init commit

output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Signers/X931Signer.cs

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+using System;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Signers;
+
+public class X931Signer : ISigner
+{
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_IMPLICIT = 188;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_RIPEMD160 = 12748;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_RIPEMD128 = 13004;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_SHA1 = 13260;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_SHA256 = 13516;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_SHA512 = 13772;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_SHA384 = 14028;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_WHIRLPOOL = 14284;
+
+	[Obsolete("Use 'IsoTrailers' instead")]
+	public const int TRAILER_SHA224 = 14540;
+
+	private IDigest digest;
+
+	private IAsymmetricBlockCipher cipher;
+
+	private RsaKeyParameters kParam;
+
+	private int trailer;
+
+	private int keyBits;
+
+	private byte[] block;
+
+	public virtual string AlgorithmName => digest.AlgorithmName + "with" + cipher.AlgorithmName + "/X9.31";
+
+	public X931Signer(IAsymmetricBlockCipher cipher, IDigest digest, bool isImplicit)
+	{
+		this.cipher = cipher;
+		this.digest = digest;
+		if (isImplicit)
+		{
+			trailer = 188;
+			return;
+		}
+		if (IsoTrailers.NoTrailerAvailable(digest))
+		{
+			throw new ArgumentException("no valid trailer", "digest");
+		}
+		trailer = IsoTrailers.GetTrailer(digest);
+	}
+
+	public X931Signer(IAsymmetricBlockCipher cipher, IDigest digest)
+		: this(cipher, digest, isImplicit: false)
+	{
+	}
+
+	public virtual void Init(bool forSigning, ICipherParameters parameters)
+	{
+		kParam = (RsaKeyParameters)parameters;
+		cipher.Init(forSigning, kParam);
+		keyBits = kParam.Modulus.BitLength;
+		block = new byte[(keyBits + 7) / 8];
+		Reset();
+	}
+
+	private void ClearBlock(byte[] block)
+	{
+		Array.Clear(block, 0, block.Length);
+	}
+
+	public virtual void Update(byte b)
+	{
+		digest.Update(b);
+	}
+
+	public virtual void BlockUpdate(byte[] input, int off, int len)
+	{
+		digest.BlockUpdate(input, off, len);
+	}
+
+	public virtual void Reset()
+	{
+		digest.Reset();
+	}
+
+	public virtual byte[] GenerateSignature()
+	{
+		CreateSignatureBlock();
+		BigInteger bigInteger = new BigInteger(1, cipher.ProcessBlock(block, 0, block.Length));
+		ClearBlock(block);
+		bigInteger = bigInteger.Min(kParam.Modulus.Subtract(bigInteger));
+		int unsignedByteLength = BigIntegers.GetUnsignedByteLength(kParam.Modulus);
+		return BigIntegers.AsUnsignedByteArray(unsignedByteLength, bigInteger);
+	}
+
+	private void CreateSignatureBlock()
+	{
+		int digestSize = digest.GetDigestSize();
+		int num;
+		if (trailer == 188)
+		{
+			num = block.Length - digestSize - 1;
+			digest.DoFinal(block, num);
+			block[block.Length - 1] = 188;
+		}
+		else
+		{
+			num = block.Length - digestSize - 2;
+			digest.DoFinal(block, num);
+			block[block.Length - 2] = (byte)(trailer >> 8);
+			block[block.Length - 1] = (byte)trailer;
+		}
+		block[0] = 107;
+		for (int num2 = num - 2; num2 != 0; num2--)
+		{
+			block[num2] = 187;
+		}
+		block[num - 1] = 186;
+	}
+
+	public virtual bool VerifySignature(byte[] signature)
+	{
+		try
+		{
+			block = cipher.ProcessBlock(signature, 0, signature.Length);
+		}
+		catch (Exception)
+		{
+			return false;
+		}
+		BigInteger bigInteger = new BigInteger(1, block);
+		BigInteger n;
+		if ((bigInteger.IntValue & 0xF) == 12)
+		{
+			n = bigInteger;
+		}
+		else
+		{
+			bigInteger = kParam.Modulus.Subtract(bigInteger);
+			if ((bigInteger.IntValue & 0xF) != 12)
+			{
+				return false;
+			}
+			n = bigInteger;
+		}
+		CreateSignatureBlock();
+		byte[] b = BigIntegers.AsUnsignedByteArray(block.Length, n);
+		bool result = Arrays.ConstantTimeAreEqual(block, b);
+		ClearBlock(block);
+		ClearBlock(b);
+		return result;
+	}
+}