
 */
-extern "C" uint64_t CryptoNative_X509IssuerNameHash(X509* x);
+DLLEXPORT uint64_t CryptoNative_X509IssuerNameHash(X509* x);
 
 /*
 Shims the X509_get_ext_count method.
 */
-extern "C" int32_t CryptoNative_X509GetExtCount(X509* x);
+DLLEXPORT int32_t CryptoNative_X509GetExtCount(X509* x);
 
 /*
 Shims the X509_get_ext method.
 */
-extern "C" X509_EXTENSION* CryptoNative_X509GetExt(X509* x, int32_t loc);
+DLLEXPORT X509_EXTENSION* CryptoNative_X509GetExt(X509* x, int32_t loc);
 
 /*
 Shims the X509_EXTENSION_get_object method.
 */
-extern "C" ASN1_OBJECT* CryptoNative_X509ExtensionGetOid(X509_EXTENSION* x);
+DLLEXPORT ASN1_OBJECT* CryptoNative_X509ExtensionGetOid(X509_EXTENSION* x);
 
 /*
 Shims the X509_EXTENSION_get_data method.
 */
-extern "C" ASN1_OCTET_STRING* CryptoNative_X509ExtensionGetData(X509_EXTENSION* x);
+DLLEXPORT ASN1_OCTET_STRING* CryptoNative_X509ExtensionGetData(X509_EXTENSION* x);
 
 /*
 Shims the X509_EXTENSION_get_critical method.
 */
-extern "C" int32_t CryptoNative_X509ExtensionGetCritical(X509_EXTENSION* x);
+DLLEXPORT int32_t CryptoNative_X509ExtensionGetCritical(X509_EXTENSION* x);
 
 /*
 Shims the X509_STORE_new method.
 */
-extern "C" X509_STORE* CryptoNative_X509StoreCreate();
+DLLEXPORT X509_STORE* CryptoNative_X509StoreCreate(void);
 
 /*
 Shims the X509_STORE_free method.
 */
-extern "C" void CryptoNative_X509StoreDestory(X509_STORE* v);
+DLLEXPORT void CryptoNative_X509StoreDestory(X509_STORE* v);
 
 /*
 Shims the X509_STORE_add_cert method.
 */
-extern "C" int32_t CryptoNative_X509StoreAddCert(X509_STORE* ctx, X509* x);
+DLLEXPORT int32_t CryptoNative_X509StoreAddCert(X509_STORE* ctx, X509* x);
 
 /*
 Shims the X509_STORE_add_crl method.
 */
-extern "C" int32_t CryptoNative_X509StoreAddCrl(X509_STORE* ctx, X509_CRL* x);
+DLLEXPORT int32_t CryptoNative_X509StoreAddCrl(X509_STORE* ctx, X509_CRL* x);
 
 /*
 Sets the correct flags on the X509_STORE for the specified X509RevocationFlag.
 
 Shims the X509_STORE_set_flags method.
 */
-extern "C" int32_t CryptoNative_X509StoreSetRevocationFlag(X509_STORE* ctx, X509RevocationFlag revocationFlag);
+DLLEXPORT int32_t CryptoNative_X509StoreSetRevocationFlag(X509_STORE* ctx, X509RevocationFlag revocationFlag);
 
 /*
 Shims the X509_STORE_CTX_new method.
 */
-extern "C" X509_STORE_CTX* CryptoNative_X509StoreCtxCreate();
+DLLEXPORT X509_STORE_CTX* CryptoNative_X509StoreCtxCreate(void);
 
 /*
 Shims the X509_STORE_CTX_free method.
 */
-extern "C" void CryptoNative_X509StoreCtxDestroy(X509_STORE_CTX* v);
+DLLEXPORT void CryptoNative_X509StoreCtxDestroy(X509_STORE_CTX* v);
 
 /*
 Shims the X509_STORE_CTX_init method.
 */
-extern "C" int32_t CryptoNative_X509StoreCtxInit(X509_STORE_CTX* ctx, X509_STORE* store, X509* x509, X509Stack* extraStore);
+DLLEXPORT int32_t CryptoNative_X509StoreCtxInit(X509_STORE_CTX* ctx, X509_STORE* store, X509* x509, X509Stack* extraStore);
 
 /*
 Shims the X509_verify_cert method.
 */
-extern "C" int32_t CryptoNative_X509VerifyCert(X509_STORE_CTX* ctx);
+DLLEXPORT int32_t CryptoNative_X509VerifyCert(X509_STORE_CTX* ctx);
 
 /*
 Shims the X509_STORE_CTX_get1_chain method.
 */
-extern "C" X509Stack* CryptoNative_X509StoreCtxGetChain(X509_STORE_CTX* ctx);
+DLLEXPORT X509Stack* CryptoNative_X509StoreCtxGetChain(X509_STORE_CTX* ctx);
 
 /*
 Returns the interior pointer to the "untrusted" certificates collection for this X509_STORE_CTX
 */
-extern "C" X509Stack* CryptoNative_X509StoreCtxGetSharedUntrusted(X509_STORE_CTX* ctx);
+DLLEXPORT X509Stack* CryptoNative_X509StoreCtxGetSharedUntrusted(X509_STORE_CTX* ctx);
 
 /*
 Returns the interior pointer to the target certificate for an X509 certificate chain
 */
-extern "C" X509* CryptoNative_X509StoreCtxGetTargetCert(X509_STORE_CTX* ctx);
+DLLEXPORT X509* CryptoNative_X509StoreCtxGetTargetCert(X509_STORE_CTX* ctx);
 
 /*
 Shims the X509_STORE_CTX_get_error method.
 */
-extern "C" X509VerifyStatusCode CryptoNative_X509StoreCtxGetError(X509_STORE_CTX* ctx);
+DLLEXPORT X509VerifyStatusCode CryptoNative_X509StoreCtxGetError(X509_STORE_CTX* ctx);
 
 /*
 Shims the X509_STORE_CTX_get_error_depth method.
 */
-extern "C" int32_t CryptoNative_X509StoreCtxGetErrorDepth(X509_STORE_CTX* ctx);
+DLLEXPORT int32_t CryptoNative_X509StoreCtxGetErrorDepth(X509_STORE_CTX* ctx);
 
 /*
 Shims the X509_STORE_CTX_set_verify_cb function.
 */
-extern "C" void CryptoNative_X509StoreCtxSetVerifyCallback(X509_STORE_CTX* ctx, X509StoreVerifyCallback callback);
+DLLEXPORT void CryptoNative_X509StoreCtxSetVerifyCallback(X509_STORE_CTX* ctx, X509StoreVerifyCallback callback);
 
 /*
 Shims the X509_verify_cert_error_string method.
 */
-extern "C" const char* CryptoNative_X509VerifyCertErrorString(X509VerifyStatusCode n);
+DLLEXPORT const char* CryptoNative_X509VerifyCertErrorString(X509VerifyStatusCode n);
 
 /*
 Shims the X509_CRL_free method.
 */
-extern "C" void CryptoNative_X509CrlDestroy(X509_CRL* a);
+DLLEXPORT void CryptoNative_X509CrlDestroy(X509_CRL* a);
 
 /*
 Shims the PEM_write_bio_X509_CRL method.
 
 Returns the number of bytes written.
 */
-extern "C" int32_t CryptoNative_PemWriteBioX509Crl(BIO* bio, X509_CRL* crl);
+DLLEXPORT int32_t CryptoNative_PemWriteBioX509Crl(BIO* bio, X509_CRL* crl);
 
 /*
 Shims the PEM_read_bio_X509_CRL method.
 
 The new X509_CRL instance.
 */
-extern "C" X509_CRL* CryptoNative_PemReadBioX509Crl(BIO* bio);
+DLLEXPORT X509_CRL* CryptoNative_PemReadBioX509Crl(BIO* bio);
 
 /*
 Returns the number of bytes it will take to convert the SubjectPublicKeyInfo
 portion of the X509 to DER format.
 */
-extern "C" int32_t CryptoNative_GetX509SubjectPublicKeyInfoDerSize(X509* x);
+DLLEXPORT int32_t CryptoNative_GetX509SubjectPublicKeyInfoDerSize(X509* x);
 
 /*
 Shims the i2d_X509_PUBKEY method, providing X509_get_X509_PUBKEY(x) as the input.
 
 Returns the number of bytes written to buf.
 */
-extern "C" int32_t CryptoNative_EncodeX509SubjectPublicKeyInfo(X509* x, uint8_t* buf);
+DLLEXPORT int32_t CryptoNative_EncodeX509SubjectPublicKeyInfo(X509* x, uint8_t* buf);
 
 /*
 Increases the reference count of the X509*, thereby increasing the number of calls
@@ -302,4 +303,4 @@ Unlike X509Duplicate, this modifies an existing object, so no new memory is allo
 
 Returns the input value.
 */
-extern "C" X509* CryptoNative_X509UpRef(X509* x509);
+DLLEXPORT X509* CryptoNative_X509UpRef(X509* x509);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.c b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.c
new file mode 100644
index 0000000000..ee77a5df03
--- /dev/null
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.c
@@ -0,0 +1,73 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include "pal_x509_name.h"
+
+int32_t CryptoNative_GetX509NameStackFieldCount(X509NameStack* sk)
+{
+    return sk_X509_NAME_num(sk);
+}
+
+X509_NAME* CryptoNative_GetX509NameStackField(X509NameStack* sk, int32_t loc)
+{
+    return sk_X509_NAME_value(sk, loc);
+}
+
+X509_NAME* CryptoNative_DecodeX509Name(const uint8_t* buf, int32_t len)
+{
+    if (!buf || !len)
+    {
+        return NULL;
+    }
+
+    return d2i_X509_NAME(NULL, &buf, len);
+}
+
+void CryptoNative_X509NameDestroy(X509_NAME* a)
+{
+    if (a != NULL)
+    {
+        X509_NAME_free(a);
+    }
+}
+
+STACK_OF(X509_NAME) * CryptoNative_NewX509NameStack()
+{
+    return sk_X509_NAME_new_null();
+}
+
+int32_t CryptoNative_PushX509NameStackField(STACK_OF(X509_NAME) * stack, X509_NAME* x509Name)
+{
+    if (!stack)
+    {
+        return 0;
+    }
+
+    return sk_X509_NAME_push(stack, x509Name);
+}
+
+void CryptoNative_RecursiveFreeX509NameStack(STACK_OF(X509_NAME) * stack)
+{
+    sk_X509_NAME_pop_free(stack, X509_NAME_free);
+}
+
+int32_t CryptoNative_GetX509NameEntryCount(X509_NAME* x509Name)
+{
+    return X509_NAME_entry_count(x509Name);
+}
+
+X509_NAME_ENTRY* CryptoNative_GetX509NameEntry(X509_NAME* x509Name, int32_t loc)
+{
+    return X509_NAME_get_entry(x509Name, loc);
+}
+
+ASN1_OBJECT* CryptoNative_GetX509NameEntryOid(X509_NAME_ENTRY* nameEntry)
+{
+    return X509_NAME_ENTRY_get_object(nameEntry);
+}
+
+ASN1_STRING* CryptoNative_GetX509NameEntryData(X509_NAME_ENTRY* nameEntry)
+{
+    return X509_NAME_ENTRY_get_data(nameEntry);
+}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.cpp
deleted file mode 100644
index 2195b74906..0000000000
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.cpp
+++ /dev/null
@@ -1,73 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-#include "pal_x509_name.h"
-
-extern "C" int32_t CryptoNative_GetX509NameStackFieldCount(X509NameStack* sk)
-{
-    return sk_X509_NAME_num(sk);
-}
-
-extern "C" X509_NAME* CryptoNative_GetX509NameStackField(X509NameStack* sk, int32_t loc)
-{
-    return sk_X509_NAME_value(sk, loc);
-}
-
-extern "C" X509_NAME* CryptoNative_DecodeX509Name(const uint8_t* buf, int32_t len)
-{
-    if (!buf || !len)
-    {
-        return nullptr;
-    }
-
-    return d2i_X509_NAME(nullptr, &buf, len);
-}
-
-extern "C" void CryptoNative_X509NameDestroy(X509_NAME* a)
-{
-    if (a != nullptr)
-    {
-        X509_NAME_free(a);
-    }
-}
-
-extern "C" STACK_OF(X509_NAME) * CryptoNative_NewX509NameStack()
-{
-    return sk_X509_NAME_new_null();
-}
-
-extern "C" int32_t CryptoNative_PushX509NameStackField(STACK_OF(X509_NAME) * stack, X509_NAME* x509Name)
-{
-    if (!stack)
-    {
-        return 0;
-    }
-
-    return sk_X509_NAME_push(stack, x509Name);
-}
-
-extern "C" void CryptoNative_RecursiveFreeX509NameStack(STACK_OF(X509_NAME) * stack)
-{
-    sk_X509_NAME_pop_free(stack, X509_NAME_free);
-}
-
-extern "C" int32_t CryptoNative_GetX509NameEntryCount(X509_NAME* x509Name)
-{
-    return X509_NAME_entry_count(x509Name);
-}
-
-extern "C" X509_NAME_ENTRY* CryptoNative_GetX509NameEntry(X509_NAME* x509Name, int32_t loc)
-{
-    return X509_NAME_get_entry(x509Name, loc);
-}
-
-extern "C" ASN1_OBJECT* CryptoNative_GetX509NameEntryOid(X509_NAME_ENTRY* nameEntry)
-{
-    return X509_NAME_ENTRY_get_object(nameEntry);
-}
-
-extern "C" ASN1_STRING* CryptoNative_GetX509NameEntryData(X509_NAME_ENTRY* nameEntry)
-{
-    return X509_NAME_ENTRY_get_data(nameEntry);
-}
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.h
index 76a77ccc1f..52231e85fb 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_name.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_crypto_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -11,17 +12,17 @@ GetX509NameStackFieldCount
 
 Direct shim to sk_X509_NAME_num
 */
-extern "C" int32_t CryptoNative_GetX509NameStackFieldCount(X509NameStack* sk);
+DLLEXPORT int32_t CryptoNative_GetX509NameStackFieldCount(X509NameStack* sk);
 
 /*
 Direct shim to sk_X509_NAME_value
 */
-extern "C" X509_NAME* CryptoNative_GetX509NameStackField(X509NameStack* sk, int32_t loc);
+DLLEXPORT X509_NAME* CryptoNative_GetX509NameStackField(X509NameStack* sk, int32_t loc);
 
 /*
 Shims the d2i_X509_NAME method and makes it easier to invoke from managed code.
 */
-extern "C" X509_NAME* CryptoNative_DecodeX509Name(const uint8_t* buf, int32_t len);
+DLLEXPORT X509_NAME* CryptoNative_DecodeX509Name(const uint8_t* buf, int32_t len);
 
 /*
 Cleans up and deletes an X509_NAME instance.
@@ -32,7 +33,7 @@ No-op if a is null.
 The given X509_NAME pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_X509NameDestroy(X509_NAME* a);
+DLLEXPORT void CryptoNative_X509NameDestroy(X509_NAME* a);
 
 /*
 Function:
@@ -40,7 +41,7 @@ NewX509NameStack
 
 Direct shim to sk_X509_NAME_new_null
 */
-extern "C" STACK_OF(X509_NAME) * CryptoNative_NewX509NameStack();
+DLLEXPORT STACK_OF(X509_NAME) * CryptoNative_NewX509NameStack(void);
 
 /*
 Function:
@@ -51,7 +52,7 @@ Return values:
 1 on success
 0 on a NULL stack, or an error within sk_X509_NAME_push
 */
-extern "C" int32_t CryptoNative_PushX509NameStackField(STACK_OF(X509_NAME) * stack, X509_NAME* x509Name);
+DLLEXPORT int32_t CryptoNative_PushX509NameStackField(STACK_OF(X509_NAME) * stack, X509_NAME* x509Name);
 
 /*
 Function:
@@ -59,24 +60,24 @@ RecursiveFreeX509NameStack
 
 Direct shim to sk_X509_NAME_pop_free
 */
-extern "C" void CryptoNative_RecursiveFreeX509NameStack(STACK_OF(X509_NAME) * stack);
+DLLEXPORT void CryptoNative_RecursiveFreeX509NameStack(STACK_OF(X509_NAME) * stack);
 
 /*
 Direct shim to X509_NAME_entry_count
 */
-extern "C" int32_t CryptoNative_GetX509NameEntryCount(X509_NAME* x509Name);
+DLLEXPORT int32_t CryptoNative_GetX509NameEntryCount(X509_NAME* x509Name);
 
 /*
 Direct shim to X509_NAME_get_entry
 */
-extern "C" X509_NAME_ENTRY* CryptoNative_GetX509NameEntry(X509_NAME* x509Name, int32_t loc);
+DLLEXPORT X509_NAME_ENTRY* CryptoNative_GetX509NameEntry(X509_NAME* x509Name, int32_t loc);
 
 /*
 Direct shim to X509_NAME_ENTRY_get_object
 */
-extern "C" ASN1_OBJECT* CryptoNative_GetX509NameEntryOid(X509_NAME_ENTRY* nameEntry);
+DLLEXPORT ASN1_OBJECT* CryptoNative_GetX509NameEntryOid(X509_NAME_ENTRY* nameEntry);
 
 /*
 Direct shim to X509_NAME_ENTRY_get_data
 */
-extern "C" ASN1_STRING* CryptoNative_GetX509NameEntryData(X509_NAME_ENTRY* nameEntry);
+DLLEXPORT ASN1_STRING* CryptoNative_GetX509NameEntryData(X509_NAME_ENTRY* nameEntry);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.c
index 2132a81836..1054caec69 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.c
@@ -6,7 +6,7 @@
 
 #include <assert.h>
 
-extern "C" const char* CryptoNative_GetX509RootStorePath()
+const char* CryptoNative_GetX509RootStorePath()
 {
     const char* dir = getenv(X509_get_default_cert_dir_env());
 
@@ -18,7 +18,7 @@ extern "C" const char* CryptoNative_GetX509RootStorePath()
     return dir;
 }
 
-extern "C" const char* CryptoNative_GetX509RootStoreFile()
+const char* CryptoNative_GetX509RootStoreFile()
 {
     const char* file = getenv(X509_get_default_cert_file_env());
 
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.h
index ef7ce5262b..f259a505fa 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509_root.h
@@ -2,17 +2,18 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
 Look up the directory in which all certificate files therein are considered
 trusted (root or trusted intermediate).
 */
-extern "C" const char* CryptoNative_GetX509RootStorePath();
+DLLEXPORT const char* CryptoNative_GetX509RootStorePath(void);
 
 /*
 Look up the file in which all certificates are considered trusted
 (root or trusted intermediate), in addition to those files in
 the root store path.
 */
-extern "C" const char* CryptoNative_GetX509RootStoreFile();
+DLLEXPORT const char* CryptoNative_GetX509RootStoreFile(void);
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.cpp b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.c
index 415602e013..9346952dcd 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.cpp
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.c
@@ -4,28 +4,29 @@
 
 #include "pal_x509ext.h"
 
+#include <stdbool.h>
 #include <assert.h>
 
-extern "C" X509_EXTENSION*
+X509_EXTENSION*
 CryptoNative_X509ExtensionCreateByObj(ASN1_OBJECT* obj, int32_t isCritical, ASN1_OCTET_STRING* data)
 {
-    return X509_EXTENSION_create_by_OBJ(nullptr, obj, isCritical, data);
+    return X509_EXTENSION_create_by_OBJ(NULL, obj, isCritical, data);
 }
 
-extern "C" void CryptoNative_X509ExtensionDestroy(X509_EXTENSION* a)
+void CryptoNative_X509ExtensionDestroy(X509_EXTENSION* a)
 {
-    if (a != nullptr)
+    if (a != NULL)
     {
         X509_EXTENSION_free(a);
     }
 }
 
-extern "C" int32_t CryptoNative_X509V3ExtPrint(BIO* out, X509_EXTENSION* ext)
+int32_t CryptoNative_X509V3ExtPrint(BIO* out, X509_EXTENSION* ext)
 {
     return X509V3_EXT_print(out, ext, X509V3_EXT_DEFAULT, /*indent*/ 0);
 }
 
-extern "C" int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8_t* encoded,
+int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8_t* encoded,
                                                                      int32_t encodedLength,
                                                                      int32_t* certificateAuthority,
                                                                      int32_t* hasPathLengthConstraint,
@@ -41,19 +42,19 @@ extern "C" int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8
     *pathLengthConstraint = 0;
     int32_t result = false;
 
-    BASIC_CONSTRAINTS* constraints = d2i_BASIC_CONSTRAINTS(nullptr, &encoded, encodedLength);
+    BASIC_CONSTRAINTS* constraints = d2i_BASIC_CONSTRAINTS(NULL, &encoded, encodedLength);
     if (constraints)
     {
         *certificateAuthority = constraints->ca != 0;
 
-        if (constraints->pathlen != nullptr)
+        if (constraints->pathlen != NULL)
         {
             *hasPathLengthConstraint = true;
             long pathLength = ASN1_INTEGER_get(constraints->pathlen);
 
             // pathLengthConstraint needs to be in the Int32 range
             assert(pathLength <= INT32_MAX);
-            *pathLengthConstraint = static_cast<int32_t>(pathLength);
+            *pathLengthConstraint = (int32_t)pathLength;
         }
         else
         {
@@ -68,19 +69,19 @@ extern "C" int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8
     return result;
 }
 
-extern "C" EXTENDED_KEY_USAGE* CryptoNative_DecodeExtendedKeyUsage(const uint8_t* buf, int32_t len)
+EXTENDED_KEY_USAGE* CryptoNative_DecodeExtendedKeyUsage(const uint8_t* buf, int32_t len)
 {
     if (!buf || !len)
     {
-        return nullptr;
+        return NULL;
     }
 
-    return d2i_EXTENDED_KEY_USAGE(nullptr, &buf, len);
+    return d2i_EXTENDED_KEY_USAGE(NULL, &buf, len);
 }
 
-extern "C" void CryptoNative_ExtendedKeyUsageDestory(EXTENDED_KEY_USAGE* a)
+void CryptoNative_ExtendedKeyUsageDestory(EXTENDED_KEY_USAGE* a)
 {
-    if (a != nullptr)
+    if (a != NULL)
     {
         EXTENDED_KEY_USAGE_free(a);
     }
diff --git a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.h b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.h
index c68d96650c..166f84d5c0 100644
--- a/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.h
+++ b/src/Native/Unix/System.Security.Cryptography.Native/pal_x509ext.h
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 #include "pal_types.h"
+#include "pal_compiler.h"
 #include "opensslshim.h"
 
 /*
@@ -12,7 +13,7 @@ Implemented by calling X509_EXTENSION_create_by_OBJ
 
 Returns new X509_EXTENSION on success, nullptr on failure.
 */
-extern "C" X509_EXTENSION*
+DLLEXPORT X509_EXTENSION*
 CryptoNative_X509ExtensionCreateByObj(ASN1_OBJECT* obj, int32_t isCritical, ASN1_OCTET_STRING* data);
 
 /*
@@ -24,14 +25,14 @@ No-op if a is null.
 The given X509_EXTENSION pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_X509ExtensionDestroy(X509_EXTENSION* a);
+DLLEXPORT void CryptoNative_X509ExtensionDestroy(X509_EXTENSION* a);
 
 /*
 Shims the X509V3_EXT_print method.
 
 Returns 1 on success, otherwise 0 if there was an error.
 */
-extern "C" int32_t CryptoNative_X509V3ExtPrint(BIO* out, X509_EXTENSION* ext);
+DLLEXPORT int32_t CryptoNative_X509V3ExtPrint(BIO* out, X509_EXTENSION* ext);
 
 /*
 Decodes the X509 BASIC_CONSTRAINTS information and fills the out variables:
@@ -42,7 +43,7 @@ Decodes the X509 BASIC_CONSTRAINTS information and fills the out variables:
 Returns 1 if the BASIC_CONSTRAINTS information was successfully decoded,
 otherwise 0.
 */
-extern "C" int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8_t* encoded,
+DLLEXPORT int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8_t* encoded,
                                                                      int32_t encodedLength,
                                                                      int32_t* certificateAuthority,
                                                                      int32_t* hasPathLengthConstraint,
@@ -51,7 +52,7 @@ extern "C" int32_t CryptoNative_DecodeX509BasicConstraints2Extension(const uint8
 /*
 Shims the d2i_EXTENDED_KEY_USAGE method and makes it easier to invoke from managed code.
 */
-extern "C" EXTENDED_KEY_USAGE* CryptoNative_DecodeExtendedKeyUsage(const uint8_t* buf, int32_t len);
+DLLEXPORT EXTENDED_KEY_USAGE* CryptoNative_DecodeExtendedKeyUsage(const uint8_t* buf, int32_t len);
 
 /*
 Cleans up and deletes an EXTENDED_KEY_USAGE instance.
@@ -62,4 +63,4 @@ No-op if a is null.
 The given EXTENDED_KEY_USAGE pointer is invalid after this call.
 Always succeeds.
 */
-extern "C" void CryptoNative_ExtendedKeyUsageDestory(EXTENDED_KEY_USAGE* a);
+DLLEXPORT void CryptoNative_ExtendedKeyUsageDestory(EXTENDED_KEY_USAGE* a);