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output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Signers/DsaDigestSigner.cs

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+using System;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Security;
+
+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 = dsa;
+		this.digest = digest;
+		encoding = StandardDsaEncoding.Instance;
+	}
+
+	public DsaDigestSigner(IDsaExt 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;
+		AsymmetricKeyParameter asymmetricKeyParameter = ((!(parameters is ParametersWithRandom)) ? ((AsymmetricKeyParameter)parameters) : ((AsymmetricKeyParameter)((ParametersWithRandom)parameters).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 length)
+	{
+		digest.BlockUpdate(input, inOff, length);
+	}
+
+	public virtual byte[] GenerateSignature()
+	{
+		if (!forSigning)
+		{
+			throw new InvalidOperationException("DSADigestSigner not initialised for signature generation.");
+		}
+		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");
+		}
+	}
+
+	public virtual bool VerifySignature(byte[] signature)
+	{
+		if (forSigning)
+		{
+			throw new InvalidOperationException("DSADigestSigner not initialised for verification");
+		}
+		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;
+		}
+	}
+
+	public virtual void Reset()
+	{
+		digest.Reset();
+	}
+
+	protected virtual BigInteger GetOrder()
+	{
+		if (!(dsa is IDsaExt))
+		{
+			return null;
+		}
+		return ((IDsaExt)dsa).Order;
+	}
+}