1 files changed, 129 insertions, 0 deletions
diff --git a/Crypto/src/crypto/signers/GenericSigner.cs b/Crypto/src/crypto/signers/GenericSigner.cs
new file mode 100644
index 000000000..1a53eee2b
--- /dev/null
+++ b/Crypto/src/crypto/signers/GenericSigner.cs
@@ -0,0 +1,129 @@
+using System;
+
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Signers
+{
+ public class GenericSigner
+ : ISigner
+ {
+ private readonly IAsymmetricBlockCipher engine;
+ private readonly IDigest digest;
+ private bool forSigning;
+
+ public GenericSigner(
+ IAsymmetricBlockCipher engine,
+ IDigest digest)
+ {
+ this.engine = engine;
+ this.digest = digest;
+ }
+
+ public string AlgorithmName
+ {
+ get { return "Generic(" + engine.AlgorithmName + "/" + digest.AlgorithmName + ")"; }
+ }
+
+ /**
+ * initialise the signer for signing or verification.
+ *
+ * @param forSigning
+ * true if for signing, false otherwise
+ * @param parameters
+ * 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();
+
+ engine.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("GenericSigner not initialised for signature generation.");
+
+ byte[] hash = new byte[digest.GetDigestSize()];
+ digest.DoFinal(hash, 0);
+
+ return engine.ProcessBlock(hash, 0, hash.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("GenericSigner not initialised for verification");
+
+ byte[] hash = new byte[digest.GetDigestSize()];
+ digest.DoFinal(hash, 0);
+
+ try
+ {
+ byte[] sig = engine.ProcessBlock(signature, 0, signature.Length);
+
+ return Arrays.ConstantTimeAreEqual(sig, hash);
+ }
+ catch (Exception)
+ {
+ return false;
+ }
+ }
+
+ public void Reset()
+ {
+ digest.Reset();
+ }
+ }
+}
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