init commit

2025-10-09 09:57:24 +09:00
commit 4d551bd74f
6636 changed files with 1218703 additions and 0 deletions
--- a/output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Engines/ElGamalEngine.cs
+++ b/output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Engines/ElGamalEngine.cs
@@ -0,0 +1,114 @@
+using System;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Crypto.Engines;
+
+public class ElGamalEngine : IAsymmetricBlockCipher
+{
+	private ElGamalKeyParameters key;
+
+	private SecureRandom random;
+
+	private bool forEncryption;
+
+	private int bitSize;
+
+	public virtual string AlgorithmName => "ElGamal";
+
+	public virtual void Init(bool forEncryption, ICipherParameters parameters)
+	{
+		if (parameters is ParametersWithRandom)
+		{
+			ParametersWithRandom parametersWithRandom = (ParametersWithRandom)parameters;
+			key = (ElGamalKeyParameters)parametersWithRandom.Parameters;
+			random = parametersWithRandom.Random;
+		}
+		else
+		{
+			key = (ElGamalKeyParameters)parameters;
+			random = new SecureRandom();
+		}
+		this.forEncryption = forEncryption;
+		bitSize = key.Parameters.P.BitLength;
+		if (forEncryption)
+		{
+			if (!(key is ElGamalPublicKeyParameters))
+			{
+				throw new ArgumentException("ElGamalPublicKeyParameters are required for encryption.");
+			}
+		}
+		else if (!(key is ElGamalPrivateKeyParameters))
+		{
+			throw new ArgumentException("ElGamalPrivateKeyParameters are required for decryption.");
+		}
+	}
+
+	public virtual int GetInputBlockSize()
+	{
+		if (forEncryption)
+		{
+			return (bitSize - 1) / 8;
+		}
+		return 2 * ((bitSize + 7) / 8);
+	}
+
+	public virtual int GetOutputBlockSize()
+	{
+		if (forEncryption)
+		{
+			return 2 * ((bitSize + 7) / 8);
+		}
+		return (bitSize - 1) / 8;
+	}
+
+	public virtual byte[] ProcessBlock(byte[] input, int inOff, int length)
+	{
+		if (key == null)
+		{
+			throw new InvalidOperationException("ElGamal engine not initialised");
+		}
+		int num = (forEncryption ? ((bitSize - 1 + 7) / 8) : GetInputBlockSize());
+		if (length > num)
+		{
+			throw new DataLengthException("input too large for ElGamal cipher.\n");
+		}
+		BigInteger p = key.Parameters.P;
+		byte[] array;
+		if (key is ElGamalPrivateKeyParameters)
+		{
+			int num2 = length / 2;
+			BigInteger bigInteger = new BigInteger(1, input, inOff, num2);
+			BigInteger val = new BigInteger(1, input, inOff + num2, num2);
+			ElGamalPrivateKeyParameters elGamalPrivateKeyParameters = (ElGamalPrivateKeyParameters)key;
+			BigInteger bigInteger2 = bigInteger.ModPow(p.Subtract(BigInteger.One).Subtract(elGamalPrivateKeyParameters.X), p).Multiply(val).Mod(p);
+			array = bigInteger2.ToByteArrayUnsigned();
+		}
+		else
+		{
+			BigInteger bigInteger3 = new BigInteger(1, input, inOff, length);
+			if (bigInteger3.BitLength >= p.BitLength)
+			{
+				throw new DataLengthException("input too large for ElGamal cipher.\n");
+			}
+			ElGamalPublicKeyParameters elGamalPublicKeyParameters = (ElGamalPublicKeyParameters)key;
+			BigInteger value = p.Subtract(BigInteger.Two);
+			BigInteger bigInteger4;
+			do
+			{
+				bigInteger4 = new BigInteger(p.BitLength, random);
+			}
+			while (bigInteger4.SignValue == 0 || bigInteger4.CompareTo(value) > 0);
+			BigInteger g = key.Parameters.G;
+			BigInteger bigInteger5 = g.ModPow(bigInteger4, p);
+			BigInteger bigInteger6 = bigInteger3.Multiply(elGamalPublicKeyParameters.Y.ModPow(bigInteger4, p)).Mod(p);
+			array = new byte[GetOutputBlockSize()];
+			byte[] array2 = bigInteger5.ToByteArrayUnsigned();
+			byte[] array3 = bigInteger6.ToByteArrayUnsigned();
+			array2.CopyTo(array, array.Length / 2 - array2.Length);
+			array3.CopyTo(array, array.Length - array3.Length);
+		}
+		return array;
+	}
+}