diff options
Diffstat (limited to 'Crypto/src/crypto/signers/RsaDigestSigner.cs')
| -rw-r--r-- | Crypto/src/crypto/signers/RsaDigestSigner.cs | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/Crypto/src/crypto/signers/RsaDigestSigner.cs b/Crypto/src/crypto/signers/RsaDigestSigner.cs new file mode 100644 index 000000000..f57bfc83d --- /dev/null +++ b/Crypto/src/crypto/signers/RsaDigestSigner.cs @@ -0,0 +1,228 @@ +using System; +using System.Collections; +using System.IO; +using System.Text; + +using Org.BouncyCastle.Asn1; +using Org.BouncyCastle.Asn1.Nist; +using Org.BouncyCastle.Asn1.Pkcs; +using Org.BouncyCastle.Asn1.TeleTrust; +using Org.BouncyCastle.Asn1.Utilities; +using Org.BouncyCastle.Asn1.X509; +using Org.BouncyCastle.Crypto.Parameters; +using Org.BouncyCastle.Crypto.Encodings; +using Org.BouncyCastle.Crypto.Engines; +using Org.BouncyCastle.Crypto.Signers; +using Org.BouncyCastle.Security; +using Org.BouncyCastle.Utilities; + +namespace Org.BouncyCastle.Crypto.Signers +{ + public class RsaDigestSigner + : ISigner + { + private readonly IAsymmetricBlockCipher rsaEngine = new Pkcs1Encoding(new RsaBlindedEngine()); + private readonly AlgorithmIdentifier algId; + private readonly IDigest digest; + private bool forSigning; + + private static readonly IDictionary oidMap = Platform.CreateHashtable(); + + /// <summary> + /// Load oid table. + /// </summary> + static RsaDigestSigner() + { + oidMap["RIPEMD128"] = TeleTrusTObjectIdentifiers.RipeMD128; + oidMap["RIPEMD160"] = TeleTrusTObjectIdentifiers.RipeMD160; + oidMap["RIPEMD256"] = TeleTrusTObjectIdentifiers.RipeMD256; + + oidMap["SHA-1"] = X509ObjectIdentifiers.IdSha1; + oidMap["SHA-224"] = NistObjectIdentifiers.IdSha224; + oidMap["SHA-256"] = NistObjectIdentifiers.IdSha256; + oidMap["SHA-384"] = NistObjectIdentifiers.IdSha384; + oidMap["SHA-512"] = NistObjectIdentifiers.IdSha512; + + oidMap["MD2"] = PkcsObjectIdentifiers.MD2; + oidMap["MD4"] = PkcsObjectIdentifiers.MD4; + oidMap["MD5"] = PkcsObjectIdentifiers.MD5; + } + + public RsaDigestSigner( + IDigest digest) + { + this.digest = digest; + + string algName = digest.AlgorithmName; + if (algName.Equals("NULL")) + { + this.algId = null; + } + else + { + this.algId = new AlgorithmIdentifier( + (DerObjectIdentifier)oidMap[digest.AlgorithmName], DerNull.Instance); + } + } + + public string AlgorithmName + { + get { return digest.AlgorithmName + "withRSA"; } + } + + /** + * Initialise the signer for signing or verification. + * + * @param forSigning true if for signing, false otherwise + * @param param necessary parameters. + */ + 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(); + + rsaEngine.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("RsaDigestSigner not initialised for signature generation."); + + byte[] hash = new byte[digest.GetDigestSize()]; + digest.DoFinal(hash, 0); + + byte[] data = DerEncode(hash); + return rsaEngine.ProcessBlock(data, 0, data.Length); + } + + /** + * return true if the internal state represents the signature described + * in the passed in array. + */ + public bool VerifySignature( + byte[] signature) + { + if (forSigning) + throw new InvalidOperationException("RsaDigestSigner not initialised for verification"); + + byte[] hash = new byte[digest.GetDigestSize()]; + digest.DoFinal(hash, 0); + + byte[] sig; + byte[] expected; + + try + { + sig = rsaEngine.ProcessBlock(signature, 0, signature.Length); + expected = DerEncode(hash); + } + catch (Exception) + { + return false; + } + + if (sig.Length == expected.Length) + { + for (int i = 0; i < sig.Length; i++) + { + if (sig[i] != expected[i]) + { + return false; + } + } + } + else if (sig.Length == expected.Length - 2) // NULL left out + { + int sigOffset = sig.Length - hash.Length - 2; + int expectedOffset = expected.Length - hash.Length - 2; + + expected[1] -= 2; // adjust lengths + expected[3] -= 2; + + for (int i = 0; i < hash.Length; i++) + { + if (sig[sigOffset + i] != expected[expectedOffset + i]) // check hash + { + return false; + } + } + + for (int i = 0; i < sigOffset; i++) + { + if (sig[i] != expected[i]) // check header less NULL + { + return false; + } + } + } + else + { + return false; + } + + return true; + } + + public void Reset() + { + digest.Reset(); + } + + private byte[] DerEncode(byte[] hash) + { + if (algId == null) + { + // For raw RSA, the DigestInfo must be prepared externally + return hash; + } + + DigestInfo dInfo = new DigestInfo(algId, hash); + + return dInfo.GetDerEncoded(); + } + } +} |