Implement rand_altern.c using gcrypt.

1 files changed, 22 insertions, 4 deletions

diff --git a/crypto/rand_altern.c b/crypto/rand_altern.c
index f5b015e..477fa6b 100644
--- a/crypto/rand_altern.c
+++ b/crypto/rand_altern.c
@@ -22,12 +22,30 @@
 
 #ifdef TGL_AVOID_OPENSSL_RAND
 
-// #include <gcrypt/rand.h>
-// Or similar
+/* Marginally speed up compilation */
+#define GCRYPT_NO_MPI_MACROS
+/* Fail-fast when something becomes deprecated. */
+#define GCRYPT_NO_DEPRECATED
+
+#include <assert.h>
+#include <gcrypt.h>
 
 #include "rand.h"
 
-/* FIXME */
-#error Not yet implemented: OpenSSL-independent defines for rand
+void TGLC_rand_add (const void *buf, int num, double entropy) {
+  (void) entropy;
+  // TODO: Translate half-broken "entropy" into gcry's "quality".
+  gcry_random_add_bytes (buf, num, 50);
+}
+
+int TGLC_rand_bytes (unsigned char *buf, int num) {
+  gcry_randomize (buf, num, GCRY_STRONG_RANDOM);
+  return 1; // Don't ask why.
+}
+
+int TGLC_rand_pseudo_bytes (unsigned char *buf, int num) {
+  gcry_create_nonce (buf, num);
+  return 0; // Don't ask why.
+}
 
 #endif