init commit

output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Engines/RsaBlindedEngine.cs

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+using System;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Engines;
+
+public class RsaBlindedEngine : IAsymmetricBlockCipher
+{
+	private readonly IRsa core;
+
+	private RsaKeyParameters key;
+
+	private SecureRandom random;
+
+	public virtual string AlgorithmName => "RSA";
+
+	public RsaBlindedEngine()
+		: this(new RsaCoreEngine())
+	{
+	}
+
+	public RsaBlindedEngine(IRsa rsa)
+	{
+		core = rsa;
+	}
+
+	public virtual void Init(bool forEncryption, ICipherParameters param)
+	{
+		core.Init(forEncryption, param);
+		if (param is ParametersWithRandom)
+		{
+			ParametersWithRandom parametersWithRandom = (ParametersWithRandom)param;
+			key = (RsaKeyParameters)parametersWithRandom.Parameters;
+			random = parametersWithRandom.Random;
+		}
+		else
+		{
+			key = (RsaKeyParameters)param;
+			random = new SecureRandom();
+		}
+	}
+
+	public virtual int GetInputBlockSize()
+	{
+		return core.GetInputBlockSize();
+	}
+
+	public virtual int GetOutputBlockSize()
+	{
+		return core.GetOutputBlockSize();
+	}
+
+	public virtual byte[] ProcessBlock(byte[] inBuf, int inOff, int inLen)
+	{
+		if (key == null)
+		{
+			throw new InvalidOperationException("RSA engine not initialised");
+		}
+		BigInteger bigInteger = core.ConvertInput(inBuf, inOff, inLen);
+		BigInteger bigInteger4;
+		if (key is RsaPrivateCrtKeyParameters)
+		{
+			RsaPrivateCrtKeyParameters rsaPrivateCrtKeyParameters = (RsaPrivateCrtKeyParameters)key;
+			BigInteger publicExponent = rsaPrivateCrtKeyParameters.PublicExponent;
+			if (publicExponent != null)
+			{
+				BigInteger modulus = rsaPrivateCrtKeyParameters.Modulus;
+				BigInteger bigInteger2 = BigIntegers.CreateRandomInRange(BigInteger.One, modulus.Subtract(BigInteger.One), random);
+				BigInteger input = bigInteger2.ModPow(publicExponent, modulus).Multiply(bigInteger).Mod(modulus);
+				BigInteger bigInteger3 = core.ProcessBlock(input);
+				BigInteger val = bigInteger2.ModInverse(modulus);
+				bigInteger4 = bigInteger3.Multiply(val).Mod(modulus);
+				if (!bigInteger.Equals(bigInteger4.ModPow(publicExponent, modulus)))
+				{
+					throw new InvalidOperationException("RSA engine faulty decryption/signing detected");
+				}
+			}
+			else
+			{
+				bigInteger4 = core.ProcessBlock(bigInteger);
+			}
+		}
+		else
+		{
+			bigInteger4 = core.ProcessBlock(bigInteger);
+		}
+		return core.ConvertOutput(bigInteger4);
+	}
+}