public void TestNISTKeyBelongsToP256()
{
var gx = BigInteger.Parse("6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296", NumberStyles.AllowHexSpecifier);
var gy = BigInteger.Parse("4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5", NumberStyles.AllowHexSpecifier);
EllipticCurveHelper.TestKeyBelongsToP256(gx, gy);
}
public void TestECDHCngKeyEncoding()
{
ECDiffieHellmanCng aliceCng = new ECDiffieHellmanCng(256)
{
HashAlgorithm = CngAlgorithm.Sha256,
KeyDerivationFunction = ECDiffieHellmanKeyDerivationFunction.Hash
};
byte[] alicePubKeyBlob = aliceCng.Key.Export(CngKeyBlobFormat.EccPublicBlob);
byte[] aliceCoordinateX = new byte[33]; //byte0 = 0 to ensure that the biginteger is positive
byte[] aliceCoordinateY = new byte[33]; //byte0 = 0 to ensure that the biginteger is positive
aliceCoordinateX[0] = 0x00;
aliceCoordinateX[0] = 0x00;
Array.Copy(alicePubKeyBlob, 8, aliceCoordinateX, 1, 32);
Array.Copy(alicePubKeyBlob, 8 + 32, aliceCoordinateY, 1, 32);
BigInteger x = new BigInteger(aliceCoordinateX.Reverse().ToArray());
BigInteger y = new BigInteger(aliceCoordinateY.Reverse().ToArray());
EllipticCurveHelper.TestKeyBelongsToP256(x, y);
}
public void TestCngGeneratP256PublicKeysWithBigEndianEncoding()
{
ECDiffieHellmanCng aliceCng = new ECDiffieHellmanCng(256)
{
HashAlgorithm = CngAlgorithm.Sha256,
KeyDerivationFunction = ECDiffieHellmanKeyDerivationFunction.Hash
};
byte[] alicePubKeyBlob = aliceCng.Key.Export(CngKeyBlobFormat.EccPublicBlob);
Assert.AreEqual(2 * 32 + 8, alicePubKeyBlob.Length);
var keyType = new byte[] { 0x45, 0x43, 0x4b, 0x31 };
var keyLength = new byte[] { 0x20, 0x00, 0x00, 0x00 };
var keyTypeAndLength = new[] { keyType, keyLength }.SelectMany(l => l).ToArray();
var startOfKey = alicePubKeyBlob.Where((b, i) => i < 8).ToArray();
Assert.IsTrue(keyTypeAndLength.SequenceEqual(startOfKey));
byte[] aliceElipticCoordinates = new byte[64];
Array.Copy(alicePubKeyBlob, 8, aliceElipticCoordinates, 0, aliceElipticCoordinates.Length);
EllipticCurveHelper.TestKeyBelongsToP256(aliceElipticCoordinates);
}
public void TestCngKeyOnP256()
{
CngKey key = ECDHHelper.CreateCngKey();
EllipticCurveHelper.TestKeyBelongsToP256(key);
}