Ejemplo n.º 1
0
        public override Boolean Verify(byte[] publicKey, byte[] message, byte[] signature, byte[] rgbContext = null)
        {
            EdDSAPoint A = DecodePoint(publicKey);

            byte[] r = new byte[signature.Length / 2];
            Array.Copy(signature, r, r.Length);
            EdDSAPoint R = DecodePoint(r);

            byte[] s = new byte[signature.Length / 2];
            Array.Copy(signature, r.Length, s, 0, r.Length);
            Array.Reverse(s);
            BigInteger S = new BigInteger(1, s);

            message = PreHash(message);

            ShakeDigest sha256 = new ShakeDigest(256);

            byte[] rgbDom = Dom(rgbContext);
            sha256.BlockUpdate(rgbDom, 0, rgbDom.Length);
            sha256.BlockUpdate(r, 0, r.Length);
            sha256.BlockUpdate(publicKey, 0, publicKey.Length);
            sha256.BlockUpdate(message, 0, message.Length);
            byte[] h = new byte[114];
            sha256.DoFinal(h, 0, 114);
            Array.Reverse(h);
            BigInteger k = new BigInteger(1, h).Mod(EdDSAPoint448.L);

            EdDSAPoint left  = EdDSAPoint448.B.MultipleByScalar(S).Normalize();
            EdDSAPoint right = EdDSAPoint448.Add((EdDSAPoint448)R, (EdDSAPoint448)A.MultipleByScalar(k)).Normalize();

            return(left.equal(right));
        }
Ejemplo n.º 2
0
        static public EdDSAPoint448 Add(EdDSAPoint448 p1, EdDSAPoint448 p2)
        {
            BigInteger A  = p1.Z.Multiply(p2.Z).Mod(p);
            BigInteger B  = A.Square().Mod(p);
            BigInteger C  = p1.X.Multiply(p2.X).Mod(p);
            BigInteger D  = p1.Y.Multiply(p2.Y).Mod(p);
            BigInteger E  = d.Multiply(C).Mod(p).Multiply(D).Mod(p);
            BigInteger F  = B.Subtract(E).Mod(p);
            BigInteger G  = B.Add(E).Mod(p);
            BigInteger H  = (p1.X.Add(p1.Y)).Mod(p).Multiply(p2.X.Add(p2.Y).Mod(p)).Mod(p);
            BigInteger X3 = A.Multiply(F).Mod(p).Multiply(H.Subtract(C).Mod(p).Subtract(D).Mod(p)).Mod(p);
            BigInteger Y3 = A.Multiply(G).Mod(p).Multiply(D.Subtract(C).Mod(p)).Mod(p);
            BigInteger Z3 = F.Multiply(G).Mod(p);

            return(new EdDSAPoint448(X3, Y3, Z3));
        }
Ejemplo n.º 3
0
        public override EdDSAPoint MultipleByScalar(BigInteger k)
        {
            int           i;
            EdDSAPoint448 result = new EdDSAPoint448(zero, one, one);
            EdDSAPoint448 pNext  = this;

            for (i = 0; i < k.BitLength; i++)
            {
                if (k.TestBit(i))
                {
                    result = Add(pNext, result);
                }
                pNext = pNext.Double();
            }

            return(result.Normalize());
        }
Ejemplo n.º 4
0
        EdDSAPoint448 Double()
        {
            EdDSAPoint tmp = new EdDSAPoint448(zero, one);
            BigInteger C   = this.X.Square().Mod(p);
            BigInteger D   = this.Y.Square().Mod(p);
            BigInteger H   = this.Z.Square().Mod(p);

            BigInteger E = C.Add(D).Mod(p);
            BigInteger B = this.X.Add(this.Y).Mod(p).Square().Mod(p);
            BigInteger J = E.Subtract(H.Add(H).Mod(p)).Mod(p);

            BigInteger X = B.Subtract(E).Mod(p).Multiply(J).Mod(p);
            BigInteger Y = E.Multiply(C.Subtract(D).Mod(p)).Mod(p);
            BigInteger Z = E.Multiply(J).Mod(p);

            return(new EdDSAPoint448(X, Y, Z));

//                return Add(this, this);
        }
Ejemplo n.º 5
0
        public override EdDSAPoint GetPublic(byte[] privateKey)
        {
            if (privateKey.Length != 57)
            {
                throw new CoseException("Invalid private key");
            }

            ShakeDigest shake = new ShakeDigest(256);

            byte[] h = new byte[114];
            shake.BlockUpdate(privateKey, 0, privateKey.Length);
            shake.DoFinal(h, 0, 114);

            Array.Resize(ref h, 57);

            h[0]  &= 0xfc; // Clear lowest 2 bits
            h[56]  = 0;    // Clear the highest byte
            h[55] |= 0x80; // Set the highest bit
            Array.Reverse(h);
            BigInteger    a         = new BigInteger(1, h);
            EdDSAPoint448 publicKey = (EdDSAPoint448)EdDSAPoint448.B.MultipleByScalar(a);

            return(publicKey);
        }