Org.BouncyCastle.Crypto.Signers.Gost3410Signer.VerifySignature C# (CSharp) Method

		public bool VerifySignature(
			byte[]		message,
			BigInteger	r,
			BigInteger	s)
		{
			byte[] mRev = new byte[message.Length]; // conversion is little-endian
			for (int i = 0; i != mRev.Length; i++)
			{
				mRev[i] = message[mRev.Length - 1 - i];
			}

			BigInteger m = new BigInteger(1, mRev);
			Gost3410Parameters parameters = key.Parameters;

			if (r.SignValue < 0 || parameters.Q.CompareTo(r) <= 0)
			{
				return false;
			}

			if (s.SignValue < 0 || parameters.Q.CompareTo(s) <= 0)
			{
				return false;
			}

			BigInteger v = m.ModPow(parameters.Q.Subtract(BigInteger.Two), parameters.Q);

			BigInteger z1 = s.Multiply(v).Mod(parameters.Q);
			BigInteger z2 = (parameters.Q.Subtract(r)).Multiply(v).Mod(parameters.Q);

			z1 = parameters.A.ModPow(z1, parameters.P);
			z2 = ((Gost3410PublicKeyParameters)key).Y.ModPow(z2, parameters.P);

			BigInteger u = z1.Multiply(z2).Mod(parameters.P).Mod(parameters.Q);

			return u.Equals(r);
		}
	}

			public ITestResult Perform()
			{
				BigInteger r = new BigInteger("860d82c60e9502cd00c0e9e1f6563feafec304801974d745c5e02079946f729e",16);
				BigInteger s = new BigInteger("7ef49264ef022801aaa03033cd97915235fbab4c823ed936b0f360c22114688a",16);
				Gost3410ParametersGenerator pGen = new Gost3410ParametersGenerator();

				pGen.Init(1024, 2, init_random);

				Gost3410Parameters parameters = pGen.GenerateParameters();

				if (!pValue.Equals(parameters.P) || !qValue.Equals(parameters.Q))
				{
					return new SimpleTestResult(false, Name + ": p or q wrong");
				}

				Gost3410KeyPairGenerator Gost3410KeyGen = new Gost3410KeyPairGenerator();
				Gost3410KeyGenerationParameters genParam = new Gost3410KeyGenerationParameters(keyRandom, parameters);

				Gost3410KeyGen.Init(genParam);

				AsymmetricCipherKeyPair pair = Gost3410KeyGen.GenerateKeyPair();

				ParametersWithRandom param = new ParametersWithRandom(pair.Private, random);

				Gost3410Signer Gost3410 = new Gost3410Signer();

				Gost3410.Init(true, param);

				BigInteger[] sig = Gost3410.GenerateSignature(hashmessage);

				if (!r.Equals(sig[0]))
				{
					return new SimpleTestResult(false, Name
						+ ": r component wrong." + SimpleTest.NewLine
						+ " expecting: " + r.ToString(16) + SimpleTest.NewLine
						+ " got      : " + sig[0].ToString(16));
				}

				if (!s.Equals(sig[1]))
				{
					return new SimpleTestResult(false, Name
						+ ": s component wrong." + SimpleTest.NewLine
						+ " expecting: " + s.ToString(16) + SimpleTest.NewLine
						+ " got      : " + sig[1].ToString(16));
				}

				Gost3410.Init(false, pair.Public);

				if (Gost3410.VerifySignature(hashmessage, sig[0], sig[1]))
				{
					return new SimpleTestResult(true, Name + ": Okay");
				}
				else
				{
					return new SimpleTestResult(false, Name + ": verification fails");
				}
			}