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fixed file name
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dghgit committed Jan 20, 2019
1 parent 5513e11 commit a6cb039
Showing 1 changed file with 153 additions and 0 deletions.
153 changes: 153 additions & 0 deletions crypto/src/crypto/signers/ECGost3410_2012Signer.cs
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using Org.BouncyCastle.Math;
using System;
using System.IO;

using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Math.EC;
using Org.BouncyCastle.Math.EC.Multiplier;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Crypto.Signers
{
public class ECGOST3410_2012Signer : IDsaExt
{
private ECKeyParameters key;
private SecureRandom secureRandom;
private bool forSigning;

public BigInteger Order
{
get { return key.Parameters.N; }
}

public string AlgorithmName
{
get { return key.AlgorithmName; }
}

public virtual void Init(bool forSigning, ICipherParameters parameters)
{
this.forSigning = forSigning;
if (forSigning)
{
if (parameters is ParametersWithRandom)
{
ParametersWithRandom rParam = (ParametersWithRandom)parameters;
this.secureRandom = rParam.Random;
this.key = (ECPrivateKeyParameters)rParam.Parameters;
}
else
{
this.secureRandom = new SecureRandom();
this.key = (ECPrivateKeyParameters)parameters;
}
}
else
{
this.key = (ECPublicKeyParameters)parameters;
}
}

public BigInteger[] GenerateSignature(byte[] message)
{
if (!forSigning)
{
throw new InvalidOperationException("not initialized for signing");
}

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 e = new BigInteger(1, mRev);

ECDomainParameters ec = key.Parameters;
BigInteger n = ec.N;
BigInteger d = ((ECPrivateKeyParameters)key).D;

BigInteger r, s;

ECMultiplier basePointMultiplier = CreateBasePointMultiplier();

do // generate s
{
BigInteger k;
do // generate r
{
do
{
k = BigIntegers.CreateRandomBigInteger(n.BitLength, secureRandom);
}
while (k.Equals(BigInteger.Zero)); // ECConstants.ZERO));

ECPoint p = basePointMultiplier.Multiply(ec.G, k).Normalize();

r = p.AffineXCoord.ToBigInteger().Mod(n);
}
while (r.Equals(BigInteger.Zero)); // ECConstants.ZERO));

s = (k.Multiply(e)).Add(d.Multiply(r)).Mod(n);
}
while (s.Equals(BigInteger.Zero)); // ECConstants.ZERO));

return new BigInteger[] { r, s };
}


public bool VerifySignature(byte[] message, BigInteger r, BigInteger s)
{
if (forSigning)
{
throw new InvalidOperationException("not initialized for verification");
}


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 e = new BigInteger(1, mRev);
BigInteger n = key.Parameters.N;

// r in the range [1,n-1]
if (r.CompareTo(BigInteger.One) < 0 || r.CompareTo(n) >= 0)
{
return false;
}

// s in the range [1,n-1]
if (s.CompareTo(BigInteger.One) < 0 || s.CompareTo(n) >= 0)
{
return false;
}

BigInteger v = e.ModInverse(n);

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

ECPoint G = key.Parameters.G; // P
ECPoint Q = ((ECPublicKeyParameters)key).Q;

ECPoint point = ECAlgorithms.SumOfTwoMultiplies(G, z1, Q, z2).Normalize();

// components must be bogus.
if (point.IsInfinity)
{
return false;
}

BigInteger R = point.AffineXCoord.ToBigInteger().Mod(n);

return R.Equals(r);
}

protected virtual ECMultiplier CreateBasePointMultiplier()
{
return new FixedPointCombMultiplier();
}
}
}

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