diff options
Diffstat (limited to 'crypto/src/crypto/signers/GOST3410DigestSigner.cs')
-rw-r--r-- | crypto/src/crypto/signers/GOST3410DigestSigner.cs | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/crypto/src/crypto/signers/GOST3410DigestSigner.cs b/crypto/src/crypto/signers/GOST3410DigestSigner.cs new file mode 100644 index 000000000..58aefa368 --- /dev/null +++ b/crypto/src/crypto/signers/GOST3410DigestSigner.cs @@ -0,0 +1,145 @@ +using System; +using System.Collections; +using System.IO; +using System.Text; + +using Org.BouncyCastle.Asn1; +using Org.BouncyCastle.Crypto.Signers; +using Org.BouncyCastle.Crypto.Parameters; +using Org.BouncyCastle.Math; +using Org.BouncyCastle.Security; + +namespace Org.BouncyCastle.Crypto.Signers +{ + public class Gost3410DigestSigner + : ISigner + { + private readonly IDigest digest; + private readonly IDsa dsaSigner; + private bool forSigning; + + public Gost3410DigestSigner( + IDsa signer, + IDigest digest) + { + this.dsaSigner = signer; + this.digest = digest; + } + + public string AlgorithmName + { + get { return digest.AlgorithmName + "with" + dsaSigner.AlgorithmName; } + } + + public void Init( + bool forSigning, + ICipherParameters parameters) + { + this.forSigning = forSigning; + + AsymmetricKeyParameter k; + if (parameters is ParametersWithRandom) + { + k = (AsymmetricKeyParameter)((ParametersWithRandom)parameters).Parameters; + } + else + { + k = (AsymmetricKeyParameter)parameters; + } + + if (forSigning && !k.IsPrivate) + { + throw new InvalidKeyException("Signing Requires Private Key."); + } + + if (!forSigning && k.IsPrivate) + { + throw new InvalidKeyException("Verification Requires Public Key."); + } + + Reset(); + + dsaSigner.Init(forSigning, parameters); + } + + /** + * update the internal digest with the byte b + */ + public void Update( + byte input) + { + digest.Update(input); + } + + /** + * update the internal digest with the byte array in + */ + public void BlockUpdate( + byte[] input, + int inOff, + int length) + { + digest.BlockUpdate(input, inOff, length); + } + + /** + * Generate a signature for the message we've been loaded with using + * the key we were initialised with. + */ + public byte[] GenerateSignature() + { + if (!forSigning) + throw new InvalidOperationException("GOST3410DigestSigner not initialised for signature generation."); + + byte[] hash = new byte[digest.GetDigestSize()]; + digest.DoFinal(hash, 0); + + try + { + BigInteger[] sig = dsaSigner.GenerateSignature(hash); + byte[] sigBytes = new byte[64]; + + // TODO Add methods to allow writing BigInteger to existing byte array? + byte[] r = sig[0].ToByteArrayUnsigned(); + byte[] s = sig[1].ToByteArrayUnsigned(); + s.CopyTo(sigBytes, 32 - s.Length); + r.CopyTo(sigBytes, 64 - r.Length); + return sigBytes; + } + catch (Exception e) + { + throw new SignatureException(e.Message, e); + } + } + + /// <returns>true if the internal state represents the signature described in the passed in array.</returns> + public bool VerifySignature( + byte[] signature) + { + if (forSigning) + throw new InvalidOperationException("DSADigestSigner not initialised for verification"); + + byte[] hash = new byte[digest.GetDigestSize()]; + digest.DoFinal(hash, 0); + + BigInteger R, S; + try + { + R = new BigInteger(1, signature, 32, 32); + S = new BigInteger(1, signature, 0, 32); + } + catch (Exception e) + { + throw new SignatureException("error decoding signature bytes.", e); + } + + return dsaSigner.VerifySignature(hash, R, S); + } + + /// <summary>Reset the internal state</summary> + public void Reset() + { + digest.Reset(); + } + } +} |