BestHTTP.SecureProtocol.Org.BouncyCastle.Math.EC.Custom.Sec.SecT163R2Point.Add C# (CSharp) Метод

        public override ECPoint Add(ECPoint b)
        {
            if (this.IsInfinity)
                return b;
            if (b.IsInfinity)
                return this;

            ECCurve curve = this.Curve;

            ECFieldElement X1 = this.RawXCoord;
            ECFieldElement X2 = b.RawXCoord;

            if (X1.IsZero)
            {
                if (X2.IsZero)
                    return curve.Infinity;

                return b.Add(this);
            }

            ECFieldElement L1 = this.RawYCoord, Z1 = this.RawZCoords[0];
            ECFieldElement L2 = b.RawYCoord, Z2 = b.RawZCoords[0];

            bool Z1IsOne = Z1.IsOne;
            ECFieldElement U2 = X2, S2 = L2;
            if (!Z1IsOne)
            {
                U2 = U2.Multiply(Z1);
                S2 = S2.Multiply(Z1);
            }

            bool Z2IsOne = Z2.IsOne;
            ECFieldElement U1 = X1, S1 = L1;
            if (!Z2IsOne)
            {
                U1 = U1.Multiply(Z2);
                S1 = S1.Multiply(Z2);
            }

            ECFieldElement A = S1.Add(S2);
            ECFieldElement B = U1.Add(U2);

            if (B.IsZero)
            {
                if (A.IsZero)
                {
                    return Twice();
                }

                return curve.Infinity;
            }

            ECFieldElement X3, L3, Z3;
            if (X2.IsZero)
            {
                // TODO This can probably be optimized quite a bit
                ECPoint p = this.Normalize();
                X1 = p.XCoord;
                ECFieldElement Y1 = p.YCoord;

                ECFieldElement Y2 = L2;
                ECFieldElement L = Y1.Add(Y2).Divide(X1);

                X3 = L.Square().Add(L).Add(X1).AddOne();
                if (X3.IsZero)
                {
                    return new SecT163R2Point(curve, X3, curve.B.Sqrt(), IsCompressed);
                }

                ECFieldElement Y3 = L.Multiply(X1.Add(X3)).Add(X3).Add(Y1);
                L3 = Y3.Divide(X3).Add(X3);
                Z3 = curve.FromBigInteger(BigInteger.One);
            }
            else
            {
                B = B.Square();

                ECFieldElement AU1 = A.Multiply(U1);
                ECFieldElement AU2 = A.Multiply(U2);

                X3 = AU1.Multiply(AU2);
                if (X3.IsZero)
                {
                    return new SecT163R2Point(curve, X3, curve.B.Sqrt(), IsCompressed);
                }

                ECFieldElement ABZ2 = A.Multiply(B);
                if (!Z2IsOne)
                {
                    ABZ2 = ABZ2.Multiply(Z2);
                }

                L3 = AU2.Add(B).SquarePlusProduct(ABZ2, L1.Add(Z1));

                Z3 = ABZ2;
                if (!Z1IsOne)
                {
                    Z3 = Z3.Multiply(Z1);
                }
            }

            return new SecT163R2Point(curve, X3, L3, new ECFieldElement[] { Z3 }, IsCompressed);
        }