private static ECPoint CalculateMqvAgreement(ECDomainParameters parameters, ECPrivateKeyParameters d1U, ECPrivateKeyParameters d2U, ECPublicKeyParameters Q2U, ECPublicKeyParameters Q1V, ECPublicKeyParameters Q2V)
{
BigInteger n = parameters.N;
int num = (n.BitLength + 1) / 2;
BigInteger m = BigInteger.One.ShiftLeft(num);
ECCurve curve = parameters.Curve;
ECPoint[] array = new ECPoint[3]
{
ECAlgorithms.ImportPoint(curve, (Q2U == null) ? parameters.G.Multiply(d2U.D) : Q2U.Q),
ECAlgorithms.ImportPoint(curve, Q1V.Q),
ECAlgorithms.ImportPoint(curve, Q2V.Q)
};
curve.NormalizeAll(array);
ECPoint eCPoint = array[0];
ECPoint p = array[1];
ECPoint eCPoint2 = array[2];
BigInteger bigInteger = eCPoint.AffineXCoord.ToBigInteger();
BigInteger bigInteger2 = bigInteger.Mod(m);
BigInteger val = bigInteger2.SetBit(num);
BigInteger val2 = d1U.D.Multiply(val).Add(d2U.D).Mod(n);
BigInteger bigInteger3 = eCPoint2.AffineXCoord.ToBigInteger();
BigInteger bigInteger4 = bigInteger3.Mod(m);
BigInteger bigInteger5 = bigInteger4.SetBit(num);
BigInteger bigInteger6 = parameters.H.Multiply(val2).Mod(n);
return(ECAlgorithms.SumOfTwoMultiplies(p, bigInteger5.Multiply(bigInteger6).Mod(n), eCPoint2, bigInteger6));
}
internal static ECPoint Validate(ECCurve c, ECPoint q)
{
if (q == null)
{
throw new ArgumentException("Point has null value", "q");
}
q = ECAlgorithms.ImportPoint(c, q).Normalize();
if (q.IsInfinity)
{
throw new ArgumentException("Point at infinity", "q");
}
if (!q.IsValid())
{
throw new ArgumentException("Point not on curve", "q");
}
return(q);
}
internal static ECPoint ValidatePublicPoint(ECCurve c, ECPoint q)
{
if (null == q)
{
throw new ArgumentNullException("q", "Point cannot be null");
}
q = ECAlgorithms.ImportPoint(c, q).Normalize();
if (q.IsInfinity)
{
throw new ArgumentException("Point at infinity", "q");
}
if (!q.IsValid())
{
throw new ArgumentException("Point not on curve", "q");
}
return(q);
}
// The ECMQV Primitive as described in SEC-1, 3.4
private static ECPoint CalculateMqvAgreement(
ECDomainParameters parameters,
ECPrivateKeyParameters d1U,
ECPrivateKeyParameters d2U,
ECPublicKeyParameters Q2U,
ECPublicKeyParameters Q1V,
ECPublicKeyParameters Q2V)
{
BigInteger n = parameters.N;
int e = (n.BitLength + 1) / 2;
BigInteger powE = BigInteger.One.ShiftLeft(e);
ECCurve curve = parameters.Curve;
ECPoint[] points = new ECPoint[] {
// The Q2U public key is optional - but will be calculated for us if it wasn't present
ECAlgorithms.ImportPoint(curve, Q2U.Q),
ECAlgorithms.ImportPoint(curve, Q1V.Q),
ECAlgorithms.ImportPoint(curve, Q2V.Q)
};
curve.NormalizeAll(points);
ECPoint q2u = points[0], q1v = points[1], q2v = points[2];
BigInteger x = q2u.AffineXCoord.ToBigInteger();
BigInteger xBar = x.Mod(powE);
BigInteger Q2UBar = xBar.SetBit(e);
BigInteger s = d1U.D.Multiply(Q2UBar).Add(d2U.D).Mod(n);
BigInteger xPrime = q2v.AffineXCoord.ToBigInteger();
BigInteger xPrimeBar = xPrime.Mod(powE);
BigInteger Q2VBar = xPrimeBar.SetBit(e);
BigInteger hs = parameters.H.Multiply(s).Mod(n);
return(ECAlgorithms.SumOfTwoMultiplies(
q1v, Q2VBar.Multiply(hs).Mod(n), q2v, hs));
}
