public static bool VerifySignature(byte[] publickKey, byte [] signature, byte [] hashToVerify)
{
EllipticCurveDsa ellipticCurveDsa = new EllipticCurveDsa(CurveOID, EllipticCurveAlgorithm.EcDsaSha2Nistp256);
ellipticCurveDsa.FromPublicKey(publickKey); // build the curve from the public key
return(ellipticCurveDsa.VerifyHash(hashToVerify, signature));
}
public static byte[] SignDataHash(byte [] Hash, string privateKey)
{
EllipticCurveDsa ellipticCurveDsa = new EllipticCurveDsa(CurveOID, EllipticCurveAlgorithm.EcDsaSha2Nistp256);
byte[] privateKeyByte = Convert.FromBase64String(privateKey);
ellipticCurveDsa.FromPrivateKey(privateKeyByte);
byte[] signature = ellipticCurveDsa.SignHash(Hash);
return(signature);
}
public void ShouldSignAndVerifyMessageWithoutKey()
{
EllipticCurveDsa ellipticCurveDsa = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
EllipticCurveDsa ellipticCurveDsaFake = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
byte[] message = new BigInteger("968236873715988614170569073515315707566766479517").ToByteArray();
byte[] signature = ellipticCurveDsa.SignMessage(message);
bool isCorrect = ellipticCurveDsa.VerifyMessage(message, signature);
bool isFake = ellipticCurveDsaFake.VerifyMessage(message, signature);
Assert.True(isCorrect, "Signature does not match message");
Assert.False(isFake, "Fake Signature does not match message");
//Both values will not be true because no common keys were used in building the curves
}
public void ShouldSignAndVerifyDataHash()
{
EllipticCurveAlgorithm curve = EllipticCurveAlgorithm.Create(EllipticCurveAlgorithm.EcDsaSha2Nistp256);
var privateKey = curve.GetPrivateKey();
EllipticCurveDsa ellipticCurveDsa = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
EllipticCurveDsa ellipticCurveDsaFake = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
ellipticCurveDsa.FromPrivateKey(privateKey);
ellipticCurveDsaFake.FromPrivateKey(privateKey);
SHA256 sHA256 = SHA256.Create();
byte[] hashBytes = sHA256.ComputeHash(Encoding.Default.GetBytes("Message to be hashed"));
byte[] signature = ellipticCurveDsa.SignHash(hashBytes);
bool isCorrect = ellipticCurveDsa.VerifyHash(hashBytes, signature);
bool isFake = ellipticCurveDsaFake.VerifyHash(hashBytes, signature);
Assert.Equal(isCorrect, isFake);
}
public void ShouldVerifyTransactionUsingPublicKey()
{
EllipticCurveAlgorithm curve = EllipticCurveAlgorithm.Create(EllipticCurveAlgorithm.EcDsaSha2Nistp256);
var privateKey = curve.GetPrivateKey();
var pubKey = curve.GetPublicKey();
//The first curve is created from the private key
EllipticCurveDsa ellipticCurveDsa = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
ellipticCurveDsa.FromPrivateKey(privateKey);
//The second curve is created from the public key of the first curve and is used to verify the transaction
//The public key can be easily shared which makes it easy for verification
EllipticCurveDsa ellipticCurveDsaFake = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
ellipticCurveDsaFake.FromPublicKey(pubKey);
SHA256 sHA256 = SHA256.Create();
byte[] hashBytes = sHA256.ComputeHash(Encoding.Default.GetBytes("Message to be hashed"));
byte[] signature = ellipticCurveDsa.SignHash(hashBytes);
bool isCorrect = ellipticCurveDsa.VerifyHash(hashBytes, signature);
bool isFake = ellipticCurveDsaFake.VerifyHash(hashBytes, signature);
Assert.Equal(isCorrect, isFake);
//Perform same operation using ChainUtility
byte[] signature2 = ChainUtility.SignDataHash(hashBytes, Convert.ToBase64String(privateKey));
var newKeyPair = ChainUtility.GenerateNewKeyPair();
Assert.True(ChainUtility.VerifySignature(pubKey, signature2, hashBytes));
Assert.False(ChainUtility.VerifySignature(Convert.FromBase64String(newKeyPair.PublicKey), signature2, hashBytes));
}
public void ShouldSignAndVerifyMessage()
{
EllipticCurveAlgorithm curve = EllipticCurveAlgorithm.Create(EllipticCurveAlgorithm.EcDsaSha2Nistp256);
var privateKey = curve.GetPrivateKey();
EllipticCurveDsa ellipticCurveDsa = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
ellipticCurveDsa.FromPrivateKey(privateKey);
EllipticCurveDsa ellipticCurveDsaFake = new EllipticCurveDsa("1.2.840.10045.3.1.7", EllipticCurveAlgorithm.EcDsaSha2Nistp256);
ellipticCurveDsaFake.FromPrivateKey(privateKey);
byte[] message = new BigInteger("968236873715988614170569073515315707566766479517").ToByteArray();
byte[] signature = ellipticCurveDsa.SignMessage(message);
bool isCorrect = ellipticCurveDsa.VerifyMessage(message, signature);
bool isFake = ellipticCurveDsaFake.VerifyMessage(message, signature);
Assert.Equal(isCorrect, isFake);
//Both values are true because the curves were built from the same private key
}