/// <summary>
/// Generates a random private-public key pair.
/// </summary>
/// <returns>The tuple consists of a private and public key</returns>
public (BigInteger privateKey, BigIntegerPoint publicKey) GenerateKeyPair()
{
BigInteger privateKey = EllipticCurveHelpers.RandomIntegerBelow(this.Curve.N);
BigIntegerPoint publicKey = this.Curve.ScalarMult(privateKey, this.Curve.G);
return(privateKey, publicKey);
}
/// <summary>
/// Generates signature.
/// </summary>
/// <param name="privateKey"></param>
/// <param name="message"></param>
/// <returns></returns>
public (BigInteger r, BigInteger s) Sign(string message, BigInteger privateKey)
{
BigInteger z = this.HashMessage(message);
BigInteger r = 0;
BigInteger s = 0;
while (r == 0 || s == 0)
{
BigInteger k = EllipticCurveHelpers.RandomIntegerBelow(this.Curve.N);
BigIntegerPoint point = this.Curve.ScalarMult(k, this.Curve.G);
r = EllipticCurveHelpers.MathMod(point.X, this.Curve.N);
s = EllipticCurveHelpers.MathMod((z + r * privateKey) * this.Curve.InverseMod(k, this.Curve.N), this.Curve.N);
}
return(r, s);
}
