public override ECPoint Twice()
{
if (this.IsInfinity)
{
return(this);
}
ECCurve curve = this.Curve;
SecP224K1FieldElement Y1 = (SecP224K1FieldElement)this.RawYCoord;
if (Y1.IsZero)
{
return(curve.Infinity);
}
SecP224K1FieldElement X1 = (SecP224K1FieldElement)this.RawXCoord, Z1 = (SecP224K1FieldElement)this.RawZCoords[0];
uint[] Y1Squared = Nat224.Create();
SecP224K1Field.Square(Y1.x, Y1Squared);
uint[] T = Nat224.Create();
SecP224K1Field.Square(Y1Squared, T);
uint[] t1 = Nat224.Create();
SecP224K1Field.Square(X1.x, t1);
uint[] M = Nat224.Create();
SecP224K1Field.Twice(t1, M);
SecP224K1Field.Add(M, t1, M);
uint[] S = Y1Squared;
SecP224K1Field.Multiply(Y1Squared, X1.x, S);
uint c = Nat.ShiftUpBits(7, S, 2, 0);
SecP224K1Field.Reduce32(c, S);
c = Nat.ShiftUpBits(7, T, 3, 0, t1);
SecP224K1Field.Reduce32(c, t1);
SecP224K1FieldElement X3 = new SecP224K1FieldElement(T);
SecP224K1Field.Square(M, X3.x);
SecP224K1Field.Subtract(X3.x, S, X3.x);
SecP224K1Field.Subtract(X3.x, S, X3.x);
SecP224K1FieldElement Y3 = new SecP224K1FieldElement(S);
SecP224K1Field.Subtract(S, X3.x, Y3.x);
SecP224K1Field.Multiply(Y3.x, M, Y3.x);
SecP224K1Field.Subtract(Y3.x, t1, Y3.x);
SecP224K1FieldElement Z3 = new SecP224K1FieldElement(M);
SecP224K1Field.Twice(Y1.x, Z3.x);
if (!Z1.IsOne)
{
SecP224K1Field.Multiply(Z3.x, Z1.x, Z3.x);
}
return(new SecP224K1Point(curve, X3, Y3, new ECFieldElement[] { Z3 }, 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;
SecP224K1FieldElement X1 = (SecP224K1FieldElement)this.RawXCoord, Y1 = (SecP224K1FieldElement)this.RawYCoord;
SecP224K1FieldElement X2 = (SecP224K1FieldElement)b.RawXCoord, Y2 = (SecP224K1FieldElement)b.RawYCoord;
SecP224K1FieldElement Z1 = (SecP224K1FieldElement)this.RawZCoords[0];
SecP224K1FieldElement Z2 = (SecP224K1FieldElement)b.RawZCoords[0];
uint[] tt1 = Nat224.CreateExt();
uint[] tt2 = Nat224.CreateExt();
uint[] t3 = Nat224.Create();
uint[] t4 = Nat224.Create();
bool Z1IsOne = Z1.IsOne;
uint[] U2, S2;
if (Z1IsOne)
{
U2 = X2.x;
S2 = Y2.x;
}
else
{
S2 = t3;
SecP224K1Field.Square(Z1.x, S2);
U2 = tt2;
SecP224K1Field.Multiply(S2, X2.x, U2);
SecP224K1Field.Multiply(S2, Z1.x, S2);
SecP224K1Field.Multiply(S2, Y2.x, S2);
}
bool Z2IsOne = Z2.IsOne;
uint[] U1, S1;
if (Z2IsOne)
{
U1 = X1.x;
S1 = Y1.x;
}
else
{
S1 = t4;
SecP224K1Field.Square(Z2.x, S1);
U1 = tt1;
SecP224K1Field.Multiply(S1, X1.x, U1);
SecP224K1Field.Multiply(S1, Z2.x, S1);
SecP224K1Field.Multiply(S1, Y1.x, S1);
}
uint[] H = Nat224.Create();
SecP224K1Field.Subtract(U1, U2, H);
uint[] R = tt2;
SecP224K1Field.Subtract(S1, S2, R);
// Check if b == this or b == -this
if (Nat224.IsZero(H))
{
if (Nat224.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 = t3;
SecP224K1Field.Square(H, HSquared);
uint[] G = Nat224.Create();
SecP224K1Field.Multiply(HSquared, H, G);
uint[] V = t3;
SecP224K1Field.Multiply(HSquared, U1, V);
Nat224.Mul(S1, G, tt1);
SecP224K1FieldElement X3 = new SecP224K1FieldElement(t4);
SecP224K1Field.Square(R, X3.x);
SecP224K1Field.Add(X3.x, G, X3.x);
SecP224K1Field.Subtract(X3.x, V, X3.x);
SecP224K1Field.Subtract(X3.x, V, X3.x);
SecP224K1FieldElement Y3 = new SecP224K1FieldElement(G);
SecP224K1Field.Subtract(V, X3.x, Y3.x);
Nat224.Mul(Y3.x, R, tt2);
SecP224K1Field.SubtractExt(tt2, tt1, tt2);
SecP224K1Field.Reduce(tt2, Y3.x);
SecP224K1FieldElement Z3 = new SecP224K1FieldElement(H);
if (!Z1IsOne)
{
SecP224K1Field.Multiply(Z3.x, Z1.x, Z3.x);
}
if (!Z2IsOne)
{
SecP224K1Field.Multiply(Z3.x, Z2.x, Z3.x);
}
ECFieldElement[] zs = new ECFieldElement[] { Z3 };
return(new SecP224K1Point(curve, X3, Y3, zs, IsCompressed));
}
public override ECFieldElement AddOne()
{
uint[] z = Nat224.Create();
SecP224K1Field.AddOne(x, z);
return(new SecP224K1FieldElement(z));
}
public override ECFieldElement Subtract(ECFieldElement b)
{
uint[] z = Nat224.Create();
SecP224K1Field.Subtract(x, ((SecP224K1FieldElement)b).x, z);
return(new SecP224K1FieldElement(z));
}
public override ECFieldElement Multiply(ECFieldElement b)
{
uint[] z = Nat224.Create();
SecP224K1Field.Multiply(x, ((SecP224K1FieldElement)b).x, z);
return(new SecP224K1FieldElement(z));
}
/**
* return a sqrt root - the routine verifies that the calculation returns the right value - if
* none exists it returns null.
*/
public override ECFieldElement Sqrt()
{
/*
* Q == 8m + 5, so we use Pocklington's method for this case.
*
* First, raise this element to the exponent 2^221 - 2^29 - 2^9 - 2^8 - 2^6 - 2^4 - 2^1 (i.e. m + 1)
*
* Breaking up the exponent's binary representation into "repunits", we get:
* { 191 1s } { 1 0s } { 19 1s } { 2 0s } { 1 1s } { 1 0s} { 1 1s } { 1 0s} { 3 1s } { 1 0s}
*
* Therefore we need an addition chain containing 1, 3, 19, 191 (the lengths of the repunits)
* We use: [1], 2, [3], 4, 8, 11, [19], 23, 42, 84, 107, [191]
*/
uint[] x1 = this.x;
if (Nat224.IsZero(x1) || Nat224.IsOne(x1))
{
return(this);
}
uint[] x2 = Nat224.Create();
SecP224K1Field.Square(x1, x2);
SecP224K1Field.Multiply(x2, x1, x2);
uint[] x3 = x2;
SecP224K1Field.Square(x2, x3);
SecP224K1Field.Multiply(x3, x1, x3);
uint[] x4 = Nat224.Create();
SecP224K1Field.Square(x3, x4);
SecP224K1Field.Multiply(x4, x1, x4);
uint[] x8 = Nat224.Create();
SecP224K1Field.SquareN(x4, 4, x8);
SecP224K1Field.Multiply(x8, x4, x8);
uint[] x11 = Nat224.Create();
SecP224K1Field.SquareN(x8, 3, x11);
SecP224K1Field.Multiply(x11, x3, x11);
uint[] x19 = x11;
SecP224K1Field.SquareN(x11, 8, x19);
SecP224K1Field.Multiply(x19, x8, x19);
uint[] x23 = x8;
SecP224K1Field.SquareN(x19, 4, x23);
SecP224K1Field.Multiply(x23, x4, x23);
uint[] x42 = x4;
SecP224K1Field.SquareN(x23, 19, x42);
SecP224K1Field.Multiply(x42, x19, x42);
uint[] x84 = Nat224.Create();
SecP224K1Field.SquareN(x42, 42, x84);
SecP224K1Field.Multiply(x84, x42, x84);
uint[] x107 = x42;
SecP224K1Field.SquareN(x84, 23, x107);
SecP224K1Field.Multiply(x107, x23, x107);
uint[] x191 = x23;
SecP224K1Field.SquareN(x107, 84, x191);
SecP224K1Field.Multiply(x191, x84, x191);
uint[] t1 = x191;
SecP224K1Field.SquareN(t1, 20, t1);
SecP224K1Field.Multiply(t1, x19, t1);
SecP224K1Field.SquareN(t1, 3, t1);
SecP224K1Field.Multiply(t1, x1, t1);
SecP224K1Field.SquareN(t1, 2, t1);
SecP224K1Field.Multiply(t1, x1, t1);
SecP224K1Field.SquareN(t1, 4, t1);
SecP224K1Field.Multiply(t1, x3, t1);
SecP224K1Field.Square(t1, t1);
uint[] t2 = x84;
SecP224K1Field.Square(t1, t2);
if (Nat224.Eq(x1, t2))
{
return(new SecP224K1FieldElement(t1));
}
/*
* If the first guess is incorrect, we multiply by a precomputed power of 2 to get the second guess,
* which is ((4x)^(m + 1))/2 mod Q
*/
SecP224K1Field.Multiply(t1, PRECOMP_POW2, t1);
SecP224K1Field.Square(t1, t2);
if (Nat224.Eq(x1, t2))
{
return(new SecP224K1FieldElement(t1));
}
return(null);
}
public override ECFieldElement Add(ECFieldElement b)
{
uint[] z = Nat224.Create();
SecP224K1Field.Add(this.x, ((SecP224K1FieldElement)b).x, z);
return(new SecP224K1FieldElement(z));
}
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;
SecP224K1FieldElement rawXCoord = (SecP224K1FieldElement)base.RawXCoord;
SecP224K1FieldElement rawYCoord = (SecP224K1FieldElement)base.RawYCoord;
SecP224K1FieldElement element3 = (SecP224K1FieldElement)b.RawXCoord;
SecP224K1FieldElement element4 = (SecP224K1FieldElement)b.RawYCoord;
SecP224K1FieldElement element5 = (SecP224K1FieldElement)base.RawZCoords[0];
SecP224K1FieldElement element6 = (SecP224K1FieldElement)b.RawZCoords[0];
uint[] zz = Nat224.CreateExt();
uint[] numArray2 = Nat224.Create();
uint[] numArray3 = Nat224.Create();
uint[] x = Nat224.Create();
bool isOne = element5.IsOne;
if (isOne)
{
numArray5 = element3.x;
numArray6 = element4.x;
}
else
{
numArray6 = numArray3;
SecP224K1Field.Square(element5.x, numArray6);
numArray5 = numArray2;
SecP224K1Field.Multiply(numArray6, element3.x, numArray5);
SecP224K1Field.Multiply(numArray6, element5.x, numArray6);
SecP224K1Field.Multiply(numArray6, element4.x, numArray6);
}
bool flag2 = element6.IsOne;
if (flag2)
{
numArray7 = rawXCoord.x;
numArray8 = rawYCoord.x;
}
else
{
numArray8 = x;
SecP224K1Field.Square(element6.x, numArray8);
numArray7 = zz;
SecP224K1Field.Multiply(numArray8, rawXCoord.x, numArray7);
SecP224K1Field.Multiply(numArray8, element6.x, numArray8);
SecP224K1Field.Multiply(numArray8, rawYCoord.x, numArray8);
}
uint[] z = Nat224.Create();
SecP224K1Field.Subtract(numArray7, numArray5, z);
uint[] numArray10 = numArray2;
SecP224K1Field.Subtract(numArray8, numArray6, numArray10);
if (Nat224.IsZero(z))
{
if (Nat224.IsZero(numArray10))
{
return(this.Twice());
}
return(curve.Infinity);
}
uint[] numArray11 = numArray3;
SecP224K1Field.Square(z, numArray11);
uint[] numArray12 = Nat224.Create();
SecP224K1Field.Multiply(numArray11, z, numArray12);
uint[] numArray13 = numArray3;
SecP224K1Field.Multiply(numArray11, numArray7, numArray13);
SecP224K1Field.Negate(numArray12, numArray12);
Nat224.Mul(numArray8, numArray12, zz);
SecP224K1Field.Reduce32(Nat224.AddBothTo(numArray13, numArray13, numArray12), numArray12);
SecP224K1FieldElement element7 = new SecP224K1FieldElement(x);
SecP224K1Field.Square(numArray10, element7.x);
SecP224K1Field.Subtract(element7.x, numArray12, element7.x);
SecP224K1FieldElement y = new SecP224K1FieldElement(numArray12);
SecP224K1Field.Subtract(numArray13, element7.x, y.x);
SecP224K1Field.MultiplyAddToExt(y.x, numArray10, zz);
SecP224K1Field.Reduce(zz, y.x);
SecP224K1FieldElement element9 = new SecP224K1FieldElement(z);
if (!isOne)
{
SecP224K1Field.Multiply(element9.x, element5.x, element9.x);
}
if (!flag2)
{
SecP224K1Field.Multiply(element9.x, element6.x, element9.x);
}
ECFieldElement[] zs = new ECFieldElement[] { element9 };
return(new SecP224K1Point(curve, element7, y, zs, base.IsCompressed));
}
public override ECFieldElement Square()
{
uint[] z = Nat224.Create();
SecP224K1Field.Square(this.x, z);
return(new SecP224K1FieldElement(z));
}
public override ECFieldElement Sqrt()
{
uint[] y = this.x;
if (Nat224.IsZero(y) || Nat224.IsOne(y))
{
return(this);
}
uint[] array = Nat224.Create();
SecP224K1Field.Square(y, array);
SecP224K1Field.Multiply(array, y, array);
uint[] array2 = array;
SecP224K1Field.Square(array, array2);
SecP224K1Field.Multiply(array2, y, array2);
uint[] array3 = Nat224.Create();
SecP224K1Field.Square(array2, array3);
SecP224K1Field.Multiply(array3, y, array3);
uint[] array4 = Nat224.Create();
SecP224K1Field.SquareN(array3, 4, array4);
SecP224K1Field.Multiply(array4, array3, array4);
uint[] array5 = Nat224.Create();
SecP224K1Field.SquareN(array4, 3, array5);
SecP224K1Field.Multiply(array5, array2, array5);
uint[] array6 = array5;
SecP224K1Field.SquareN(array5, 8, array6);
SecP224K1Field.Multiply(array6, array4, array6);
uint[] array7 = array4;
SecP224K1Field.SquareN(array6, 4, array7);
SecP224K1Field.Multiply(array7, array3, array7);
uint[] array8 = array3;
SecP224K1Field.SquareN(array7, 19, array8);
SecP224K1Field.Multiply(array8, array6, array8);
uint[] array9 = Nat224.Create();
SecP224K1Field.SquareN(array8, 42, array9);
SecP224K1Field.Multiply(array9, array8, array9);
uint[] z = array8;
SecP224K1Field.SquareN(array9, 23, z);
SecP224K1Field.Multiply(z, array7, z);
uint[] array10 = array7;
SecP224K1Field.SquareN(z, 84, array10);
SecP224K1Field.Multiply(array10, array9, array10);
uint[] z2 = array10;
SecP224K1Field.SquareN(z2, 20, z2);
SecP224K1Field.Multiply(z2, array6, z2);
SecP224K1Field.SquareN(z2, 3, z2);
SecP224K1Field.Multiply(z2, y, z2);
SecP224K1Field.SquareN(z2, 2, z2);
SecP224K1Field.Multiply(z2, y, z2);
SecP224K1Field.SquareN(z2, 4, z2);
SecP224K1Field.Multiply(z2, array2, z2);
SecP224K1Field.Square(z2, z2);
uint[] array11 = array9;
SecP224K1Field.Square(z2, array11);
if (Nat224.Eq(y, array11))
{
return(new SecP224K1FieldElement(z2));
}
SecP224K1Field.Multiply(z2, SecP224K1FieldElement.PRECOMP_POW2, z2);
SecP224K1Field.Square(z2, array11);
if (Nat224.Eq(y, array11))
{
return(new SecP224K1FieldElement(z2));
}
return(null);
}
public override ECPoint Add(ECPoint b)
{
if (base.IsInfinity)
{
return(b);
}
if (b.IsInfinity)
{
return(this);
}
if (this == b)
{
return(Twice());
}
ECCurve curve = Curve;
SecP224K1FieldElement secP224K1FieldElement = (SecP224K1FieldElement)base.RawXCoord;
SecP224K1FieldElement secP224K1FieldElement2 = (SecP224K1FieldElement)base.RawYCoord;
SecP224K1FieldElement secP224K1FieldElement3 = (SecP224K1FieldElement)b.RawXCoord;
SecP224K1FieldElement secP224K1FieldElement4 = (SecP224K1FieldElement)b.RawYCoord;
SecP224K1FieldElement secP224K1FieldElement5 = (SecP224K1FieldElement)base.RawZCoords[0];
SecP224K1FieldElement secP224K1FieldElement6 = (SecP224K1FieldElement)b.RawZCoords[0];
uint[] array = Nat224.CreateExt();
uint[] array2 = Nat224.Create();
uint[] array3 = Nat224.Create();
uint[] array4 = Nat224.Create();
bool isOne = secP224K1FieldElement5.IsOne;
uint[] array5;
uint[] array6;
if (isOne)
{
array5 = secP224K1FieldElement3.x;
array6 = secP224K1FieldElement4.x;
}
else
{
array6 = array3;
SecP224K1Field.Square(secP224K1FieldElement5.x, array6);
array5 = array2;
SecP224K1Field.Multiply(array6, secP224K1FieldElement3.x, array5);
SecP224K1Field.Multiply(array6, secP224K1FieldElement5.x, array6);
SecP224K1Field.Multiply(array6, secP224K1FieldElement4.x, array6);
}
bool isOne2 = secP224K1FieldElement6.IsOne;
uint[] array7;
uint[] array8;
if (isOne2)
{
array7 = secP224K1FieldElement.x;
array8 = secP224K1FieldElement2.x;
}
else
{
array8 = array4;
SecP224K1Field.Square(secP224K1FieldElement6.x, array8);
array7 = array;
SecP224K1Field.Multiply(array8, secP224K1FieldElement.x, array7);
SecP224K1Field.Multiply(array8, secP224K1FieldElement6.x, array8);
SecP224K1Field.Multiply(array8, secP224K1FieldElement2.x, array8);
}
uint[] array9 = Nat224.Create();
SecP224K1Field.Subtract(array7, array5, array9);
uint[] array10 = array2;
SecP224K1Field.Subtract(array8, array6, array10);
if (Nat224.IsZero(array9))
{
if (Nat224.IsZero(array10))
{
return(Twice());
}
return(curve.Infinity);
}
uint[] array11 = array3;
SecP224K1Field.Square(array9, array11);
uint[] array12 = Nat224.Create();
SecP224K1Field.Multiply(array11, array9, array12);
uint[] array13 = array3;
SecP224K1Field.Multiply(array11, array7, array13);
SecP224K1Field.Negate(array12, array12);
Nat224.Mul(array8, array12, array);
uint x = Nat224.AddBothTo(array13, array13, array12);
SecP224K1Field.Reduce32(x, array12);
SecP224K1FieldElement secP224K1FieldElement7 = new SecP224K1FieldElement(array4);
SecP224K1Field.Square(array10, secP224K1FieldElement7.x);
SecP224K1Field.Subtract(secP224K1FieldElement7.x, array12, secP224K1FieldElement7.x);
SecP224K1FieldElement secP224K1FieldElement8 = new SecP224K1FieldElement(array12);
SecP224K1Field.Subtract(array13, secP224K1FieldElement7.x, secP224K1FieldElement8.x);
SecP224K1Field.MultiplyAddToExt(secP224K1FieldElement8.x, array10, array);
SecP224K1Field.Reduce(array, secP224K1FieldElement8.x);
SecP224K1FieldElement secP224K1FieldElement9 = new SecP224K1FieldElement(array9);
if (!isOne)
{
SecP224K1Field.Multiply(secP224K1FieldElement9.x, secP224K1FieldElement5.x, secP224K1FieldElement9.x);
}
if (!isOne2)
{
SecP224K1Field.Multiply(secP224K1FieldElement9.x, secP224K1FieldElement6.x, secP224K1FieldElement9.x);
}
ECFieldElement[] zs = new ECFieldElement[1] {
secP224K1FieldElement9
};
return(new SecP224K1Point(curve, secP224K1FieldElement7, secP224K1FieldElement8, zs, base.IsCompressed));
}
public override ECFieldElement RandomFieldElement(SecureRandom r)
{
uint[] x = Nat224.Create();
SecP224K1Field.Random(r, x);
return(new SecP224K1FieldElement(x));
}
public static void Square(uint[] x, uint[] z)
{
uint[] array = Nat224.CreateExt();
Nat224.Square(x, array);
SecP224K1Field.Reduce(array, z);
}
public static void Multiply(uint[] x, uint[] y, uint[] z)
{
uint[] array = Nat224.CreateExt();
Nat224.Mul(x, y, array);
SecP224K1Field.Reduce(array, z);
}
public override ECFieldElement Sqrt()
{
uint[] x = this.x;
if (Nat224.IsZero(x) || Nat224.IsOne(x))
{
return(this);
}
uint[] z = Nat224.Create();
SecP224K1Field.Square(x, z);
SecP224K1Field.Multiply(z, x, z);
uint[] numArray3 = z;
SecP224K1Field.Square(z, numArray3);
SecP224K1Field.Multiply(numArray3, x, numArray3);
uint[] numArray4 = Nat224.Create();
SecP224K1Field.Square(numArray3, numArray4);
SecP224K1Field.Multiply(numArray4, x, numArray4);
uint[] numArray5 = Nat224.Create();
SecP224K1Field.SquareN(numArray4, 4, numArray5);
SecP224K1Field.Multiply(numArray5, numArray4, numArray5);
uint[] numArray6 = Nat224.Create();
SecP224K1Field.SquareN(numArray5, 3, numArray6);
SecP224K1Field.Multiply(numArray6, numArray3, numArray6);
uint[] numArray7 = numArray6;
SecP224K1Field.SquareN(numArray6, 8, numArray7);
SecP224K1Field.Multiply(numArray7, numArray5, numArray7);
uint[] numArray8 = numArray5;
SecP224K1Field.SquareN(numArray7, 4, numArray8);
SecP224K1Field.Multiply(numArray8, numArray4, numArray8);
uint[] numArray9 = numArray4;
SecP224K1Field.SquareN(numArray8, 0x13, numArray9);
SecP224K1Field.Multiply(numArray9, numArray7, numArray9);
uint[] numArray10 = Nat224.Create();
SecP224K1Field.SquareN(numArray9, 0x2a, numArray10);
SecP224K1Field.Multiply(numArray10, numArray9, numArray10);
uint[] numArray11 = numArray9;
SecP224K1Field.SquareN(numArray10, 0x17, numArray11);
SecP224K1Field.Multiply(numArray11, numArray8, numArray11);
uint[] numArray12 = numArray8;
SecP224K1Field.SquareN(numArray11, 0x54, numArray12);
SecP224K1Field.Multiply(numArray12, numArray10, numArray12);
uint[] numArray13 = numArray12;
SecP224K1Field.SquareN(numArray13, 20, numArray13);
SecP224K1Field.Multiply(numArray13, numArray7, numArray13);
SecP224K1Field.SquareN(numArray13, 3, numArray13);
SecP224K1Field.Multiply(numArray13, x, numArray13);
SecP224K1Field.SquareN(numArray13, 2, numArray13);
SecP224K1Field.Multiply(numArray13, x, numArray13);
SecP224K1Field.SquareN(numArray13, 4, numArray13);
SecP224K1Field.Multiply(numArray13, numArray3, numArray13);
SecP224K1Field.Square(numArray13, numArray13);
uint[] numArray14 = numArray10;
SecP224K1Field.Square(numArray13, numArray14);
if (Nat224.Eq(x, numArray14))
{
return(new SecP224K1FieldElement(numArray13));
}
SecP224K1Field.Multiply(numArray13, PRECOMP_POW2, numArray13);
SecP224K1Field.Square(numArray13, numArray14);
if (Nat224.Eq(x, numArray14))
{
return(new SecP224K1FieldElement(numArray13));
}
return(null);
}