public override ECPoint Add(ECPoint b)
    {
        if (base.IsInfinity)
        {
            return(b);
        }
        if (b.IsInfinity)
        {
            return(this);
        }
        if (this == b)
        {
            return(Twice());
        }
        ECCurve curve = Curve;
        Curve25519FieldElement curve25519FieldElement  = (Curve25519FieldElement)base.RawXCoord;
        Curve25519FieldElement curve25519FieldElement2 = (Curve25519FieldElement)base.RawYCoord;
        Curve25519FieldElement curve25519FieldElement3 = (Curve25519FieldElement)base.RawZCoords[0];
        Curve25519FieldElement curve25519FieldElement4 = (Curve25519FieldElement)b.RawXCoord;
        Curve25519FieldElement curve25519FieldElement5 = (Curve25519FieldElement)b.RawYCoord;
        Curve25519FieldElement curve25519FieldElement6 = (Curve25519FieldElement)b.RawZCoords[0];

        uint[] array  = Nat256.CreateExt();
        uint[] array2 = Nat256.Create();
        uint[] array3 = Nat256.Create();
        uint[] array4 = Nat256.Create();
        bool   isOne  = curve25519FieldElement3.IsOne;

        uint[] array5;
        uint[] array6;
        if (isOne)
        {
            array5 = curve25519FieldElement4.x;
            array6 = curve25519FieldElement5.x;
        }
        else
        {
            array6 = array3;
            Curve25519Field.Square(curve25519FieldElement3.x, array6);
            array5 = array2;
            Curve25519Field.Multiply(array6, curve25519FieldElement4.x, array5);
            Curve25519Field.Multiply(array6, curve25519FieldElement3.x, array6);
            Curve25519Field.Multiply(array6, curve25519FieldElement5.x, array6);
        }
        bool isOne2 = curve25519FieldElement6.IsOne;

        uint[] array7;
        uint[] array8;
        if (isOne2)
        {
            array7 = curve25519FieldElement.x;
            array8 = curve25519FieldElement2.x;
        }
        else
        {
            array8 = array4;
            Curve25519Field.Square(curve25519FieldElement6.x, array8);
            array7 = array;
            Curve25519Field.Multiply(array8, curve25519FieldElement.x, array7);
            Curve25519Field.Multiply(array8, curve25519FieldElement6.x, array8);
            Curve25519Field.Multiply(array8, curve25519FieldElement2.x, array8);
        }
        uint[] array9 = Nat256.Create();
        Curve25519Field.Subtract(array7, array5, array9);
        uint[] array10 = array2;
        Curve25519Field.Subtract(array8, array6, array10);
        if (Nat256.IsZero(array9))
        {
            if (Nat256.IsZero(array10))
            {
                return(Twice());
            }
            return(curve.Infinity);
        }
        uint[] array11 = Nat256.Create();
        Curve25519Field.Square(array9, array11);
        uint[] array12 = Nat256.Create();
        Curve25519Field.Multiply(array11, array9, array12);
        uint[] array13 = array3;
        Curve25519Field.Multiply(array11, array7, array13);
        Curve25519Field.Negate(array12, array12);
        Nat256.Mul(array8, array12, array);
        uint x = Nat256.AddBothTo(array13, array13, array12);

        Curve25519Field.Reduce27(x, array12);
        Curve25519FieldElement curve25519FieldElement7 = new Curve25519FieldElement(array4);

        Curve25519Field.Square(array10, curve25519FieldElement7.x);
        Curve25519Field.Subtract(curve25519FieldElement7.x, array12, curve25519FieldElement7.x);
        Curve25519FieldElement curve25519FieldElement8 = new Curve25519FieldElement(array12);

        Curve25519Field.Subtract(array13, curve25519FieldElement7.x, curve25519FieldElement8.x);
        Curve25519Field.MultiplyAddToExt(curve25519FieldElement8.x, array10, array);
        Curve25519Field.Reduce(array, curve25519FieldElement8.x);
        Curve25519FieldElement curve25519FieldElement9 = new Curve25519FieldElement(array9);

        if (!isOne)
        {
            Curve25519Field.Multiply(curve25519FieldElement9.x, curve25519FieldElement3.x, curve25519FieldElement9.x);
        }
        if (!isOne2)
        {
            Curve25519Field.Multiply(curve25519FieldElement9.x, curve25519FieldElement6.x, curve25519FieldElement9.x);
        }
        uint[] zSquared = (isOne && isOne2) ? array11 : null;
        Curve25519FieldElement curve25519FieldElement10 = CalculateJacobianModifiedW(curve25519FieldElement9, zSquared);

        ECFieldElement[] zs = new ECFieldElement[2]
        {
            curve25519FieldElement9,
            curve25519FieldElement10
        };
        return(new Curve25519Point(curve, curve25519FieldElement7, curve25519FieldElement8, zs, base.IsCompressed));
    }
Exemple #2
0
 public override ECFieldElement Negate()
 {
     uint[] z = Nat256.Create();
     Curve25519Field.Negate(x, z);
     return(new Curve25519FieldElement(z));
 }