DsaDigestSigner
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Security;
using System;
namespace Org.BouncyCastle.Crypto.Signers
{
public class DsaDigestSigner : ISigner
{
private readonly IDsa dsa;
private readonly IDigest digest;
private readonly IDsaEncoding encoding;
private bool forSigning;
public virtual string AlgorithmName => digest.AlgorithmName + "with" + dsa.AlgorithmName;
public DsaDigestSigner(IDsa dsa, IDigest digest)
: this(dsa, digest, StandardDsaEncoding.Instance)
{
}
public DsaDigestSigner(IDsa dsa, IDigest digest, IDsaEncoding encoding)
{
this.dsa = dsa;
this.digest = digest;
this.encoding = encoding;
}
public virtual void Init(bool forSigning, ICipherParameters parameters)
{
this.forSigning = forSigning;
ParametersWithRandom parametersWithRandom = parameters as ParametersWithRandom;
AsymmetricKeyParameter asymmetricKeyParameter = (parametersWithRandom == null) ? ((AsymmetricKeyParameter)parameters) : ((AsymmetricKeyParameter)parametersWithRandom.Parameters);
if (forSigning && !asymmetricKeyParameter.IsPrivate)
throw new InvalidKeyException("Signing Requires Private Key.");
if (!forSigning && asymmetricKeyParameter.IsPrivate)
throw new InvalidKeyException("Verification Requires Public Key.");
Reset();
dsa.Init(forSigning, parameters);
}
public virtual void Update(byte input)
{
digest.Update(input);
}
public virtual void BlockUpdate(byte[] input, int inOff, int inLen)
{
digest.BlockUpdate(input, inOff, inLen);
}
public virtual void BlockUpdate(ReadOnlySpan<byte> input)
{
digest.BlockUpdate(input);
}
public virtual int GetMaxSignatureSize()
{
return encoding.GetMaxEncodingSize(GetOrder());
}
public virtual byte[] GenerateSignature()
{
if (forSigning) {
byte[] array = new byte[digest.GetDigestSize()];
digest.DoFinal(array, 0);
BigInteger[] array2 = dsa.GenerateSignature(array);
try {
return encoding.Encode(GetOrder(), array2[0], array2[1]);
} catch (Exception) {
throw new InvalidOperationException("unable to encode signature");
}
}
throw new InvalidOperationException("DsaDigestSigner not initialized for signature generation.");
}
public virtual bool VerifySignature(byte[] signature)
{
if (!forSigning) {
byte[] array = new byte[digest.GetDigestSize()];
digest.DoFinal(array, 0);
try {
BigInteger[] array2 = encoding.Decode(GetOrder(), signature);
return dsa.VerifySignature(array, array2[0], array2[1]);
} catch (Exception) {
return false;
}
}
throw new InvalidOperationException("DsaDigestSigner not initialized for verification");
}
public virtual void Reset()
{
digest.Reset();
}
protected virtual BigInteger GetOrder()
{
return dsa.Order;
}
}
}