protected virtual Curve25519Point TwiceJacobianModified(bool calculateW)
{
Curve25519FieldElement X1 = (Curve25519FieldElement)this.RawXCoord, Y1 = (Curve25519FieldElement)this.RawYCoord,
Z1 = (Curve25519FieldElement)this.RawZCoords[0], W1 = GetJacobianModifiedW();
uint c;
uint[] M = Nat256.Create();
Curve25519Field.Square(X1.x, M);
c = Nat256.AddBothTo(M, M, M);
c += Nat256.AddTo(W1.x, M);
Curve25519Field.Reduce27(c, M);
uint[] _2Y1 = Nat256.Create();
Curve25519Field.Twice(Y1.x, _2Y1);
uint[] _2Y1Squared = Nat256.Create();
Curve25519Field.Multiply(_2Y1, Y1.x, _2Y1Squared);
uint[] S = Nat256.Create();
Curve25519Field.Multiply(_2Y1Squared, X1.x, S);
Curve25519Field.Twice(S, S);
uint[] _8T = Nat256.Create();
Curve25519Field.Square(_2Y1Squared, _8T);
Curve25519Field.Twice(_8T, _8T);
Curve25519FieldElement X3 = new Curve25519FieldElement(_2Y1Squared);
Curve25519Field.Square(M, X3.x);
Curve25519Field.Subtract(X3.x, S, X3.x);
Curve25519Field.Subtract(X3.x, S, X3.x);
Curve25519FieldElement Y3 = new Curve25519FieldElement(S);
Curve25519Field.Subtract(S, X3.x, Y3.x);
Curve25519Field.Multiply(Y3.x, M, Y3.x);
Curve25519Field.Subtract(Y3.x, _8T, Y3.x);
Curve25519FieldElement Z3 = new Curve25519FieldElement(_2Y1);
if (!Nat256.IsOne(Z1.x))
{
Curve25519Field.Multiply(Z3.x, Z1.x, Z3.x);
}
Curve25519FieldElement W3 = null;
if (calculateW)
{
W3 = new Curve25519FieldElement(_8T);
Curve25519Field.Multiply(W3.x, W1.x, W3.x);
Curve25519Field.Twice(W3.x, W3.x);
}
return(new Curve25519Point(this.Curve, X3, Y3, new ECFieldElement[] { Z3, W3 }, IsCompressed));
}
protected virtual Curve25519FieldElement GetJacobianModifiedW()
{
ECFieldElement[] rawZCoords = base.RawZCoords;
Curve25519FieldElement curve25519FieldElement = (Curve25519FieldElement)rawZCoords[1];
if (curve25519FieldElement == null)
{
curve25519FieldElement = (Curve25519FieldElement)(rawZCoords[1] = CalculateJacobianModifiedW((Curve25519FieldElement)rawZCoords[0], null));
}
return(curve25519FieldElement);
}
protected virtual Curve25519Point TwiceJacobianModified(bool calculateW)
{
Curve25519FieldElement curve25519FieldElement = (Curve25519FieldElement)base.RawXCoord;
Curve25519FieldElement curve25519FieldElement2 = (Curve25519FieldElement)base.RawYCoord;
Curve25519FieldElement curve25519FieldElement3 = (Curve25519FieldElement)base.RawZCoords[0];
Curve25519FieldElement jacobianModifiedW = GetJacobianModifiedW();
uint[] array = Nat256.Create();
Curve25519Field.Square(curve25519FieldElement.x, array);
uint num = Nat256.AddBothTo(array, array, array);
num += Nat256.AddTo(jacobianModifiedW.x, array);
Curve25519Field.Reduce27(num, array);
uint[] array2 = Nat256.Create();
Curve25519Field.Twice(curve25519FieldElement2.x, array2);
uint[] array3 = Nat256.Create();
Curve25519Field.Multiply(array2, curve25519FieldElement2.x, array3);
uint[] array4 = Nat256.Create();
Curve25519Field.Multiply(array3, curve25519FieldElement.x, array4);
Curve25519Field.Twice(array4, array4);
uint[] array5 = Nat256.Create();
Curve25519Field.Square(array3, array5);
Curve25519Field.Twice(array5, array5);
Curve25519FieldElement curve25519FieldElement4 = new Curve25519FieldElement(array3);
Curve25519Field.Square(array, curve25519FieldElement4.x);
Curve25519Field.Subtract(curve25519FieldElement4.x, array4, curve25519FieldElement4.x);
Curve25519Field.Subtract(curve25519FieldElement4.x, array4, curve25519FieldElement4.x);
Curve25519FieldElement curve25519FieldElement5 = new Curve25519FieldElement(array4);
Curve25519Field.Subtract(array4, curve25519FieldElement4.x, curve25519FieldElement5.x);
Curve25519Field.Multiply(curve25519FieldElement5.x, array, curve25519FieldElement5.x);
Curve25519Field.Subtract(curve25519FieldElement5.x, array5, curve25519FieldElement5.x);
Curve25519FieldElement curve25519FieldElement6 = new Curve25519FieldElement(array2);
if (!Nat256.IsOne(curve25519FieldElement3.x))
{
Curve25519Field.Multiply(curve25519FieldElement6.x, curve25519FieldElement3.x, curve25519FieldElement6.x);
}
Curve25519FieldElement curve25519FieldElement7 = null;
if (calculateW)
{
curve25519FieldElement7 = new Curve25519FieldElement(array5);
Curve25519Field.Multiply(curve25519FieldElement7.x, jacobianModifiedW.x, curve25519FieldElement7.x);
Curve25519Field.Twice(curve25519FieldElement7.x, curve25519FieldElement7.x);
}
return(new Curve25519Point(Curve, curve25519FieldElement4, curve25519FieldElement5, new ECFieldElement[2]
{
curve25519FieldElement6,
curve25519FieldElement7
}, base.IsCompressed));
}
public virtual bool Equals(Curve25519FieldElement other)
{
if (this == other)
{
return(true);
}
if (null == other)
{
return(false);
}
return(Nat256.Eq(x, other.x));
}
protected virtual Curve25519FieldElement GetJacobianModifiedW()
{
ECFieldElement[] ZZ = this.RawZCoords;
Curve25519FieldElement W = (Curve25519FieldElement)ZZ[1];
if (W == null)
{
// NOTE: Rarely, TwicePlus will result in the need for a lazy W1 calculation here
ZZ[1] = W = CalculateJacobianModifiedW((Curve25519FieldElement)ZZ[0], null);
}
return(W);
}
protected virtual Curve25519Point TwiceJacobianModified(bool calculateW)
{
Curve25519FieldElement rawXCoord = (Curve25519FieldElement)base.RawXCoord;
Curve25519FieldElement rawYCoord = (Curve25519FieldElement)base.RawYCoord;
Curve25519FieldElement element3 = (Curve25519FieldElement)base.RawZCoords[0];
Curve25519FieldElement jacobianModifiedW = this.GetJacobianModifiedW();
uint[] z = Nat256.Create();
Curve25519Field.Square(rawXCoord.x, z);
uint x = Nat256.AddBothTo(z, z, z) + Nat256.AddTo(jacobianModifiedW.x, z);
Curve25519Field.Reduce27(x, z);
uint[] numArray2 = Nat256.Create();
Curve25519Field.Twice(rawYCoord.x, numArray2);
uint[] numArray3 = Nat256.Create();
Curve25519Field.Multiply(numArray2, rawYCoord.x, numArray3);
uint[] numArray4 = Nat256.Create();
Curve25519Field.Multiply(numArray3, rawXCoord.x, numArray4);
Curve25519Field.Twice(numArray4, numArray4);
uint[] numArray5 = Nat256.Create();
Curve25519Field.Square(numArray3, numArray5);
Curve25519Field.Twice(numArray5, numArray5);
Curve25519FieldElement element5 = new Curve25519FieldElement(numArray3);
Curve25519Field.Square(z, element5.x);
Curve25519Field.Subtract(element5.x, numArray4, element5.x);
Curve25519Field.Subtract(element5.x, numArray4, element5.x);
Curve25519FieldElement y = new Curve25519FieldElement(numArray4);
Curve25519Field.Subtract(numArray4, element5.x, y.x);
Curve25519Field.Multiply(y.x, z, y.x);
Curve25519Field.Subtract(y.x, numArray5, y.x);
Curve25519FieldElement element7 = new Curve25519FieldElement(numArray2);
if (!Nat256.IsOne(element3.x))
{
Curve25519Field.Multiply(element7.x, element3.x, element7.x);
}
Curve25519FieldElement element8 = null;
if (calculateW)
{
element8 = new Curve25519FieldElement(numArray5);
Curve25519Field.Multiply(element8.x, jacobianModifiedW.x, element8.x);
Curve25519Field.Twice(element8.x, element8.x);
}
return(new Curve25519Point(this.Curve, element5, y, new ECFieldElement[] { element7, element8 }, base.IsCompressed));
}
protected virtual Curve25519FieldElement CalculateJacobianModifiedW(Curve25519FieldElement Z, uint[] ZSquared)
{
Curve25519FieldElement curve25519FieldElement = (Curve25519FieldElement)Curve.A;
if (Z.IsOne)
{
return(curve25519FieldElement);
}
Curve25519FieldElement curve25519FieldElement2 = new Curve25519FieldElement();
if (ZSquared == null)
{
ZSquared = curve25519FieldElement2.x;
Curve25519Field.Square(Z.x, ZSquared);
}
Curve25519Field.Square(ZSquared, curve25519FieldElement2.x);
Curve25519Field.Multiply(curve25519FieldElement2.x, curve25519FieldElement.x, curve25519FieldElement2.x);
return(curve25519FieldElement2);
}
protected virtual Curve25519FieldElement CalculateJacobianModifiedW(Curve25519FieldElement Z, uint[] ZSquared)
{
Curve25519FieldElement a = (Curve25519FieldElement)this.Curve.A;
if (Z.IsOne)
{
return(a);
}
Curve25519FieldElement element2 = new Curve25519FieldElement();
if (ZSquared == null)
{
ZSquared = element2.x;
Curve25519Field.Square(Z.x, ZSquared);
}
Curve25519Field.Square(ZSquared, element2.x);
Curve25519Field.Multiply(element2.x, a.x, element2.x);
return(element2);
}
protected virtual Curve25519FieldElement CalculateJacobianModifiedW(Curve25519FieldElement Z, uint[] ZSquared)
{
Curve25519FieldElement a4 = (Curve25519FieldElement)this.Curve.A;
if (Z.IsOne)
{
return(a4);
}
Curve25519FieldElement W = new Curve25519FieldElement();
if (ZSquared == null)
{
ZSquared = W.x;
Curve25519Field.Square(Z.x, ZSquared);
}
Curve25519Field.Square(ZSquared, W.x);
Curve25519Field.Multiply(W.x, a4.x, W.x);
return(W);
}
public override ECPoint Add(ECPoint b)
{
if (this.IsInfinity)
return b;
if (b.IsInfinity)
return this;
if (this == b)
return Twice();
ECCurve curve = this.Curve;
Curve25519FieldElement X1 = (Curve25519FieldElement)this.RawXCoord, Y1 = (Curve25519FieldElement)this.RawYCoord,
Z1 = (Curve25519FieldElement)this.RawZCoords[0];
Curve25519FieldElement X2 = (Curve25519FieldElement)b.RawXCoord, Y2 = (Curve25519FieldElement)b.RawYCoord,
Z2 = (Curve25519FieldElement)b.RawZCoords[0];
uint c;
uint[] tt1 = Nat256.CreateExt();
uint[] t2 = Nat256.Create();
uint[] t3 = Nat256.Create();
uint[] t4 = Nat256.Create();
bool Z1IsOne = Z1.IsOne;
uint[] U2, S2;
if (Z1IsOne)
{
U2 = X2.x;
S2 = Y2.x;
}
else
{
S2 = t3;
Curve25519Field.Square(Z1.x, S2);
U2 = t2;
Curve25519Field.Multiply(S2, X2.x, U2);
Curve25519Field.Multiply(S2, Z1.x, S2);
Curve25519Field.Multiply(S2, Y2.x, S2);
}
bool Z2IsOne = Z2.IsOne;
uint[] U1, S1;
if (Z2IsOne)
{
U1 = X1.x;
S1 = Y1.x;
}
else
{
S1 = t4;
Curve25519Field.Square(Z2.x, S1);
U1 = tt1;
Curve25519Field.Multiply(S1, X1.x, U1);
Curve25519Field.Multiply(S1, Z2.x, S1);
Curve25519Field.Multiply(S1, Y1.x, S1);
}
uint[] H = Nat256.Create();
Curve25519Field.Subtract(U1, U2, H);
uint[] R = t2;
Curve25519Field.Subtract(S1, S2, R);
// Check if b == this or b == -this
if (Nat256.IsZero(H))
{
if (Nat256.IsZero(R))
{
// this == b, i.e. this must be doubled
return this.Twice();
}
// this == -b, i.e. the result is the point at infinity
return curve.Infinity;
}
uint[] HSquared = Nat256.Create();
Curve25519Field.Square(H, HSquared);
uint[] G = Nat256.Create();
Curve25519Field.Multiply(HSquared, H, G);
uint[] V = t3;
Curve25519Field.Multiply(HSquared, U1, V);
Curve25519Field.Negate(G, G);
Nat256.Mul(S1, G, tt1);
c = Nat256.AddBothTo(V, V, G);
Curve25519Field.Reduce27(c, G);
Curve25519FieldElement X3 = new Curve25519FieldElement(t4);
Curve25519Field.Square(R, X3.x);
Curve25519Field.Subtract(X3.x, G, X3.x);
Curve25519FieldElement Y3 = new Curve25519FieldElement(G);
Curve25519Field.Subtract(V, X3.x, Y3.x);
Curve25519Field.MultiplyAddToExt(Y3.x, R, tt1);
Curve25519Field.Reduce(tt1, Y3.x);
Curve25519FieldElement Z3 = new Curve25519FieldElement(H);
if (!Z1IsOne)
{
Curve25519Field.Multiply(Z3.x, Z1.x, Z3.x);
}
if (!Z2IsOne)
{
Curve25519Field.Multiply(Z3.x, Z2.x, Z3.x);
}
uint[] Z3Squared = (Z1IsOne && Z2IsOne) ? HSquared : null;
// TODO If the result will only be used in a subsequent addition, we don't need W3
Curve25519FieldElement W3 = CalculateJacobianModifiedW((Curve25519FieldElement)Z3, Z3Squared);
ECFieldElement[] zs = new ECFieldElement[] { Z3, W3 };
return new Curve25519Point(curve, X3, Y3, zs, IsCompressed);
}
protected virtual Curve25519Point TwiceJacobianModified(bool calculateW)
{
Curve25519FieldElement X1 = (Curve25519FieldElement)this.RawXCoord, Y1 = (Curve25519FieldElement)this.RawYCoord,
Z1 = (Curve25519FieldElement)this.RawZCoords[0], W1 = GetJacobianModifiedW();
uint c;
uint[] M = Nat256.Create();
Curve25519Field.Square(X1.x, M);
c = Nat256.AddBothTo(M, M, M);
c += Nat256.AddTo(W1.x, M);
Curve25519Field.Reduce27(c, M);
uint[] _2Y1 = Nat256.Create();
Curve25519Field.Twice(Y1.x, _2Y1);
uint[] _2Y1Squared = Nat256.Create();
Curve25519Field.Multiply(_2Y1, Y1.x, _2Y1Squared);
uint[] S = Nat256.Create();
Curve25519Field.Multiply(_2Y1Squared, X1.x, S);
Curve25519Field.Twice(S, S);
uint[] _8T = Nat256.Create();
Curve25519Field.Square(_2Y1Squared, _8T);
Curve25519Field.Twice(_8T, _8T);
Curve25519FieldElement X3 = new Curve25519FieldElement(_2Y1Squared);
Curve25519Field.Square(M, X3.x);
Curve25519Field.Subtract(X3.x, S, X3.x);
Curve25519Field.Subtract(X3.x, S, X3.x);
Curve25519FieldElement Y3 = new Curve25519FieldElement(S);
Curve25519Field.Subtract(S, X3.x, Y3.x);
Curve25519Field.Multiply(Y3.x, M, Y3.x);
Curve25519Field.Subtract(Y3.x, _8T, Y3.x);
Curve25519FieldElement Z3 = new Curve25519FieldElement(_2Y1);
if (!Nat256.IsOne(Z1.x))
{
Curve25519Field.Multiply(Z3.x, Z1.x, Z3.x);
}
Curve25519FieldElement W3 = null;
if (calculateW)
{
W3 = new Curve25519FieldElement(_8T);
Curve25519Field.Multiply(W3.x, W1.x, W3.x);
Curve25519Field.Twice(W3.x, W3.x);
}
return new Curve25519Point(this.Curve, X3, Y3, new ECFieldElement[] { Z3, W3 }, IsCompressed);
}
protected virtual Curve25519FieldElement CalculateJacobianModifiedW(Curve25519FieldElement Z, uint[] ZSquared)
{
Curve25519FieldElement a4 = (Curve25519FieldElement)this.Curve.A;
if (Z.IsOne)
return a4;
Curve25519FieldElement W = new Curve25519FieldElement();
if (ZSquared == null)
{
ZSquared = W.x;
Curve25519Field.Square(Z.x, ZSquared);
}
Curve25519Field.Square(ZSquared, W.x);
Curve25519Field.Multiply(W.x, a4.x, W.x);
return W;
}
public virtual bool Equals(Curve25519FieldElement other)
{
if (this == other)
return true;
if (null == other)
return false;
return Nat256.Eq(x, other.x);
}
public override ECPoint Add(ECPoint b)
{
uint[] numArray5;
uint[] numArray6;
uint[] numArray7;
uint[] numArray8;
if (base.IsInfinity)
{
return(b);
}
if (b.IsInfinity)
{
return(this);
}
if (this == b)
{
return(this.Twice());
}
ECCurve curve = this.Curve;
Curve25519FieldElement rawXCoord = (Curve25519FieldElement)base.RawXCoord;
Curve25519FieldElement rawYCoord = (Curve25519FieldElement)base.RawYCoord;
Curve25519FieldElement element3 = (Curve25519FieldElement)base.RawZCoords[0];
Curve25519FieldElement element4 = (Curve25519FieldElement)b.RawXCoord;
Curve25519FieldElement element5 = (Curve25519FieldElement)b.RawYCoord;
Curve25519FieldElement element6 = (Curve25519FieldElement)b.RawZCoords[0];
uint[] zz = Nat256.CreateExt();
uint[] numArray2 = Nat256.Create();
uint[] numArray3 = Nat256.Create();
uint[] x = Nat256.Create();
bool isOne = element3.IsOne;
if (isOne)
{
numArray5 = element4.x;
numArray6 = element5.x;
}
else
{
numArray6 = numArray3;
Curve25519Field.Square(element3.x, numArray6);
numArray5 = numArray2;
Curve25519Field.Multiply(numArray6, element4.x, numArray5);
Curve25519Field.Multiply(numArray6, element3.x, numArray6);
Curve25519Field.Multiply(numArray6, element5.x, numArray6);
}
bool flag2 = element6.IsOne;
if (flag2)
{
numArray7 = rawXCoord.x;
numArray8 = rawYCoord.x;
}
else
{
numArray8 = x;
Curve25519Field.Square(element6.x, numArray8);
numArray7 = zz;
Curve25519Field.Multiply(numArray8, rawXCoord.x, numArray7);
Curve25519Field.Multiply(numArray8, element6.x, numArray8);
Curve25519Field.Multiply(numArray8, rawYCoord.x, numArray8);
}
uint[] z = Nat256.Create();
Curve25519Field.Subtract(numArray7, numArray5, z);
uint[] numArray10 = numArray2;
Curve25519Field.Subtract(numArray8, numArray6, numArray10);
if (Nat256.IsZero(z))
{
if (Nat256.IsZero(numArray10))
{
return(this.Twice());
}
return(curve.Infinity);
}
uint[] numArray11 = Nat256.Create();
Curve25519Field.Square(z, numArray11);
uint[] numArray12 = Nat256.Create();
Curve25519Field.Multiply(numArray11, z, numArray12);
uint[] numArray13 = numArray3;
Curve25519Field.Multiply(numArray11, numArray7, numArray13);
Curve25519Field.Negate(numArray12, numArray12);
Nat256.Mul(numArray8, numArray12, zz);
Curve25519Field.Reduce27(Nat256.AddBothTo(numArray13, numArray13, numArray12), numArray12);
Curve25519FieldElement element7 = new Curve25519FieldElement(x);
Curve25519Field.Square(numArray10, element7.x);
Curve25519Field.Subtract(element7.x, numArray12, element7.x);
Curve25519FieldElement y = new Curve25519FieldElement(numArray12);
Curve25519Field.Subtract(numArray13, element7.x, y.x);
Curve25519Field.MultiplyAddToExt(y.x, numArray10, zz);
Curve25519Field.Reduce(zz, y.x);
Curve25519FieldElement element9 = new Curve25519FieldElement(z);
if (!isOne)
{
Curve25519Field.Multiply(element9.x, element3.x, element9.x);
}
if (!flag2)
{
Curve25519Field.Multiply(element9.x, element6.x, element9.x);
}
uint[] zSquared = (!isOne || !flag2) ? null : numArray11;
Curve25519FieldElement element10 = this.CalculateJacobianModifiedW(element9, zSquared);
ECFieldElement[] zs = new ECFieldElement[] { element9, element10 };
return(new Curve25519Point(curve, element7, y, zs, base.IsCompressed));
}
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) ? null : array11;
Curve25519FieldElement curve25519FieldElement10 = CalculateJacobianModifiedW(curve25519FieldElement9, zSquared);
ECFieldElement[] zs = new ECFieldElement[2]
{
curve25519FieldElement9,
curve25519FieldElement10
};
return(new Curve25519Point(curve, curve25519FieldElement7, curve25519FieldElement8, zs, base.IsCompressed));
}
public override ECPoint Add(ECPoint b)
{
if (this.IsInfinity)
{
return(b);
}
if (b.IsInfinity)
{
return(this);
}
if (this == b)
{
return(Twice());
}
ECCurve curve = this.Curve;
Curve25519FieldElement X1 = (Curve25519FieldElement)this.RawXCoord, Y1 = (Curve25519FieldElement)this.RawYCoord,
Z1 = (Curve25519FieldElement)this.RawZCoords[0];
Curve25519FieldElement X2 = (Curve25519FieldElement)b.RawXCoord, Y2 = (Curve25519FieldElement)b.RawYCoord,
Z2 = (Curve25519FieldElement)b.RawZCoords[0];
uint c;
uint[] tt1 = Nat256.CreateExt();
uint[] t2 = Nat256.Create();
uint[] t3 = Nat256.Create();
uint[] t4 = Nat256.Create();
bool Z1IsOne = Z1.IsOne;
uint[] U2, S2;
if (Z1IsOne)
{
U2 = X2.x;
S2 = Y2.x;
}
else
{
S2 = t3;
Curve25519Field.Square(Z1.x, S2);
U2 = t2;
Curve25519Field.Multiply(S2, X2.x, U2);
Curve25519Field.Multiply(S2, Z1.x, S2);
Curve25519Field.Multiply(S2, Y2.x, S2);
}
bool Z2IsOne = Z2.IsOne;
uint[] U1, S1;
if (Z2IsOne)
{
U1 = X1.x;
S1 = Y1.x;
}
else
{
S1 = t4;
Curve25519Field.Square(Z2.x, S1);
U1 = tt1;
Curve25519Field.Multiply(S1, X1.x, U1);
Curve25519Field.Multiply(S1, Z2.x, S1);
Curve25519Field.Multiply(S1, Y1.x, S1);
}
uint[] H = Nat256.Create();
Curve25519Field.Subtract(U1, U2, H);
uint[] R = t2;
Curve25519Field.Subtract(S1, S2, R);
// Check if b == this or b == -this
if (Nat256.IsZero(H))
{
if (Nat256.IsZero(R))
{
// this == b, i.e. this must be doubled
return(this.Twice());
}
// this == -b, i.e. the result is the point at infinity
return(curve.Infinity);
}
uint[] HSquared = Nat256.Create();
Curve25519Field.Square(H, HSquared);
uint[] G = Nat256.Create();
Curve25519Field.Multiply(HSquared, H, G);
uint[] V = t3;
Curve25519Field.Multiply(HSquared, U1, V);
Curve25519Field.Negate(G, G);
Nat256.Mul(S1, G, tt1);
c = Nat256.AddBothTo(V, V, G);
Curve25519Field.Reduce27(c, G);
Curve25519FieldElement X3 = new Curve25519FieldElement(t4);
Curve25519Field.Square(R, X3.x);
Curve25519Field.Subtract(X3.x, G, X3.x);
Curve25519FieldElement Y3 = new Curve25519FieldElement(G);
Curve25519Field.Subtract(V, X3.x, Y3.x);
Curve25519Field.MultiplyAddToExt(Y3.x, R, tt1);
Curve25519Field.Reduce(tt1, Y3.x);
Curve25519FieldElement Z3 = new Curve25519FieldElement(H);
if (!Z1IsOne)
{
Curve25519Field.Multiply(Z3.x, Z1.x, Z3.x);
}
if (!Z2IsOne)
{
Curve25519Field.Multiply(Z3.x, Z2.x, Z3.x);
}
uint[] Z3Squared = (Z1IsOne && Z2IsOne) ? HSquared : null;
// TODO If the result will only be used in a subsequent addition, we don't need W3
Curve25519FieldElement W3 = CalculateJacobianModifiedW((Curve25519FieldElement)Z3, Z3Squared);
ECFieldElement[] zs = new ECFieldElement[] { Z3, W3 };
return(new Curve25519Point(curve, X3, Y3, zs, IsCompressed));
}
public virtual bool Equals(Curve25519FieldElement other)
{
return(this == other || (other != null && Nat256.Eq(this.x, other.x)));
}
