public void KnowledgeOfDiscreteLogVerifiesToFalse()
{
// Even if the challenge is correct, because the public input in the hash is right,
// if the final response is not valid wrt the verification equation,
// the verifier should still reject.
var secret = new Scalar(7);
var generator = Generators.G;
var publicPoint = secret * generator;
Scalar randomScalar = new Scalar(14);
var nonce = randomScalar * generator;
var statement = new Statement(publicPoint, generator);
var challenge = Challenge.Build(nonce, statement);
var response = randomScalar + (secret + Scalar.One) * challenge;
var proof = new KnowledgeOfDlog(nonce, response);
Assert.False(Verifier.Verify(proof, statement));
// Other false verification tests.
var point1 = new Scalar(3) * Generators.G;
var point2 = new Scalar(7) * Generators.G;
var scalar = new Scalar(11);
var gen = Generators.G;
proof = new KnowledgeOfDlog(point1, scalar);
var statement2 = new Statement(point2, gen);
Assert.False(Verifier.Verify(proof, statement2));
}
public void Throws()
{
var dlProof = new KnowledgeOfDlog(Generators.G, Scalar.One);
var repProof = new KnowledgeOfRep(Generators.G, Scalar.One, CryptoHelpers.ScalarThree);
// Demonstrate when it shouldn't throw.
var validStatement1 = new Statement(Generators.Ga, Generators.Gg);
var validStatement2 = new Statement(Generators.Ga, Generators.Gg, Generators.Ga);
Verifier.Verify(dlProof, validStatement1);
Verifier.Verify(repProof, validStatement2);
// Public point should not be equal to the random point of the proof.
Assert.ThrowsAny <InvalidOperationException>(() => Verifier.Verify(dlProof, new Statement(Generators.G, Generators.Ga)));
Assert.ThrowsAny <InvalidOperationException>(() => Verifier.Verify(repProof, new Statement(Generators.G, Generators.Gg, Generators.Ga)));
// Same number of generators must be provided as the responses.
Assert.ThrowsAny <InvalidOperationException>(() => Verifier.Verify(dlProof, new Statement(Generators.Ga, Generators.Gg, Generators.GV)));
Assert.ThrowsAny <InvalidOperationException>(() => Verifier.Verify(repProof, new Statement(Generators.Ga, Generators.Gg)));
Assert.ThrowsAny <InvalidOperationException>(() => Verifier.Verify(repProof, new Statement(Generators.Ga, Generators.Gg, Generators.Ga, Generators.GV)));
}