public override ECFieldElement Divide(ECFieldElement b)
 {
     uint[] z = Nat224.Create();
     Mod.Invert(SecP224K1Field.P, ((SecP224K1FieldElement)b).x, z);
     SecP224K1Field.Multiply(z, this.x, z);
     return(new SecP224K1FieldElement(z));
 }
 public override ECFieldElement Invert()
 {
     //return new SecP224K1FieldElement(ToBigInteger().ModInverse(Q));
     uint[] z = Nat224.Create();
     Mod.Invert(SecP224K1Field.P, x, z);
     return(new SecP224K1FieldElement(z));
 }
 public override ECFieldElement Divide(ECFieldElement b)
 {
     //return Multiply(b.Invert());
     uint[] z = Nat224.Create();
     SecP224K1Field.Inv(((SecP224K1FieldElement)b).x, z);
     SecP224K1Field.Multiply(z, x, z);
     return(new SecP224K1FieldElement(z));
 }
Esempio n. 4
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        public override ECPoint Twice()
        {
            if (base.IsInfinity)
            {
                return(this);
            }
            ECCurve curve = this.Curve;
            SecP224R1FieldElement rawYCoord = (SecP224R1FieldElement)base.RawYCoord;

            if (rawYCoord.IsZero)
            {
                return(curve.Infinity);
            }
            SecP224R1FieldElement rawXCoord = (SecP224R1FieldElement)base.RawXCoord;
            SecP224R1FieldElement element3  = (SecP224R1FieldElement)base.RawZCoords[0];

            uint[] z         = Nat224.Create();
            uint[] numArray2 = Nat224.Create();
            uint[] numArray3 = Nat224.Create();
            SecP224R1Field.Square(rawYCoord.x, numArray3);
            uint[] numArray4 = Nat224.Create();
            SecP224R1Field.Square(numArray3, numArray4);
            bool isOne = element3.IsOne;

            uint[] x = element3.x;
            if (!isOne)
            {
                x = numArray2;
                SecP224R1Field.Square(element3.x, x);
            }
            SecP224R1Field.Subtract(rawXCoord.x, x, z);
            uint[] numArray6 = numArray2;
            SecP224R1Field.Add(rawXCoord.x, x, numArray6);
            SecP224R1Field.Multiply(numArray6, z, numArray6);
            SecP224R1Field.Reduce32(Nat224.AddBothTo(numArray6, numArray6, numArray6), numArray6);
            uint[] numArray7 = numArray3;
            SecP224R1Field.Multiply(numArray3, rawXCoord.x, numArray7);
            SecP224R1Field.Reduce32(Nat.ShiftUpBits(7, numArray7, 2, 0), numArray7);
            SecP224R1Field.Reduce32(Nat.ShiftUpBits(7, numArray4, 3, 0, z), z);
            SecP224R1FieldElement element4 = new SecP224R1FieldElement(numArray4);

            SecP224R1Field.Square(numArray6, element4.x);
            SecP224R1Field.Subtract(element4.x, numArray7, element4.x);
            SecP224R1Field.Subtract(element4.x, numArray7, element4.x);
            SecP224R1FieldElement y = new SecP224R1FieldElement(numArray7);

            SecP224R1Field.Subtract(numArray7, element4.x, y.x);
            SecP224R1Field.Multiply(y.x, numArray6, y.x);
            SecP224R1Field.Subtract(y.x, z, y.x);
            SecP224R1FieldElement element6 = new SecP224R1FieldElement(numArray6);

            SecP224R1Field.Twice(rawYCoord.x, element6.x);
            if (!isOne)
            {
                SecP224R1Field.Multiply(element6.x, element3.x, element6.x);
            }
            return(new SecP224R1Point(curve, element4, y, new ECFieldElement[] { element6 }, base.IsCompressed));
        }
Esempio n. 5
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        public override ECPoint Twice()
        {
            if (base.IsInfinity)
            {
                return(this);
            }
            ECCurve curve = Curve;
            SecP224K1FieldElement secP224K1FieldElement = (SecP224K1FieldElement)base.RawYCoord;

            if (secP224K1FieldElement.IsZero)
            {
                return(curve.Infinity);
            }
            SecP224K1FieldElement secP224K1FieldElement2 = (SecP224K1FieldElement)base.RawXCoord;
            SecP224K1FieldElement secP224K1FieldElement3 = (SecP224K1FieldElement)base.RawZCoords[0];

            uint[] array = Nat224.Create();
            SecP224K1Field.Square(secP224K1FieldElement.x, array);
            uint[] array2 = Nat224.Create();
            SecP224K1Field.Square(array, array2);
            uint[] array3 = Nat224.Create();
            SecP224K1Field.Square(secP224K1FieldElement2.x, array3);
            uint x = Nat224.AddBothTo(array3, array3, array3);

            SecP224K1Field.Reduce32(x, array3);
            uint[] array4 = array;
            SecP224K1Field.Multiply(array, secP224K1FieldElement2.x, array4);
            x = Nat.ShiftUpBits(7, array4, 2, 0u);
            SecP224K1Field.Reduce32(x, array4);
            uint[] array5 = Nat224.Create();
            x = Nat.ShiftUpBits(7, array2, 3, 0u, array5);
            SecP224K1Field.Reduce32(x, array5);
            SecP224K1FieldElement secP224K1FieldElement4 = new SecP224K1FieldElement(array2);

            SecP224K1Field.Square(array3, secP224K1FieldElement4.x);
            SecP224K1Field.Subtract(secP224K1FieldElement4.x, array4, secP224K1FieldElement4.x);
            SecP224K1Field.Subtract(secP224K1FieldElement4.x, array4, secP224K1FieldElement4.x);
            SecP224K1FieldElement secP224K1FieldElement5 = new SecP224K1FieldElement(array4);

            SecP224K1Field.Subtract(array4, secP224K1FieldElement4.x, secP224K1FieldElement5.x);
            SecP224K1Field.Multiply(secP224K1FieldElement5.x, array3, secP224K1FieldElement5.x);
            SecP224K1Field.Subtract(secP224K1FieldElement5.x, array5, secP224K1FieldElement5.x);
            SecP224K1FieldElement secP224K1FieldElement6 = new SecP224K1FieldElement(array3);

            SecP224K1Field.Twice(secP224K1FieldElement.x, secP224K1FieldElement6.x);
            if (!secP224K1FieldElement3.IsOne)
            {
                SecP224K1Field.Multiply(secP224K1FieldElement6.x, secP224K1FieldElement3.x, secP224K1FieldElement6.x);
            }
            return(new SecP224K1Point(curve, secP224K1FieldElement4, secP224K1FieldElement5, new ECFieldElement[1]
            {
                secP224K1FieldElement6
            }, base.IsCompressed));
        }
Esempio n. 6
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        private static void RS(uint[] d, uint[] e, uint[] f)
        {
            SecP224R1Field.Multiply(e, d, e);
            uint[] t = Nat224.Create();
            SecP224R1Field.Square(d, t);
            SecP224R1Field.Add(f, t, d);
            SecP224R1Field.Twice(e, e);
            SecP224R1Field.Multiply(f, t, f);
            uint c = Nat.ShiftUpBits(7, f, 2, 0);

            SecP224R1Field.Reduce32(c, f);
        }
Esempio n. 7
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        public static void Inv(uint[] x, uint[] z)
        {
            /*
             * Raise this element to the exponent 2^224 - 2^96 - 1
             *
             * Breaking up the exponent's binary representation into "repunits", we get:
             * { 127 1s } { 1 0s } { 96 1s }
             *
             * Therefore we need an addition chain containing 96, 127 (the lengths of the repunits)
             * We use: 1, 2, 3, 6, 12, 24, 48, [96], 120, 126, [127]
             */

            if (0 != IsZero(x))
            {
                throw new ArgumentException("cannot be 0", "x");
            }

            uint[] x1 = x;
            uint[] x2 = Nat224.Create();
            Square(x1, x2);
            Multiply(x2, x1, x2);
            uint[] x3 = x2;
            Square(x2, x3);
            Multiply(x3, x1, x3);
            uint[] x6 = Nat224.Create();
            SquareN(x3, 3, x6);
            Multiply(x6, x3, x6);
            uint[] x12 = x3;
            SquareN(x6, 6, x12);
            Multiply(x12, x6, x12);
            uint[] x24 = Nat224.Create();
            SquareN(x12, 12, x24);
            Multiply(x24, x12, x24);
            uint[] x48 = x12;
            SquareN(x24, 24, x48);
            Multiply(x48, x24, x48);
            uint[] x96 = Nat224.Create();
            SquareN(x48, 48, x96);
            Multiply(x96, x48, x96);
            uint[] x120 = x48;
            SquareN(x96, 24, x120);
            Multiply(x120, x24, x120);
            uint[] x126 = x24;
            SquareN(x120, 6, x126);
            Multiply(x126, x6, x126);
            uint[] x127 = x6;
            Square(x126, x127);
            Multiply(x127, x1, x127);

            uint[] t = x127;
            SquareN(t, 97, t);
            Multiply(t, x96, z);
        }
Esempio n. 8
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            public override ECPoint LookupVar(int index)
            {
                uint[] x   = Nat224.Create(), y = Nat224.Create();
                int    pos = index * SECP224R1_FE_INTS * 2;

                for (int j = 0; j < SECP224R1_FE_INTS; ++j)
                {
                    x[j] = m_table[pos + j];
                    y[j] = m_table[pos + SECP224R1_FE_INTS + j];
                }

                return(CreatePoint(x, y));
            }
 private static bool IsSquare(uint[] x)
 {
     uint[] z     = Nat224.Create();
     uint[] array = Nat224.Create();
     Nat224.Copy(x, z);
     for (int i = 0; i < 7; i++)
     {
         Nat224.Copy(z, array);
         SecP224R1Field.SquareN(z, 1 << i, z);
         SecP224R1Field.Multiply(z, array, z);
     }
     SecP224R1Field.SquareN(z, 95, z);
     return(Nat224.IsOne(z));
 }
Esempio n. 10
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 private static bool IsSquare(uint[] x)
 {
     uint[] z         = Nat224.Create();
     uint[] numArray2 = Nat224.Create();
     Nat224.Copy(x, z);
     for (int i = 0; i < 7; i++)
     {
         Nat224.Copy(z, numArray2);
         SecP224R1Field.SquareN(z, ((int)1) << i, z);
         SecP224R1Field.Multiply(z, numArray2, z);
     }
     SecP224R1Field.SquareN(z, 0x5f, z);
     return(Nat224.IsOne(z));
 }
Esempio n. 11
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 private static void RM(uint[] nc, uint[] d0, uint[] e0, uint[] d1, uint[] e1, uint[] f1)
 {
     uint[] t = Nat224.Create();
     SecP224R1Field.Multiply(e1, e0, t);
     SecP224R1Field.Multiply(t, nc, t);
     SecP224R1Field.Multiply(d1, d0, f1);
     SecP224R1Field.Add(f1, t, f1);
     SecP224R1Field.Multiply(d1, e0, t);
     Nat224.Copy(f1, d1);
     SecP224R1Field.Multiply(e1, d0, e1);
     SecP224R1Field.Add(e1, t, e1);
     SecP224R1Field.Square(e1, f1);
     SecP224R1Field.Multiply(f1, nc, f1);
 }
        private static bool IsSquare(uint[] x)
        {
            uint[] t1 = Nat224.Create();
            uint[] t2 = Nat224.Create();
            Nat224.Copy(x, t1);

            for (int i = 0; i < 7; ++i)
            {
                Nat224.Copy(t1, t2);
                SecP224R1Field.SquareN(t1, 1 << i, t1);
                SecP224R1Field.Multiply(t1, t2, t1);
            }

            SecP224R1Field.SquareN(t1, 95, t1);
            return(Nat224.IsOne(t1));
        }
Esempio n. 13
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        /**
         * return a sqrt root - the routine verifies that the calculation returns the right value - if
         * none exists it returns null.
         */
        public override ECFieldElement Sqrt()
        {
            uint[] c = this.x;
            if (Nat224.IsZero(c) || Nat224.IsOne(c))
            {
                return(this);
            }

            uint[] nc = Nat224.Create();
            SecP224R1Field.Negate(c, nc);

            uint[] r = Mod.Random(SecP224R1Field.P);

            for (;;)
            {
                uint[] d1 = Nat224.Create();
                Nat224.Copy(r, d1);
                uint[] e1 = Nat224.Create();
                e1[0] = 1;
                uint[] f1 = Nat224.Create();
                RP(nc, d1, e1, f1);

                uint[] d0 = Nat224.Create();
                uint[] e0 = Nat224.Create();

                for (int k = 1; k < 96; ++k)
                {
                    Nat224.Copy(d1, d0);
                    Nat224.Copy(e1, e0);

                    RS(d1, e1, f1);

                    if (Nat224.IsZero(d1))
                    {
                        Mod.Invert(SecP224R1Field.P, e0, f1);
                        SecP224R1Field.Multiply(f1, d0, f1);

                        SecP224R1Field.Square(f1, d1);

                        return(Nat224.Eq(c, d1) ? new SecP224R1FieldElement(f1) : null);
                    }
                }

                // Avoid any possible infinite loop due to a bad random number generator
                SecP224R1Field.AddOne(r, r);
            }
        }
Esempio n. 14
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        public override ECPoint Twice()
        {
            if (base.IsInfinity)
            {
                return(this);
            }
            ECCurve curve = this.Curve;
            SecP224K1FieldElement rawYCoord = (SecP224K1FieldElement)base.RawYCoord;

            if (rawYCoord.IsZero)
            {
                return(curve.Infinity);
            }
            SecP224K1FieldElement rawXCoord = (SecP224K1FieldElement)base.RawXCoord;
            SecP224K1FieldElement element3  = (SecP224K1FieldElement)base.RawZCoords[0];

            uint[] z = Nat224.Create();
            SecP224K1Field.Square(rawYCoord.x, z);
            uint[] numArray2 = Nat224.Create();
            SecP224K1Field.Square(z, numArray2);
            uint[] numArray3 = Nat224.Create();
            SecP224K1Field.Square(rawXCoord.x, numArray3);
            SecP224K1Field.Reduce32(Nat224.AddBothTo(numArray3, numArray3, numArray3), numArray3);
            uint[] numArray4 = z;
            SecP224K1Field.Multiply(z, rawXCoord.x, numArray4);
            SecP224K1Field.Reduce32(Nat.ShiftUpBits(7, numArray4, 2, 0), numArray4);
            uint[] numArray5 = Nat224.Create();
            SecP224K1Field.Reduce32(Nat.ShiftUpBits(7, numArray2, 3, 0, numArray5), numArray5);
            SecP224K1FieldElement x = new SecP224K1FieldElement(numArray2);

            SecP224K1Field.Square(numArray3, x.x);
            SecP224K1Field.Subtract(x.x, numArray4, x.x);
            SecP224K1Field.Subtract(x.x, numArray4, x.x);
            SecP224K1FieldElement y = new SecP224K1FieldElement(numArray4);

            SecP224K1Field.Subtract(numArray4, x.x, y.x);
            SecP224K1Field.Multiply(y.x, numArray3, y.x);
            SecP224K1Field.Subtract(y.x, numArray5, y.x);
            SecP224K1FieldElement element6 = new SecP224K1FieldElement(numArray3);

            SecP224K1Field.Twice(rawYCoord.x, element6.x);
            if (!element3.IsOne)
            {
                SecP224K1Field.Multiply(element6.x, element3.x, element6.x);
            }
            return(new SecP224K1Point(curve, x, y, new ECFieldElement[] { element6 }, base.IsCompressed));
        }
Esempio n. 15
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 private static void RP(uint[] nc, uint[] d1, uint[] e1, uint[] f1, uint[] t)
 {
     Nat224.Copy(nc, f1);
     uint[] z         = Nat224.Create();
     uint[] numArray2 = Nat224.Create();
     for (int i = 0; i < 7; i++)
     {
         Nat224.Copy(d1, z);
         Nat224.Copy(e1, numArray2);
         int num2 = ((int)1) << i;
         while (--num2 >= 0)
         {
             RS(d1, e1, f1, t);
         }
         RM(nc, z, numArray2, d1, e1, f1, t);
     }
 }
 private static void RP(uint[] nc, uint[] d1, uint[] e1, uint[] f1, uint[] t)
 {
     Nat224.Copy(nc, f1);
     uint[] array  = Nat224.Create();
     uint[] array2 = Nat224.Create();
     for (int i = 0; i < 7; i++)
     {
         Nat224.Copy(d1, array);
         Nat224.Copy(e1, array2);
         int num = 1 << i;
         while (--num >= 0)
         {
             SecP224R1FieldElement.RS(d1, e1, f1, t);
         }
         SecP224R1FieldElement.RM(nc, array, array2, d1, e1, f1, t);
     }
 }
Esempio n. 17
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            public override ECPoint Lookup(int index)
            {
                uint[] x   = Nat224.Create(), y = Nat224.Create();
                int    pos = 0;

                for (int i = 0; i < m_size; ++i)
                {
                    uint MASK = (uint)(((i ^ index) - 1) >> 31);

                    for (int j = 0; j < SECP224R1_FE_INTS; ++j)
                    {
                        x[j] ^= m_table[pos + j] & MASK;
                        y[j] ^= m_table[pos + SECP224R1_FE_INTS + j] & MASK;
                    }

                    pos += (SECP224R1_FE_INTS * 2);
                }

                return(CreatePoint(x, y));
            }
Esempio n. 18
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            public virtual ECPoint Lookup(int index)
            {
                uint[] x   = Nat224.Create(), y = Nat224.Create();
                int    pos = 0;

                for (int i = 0; i < m_size; ++i)
                {
                    uint MASK = (uint)(((i ^ index) - 1) >> 31);

                    for (int j = 0; j < SECP224K1_FE_INTS; ++j)
                    {
                        x[j] ^= m_table[pos + j] & MASK;
                        y[j] ^= m_table[pos + SECP224K1_FE_INTS + j] & MASK;
                    }

                    pos += (SECP224K1_FE_INTS * 2);
                }

                return(m_outer.CreateRawPoint(new SecP224K1FieldElement(x), new SecP224K1FieldElement(y), false));
            }
        private static void RP(uint[] nc, uint[] d1, uint[] e1, uint[] f1, uint[] t)
        {
            Nat224.Copy(nc, f1);

            uint[] d0 = Nat224.Create();
            uint[] e0 = Nat224.Create();

            for (int i = 0; i < 7; ++i)
            {
                Nat224.Copy(d1, d0);
                Nat224.Copy(e1, e0);

                int j = 1 << i;
                while (--j >= 0)
                {
                    RS(d1, e1, f1, t);
                }

                RM(nc, d0, e0, d1, e1, f1, t);
            }
        }
Esempio n. 20
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 public override ECFieldElement Sqrt()
 {
     uint[] x = this.x;
     if (Nat224.IsZero(x) || Nat224.IsOne(x))
     {
         return(this);
     }
     uint[] z = Nat224.Create();
     SecP224R1Field.Negate(x, z);
     uint[] r = Mod.Random(SecP224R1Field.P);
     uint[] t = Nat224.Create();
     if (!IsSquare(x))
     {
         return(null);
     }
     while (!TrySqrt(z, r, t))
     {
         SecP224R1Field.AddOne(r, r);
     }
     SecP224R1Field.Square(t, r);
     return(!Nat224.Eq(x, r) ? null : new SecP224R1FieldElement(t));
 }
 public override ECFieldElement Sqrt()
 {
     uint[] array = x;
     if (Nat224.IsZero(array) || Nat224.IsOne(array))
     {
         return(this);
     }
     uint[] array2 = Nat224.Create();
     SecP224R1Field.Negate(array, array2);
     uint[] array3 = Mod.Random(SecP224R1Field.P);
     uint[] t      = Nat224.Create();
     if (!IsSquare(array))
     {
         return(null);
     }
     while (!TrySqrt(array2, array3, t))
     {
         SecP224R1Field.AddOne(array3, array3);
     }
     SecP224R1Field.Square(t, array3);
     return((!Nat224.Eq(array, array3)) ? null : new SecP224R1FieldElement(t));
 }
Esempio n. 22
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        /**
         * return a sqrt root - the routine verifies that the calculation returns the right value - if
         * none exists it returns null.
         */
        public override ECFieldElement Sqrt()
        {
            uint[] c = this.x;
            if (Nat224.IsZero(c) || Nat224.IsOne(c))
                return this;

            uint[] nc = Nat224.Create();
            SecP224R1Field.Negate(c, nc);

            uint[] r = Mod.Random(SecP224R1Field.P);
            uint[] t = Nat224.Create();

            if (!IsSquare(c))
                return null;

            while (!TrySqrt(nc, r, t))
            {
                SecP224R1Field.AddOne(r, r);
            }

            SecP224R1Field.Square(t, r);

            return Nat224.Eq(c, r) ? new SecP224R1FieldElement(t) : null;
        }
 private static bool TrySqrt(uint[] nc, uint[] r, uint[] t)
 {
     uint[] array = Nat224.Create();
     Nat224.Copy(r, array);
     uint[] array2 = Nat224.Create();
     array2[0] = 1u;
     uint[] array3 = Nat224.Create();
     SecP224R1FieldElement.RP(nc, array, array2, array3, t);
     uint[] array4 = Nat224.Create();
     uint[] z      = Nat224.Create();
     for (int i = 1; i < 96; i++)
     {
         Nat224.Copy(array, array4);
         Nat224.Copy(array2, z);
         SecP224R1FieldElement.RS(array, array2, array3, t);
         if (Nat224.IsZero(array))
         {
             Mod.Invert(SecP224R1Field.P, z, t);
             SecP224R1Field.Multiply(t, array4, t);
             return(true);
         }
     }
     return(false);
 }
Esempio n. 24
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 private static bool TrySqrt(uint[] nc, uint[] r, uint[] t)
 {
     uint[] z = Nat224.Create();
     Nat224.Copy(r, z);
     uint[] numArray2 = Nat224.Create();
     numArray2[0] = 1;
     uint[] numArray3 = Nat224.Create();
     RP(nc, z, numArray2, numArray3, t);
     uint[] numArray4 = Nat224.Create();
     uint[] numArray5 = Nat224.Create();
     for (int i = 1; i < 0x60; i++)
     {
         Nat224.Copy(z, numArray4);
         Nat224.Copy(numArray2, numArray5);
         RS(z, numArray2, numArray3, t);
         if (Nat224.IsZero(z))
         {
             Mod.Invert(SecP224R1Field.P, numArray5, t);
             SecP224R1Field.Multiply(t, numArray4, t);
             return(true);
         }
     }
     return(false);
 }
 public override ECFieldElement Multiply(ECFieldElement b)
 {
     uint[] z = Nat224.Create();
     SecP224R1Field.Multiply(x, ((SecP224R1FieldElement)b).x, z);
     return(new SecP224R1FieldElement(z));
 }
 public override ECFieldElement Subtract(ECFieldElement b)
 {
     uint[] z = Nat224.Create();
     SecP224R1Field.Subtract(x, ((SecP224R1FieldElement)b).x, z);
     return(new SecP224R1FieldElement(z));
 }
 public override ECFieldElement AddOne()
 {
     uint[] z = Nat224.Create();
     SecP224R1Field.AddOne(x, z);
     return(new SecP224R1FieldElement(z));
 }
 public SecP224R1FieldElement()
 {
     this.x = Nat224.Create();
 }
        /**
         * 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(x, ((SecP224K1FieldElement)b).x, z);
     return(new SecP224K1FieldElement(z));
 }