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//
// PKCS8.cs: PKCS #8 - Private-Key Information Syntax Standard
// ftp://ftp.rsasecurity.com/pub/pkcs/doc/pkcs-8.doc
//
// Author:
// Sebastien Pouliot <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// (C) 2004 Novell (http://www.novell.com)
//
using System;
using System.Collections;
using System.Security.Cryptography;
using System.Text;
using Mono.Security.Cryptography;
using Mono.Security.X509;
namespace Mono.Security.Cryptography {
public sealed class PKCS8 {
public enum KeyInfo {
PrivateKey,
EncryptedPrivateKey,
Unknown
}
private PKCS8 ()
{
}
static public KeyInfo GetType (byte[] data)
{
if (data == null)
throw new ArgumentNullException ("data");
KeyInfo ki = KeyInfo.Unknown;
try {
ASN1 top = new ASN1 (data);
if ((top.Tag == 0x30) && (top.Count > 0)) {
ASN1 firstLevel = top [0];
switch (firstLevel.Tag) {
case 0x02:
ki = KeyInfo.PrivateKey;
break;
case 0x30:
ki = KeyInfo.EncryptedPrivateKey;
break;
}
}
}
catch {
throw new CryptographicException ("invalid ASN.1 data");
}
return ki;
}
/*
* PrivateKeyInfo ::= SEQUENCE {
* version Version,
* privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
* privateKey PrivateKey,
* attributes [0] IMPLICIT Attributes OPTIONAL
* }
*
* Version ::= INTEGER
*
* PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier
*
* PrivateKey ::= OCTET STRING
*
* Attributes ::= SET OF Attribute
*/
public class PrivateKeyInfo {
private int _version;
private string _algorithm;
private byte[] _key;
private ArrayList _list;
public PrivateKeyInfo ()
{
_version = 0;
_list = new ArrayList ();
}
public PrivateKeyInfo (byte[] data) : this ()
{
Decode (data);
}
// properties
public string Algorithm {
get { return _algorithm; }
set { _algorithm = value; }
}
public ArrayList Attributes {
get { return _list; }
}
public byte[] PrivateKey {
get {
if (_key == null)
return null;
return (byte[]) _key.Clone ();
}
set {
if (value == null)
throw new ArgumentNullException ("PrivateKey");
_key = (byte[]) value.Clone ();
}
}
public int Version {
get { return _version; }
set {
if (value < 0)
throw new ArgumentOutOfRangeException ("negative version");
_version = value;
}
}
// methods
private void Decode (byte[] data)
{
ASN1 privateKeyInfo = new ASN1 (data);
if (privateKeyInfo.Tag != 0x30)
throw new CryptographicException ("invalid PrivateKeyInfo");
ASN1 version = privateKeyInfo [0];
if (version.Tag != 0x02)
throw new CryptographicException ("invalid version");
_version = version.Value [0];
ASN1 privateKeyAlgorithm = privateKeyInfo [1];
if (privateKeyAlgorithm.Tag != 0x30)
throw new CryptographicException ("invalid algorithm");
ASN1 algorithm = privateKeyAlgorithm [0];
if (algorithm.Tag != 0x06)
throw new CryptographicException ("missing algorithm OID");
_algorithm = ASN1Convert.ToOid (algorithm);
ASN1 privateKey = privateKeyInfo [2];
_key = privateKey.Value;
// attributes [0] IMPLICIT Attributes OPTIONAL
if (privateKeyInfo.Count > 3) {
ASN1 attributes = privateKeyInfo [3];
for (int i=0; i < attributes.Count; i++) {
_list.Add (attributes [i]);
}
}
}
public byte[] GetBytes ()
{
ASN1 privateKeyAlgorithm = new ASN1 (0x30);
privateKeyAlgorithm.Add (ASN1Convert.FromOid (_algorithm));
privateKeyAlgorithm.Add (new ASN1 (0x05)); // ASN.1 NULL
ASN1 pki = new ASN1 (0x30);
pki.Add (new ASN1 (0x02, new byte [1] { (byte) _version }));
pki.Add (privateKeyAlgorithm);
pki.Add (new ASN1 (0x04, _key));
if (_list.Count > 0) {
ASN1 attributes = new ASN1 (0xA0);
foreach (ASN1 attribute in _list) {
attributes.Add (attribute);
}
pki.Add (attributes);
}
return pki.GetBytes ();
}
// static methods
static private byte[] RemoveLeadingZero (byte[] bigInt)
{
int start = 0;
int length = bigInt.Length;
if (bigInt [0] == 0x00) {
start = 1;
length--;
}
byte[] bi = new byte [length];
Buffer.BlockCopy (bigInt, start, bi, 0, length);
return bi;
}
static private byte[] Normalize (byte[] bigInt, int length)
{
if (bigInt.Length == length)
return bigInt;
else if (bigInt.Length > length)
return RemoveLeadingZero (bigInt);
else {
// pad with 0
byte[] bi = new byte [length];
Buffer.BlockCopy (bigInt, 0, bi, (length - bigInt.Length), bigInt.Length);
return bi;
}
}
/*
* RSAPrivateKey ::= SEQUENCE {
* version Version,
* modulus INTEGER, -- n
* publicExponent INTEGER, -- e
* privateExponent INTEGER, -- d
* prime1 INTEGER, -- p
* prime2 INTEGER, -- q
* exponent1 INTEGER, -- d mod (p-1)
* exponent2 INTEGER, -- d mod (q-1)
* coefficient INTEGER, -- (inverse of q) mod p
* otherPrimeInfos OtherPrimeInfos OPTIONAL
* }
*/
static public RSA DecodeRSA (byte[] keypair)
{
ASN1 privateKey = new ASN1 (keypair);
if (privateKey.Tag != 0x30)
throw new CryptographicException ("invalid private key format");
ASN1 version = privateKey [0];
if (version.Tag != 0x02)
throw new CryptographicException ("missing version");
if (privateKey.Count < 9)
throw new CryptographicException ("not enough key parameters");
RSAParameters param = new RSAParameters ();
// note: MUST remove leading 0 - else MS wont import the key
param.Modulus = RemoveLeadingZero (privateKey [1].Value);
int keysize = param.Modulus.Length;
int keysize2 = (keysize >> 1); // half-size
// size must be normalized - else MS wont import the key
param.D = Normalize (privateKey [3].Value, keysize);
param.DP = Normalize (privateKey [6].Value, keysize2);
param.DQ = Normalize (privateKey [7].Value, keysize2);
param.Exponent = RemoveLeadingZero (privateKey [2].Value);
param.InverseQ = Normalize (privateKey [8].Value, keysize2);
param.P = Normalize (privateKey [4].Value, keysize2);
param.Q = Normalize (privateKey [5].Value, keysize2);
RSA rsa = RSA.Create ();
rsa.ImportParameters (param);
return rsa;
}
/*
* RSAPrivateKey ::= SEQUENCE {
* version Version,
* modulus INTEGER, -- n
* publicExponent INTEGER, -- e
* privateExponent INTEGER, -- d
* prime1 INTEGER, -- p
* prime2 INTEGER, -- q
* exponent1 INTEGER, -- d mod (p-1)
* exponent2 INTEGER, -- d mod (q-1)
* coefficient INTEGER, -- (inverse of q) mod p
* otherPrimeInfos OtherPrimeInfos OPTIONAL
* }
*/
static public byte[] Encode (RSA rsa)
{
RSAParameters param = rsa.ExportParameters (true);
ASN1 rsaPrivateKey = new ASN1 (0x30);
rsaPrivateKey.Add (new ASN1 (0x02, new byte [1] { 0x00 }));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.Modulus));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.Exponent));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.D));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.P));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.Q));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.DP));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.DQ));
rsaPrivateKey.Add (ASN1Convert.FromUnsignedBigInteger (param.InverseQ));
return rsaPrivateKey.GetBytes ();
}
// DSA only encode it's X private key inside an ASN.1 INTEGER (Hint: Tag == 0x02)
// which isn't enough for rebuilding the keypair. The other parameters
// can be found (98% of the time) in the X.509 certificate associated
// with the private key or (2% of the time) the parameters are in it's
// issuer X.509 certificate (not supported in the .NET framework).
static public DSA DecodeDSA (byte[] privateKey, DSAParameters dsaParameters)
{
ASN1 pvk = new ASN1 (privateKey);
if (pvk.Tag != 0x02)
throw new CryptographicException ("invalid private key format");
// X is ALWAYS 20 bytes (no matter if the key length is 512 or 1024 bits)
dsaParameters.X = Normalize (privateKey, 20);
DSA dsa = DSA.Create ();
dsa.ImportParameters (dsaParameters);
return dsa;
}
static public byte[] Encode (DSA dsa)
{
DSAParameters param = dsa.ExportParameters (true);
return ASN1Convert.FromUnsignedBigInteger (param.X).GetBytes ();
}
static public byte[] Encode (AsymmetricAlgorithm aa)
{
if (aa is RSA)
return Encode ((RSA)aa);
else if (aa is DSA)
return Encode ((DSA)aa);
else
throw new CryptographicException ("Unknown asymmetric algorithm {0}", aa.ToString ());
}
}
/*
* EncryptedPrivateKeyInfo ::= SEQUENCE {
* encryptionAlgorithm EncryptionAlgorithmIdentifier,
* encryptedData EncryptedData
* }
*
* EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
*
* EncryptedData ::= OCTET STRING
*
* --
* AlgorithmIdentifier ::= SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* parameters ANY DEFINED BY algorithm OPTIONAL
* }
*
* -- from PKCS#5
* PBEParameter ::= SEQUENCE {
* salt OCTET STRING SIZE(8),
* iterationCount INTEGER
* }
*/
public class EncryptedPrivateKeyInfo {
private string _algorithm;
private byte[] _salt;
private int _iterations;
private byte[] _data;
public EncryptedPrivateKeyInfo () {}
public EncryptedPrivateKeyInfo (byte[] data) : this ()
{
Decode (data);
}
// properties
public string Algorithm {
get { return _algorithm; }
set { _algorithm = value; }
}
public byte[] EncryptedData {
get { return (_data == null) ? null : (byte[]) _data.Clone (); }
set { _data = (value == null) ? null : (byte[]) value.Clone (); }
}
public byte[] Salt {
get {
if (_salt == null) {
RandomNumberGenerator rng = RandomNumberGenerator.Create ();
_salt = new byte [8];
rng.GetBytes (_salt);
}
return (byte[]) _salt.Clone ();
}
set { _salt = (byte[]) value.Clone (); }
}
public int IterationCount {
get { return _iterations; }
set {
if (value < 0)
throw new ArgumentOutOfRangeException ("IterationCount", "Negative");
_iterations = value;
}
}
// methods
private void Decode (byte[] data)
{
ASN1 encryptedPrivateKeyInfo = new ASN1 (data);
if (encryptedPrivateKeyInfo.Tag != 0x30)
throw new CryptographicException ("invalid EncryptedPrivateKeyInfo");
ASN1 encryptionAlgorithm = encryptedPrivateKeyInfo [0];
if (encryptionAlgorithm.Tag != 0x30)
throw new CryptographicException ("invalid encryptionAlgorithm");
ASN1 algorithm = encryptionAlgorithm [0];
if (algorithm.Tag != 0x06)
throw new CryptographicException ("invalid algorithm");
_algorithm = ASN1Convert.ToOid (algorithm);
// parameters ANY DEFINED BY algorithm OPTIONAL
if (encryptionAlgorithm.Count > 1) {
ASN1 parameters = encryptionAlgorithm [1];
if (parameters.Tag != 0x30)
throw new CryptographicException ("invalid parameters");
ASN1 salt = parameters [0];
if (salt.Tag != 0x04)
throw new CryptographicException ("invalid salt");
_salt = salt.Value;
ASN1 iterationCount = parameters [1];
if (iterationCount.Tag != 0x02)
throw new CryptographicException ("invalid iterationCount");
_iterations = ASN1Convert.ToInt32 (iterationCount);
}
ASN1 encryptedData = encryptedPrivateKeyInfo [1];
if (encryptedData.Tag != 0x04)
throw new CryptographicException ("invalid EncryptedData");
_data = encryptedData.Value;
}
// Note: PKCS#8 doesn't define how to generate the key required for encryption
// so you're on your own. Just don't try to copy the big guys too much ;)
// Netscape: http://www.cs.auckland.ac.nz/~pgut001/pubs/netscape.txt
// Microsoft: http://www.cs.auckland.ac.nz/~pgut001/pubs/breakms.txt
public byte[] GetBytes ()
{
if (_algorithm == null)
throw new CryptographicException ("No algorithm OID specified");
ASN1 encryptionAlgorithm = new ASN1 (0x30);
encryptionAlgorithm.Add (ASN1Convert.FromOid (_algorithm));
// parameters ANY DEFINED BY algorithm OPTIONAL
if ((_iterations > 0) || (_salt != null)) {
ASN1 salt = new ASN1 (0x04, _salt);
ASN1 iterations = ASN1Convert.FromInt32 (_iterations);
ASN1 parameters = new ASN1 (0x30);
parameters.Add (salt);
parameters.Add (iterations);
encryptionAlgorithm.Add (parameters);
}
// encapsulates EncryptedData into an OCTET STRING
ASN1 encryptedData = new ASN1 (0x04, _data);
ASN1 encryptedPrivateKeyInfo = new ASN1 (0x30);
encryptedPrivateKeyInfo.Add (encryptionAlgorithm);
encryptedPrivateKeyInfo.Add (encryptedData);
return encryptedPrivateKeyInfo.GetBytes ();
}
}
}
}
|