public static void KeyExchange(ArraySegment <byte> sharedKey, ArraySegment <byte> publicKey, ArraySegment <byte> privateKey, bool naclCompat = false)
{
if (sharedKey.Array == null)
{
throw new ArgumentNullException("sharedKey.Array");
}
if (publicKey.Array == null)
{
throw new ArgumentNullException("publicKey.Array");
}
if (privateKey.Array == null)
{
throw new ArgumentNullException("privateKey");
}
if (sharedKey.Count != SharedKeySizeInBytes)
{
throw new ArgumentException("sharedKey.Count != 32");
}
if (publicKey.Count != PublicKeySizeInBytes)
{
throw new ArgumentException("publicKey.Count != 32");
}
if (privateKey.Count != ExpandedPrivateKeySizeInBytes)
{
throw new ArgumentException("privateKey.Count != 64");
}
FieldElement montgomeryX, edwardsY, edwardsZ, sharedMontgomeryX;
FieldOperations.fe_frombytes(out edwardsY, publicKey.Array, publicKey.Offset);
FieldOperations.fe_1(out edwardsZ);
Curve25519.EdwardsToMontgomeryX(out montgomeryX, ref edwardsY, ref edwardsZ);
IHash hasher = AuthenticatorFactory.CreateHashPrimitive(HashFunction.Sha512);
hasher.BlockUpdate(privateKey.Array, privateKey.Offset, 32);
byte[] h = new byte[64];
hasher.DoFinal(h, 0);
ScalarOperations.sc_clamp(h, 0);
MontgomeryOperations.scalarmult(out sharedMontgomeryX, h, 0, ref montgomeryX);
h.SecureWipe();
FieldOperations.fe_tobytes(sharedKey.Array, sharedKey.Offset, ref sharedMontgomeryX);
if (naclCompat)
{
Curve25519.KeyExchangeOutputHashNaCl(sharedKey.Array, sharedKey.Offset);
}
}