コード例 #1
0
 internal static void EdwardsToMontgomeryX(out FieldElement montgomeryX, ref FieldElement edwardsY,
                                           ref FieldElement edwardsZ)
 {
     FieldOperations.fe_add(out var tempX, ref edwardsZ, ref edwardsY);
     FieldOperations.fe_sub(out var tempZ, ref edwardsZ, ref edwardsY);
     FieldOperations.fe_invert(out tempZ, ref tempZ);
     FieldOperations.fe_mul(out montgomeryX, ref tempX, ref tempZ);
 }
コード例 #2
0
        public static void KeyExchange(ArraySegment <byte> sharedKey, ArraySegment <byte> publicKey,
                                       ArraySegment <byte> privateKey)
        {
            if (sharedKey.Array == null)
            {
                throw new ArgumentNullException(nameof(sharedKey));
            }
            if (publicKey.Array == null)
            {
                throw new ArgumentNullException(nameof(sharedKey));
            }
            if (privateKey.Array == null)
            {
                throw new ArgumentNullException("privateKey");
            }
            if (sharedKey.Count != 32)
            {
                throw new ArgumentException("sharedKey.Count != 32");
            }
            if (publicKey.Count != 32)
            {
                throw new ArgumentException("publicKey.Count != 32");
            }
            if (privateKey.Count != 64)
            {
                throw new ArgumentException("privateKey.Count != 64");
            }

            FieldOperations.fe_frombytes(out var edwardsY, publicKey.Array, publicKey.Offset);
            FieldOperations.fe_1(out var edwardsZ);
            MontgomeryCurve25519.EdwardsToMontgomeryX(out var montgomeryX, ref edwardsY, ref edwardsZ);
            var h = Sha512.Hash(privateKey.Array, privateKey.Offset, 32);

            ScalarOperations.ScClamp(h, 0);
            MontgomeryOperations.ScalarMult(out var sharedMontgomeryX, h, 0, ref montgomeryX);
            CryptoBytes.Wipe(h);
            FieldOperations.fe_tobytes(sharedKey.Array, sharedKey.Offset, ref sharedMontgomeryX);
            MontgomeryCurve25519.KeyExchangeOutputHashNaCl(sharedKey.Array, sharedKey.Offset);
        }