Custom curves for secp128r1 and secp160r1/r2/k1

14 files changed, 2615 insertions, 0 deletions

diff --git a/crypto/src/math/ec/custom/sec/SecP128R1Curve.cs b/crypto/src/math/ec/custom/sec/SecP128R1Curve.cs
new file mode 100644
index 000000000..9da27b470
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP128R1Curve.cs
@@ -0,0 +1,78 @@
+using System;
+
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP128R1Curve
+        : AbstractFpCurve
+    {
+        public static readonly BigInteger q = new BigInteger(1,
+            Hex.Decode("FFFFFFFDFFFFFFFFFFFFFFFFFFFFFFFF"));
+
+        private const int SecP128R1_DEFAULT_COORDS = COORD_JACOBIAN;
+
+        protected readonly SecP128R1Point m_infinity;
+
+        public SecP128R1Curve()
+            : base(q)
+        {
+            this.m_infinity = new SecP128R1Point(this, null, null);
+
+            this.m_a = FromBigInteger(new BigInteger(1,
+                Hex.Decode("FFFFFFFDFFFFFFFFFFFFFFFFFFFFFFFC")));
+            this.m_b = FromBigInteger(new BigInteger(1,
+                Hex.Decode("E87579C11079F43DD824993C2CEE5ED3")));
+            this.m_order = new BigInteger(1, Hex.Decode("FFFFFFFE0000000075A30D1B9038A115"));
+            this.m_cofactor = BigInteger.One;
+
+            this.m_coord = SecP128R1_DEFAULT_COORDS;
+        }
+
+        protected override ECCurve CloneCurve()
+        {
+            return new SecP128R1Curve();
+        }
+
+        public override bool SupportsCoordinateSystem(int coord)
+        {
+            switch (coord)
+            {
+            case COORD_JACOBIAN:
+                return true;
+            default:
+                return false;
+            }
+        }
+
+        public virtual BigInteger Q
+        {
+            get { return q; }
+        }
+
+        public override ECPoint Infinity
+        {
+            get { return m_infinity; }
+        }
+
+        public override int FieldSize
+        {
+            get { return q.BitLength; }
+        }
+
+        public override ECFieldElement FromBigInteger(BigInteger x)
+        {
+            return new SecP128R1FieldElement(x);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
+        {
+            return new SecP128R1Point(this, x, y, withCompression);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+        {
+            return new SecP128R1Point(this, x, y, zs, withCompression);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP128R1Field.cs b/crypto/src/math/ec/custom/sec/SecP128R1Field.cs
new file mode 100644
index 000000000..ff6fb6b65
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP128R1Field.cs
@@ -0,0 +1,218 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP128R1Field
+    {
+        // 2^128 - 2^97 - 1
+        internal static readonly uint[] P = new uint[] { 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFD };
+        internal static readonly uint[] PExt = new uint[] { 0x00000001, 0x00000000, 0x00000000, 0x00000004, 0xFFFFFFFE,
+            0xFFFFFFFF, 0x00000003, 0xFFFFFFFC };
+        private static readonly uint[] PExtInv = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFB,
+            0x00000001, 0x00000000, 0xFFFFFFFC, 0x00000003 };
+        private const uint P3 = 0xFFFFFFFD;
+        private const uint PExt7 = 0xFFFFFFFC;
+
+        public static void Add(uint[] x, uint[] y, uint[] z)
+        {
+            uint c = Nat128.Add(x, y, z);
+            if (c != 0 || (z[3] == P3 && Nat128.Gte(z, P)))
+            {
+                AddPInvTo(z);
+            }
+        }
+
+        public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
+        {
+            uint c = Nat256.Add(xx, yy, zz);
+            if (c != 0 || (zz[7] == PExt7 && Nat256.Gte(zz, PExt)))
+            {
+                Nat.AddTo(PExtInv.Length, PExtInv, zz);
+            }
+        }
+
+        public static void AddOne(uint[] x, uint[] z)
+        {
+            uint c = Nat.Inc(4, x, z);
+            if (c != 0 || (z[3] == P3 && Nat128.Gte(z, P)))
+            {
+                AddPInvTo(z);
+            }
+        }
+
+        public static uint[] FromBigInteger(BigInteger x)
+        {
+            uint[] z = Nat128.FromBigInteger(x);
+            if (z[3] == P3 && Nat128.Gte(z, P))
+            {
+                Nat128.SubFrom(P, z);
+            }
+            return z;
+        }
+
+        public static void Half(uint[] x, uint[] z)
+        {
+            if ((x[0] & 1) == 0)
+            {
+                Nat.ShiftDownBit(4, x, 0, z);
+            }
+            else
+            {
+                uint c = Nat128.Add(x, P, z);
+                Nat.ShiftDownBit(4, z, c);
+            }
+        }
+
+        public static void Multiply(uint[] x, uint[] y, uint[] z)
+        {
+            uint[] tt = Nat128.CreateExt();
+            Nat128.Mul(x, y, tt);
+            Reduce(tt, z);
+        }
+
+        public static void MultiplyAddToExt(uint[] x, uint[] y, uint[] zz)
+        {
+            uint c = Nat128.MulAddTo(x, y, zz);
+            if (c != 0 || (zz[7] == PExt7 && Nat256.Gte(zz, PExt)))
+            {
+                Nat.AddTo(PExtInv.Length, PExtInv, zz);
+            }
+        }
+
+        public static void Negate(uint[] x, uint[] z)
+        {
+            if (Nat128.IsZero(x))
+            {
+                Nat128.Zero(z);
+            }
+            else
+            {
+                Nat128.Sub(P, x, z);
+            }
+        }
+
+        public static void Reduce(uint[] xx, uint[] z)
+        {
+            ulong x0 = xx[0], x1 = xx[1], x2 = xx[2], x3 = xx[3];
+            ulong x4 = xx[4], x5 = xx[5], x6 = xx[6], x7 = xx[7];
+
+            x3 += x7; x6 += (x7 << 1);
+            x2 += x6; x5 += (x6 << 1);
+            x1 += x5; x4 += (x5 << 1);
+            x0 += x4; x3 += (x4 << 1);
+
+            z[0] = (uint)x0; x1 += (x0 >> 32);
+            z[1] = (uint)x1; x2 += (x1 >> 32);
+            z[2] = (uint)x2; x3 += (x2 >> 32);
+            z[3] = (uint)x3;
+
+            Reduce32((uint)(x3 >> 32), z);
+        }
+
+        public static void Reduce32(uint x, uint[] z)
+        {
+            while (x != 0)
+            {
+                ulong c, x4 = x;
+    
+                c = (ulong)z[0] + x4;
+                z[0] = (uint)c; c >>= 32;
+                if (c != 0)
+                {
+                    c += (ulong)z[1];
+                    z[1] = (uint)c; c >>= 32;
+                    c += (ulong)z[2];
+                    z[2] = (uint)c; c >>= 32;
+                }
+                c += (ulong)z[3] + (x4 << 1);
+                z[3] = (uint)c; c >>= 32;
+
+                Debug.Assert(c >= 0 && c <= 2);
+
+                x = (uint)c;
+            }
+        }
+
+        public static void Square(uint[] x, uint[] z)
+        {
+            uint[] tt = Nat128.CreateExt();
+            Nat128.Square(x, tt);
+            Reduce(tt, z);
+        }
+
+        public static void SquareN(uint[] x, int n, uint[] z)
+        {
+            Debug.Assert(n > 0);
+
+            uint[] tt = Nat128.CreateExt();
+            Nat128.Square(x, tt);
+            Reduce(tt, z);
+
+            while (--n > 0)
+            {
+                Nat128.Square(z, tt);
+                Reduce(tt, z);
+            }
+        }
+
+        public static void Subtract(uint[] x, uint[] y, uint[] z)
+        {
+            int c = Nat128.Sub(x, y, z);
+            if (c != 0)
+            {
+                SubPInvFrom(z);
+            }
+        }
+
+        public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
+        {
+            int c = Nat.Sub(10, xx, yy, zz);
+            if (c != 0)
+            {
+                Nat.SubFrom(PExtInv.Length, PExtInv, zz);
+            }
+        }
+
+        public static void Twice(uint[] x, uint[] z)
+        {
+            uint c = Nat.ShiftUpBit(4, x, 0, z);
+            if (c != 0 || (z[3] == P3 && Nat128.Gte(z, P)))
+            {
+                AddPInvTo(z);
+            }
+        }
+
+        private static void AddPInvTo(uint[] z)
+        {
+            long c = (long)z[0] + 1;
+            z[0] = (uint)c; c >>= 32;
+            if (c != 0)
+            {
+                c += (long)z[1];
+                z[1] = (uint)c; c >>= 32;
+                c += (long)z[2];
+                z[2] = (uint)c; c >>= 32;
+            }
+            c += (long)z[3] + 2;
+            z[3] = (uint)c;
+        }
+
+        private static void SubPInvFrom(uint[] z)
+        {
+            long c = (long)z[0] - 1;
+            z[0] = (uint)c; c >>= 32;
+            if (c != 0)
+            {
+                c += (long)z[1];
+                z[1] = (uint)c; c >>= 32;
+                c += (long)z[2];
+                z[2] = (uint)c; c >>= 32;
+            }
+            c += (long)z[3] - 2;
+            z[3] = (uint)c;
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP128R1FieldElement.cs b/crypto/src/math/ec/custom/sec/SecP128R1FieldElement.cs
new file mode 100644
index 000000000..fa7951d5d
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP128R1FieldElement.cs
@@ -0,0 +1,198 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP128R1FieldElement
+        : ECFieldElement
+    {
+        public static readonly BigInteger Q = SecP128R1Curve.q;
+
+        protected internal readonly uint[] x;
+
+        public SecP128R1FieldElement(BigInteger x)
+        {
+            if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0)
+                throw new ArgumentException("value invalid for SecP128R1FieldElement", "x");
+
+            this.x = SecP128R1Field.FromBigInteger(x);
+        }
+
+        public SecP128R1FieldElement()
+        {
+            this.x = Nat128.Create();
+        }
+
+        protected internal SecP128R1FieldElement(uint[] x)
+        {
+            this.x = x;
+        }
+
+        public override bool IsZero
+        {
+            get { return Nat128.IsZero(x); }
+        }
+
+        public override bool IsOne
+        {
+            get { return Nat128.IsOne(x); }
+        }
+
+        public override bool TestBitZero()
+        {
+            return Nat128.GetBit(x, 0) == 1;
+        }
+
+        public override BigInteger ToBigInteger()
+        {
+            return Nat128.ToBigInteger(x);
+        }
+
+        public override string FieldName
+        {
+            get { return "SecP128R1Field"; }
+        }
+
+        public override int FieldSize
+        {
+            get { return Q.BitLength; }
+        }
+
+        public override ECFieldElement Add(ECFieldElement b)
+        {
+            uint[] z = Nat128.Create();
+            SecP128R1Field.Add(x, ((SecP128R1FieldElement)b).x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement AddOne()
+        {
+            uint[] z = Nat128.Create();
+            SecP128R1Field.AddOne(x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement Subtract(ECFieldElement b)
+        {
+            uint[] z = Nat128.Create();
+            SecP128R1Field.Subtract(x, ((SecP128R1FieldElement)b).x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement Multiply(ECFieldElement b)
+        {
+            uint[] z = Nat128.Create();
+            SecP128R1Field.Multiply(x, ((SecP128R1FieldElement)b).x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement Divide(ECFieldElement b)
+        {
+    //        return multiply(b.invert());
+            uint[] z = Nat128.Create();
+            Mod.Invert(SecP128R1Field.P, ((SecP128R1FieldElement)b).x, z);
+            SecP128R1Field.Multiply(z, x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement Negate()
+        {
+            uint[] z = Nat128.Create();
+            SecP128R1Field.Negate(x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement Square()
+        {
+            uint[] z = Nat128.Create();
+            SecP128R1Field.Square(x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        public override ECFieldElement Invert()
+        {
+    //        return new SecP128R1FieldElement(toBigInteger().modInverse(Q));
+            uint[] z = Nat128.Create();
+            Mod.Invert(SecP128R1Field.P, x, z);
+            return new SecP128R1FieldElement(z);
+        }
+
+        // D.1.4 91
+        /**
+         * return a sqrt root - the routine verifies that the calculation returns the right value - if
+         * none exists it returns null.
+         */
+        public override ECFieldElement Sqrt()
+        {
+            /*
+             * Raise this element to the exponent 2^126 - 2^95
+             * 
+             * Breaking up the exponent's binary representation into "repunits", we get:
+             *     { 31 1s } { 95 0s }
+             * 
+             * Therefore we need an addition chain containing 31 (the length of the repunit) We use:
+             *     1, 2, 4, 8, 10, 20, 30, [31] 
+             */
+
+            uint[] x1 = this.x;
+            if (Nat128.IsZero(x1) || Nat128.IsOne(x1))
+                return this;
+
+            uint[] x2 = Nat128.Create();
+            SecP128R1Field.Square(x1, x2);
+            SecP128R1Field.Multiply(x2, x1, x2);
+            uint[] x4 = Nat128.Create();
+            SecP128R1Field.SquareN(x2, 2, x4);
+            SecP128R1Field.Multiply(x4, x2, x4);
+            uint[] x8 = Nat128.Create();
+            SecP128R1Field.SquareN(x4, 4, x8);
+            SecP128R1Field.Multiply(x8, x4, x8);
+            uint[] x10 = x4;
+            SecP128R1Field.SquareN(x8, 2, x10);
+            SecP128R1Field.Multiply(x10, x2, x10);
+            uint[] x20 = x2;
+            SecP128R1Field.SquareN(x10, 10, x20);
+            SecP128R1Field.Multiply(x20, x10, x20);
+            uint[] x30 = x8;
+            SecP128R1Field.SquareN(x20, 10, x30);
+            SecP128R1Field.Multiply(x30, x10, x30);
+            uint[] x31 = x10;
+            SecP128R1Field.Square(x30, x31);
+            SecP128R1Field.Multiply(x31, x1, x31);
+
+            uint[] t1 = x31;
+            SecP128R1Field.SquareN(t1, 95, t1);
+
+            uint[] t2 = x30;
+            SecP128R1Field.Square(t1, t2);
+
+            return Nat128.Eq(x1, t2) ? new SecP128R1FieldElement(t1) : null;        
+        }
+
+        public override bool Equals(object obj)
+        {
+            return Equals(obj as SecP128R1FieldElement);
+        }
+
+        public override bool Equals(ECFieldElement other)
+        {
+            return Equals(other as SecP128R1FieldElement);
+        }
+
+        public virtual bool Equals(SecP128R1FieldElement other)
+        {
+            if (this == other)
+                return true;
+            if (null == other)
+                return false;
+            return Nat128.Eq(x, other.x);
+        }
+
+        public override int GetHashCode()
+        {
+            return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 4);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP128R1Point.cs b/crypto/src/math/ec/custom/sec/SecP128R1Point.cs
new file mode 100644
index 000000000..ae76d3cd1
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP128R1Point.cs
@@ -0,0 +1,279 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP128R1Point
+        : AbstractFpPoint
+    {
+        /**
+         * Create a point which encodes with point compression.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * 
+         * @deprecated Use ECCurve.createPoint to construct points
+         */
+        public SecP128R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y)
+            : this(curve, x, y, false)
+        {
+        }
+
+        /**
+         * Create a point that encodes with or without point compresion.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * @param withCompression
+         *            if true encode with point compression
+         * 
+         * @deprecated per-point compression property will be removed, refer
+         *             {@link #getEncoded(boolean)}
+         */
+        public SecP128R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, bool withCompression)
+            : base(curve, x, y, withCompression)
+        {
+            if ((x == null) != (y == null))
+                throw new ArgumentException("Exactly one of the field elements is null");
+        }
+
+        internal SecP128R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+            : base(curve, x, y, zs, withCompression)
+        {
+        }
+
+        protected override ECPoint Detach()
+        {
+            return new SecP128R1Point(null, AffineXCoord, AffineYCoord);
+        }
+
+        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;
+
+            SecP128R1FieldElement X1 = (SecP128R1FieldElement)this.RawXCoord, Y1 = (SecP128R1FieldElement)this.RawYCoord;
+            SecP128R1FieldElement X2 = (SecP128R1FieldElement)b.RawXCoord, Y2 = (SecP128R1FieldElement)b.RawYCoord;
+
+            SecP128R1FieldElement Z1 = (SecP128R1FieldElement)this.RawZCoords[0];
+            SecP128R1FieldElement Z2 = (SecP128R1FieldElement)b.RawZCoords[0];
+
+            uint c;
+            uint[] tt1 = Nat128.CreateExt();
+            uint[] t2 = Nat128.Create();
+            uint[] t3 = Nat128.Create();
+            uint[] t4 = Nat128.Create();
+
+            bool Z1IsOne = Z1.IsOne;
+            uint[] U2, S2;
+            if (Z1IsOne)
+            {
+                U2 = X2.x;
+                S2 = Y2.x;
+            }
+            else
+            {
+                S2 = t3;
+                SecP128R1Field.Square(Z1.x, S2);
+
+                U2 = t2;
+                SecP128R1Field.Multiply(S2, X2.x, U2);
+
+                SecP128R1Field.Multiply(S2, Z1.x, S2);
+                SecP128R1Field.Multiply(S2, Y2.x, S2);
+            }
+
+            bool Z2IsOne = Z2.IsOne;
+            uint[] U1, S1;
+            if (Z2IsOne)
+            {
+                U1 = X1.x;
+                S1 = Y1.x;
+            }
+            else
+            {
+                S1 = t4;
+                SecP128R1Field.Square(Z2.x, S1);
+
+                U1 = tt1;
+                SecP128R1Field.Multiply(S1, X1.x, U1);
+
+                SecP128R1Field.Multiply(S1, Z2.x, S1);
+                SecP128R1Field.Multiply(S1, Y1.x, S1);
+            }
+
+            uint[] H = Nat128.Create();
+            SecP128R1Field.Subtract(U1, U2, H);
+
+            uint[] R = t2;
+            SecP128R1Field.Subtract(S1, S2, R);
+
+            // Check if b == this or b == -this
+            if (Nat128.IsZero(H))
+            {
+                if (Nat128.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;
+            SecP128R1Field.Square(H, HSquared);
+
+            uint[] G = Nat128.Create();
+            SecP128R1Field.Multiply(HSquared, H, G);
+
+            uint[] V = t3;
+            SecP128R1Field.Multiply(HSquared, U1, V);
+
+            SecP128R1Field.Negate(G, G);
+            Nat128.Mul(S1, G, tt1);
+
+            c = Nat128.AddBothTo(V, V, G);
+            SecP128R1Field.Reduce32(c, G);
+
+            SecP128R1FieldElement X3 = new SecP128R1FieldElement(t4);
+            SecP128R1Field.Square(R, X3.x);
+            SecP128R1Field.Subtract(X3.x, G, X3.x);
+
+            SecP128R1FieldElement Y3 = new SecP128R1FieldElement(G);
+            SecP128R1Field.Subtract(V, X3.x, Y3.x);
+            SecP128R1Field.MultiplyAddToExt(Y3.x, R, tt1);
+            SecP128R1Field.Reduce(tt1, Y3.x);
+
+            SecP128R1FieldElement Z3 = new SecP128R1FieldElement(H);
+            if (!Z1IsOne)
+            {
+                SecP128R1Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+            if (!Z2IsOne)
+            {
+                SecP128R1Field.Multiply(Z3.x, Z2.x, Z3.x);
+            }
+
+            ECFieldElement[] zs = new ECFieldElement[]{ Z3 };
+
+            return new SecP128R1Point(curve, X3, Y3, zs, IsCompressed);
+        }
+
+        public override ECPoint Twice()
+        {
+            if (this.IsInfinity)
+                return this;
+
+            ECCurve curve = this.Curve;
+
+            SecP128R1FieldElement Y1 = (SecP128R1FieldElement)this.RawYCoord;
+            if (Y1.IsZero)
+                return curve.Infinity;
+
+            SecP128R1FieldElement X1 = (SecP128R1FieldElement)this.RawXCoord, Z1 = (SecP128R1FieldElement)this.RawZCoords[0];
+
+            uint c;
+            uint[] t1 = Nat128.Create();
+            uint[] t2 = Nat128.Create();
+
+            uint[] Y1Squared = Nat128.Create();
+            SecP128R1Field.Square(Y1.x, Y1Squared);
+
+            uint[] T = Nat128.Create();
+            SecP128R1Field.Square(Y1Squared, T);
+
+            bool Z1IsOne = Z1.IsOne;
+
+            uint[] Z1Squared = Z1.x;
+            if (!Z1IsOne)
+            {
+                Z1Squared = t2;
+                SecP128R1Field.Square(Z1.x, Z1Squared);
+            }
+
+            SecP128R1Field.Subtract(X1.x, Z1Squared, t1);
+
+            uint[] M = t2;
+            SecP128R1Field.Add(X1.x, Z1Squared, M);
+            SecP128R1Field.Multiply(M, t1, M);
+            c = Nat128.AddBothTo(M, M, M);
+            SecP128R1Field.Reduce32(c, M);
+
+            uint[] S = Y1Squared;
+            SecP128R1Field.Multiply(Y1Squared, X1.x, S);
+            c = Nat.ShiftUpBits(4, S, 2, 0);
+            SecP128R1Field.Reduce32(c, S);
+
+            c = Nat.ShiftUpBits(4, T, 3, 0, t1);
+            SecP128R1Field.Reduce32(c, t1);
+
+            SecP128R1FieldElement X3 = new SecP128R1FieldElement(T);
+            SecP128R1Field.Square(M, X3.x);
+            SecP128R1Field.Subtract(X3.x, S, X3.x);
+            SecP128R1Field.Subtract(X3.x, S, X3.x);
+
+            SecP128R1FieldElement Y3 = new SecP128R1FieldElement(S);
+            SecP128R1Field.Subtract(S, X3.x, Y3.x);
+            SecP128R1Field.Multiply(Y3.x, M, Y3.x);
+            SecP128R1Field.Subtract(Y3.x, t1, Y3.x);
+
+            SecP128R1FieldElement Z3 = new SecP128R1FieldElement(M);
+            SecP128R1Field.Twice(Y1.x, Z3.x);
+            if (!Z1IsOne)
+            {
+                SecP128R1Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+
+            return new SecP128R1Point(curve, X3, Y3, new ECFieldElement[]{ Z3 }, IsCompressed);
+        }
+
+        public override ECPoint TwicePlus(ECPoint b)
+        {
+            if (this == b)
+                return ThreeTimes();
+            if (this.IsInfinity)
+                return b;
+            if (b.IsInfinity)
+                return Twice();
+
+            ECFieldElement Y1 = this.RawYCoord;
+            if (Y1.IsZero)
+                return b;
+
+            return Twice().Add(b);
+        }
+
+        public override ECPoint ThreeTimes()
+        {
+            if (this.IsInfinity || this.RawYCoord.IsZero)
+                return this;
+
+            // NOTE: Be careful about recursions between twicePlus and threeTimes
+            return Twice().Add(this);
+        }
+
+        public override ECPoint Negate()
+        {
+            if (IsInfinity)
+                return this;
+
+            return new SecP128R1Point(Curve, RawXCoord, RawYCoord.Negate(), RawZCoords, IsCompressed);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160K1Curve.cs b/crypto/src/math/ec/custom/sec/SecP160K1Curve.cs
new file mode 100644
index 000000000..7d45c6227
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160K1Curve.cs
@@ -0,0 +1,74 @@
+using System;
+
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160K1Curve
+        : AbstractFpCurve
+    {
+        public static readonly BigInteger q = SecP160R2Curve.q;
+
+        private const int SECP160K1_DEFAULT_COORDS = COORD_JACOBIAN;
+
+        protected readonly SecP160K1Point m_infinity;
+
+        public SecP160K1Curve()
+            : base(q)
+        {
+            this.m_infinity = new SecP160K1Point(this, null, null);
+
+            this.m_a = FromBigInteger(BigInteger.Zero);
+            this.m_b = FromBigInteger(BigInteger.ValueOf(7));
+            this.m_order = new BigInteger(1, Hex.Decode("0100000000000000000001B8FA16DFAB9ACA16B6B3"));
+            this.m_cofactor = BigInteger.One;
+            this.m_coord = SECP160K1_DEFAULT_COORDS;
+        }
+
+        protected override ECCurve CloneCurve()
+        {
+            return new SecP160K1Curve();
+        }
+
+        public override bool SupportsCoordinateSystem(int coord)
+        {
+            switch (coord)
+            {
+            case COORD_JACOBIAN:
+                return true;
+            default:
+                return false;
+            }
+        }
+
+        public virtual BigInteger Q
+        {
+            get { return q; }
+        }
+
+        public override ECPoint Infinity
+        {
+            get { return m_infinity; }
+        }
+
+        public override int FieldSize
+        {
+            get { return q.BitLength; }
+        }
+
+        public override ECFieldElement FromBigInteger(BigInteger x)
+        {
+            return new SecP160R2FieldElement(x);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
+        {
+            return new SecP160K1Point(this, x, y, withCompression);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+        {
+            return new SecP160K1Point(this, x, y, zs, withCompression);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160K1Point.cs b/crypto/src/math/ec/custom/sec/SecP160K1Point.cs
new file mode 100644
index 000000000..1bcbadb33
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160K1Point.cs
@@ -0,0 +1,269 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160K1Point
+        : AbstractFpPoint
+    {
+        /**
+         * Create a point which encodes with point compression.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * 
+         * @deprecated Use ECCurve.CreatePoint to construct points
+         */
+        public SecP160K1Point(ECCurve curve, ECFieldElement x, ECFieldElement y)
+            : this(curve, x, y, false)
+        {
+        }
+
+        /**
+         * Create a point that encodes with or without point compresion.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * @param withCompression
+         *            if true encode with point compression
+         * 
+         * @deprecated per-point compression property will be removed, refer
+         *             {@link #getEncoded(bool)}
+         */
+        public SecP160K1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, bool withCompression)
+            : base(curve, x, y, withCompression)
+        {
+            if ((x == null) != (y == null))
+                throw new ArgumentException("Exactly one of the field elements is null");
+        }
+
+        internal SecP160K1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs,
+            bool withCompression)
+            : base(curve, x, y, zs, withCompression)
+        {
+        }
+
+        protected override ECPoint Detach()
+        {
+            return new SecP160K1Point(null, AffineXCoord, AffineYCoord);
+        }
+
+        // B.3 pg 62
+        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;
+
+            SecP160R2FieldElement X1 = (SecP160R2FieldElement)this.RawXCoord, Y1 = (SecP160R2FieldElement)this.RawYCoord;
+            SecP160R2FieldElement X2 = (SecP160R2FieldElement)b.RawXCoord, Y2 = (SecP160R2FieldElement)b.RawYCoord;
+
+            SecP160R2FieldElement Z1 = (SecP160R2FieldElement)this.RawZCoords[0];
+            SecP160R2FieldElement Z2 = (SecP160R2FieldElement)b.RawZCoords[0];
+
+            uint c;
+            uint[] tt1 = Nat160.CreateExt();
+            uint[] t2 = Nat160.Create();
+            uint[] t3 = Nat160.Create();
+            uint[] t4 = Nat160.Create();
+
+            bool Z1IsOne = Z1.IsOne;
+            uint[] U2, S2;
+            if (Z1IsOne)
+            {
+                U2 = X2.x;
+                S2 = Y2.x;
+            }
+            else
+            {
+                S2 = t3;
+                SecP160R2Field.Square(Z1.x, S2);
+
+                U2 = t2;
+                SecP160R2Field.Multiply(S2, X2.x, U2);
+
+                SecP160R2Field.Multiply(S2, Z1.x, S2);
+                SecP160R2Field.Multiply(S2, Y2.x, S2);
+            }
+
+            bool Z2IsOne = Z2.IsOne;
+            uint[] U1, S1;
+            if (Z2IsOne)
+            {
+                U1 = X1.x;
+                S1 = Y1.x;
+            }
+            else
+            {
+                S1 = t4;
+                SecP160R2Field.Square(Z2.x, S1);
+
+                U1 = tt1;
+                SecP160R2Field.Multiply(S1, X1.x, U1);
+
+                SecP160R2Field.Multiply(S1, Z2.x, S1);
+                SecP160R2Field.Multiply(S1, Y1.x, S1);
+            }
+
+            uint[] H = Nat160.Create();
+            SecP160R2Field.Subtract(U1, U2, H);
+
+            uint[] R = t2;
+            SecP160R2Field.Subtract(S1, S2, R);
+
+            // Check if b == this or b == -this
+            if (Nat160.IsZero(H))
+            {
+                if (Nat160.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;
+            SecP160R2Field.Square(H, HSquared);
+
+            uint[] G = Nat160.Create();
+            SecP160R2Field.Multiply(HSquared, H, G);
+
+            uint[] V = t3;
+            SecP160R2Field.Multiply(HSquared, U1, V);
+
+            SecP160R2Field.Negate(G, G);
+            Nat160.Mul(S1, G, tt1);
+
+            c = Nat160.AddBothTo(V, V, G);
+            SecP160R2Field.Reduce32(c, G);
+
+            SecP160R2FieldElement X3 = new SecP160R2FieldElement(t4);
+            SecP160R2Field.Square(R, X3.x);
+            SecP160R2Field.Subtract(X3.x, G, X3.x);
+
+            SecP160R2FieldElement Y3 = new SecP160R2FieldElement(G);
+            SecP160R2Field.Subtract(V, X3.x, Y3.x);
+            SecP160R2Field.MultiplyAddToExt(Y3.x, R, tt1);
+            SecP160R2Field.Reduce(tt1, Y3.x);
+
+            SecP160R2FieldElement Z3 = new SecP160R2FieldElement(H);
+            if (!Z1IsOne)
+            {
+                SecP160R2Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+            if (!Z2IsOne)
+            {
+                SecP160R2Field.Multiply(Z3.x, Z2.x, Z3.x);
+            }
+
+            ECFieldElement[] zs = new ECFieldElement[] { Z3 };
+
+            return new SecP160K1Point(curve, X3, Y3, zs, IsCompressed);
+        }
+
+        // B.3 pg 62
+        public override ECPoint Twice()
+        {
+            if (this.IsInfinity)
+                return this;
+
+            ECCurve curve = this.Curve;
+
+            SecP160R2FieldElement Y1 = (SecP160R2FieldElement)this.RawYCoord;
+            if (Y1.IsZero)
+                return curve.Infinity;
+
+            SecP160R2FieldElement X1 = (SecP160R2FieldElement)this.RawXCoord, Z1 = (SecP160R2FieldElement)this.RawZCoords[0];
+
+            uint c;
+
+            uint[] Y1Squared = Nat160.Create();
+            SecP160R2Field.Square(Y1.x, Y1Squared);
+
+            uint[] T = Nat160.Create();
+            SecP160R2Field.Square(Y1Squared, T);
+
+            uint[] M = Nat160.Create();
+            SecP160R2Field.Square(X1.x, M);
+            c = Nat160.AddBothTo(M, M, M);
+            SecP160R2Field.Reduce32(c, M);
+
+            uint[] S = Y1Squared;
+            SecP160R2Field.Multiply(Y1Squared, X1.x, S);
+            c = Nat.ShiftUpBits(5, S, 2, 0);
+            SecP160R2Field.Reduce32(c, S);
+
+            uint[] t1 = Nat160.Create();
+            c = Nat.ShiftUpBits(5, T, 3, 0, t1);
+            SecP160R2Field.Reduce32(c, t1);
+
+            SecP160R2FieldElement X3 = new SecP160R2FieldElement(T);
+            SecP160R2Field.Square(M, X3.x);
+            SecP160R2Field.Subtract(X3.x, S, X3.x);
+            SecP160R2Field.Subtract(X3.x, S, X3.x);
+
+            SecP160R2FieldElement Y3 = new SecP160R2FieldElement(S);
+            SecP160R2Field.Subtract(S, X3.x, Y3.x);
+            SecP160R2Field.Multiply(Y3.x, M, Y3.x);
+            SecP160R2Field.Subtract(Y3.x, t1, Y3.x);
+
+            SecP160R2FieldElement Z3 = new SecP160R2FieldElement(M);
+            SecP160R2Field.Twice(Y1.x, Z3.x);
+            if (!Z1.IsOne)
+            {
+                SecP160R2Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+
+            return new SecP160K1Point(curve, X3, Y3, new ECFieldElement[] { Z3 }, IsCompressed);
+        }
+
+        public override ECPoint TwicePlus(ECPoint b)
+        {
+            if (this == b)
+                return ThreeTimes();
+            if (this.IsInfinity)
+                return b;
+            if (b.IsInfinity)
+                return Twice();
+
+            ECFieldElement Y1 = this.RawYCoord;
+            if (Y1.IsZero)
+                return b;
+
+            return Twice().Add(b);
+        }
+
+        public override ECPoint ThreeTimes()
+        {
+            if (this.IsInfinity || this.RawYCoord.IsZero)
+                return this;
+
+            // NOTE: Be careful about recursions between TwicePlus and threeTimes
+            return Twice().Add(this);
+        }
+
+        public override ECPoint Negate()
+        {
+            if (IsInfinity)
+                return this;
+
+            return new SecP160K1Point(Curve, this.RawXCoord, this.RawYCoord.Negate(), this.RawZCoords, IsCompressed);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R1Curve.cs b/crypto/src/math/ec/custom/sec/SecP160R1Curve.cs
new file mode 100644
index 000000000..87389af36
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R1Curve.cs
@@ -0,0 +1,78 @@
+using System;
+
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R1Curve
+        : AbstractFpCurve
+    {
+        public static readonly BigInteger q = new BigInteger(1,
+            Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFF"));
+
+        private const int SecP160R1_DEFAULT_COORDS = COORD_JACOBIAN;
+
+        protected readonly SecP160R1Point m_infinity;
+
+        public SecP160R1Curve()
+            : base(q)
+        {
+            this.m_infinity = new SecP160R1Point(this, null, null);
+
+            this.m_a = FromBigInteger(new BigInteger(1,
+                Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFC")));
+            this.m_b = FromBigInteger(new BigInteger(1,
+                Hex.Decode("1C97BEFC54BD7A8B65ACF89F81D4D4ADC565FA45")));
+            this.m_order = new BigInteger(1, Hex.Decode("0100000000000000000001F4C8F927AED3CA752257"));
+            this.m_cofactor = BigInteger.One;
+
+            this.m_coord = SecP160R1_DEFAULT_COORDS;
+        }
+
+        protected override ECCurve CloneCurve()
+        {
+            return new SecP160R1Curve();
+        }
+
+        public override  bool SupportsCoordinateSystem(int coord)
+        {
+            switch (coord)
+            {
+            case COORD_JACOBIAN:
+                return true;
+            default:
+                return false;
+            }
+        }
+
+        public virtual BigInteger Q
+        {
+            get { return q; }
+        }
+
+        public override ECPoint Infinity
+        {
+            get { return m_infinity; }
+        }
+
+        public override int FieldSize
+        {
+            get { return q.BitLength; }
+        }
+
+        public override ECFieldElement FromBigInteger(BigInteger x)
+        {
+            return new SecP160R1FieldElement(x);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
+        {
+            return new SecP160R1Point(this, x, y, withCompression);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+        {
+            return new SecP160R1Point(this, x, y, zs, withCompression);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R1Field.cs b/crypto/src/math/ec/custom/sec/SecP160R1Field.cs
new file mode 100644
index 000000000..6a5a2ef64
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R1Field.cs
@@ -0,0 +1,186 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R1Field
+    {
+        // 2^160 - 2^31 - 1
+        internal static readonly uint[] P = new uint[] { 0x7FFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF};
+        internal static readonly uint[] PExt = new uint[] { 0x00000001, 0x40000001, 0x00000000, 0x00000000, 0x00000000,
+            0xFFFFFFFE, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+        private static readonly uint[] PExtInv = new uint[]{ 0xFFFFFFFF, 0xBFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF,
+            0xFFFFFFFF, 0x00000001, 0x00000001 };
+        private const uint P4 = 0xFFFFFFFF;
+        private const uint PExt9 = 0xFFFFFFFF;
+        private const uint PInv = 0x80000001;
+
+        public static void Add(uint[] x, uint[] y, uint[] z)
+        {
+            uint c = Nat160.Add(x, y, z);
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.AddWordTo(5, PInv, z);
+            }
+        }
+
+        public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
+        {
+            uint c = Nat.Add(10, xx, yy, zz);
+            if (c != 0 || (zz[9] == PExt9 && Nat.Gte(10, zz, PExt)))
+            {
+                if (Nat.AddTo(PExtInv.Length, PExtInv, zz) != 0)
+                {
+                    Nat.IncAt(10, zz, PExtInv.Length);
+                }
+            }
+        }
+
+        public static void AddOne(uint[] x, uint[] z)
+        {
+            uint c = Nat.Inc(5, x, z);
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.AddWordTo(5, PInv, z);
+            }
+        }
+
+        public static uint[] FromBigInteger(BigInteger x)
+        {
+            uint[] z = Nat160.FromBigInteger(x);
+            if (z[4] == P4 && Nat160.Gte(z, P))
+            {
+                Nat160.SubFrom(P, z);
+            }
+            return z;
+        }
+
+        public static void Half(uint[] x, uint[] z)
+        {
+            if ((x[0] & 1) == 0)
+            {
+                Nat.ShiftDownBit(5, x, 0, z);
+            }
+            else
+            {
+                uint c = Nat160.Add(x, P, z);
+                Nat.ShiftDownBit(5, z, c);
+            }
+        }
+
+        public static void Multiply(uint[] x, uint[] y, uint[] z)
+        {
+            uint[] tt = Nat160.CreateExt();
+            Nat160.Mul(x, y, tt);
+            Reduce(tt, z);
+        }
+
+        public static void MultiplyAddToExt(uint[] x, uint[] y, uint[] zz)
+        {
+            uint c = Nat160.MulAddTo(x, y, zz);
+            if (c != 0 || (zz[9] == PExt9 && Nat.Gte(10, zz, PExt)))
+            {
+                if (Nat.AddTo(PExtInv.Length, PExtInv, zz) != 0)
+                {
+                    Nat.IncAt(10, zz, PExtInv.Length);
+                }
+            }
+        }
+
+        public static void Negate(uint[] x, uint[] z)
+        {
+            if (Nat160.IsZero(x))
+            {
+                Nat160.Zero(z);
+            }
+            else
+            {
+                Nat160.Sub(P, x, z);
+            }
+        }
+
+        public static void Reduce(uint[] xx, uint[] z)
+        {
+            ulong x5 = xx[5], x6 = xx[6], x7 = xx[7], x8 = xx[8], x9 = xx[9];
+
+            ulong c = 0;
+            c += (ulong)xx[0] + x5 + (x5 << 31);
+            z[0] = (uint)c; c >>= 32;
+            c += (ulong)xx[1] + x6 + (x6 << 31);
+            z[1] = (uint)c; c >>= 32;
+            c += (ulong)xx[2] + x7 + (x7 << 31);
+            z[2] = (uint)c; c >>= 32;
+            c += (ulong)xx[3] + x8 + (x8 << 31);
+            z[3] = (uint)c; c >>= 32;
+            c += (ulong)xx[4] + x9 + (x9 << 31);
+            z[4] = (uint)c; c >>= 32;
+
+            Debug.Assert(c >> 32 == 0);
+
+            Reduce32((uint)c, z);
+        }
+
+        public static void Reduce32(uint x, uint[] z)
+        {
+            if ((x != 0 && Nat160.MulWordsAdd(PInv, x, z, 0) != 0)
+                || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.AddWordTo(5, PInv, z);
+            }
+        }
+
+        public static void Square(uint[] x, uint[] z)
+        {
+            uint[] tt = Nat160.CreateExt();
+            Nat160.Square(x, tt);
+            Reduce(tt, z);
+        }
+
+        public static void SquareN(uint[] x, int n, uint[] z)
+        {
+            Debug.Assert(n > 0);
+
+            uint[] tt = Nat160.CreateExt();
+            Nat160.Square(x, tt);
+            Reduce(tt, z);
+
+            while (--n > 0)
+            {
+                Nat160.Square(z, tt);
+                Reduce(tt, z);
+            }
+        }
+
+        public static void Subtract(uint[] x, uint[] y, uint[] z)
+        {
+            int c = Nat160.Sub(x, y, z);
+            if (c != 0)
+            {
+                Nat.SubWordFrom(5, PInv, z);
+            }
+        }
+
+        public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
+        {
+            int c = Nat.Sub(10, xx, yy, zz);
+            if (c != 0)
+            {
+                if (Nat.SubFrom(PExtInv.Length, PExtInv, zz) != 0)
+                {
+                    Nat.DecAt(10, zz, PExtInv.Length);
+                }
+            }
+        }
+
+        public static void Twice(uint[] x, uint[] z)
+        {
+            uint c = Nat.ShiftUpBit(5, x, 0, z);
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.AddWordTo(5, PInv, z);
+            }
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R1FieldElement.cs b/crypto/src/math/ec/custom/sec/SecP160R1FieldElement.cs
new file mode 100644
index 000000000..d1fc75644
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R1FieldElement.cs
@@ -0,0 +1,203 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R1FieldElement
+        : ECFieldElement
+    {
+        public static readonly BigInteger Q = SecP160R1Curve.q;
+
+        protected internal readonly uint[] x;
+
+        public SecP160R1FieldElement(BigInteger x)
+        {
+            if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0)
+                throw new ArgumentException("value invalid for SecP160R1FieldElement", "x");
+
+            this.x = SecP160R1Field.FromBigInteger(x);
+        }
+
+        public SecP160R1FieldElement()
+        {
+            this.x = Nat160.Create();
+        }
+
+        protected internal SecP160R1FieldElement(uint[] x)
+        {
+            this.x = x;
+        }
+
+        public override bool IsZero
+        {
+            get { return Nat160.IsZero(x); }
+        }
+
+        public override bool IsOne
+        {
+            get { return Nat160.IsOne(x); }
+        }
+
+        public override bool TestBitZero()
+        {
+            return Nat160.GetBit(x, 0) == 1;
+        }
+
+        public override BigInteger ToBigInteger()
+        {
+            return Nat160.ToBigInteger(x);
+        }
+
+        public override string FieldName
+        {
+            get { return "SecP160R1Field"; }
+        }
+
+        public override int FieldSize
+        {
+            get { return Q.BitLength; }
+        }
+
+        public override ECFieldElement Add(ECFieldElement b)
+        {
+            uint[] z = Nat160.Create();
+            SecP160R1Field.Add(x, ((SecP160R1FieldElement)b).x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement AddOne()
+        {
+            uint[] z = Nat160.Create();
+            SecP160R1Field.AddOne(x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement Subtract(ECFieldElement b)
+        {
+            uint[] z = Nat160.Create();
+            SecP160R1Field.Subtract(x, ((SecP160R1FieldElement)b).x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement Multiply(ECFieldElement b)
+        {
+            uint[] z = Nat160.Create();
+            SecP160R1Field.Multiply(x, ((SecP160R1FieldElement)b).x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement Divide(ECFieldElement b)
+        {
+    //        return multiply(b.invert());
+            uint[] z = Nat160.Create();
+            Mod.Invert(SecP160R1Field.P, ((SecP160R1FieldElement)b).x, z);
+            SecP160R1Field.Multiply(z, x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement Negate()
+        {
+            uint[] z = Nat160.Create();
+            SecP160R1Field.Negate(x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement Square()
+        {
+            uint[] z = Nat160.Create();
+            SecP160R1Field.Square(x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        public override ECFieldElement Invert()
+        {
+    //        return new SecP160R1FieldElement(ToBigInteger().modInverse(Q));
+            uint[] z = Nat160.Create();
+            Mod.Invert(SecP160R1Field.P, x, z);
+            return new SecP160R1FieldElement(z);
+        }
+
+        // D.1.4 91
+        /**
+         * return a sqrt root - the routine verifies that the calculation returns the right value - if
+         * none exists it returns null.
+         */
+        public override ECFieldElement Sqrt()
+        {
+            /*
+             * Raise this element to the exponent 2^158 - 2^29
+             * 
+             * Breaking up the exponent's binary representation into "repunits", we get:
+             *     { 129 1s } { 29 0s }
+             * 
+             * Therefore we need an addition chain containing 129 (the length of the repunit) We use:
+             *     1, 2, 4, 8, 16, 32, 64, 128, [129]
+             */
+
+            uint[] x1 = this.x;
+            if (Nat160.IsZero(x1) || Nat160.IsOne(x1))
+            {
+                return this;
+            }
+
+            uint[] x2 = Nat160.Create();
+            SecP160R1Field.Square(x1, x2);
+            SecP160R1Field.Multiply(x2, x1, x2);
+            uint[] x4 = Nat160.Create();
+            SecP160R1Field.SquareN(x2, 2, x4);
+            SecP160R1Field.Multiply(x4, x2, x4);
+            uint[] x8 = x2;
+            SecP160R1Field.SquareN(x4, 4, x8);
+            SecP160R1Field.Multiply(x8, x4, x8);
+            uint[] x16 = x4;
+            SecP160R1Field.SquareN(x8, 8, x16);
+            SecP160R1Field.Multiply(x16, x8, x16);
+            uint[] x32 = x8;
+            SecP160R1Field.SquareN(x16, 16, x32);
+            SecP160R1Field.Multiply(x32, x16, x32);
+            uint[] x64 = x16;
+            SecP160R1Field.SquareN(x32, 32, x64);
+            SecP160R1Field.Multiply(x64, x32, x64);
+            uint[] x128 = x32;
+            SecP160R1Field.SquareN(x64, 64, x128);
+            SecP160R1Field.Multiply(x128, x64, x128);
+            uint[] x129 = x64;
+            SecP160R1Field.Square(x128, x129);
+            SecP160R1Field.Multiply(x129, x1, x129);
+
+            uint[] t1 = x129;
+            SecP160R1Field.SquareN(t1, 29, t1);
+
+            uint[] t2 = x128;
+            SecP160R1Field.Square(t1, t2);
+
+            return Nat160.Eq(x1, t2) ? new SecP160R1FieldElement(t1) : null;        
+        }
+
+        public override bool Equals(object obj)
+        {
+            return Equals(obj as SecP160R1FieldElement);
+        }
+
+        public override bool Equals(ECFieldElement other)
+        {
+            return Equals(other as SecP160R1FieldElement);
+        }
+
+        public virtual bool Equals(SecP160R1FieldElement other)
+        {
+            if (this == other)
+                return true;
+            if (null == other)
+                return false;
+            return Nat160.Eq(x, other.x);
+        }
+
+        public override int GetHashCode()
+        {
+            return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 5);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R1Point.cs b/crypto/src/math/ec/custom/sec/SecP160R1Point.cs
new file mode 100644
index 000000000..f9f065de6
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R1Point.cs
@@ -0,0 +1,279 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R1Point
+        : AbstractFpPoint
+    {
+        /**
+         * Create a point which encodes with point compression.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * 
+         * @deprecated Use ECCurve.CreatePoint to construct points
+         */
+        public SecP160R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y)
+            : this(curve, x, y, false)
+        {
+        }
+
+        /**
+         * Create a point that encodes with or without point compresion.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * @param withCompression
+         *            if true encode with point compression
+         * 
+         * @deprecated per-point compression property will be removed, refer
+         *             {@link #getEncoded(bool)}
+         */
+        public SecP160R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, bool withCompression)
+            : base(curve, x, y, withCompression)
+        {
+            if ((x == null) != (y == null))
+                throw new ArgumentException("Exactly one of the field elements is null");
+        }
+
+        internal SecP160R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+            : base(curve, x, y, zs, withCompression)
+        {
+        }
+
+        protected override ECPoint Detach()
+        {
+            return new SecP160R1Point(null, AffineXCoord, AffineYCoord);
+        }
+
+        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;
+
+            SecP160R1FieldElement X1 = (SecP160R1FieldElement)this.RawXCoord, Y1 = (SecP160R1FieldElement)this.RawYCoord;
+            SecP160R1FieldElement X2 = (SecP160R1FieldElement)b.RawXCoord, Y2 = (SecP160R1FieldElement)b.RawYCoord;
+
+            SecP160R1FieldElement Z1 = (SecP160R1FieldElement)this.RawZCoords[0];
+            SecP160R1FieldElement Z2 = (SecP160R1FieldElement)b.RawZCoords[0];
+
+            uint c;
+            uint[] tt1 = Nat160.CreateExt();
+            uint[] t2 = Nat160.Create();
+            uint[] t3 = Nat160.Create();
+            uint[] t4 = Nat160.Create();
+
+            bool Z1IsOne = Z1.IsOne;
+            uint[] U2, S2;
+            if (Z1IsOne)
+            {
+                U2 = X2.x;
+                S2 = Y2.x;
+            }
+            else
+            {
+                S2 = t3;
+                SecP160R1Field.Square(Z1.x, S2);
+
+                U2 = t2;
+                SecP160R1Field.Multiply(S2, X2.x, U2);
+
+                SecP160R1Field.Multiply(S2, Z1.x, S2);
+                SecP160R1Field.Multiply(S2, Y2.x, S2);
+            }
+
+            bool Z2IsOne = Z2.IsOne;
+            uint[] U1, S1;
+            if (Z2IsOne)
+            {
+                U1 = X1.x;
+                S1 = Y1.x;
+            }
+            else
+            {
+                S1 = t4;
+                SecP160R1Field.Square(Z2.x, S1);
+
+                U1 = tt1;
+                SecP160R1Field.Multiply(S1, X1.x, U1);
+
+                SecP160R1Field.Multiply(S1, Z2.x, S1);
+                SecP160R1Field.Multiply(S1, Y1.x, S1);
+            }
+
+            uint[] H = Nat160.Create();
+            SecP160R1Field.Subtract(U1, U2, H);
+
+            uint[] R = t2;
+            SecP160R1Field.Subtract(S1, S2, R);
+
+            // Check if b == this or b == -this
+            if (Nat160.IsZero(H))
+            {
+                if (Nat160.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;
+            SecP160R1Field.Square(H, HSquared);
+
+            uint[] G = Nat160.Create();
+            SecP160R1Field.Multiply(HSquared, H, G);
+
+            uint[] V = t3;
+            SecP160R1Field.Multiply(HSquared, U1, V);
+
+            SecP160R1Field.Negate(G, G);
+            Nat160.Mul(S1, G, tt1);
+
+            c = Nat160.AddBothTo(V, V, G);
+            SecP160R1Field.Reduce32(c, G);
+
+            SecP160R1FieldElement X3 = new SecP160R1FieldElement(t4);
+            SecP160R1Field.Square(R, X3.x);
+            SecP160R1Field.Subtract(X3.x, G, X3.x);
+
+            SecP160R1FieldElement Y3 = new SecP160R1FieldElement(G);
+            SecP160R1Field.Subtract(V, X3.x, Y3.x);
+            SecP160R1Field.MultiplyAddToExt(Y3.x, R, tt1);
+            SecP160R1Field.Reduce(tt1, Y3.x);
+
+            SecP160R1FieldElement Z3 = new SecP160R1FieldElement(H);
+            if (!Z1IsOne)
+            {
+                SecP160R1Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+            if (!Z2IsOne)
+            {
+                SecP160R1Field.Multiply(Z3.x, Z2.x, Z3.x);
+            }
+
+            ECFieldElement[] zs = new ECFieldElement[]{ Z3 };
+
+            return new SecP160R1Point(curve, X3, Y3, zs, IsCompressed);
+        }
+
+        public override ECPoint Twice()
+        {
+            if (this.IsInfinity)
+                return this;
+
+            ECCurve curve = this.Curve;
+
+            SecP160R1FieldElement Y1 = (SecP160R1FieldElement)this.RawYCoord;
+            if (Y1.IsZero)
+                return curve.Infinity;
+
+            SecP160R1FieldElement X1 = (SecP160R1FieldElement)this.RawXCoord, Z1 = (SecP160R1FieldElement)this.RawZCoords[0];
+
+            uint c;
+            uint[] t1 = Nat160.Create();
+            uint[] t2 = Nat160.Create();
+
+            uint[] Y1Squared = Nat160.Create();
+            SecP160R1Field.Square(Y1.x, Y1Squared);
+
+            uint[] T = Nat160.Create();
+            SecP160R1Field.Square(Y1Squared, T);
+
+            bool Z1IsOne = Z1.IsOne;
+
+            uint[] Z1Squared = Z1.x;
+            if (!Z1IsOne)
+            {
+                Z1Squared = t2;
+                SecP160R1Field.Square(Z1.x, Z1Squared);
+            }
+
+            SecP160R1Field.Subtract(X1.x, Z1Squared, t1);
+
+            uint[] M = t2;
+            SecP160R1Field.Add(X1.x, Z1Squared, M);
+            SecP160R1Field.Multiply(M, t1, M);
+            c = Nat160.AddBothTo(M, M, M);
+            SecP160R1Field.Reduce32(c, M);
+
+            uint[] S = Y1Squared;
+            SecP160R1Field.Multiply(Y1Squared, X1.x, S);
+            c = Nat.ShiftUpBits(5, S, 2, 0);
+            SecP160R1Field.Reduce32(c, S);
+
+            c = Nat.ShiftUpBits(5, T, 3, 0, t1);
+            SecP160R1Field.Reduce32(c, t1);
+
+            SecP160R1FieldElement X3 = new SecP160R1FieldElement(T);
+            SecP160R1Field.Square(M, X3.x);
+            SecP160R1Field.Subtract(X3.x, S, X3.x);
+            SecP160R1Field.Subtract(X3.x, S, X3.x);
+
+            SecP160R1FieldElement Y3 = new SecP160R1FieldElement(S);
+            SecP160R1Field.Subtract(S, X3.x, Y3.x);
+            SecP160R1Field.Multiply(Y3.x, M, Y3.x);
+            SecP160R1Field.Subtract(Y3.x, t1, Y3.x);
+
+            SecP160R1FieldElement Z3 = new SecP160R1FieldElement(M);
+            SecP160R1Field.Twice(Y1.x, Z3.x);
+            if (!Z1IsOne)
+            {
+                SecP160R1Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+
+            return new SecP160R1Point(curve, X3, Y3, new ECFieldElement[]{ Z3 }, IsCompressed);
+        }
+
+        public override ECPoint TwicePlus(ECPoint b)
+        {
+            if (this == b)
+                return ThreeTimes();
+            if (this.IsInfinity)
+                return b;
+            if (b.IsInfinity)
+                return Twice();
+
+            ECFieldElement Y1 = this.RawYCoord;
+            if (Y1.IsZero)
+                return b;
+
+            return Twice().Add(b);
+        }
+
+        public override ECPoint ThreeTimes()
+        {
+            if (this.IsInfinity || this.RawYCoord.IsZero)
+                return this;
+
+            // NOTE: Be careful about recursions between TwicePlus and ThreeTimes
+            return Twice().Add(this);
+        }
+
+        public override ECPoint Negate()
+        {
+            if (IsInfinity)
+                return this;
+
+            return new SecP160R1Point(Curve, RawXCoord, RawYCoord.Negate(), RawZCoords, IsCompressed);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R2Curve.cs b/crypto/src/math/ec/custom/sec/SecP160R2Curve.cs
new file mode 100644
index 000000000..100561453
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R2Curve.cs
@@ -0,0 +1,78 @@
+using System;
+
+using Org.BouncyCastle.Utilities.Encoders;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R2Curve
+        : AbstractFpCurve
+    {
+        public static readonly BigInteger q = new BigInteger(1,
+            Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFAC73"));
+
+        private const int SecP160R2_DEFAULT_COORDS = COORD_JACOBIAN;
+
+        protected readonly SecP160R2Point m_infinity;
+
+        public SecP160R2Curve()
+            : base(q)
+        {
+            this.m_infinity = new SecP160R2Point(this, null, null);
+
+            this.m_a = FromBigInteger(new BigInteger(1,
+                Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFAC70")));
+            this.m_b = FromBigInteger(new BigInteger(1,
+                Hex.Decode("B4E134D3FB59EB8BAB57274904664D5AF50388BA")));
+            this.m_order = new BigInteger(1, Hex.Decode("0100000000000000000000351EE786A818F3A1A16B"));
+            this.m_cofactor = BigInteger.One;
+
+            this.m_coord = SecP160R2_DEFAULT_COORDS;
+        }
+
+        protected override ECCurve CloneCurve()
+        {
+            return new SecP160R2Curve();
+        }
+
+        public override bool SupportsCoordinateSystem(int coord)
+        {
+            switch (coord)
+            {
+            case COORD_JACOBIAN:
+                return true;
+            default:
+                return false;
+            }
+        }
+
+        public virtual BigInteger Q
+        {
+            get { return q; }
+        }
+
+        public override ECPoint Infinity
+        {
+            get { return m_infinity; }
+        }
+
+        public override int FieldSize
+        {
+            get { return q.BitLength; }
+        }
+
+        public override ECFieldElement FromBigInteger(BigInteger x)
+        {
+            return new SecP160R2FieldElement(x);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
+        {
+            return new SecP160R2Point(this, x, y, withCompression);
+        }
+
+        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+        {
+            return new SecP160R2Point(this, x, y, zs, withCompression);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R2Field.cs b/crypto/src/math/ec/custom/sec/SecP160R2Field.cs
new file mode 100644
index 000000000..1bef32eea
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R2Field.cs
@@ -0,0 +1,178 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R2Field
+    {
+        // 2^160 - 2^32 - 2^14 - 2^12 - 2^9 - 2^8 - 2^7 - 2^3 - 2^2 - 1
+        internal static readonly uint[] P = new uint[]{ 0xFFFFAC73, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+        internal static readonly uint[] PExt = new uint[]{ 0x1B44BBA9, 0x0000A71A, 0x00000001, 0x00000000, 0x00000000,
+            0xFFFF58E6, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
+        private static readonly uint[] PExtInv = new uint[]{ 0xE4BB4457, 0xFFFF58E5, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF,
+            0x0000A719, 0x00000002 };
+        private const uint P4 = 0xFFFFFFFF;
+        private const uint PExt9 = 0xFFFFFFFF;
+        private const uint PInv33 = 0x538D;
+
+        public static void Add(uint[] x, uint[] y, uint[] z)
+        {
+            uint c = Nat160.Add(x, y, z);
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.Add33To(5, PInv33, z);
+            }
+        }
+
+        public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
+        {
+            uint c = Nat.Add(10, xx, yy, zz);
+            if (c != 0 || (zz[9] == PExt9 && Nat.Gte(10, zz, PExt)))
+            {
+                if (Nat.AddTo(PExtInv.Length, PExtInv, zz) != 0)
+                {
+                    Nat.IncAt(10, zz, PExtInv.Length);
+                }
+            }
+        }
+
+        public static void AddOne(uint[] x, uint[] z)
+        {
+            uint c = Nat.Inc(5, x, z);
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.Add33To(5, PInv33, z);
+            }
+        }
+
+        public static uint[] FromBigInteger(BigInteger x)
+        {
+            uint[] z = Nat160.FromBigInteger(x);
+            if (z[4] == P4 && Nat160.Gte(z, P))
+            {
+                Nat160.SubFrom(P, z);
+            }
+            return z;
+        }
+
+        public static void Half(uint[] x, uint[] z)
+        {
+            if ((x[0] & 1) == 0)
+            {
+                Nat.ShiftDownBit(5, x, 0, z);
+            }
+            else
+            {
+                uint c = Nat160.Add(x, P, z);
+                Nat.ShiftDownBit(5, z, c);
+            }
+        }
+
+        public static void Multiply(uint[] x, uint[] y, uint[] z)
+        {
+            uint[] tt = Nat160.CreateExt();
+            Nat160.Mul(x, y, tt);
+            Reduce(tt, z);
+        }
+
+        public static void MultiplyAddToExt(uint[] x, uint[] y, uint[] zz)
+        {
+            uint c = Nat160.MulAddTo(x, y, zz);
+            if (c != 0 || (zz[9] == PExt9 && Nat.Gte(10, zz, PExt)))
+            {
+                if (Nat.AddTo(PExtInv.Length, PExtInv, zz) != 0)
+                {
+                    Nat.IncAt(10, zz, PExtInv.Length);
+                }
+            }
+        }
+
+        public static void Negate(uint[] x, uint[] z)
+        {
+            if (Nat160.IsZero(x))
+            {
+                Nat160.Zero(z);
+            }
+            else
+            {
+                Nat160.Sub(P, x, z);
+            }
+        }
+
+        public static void Reduce(uint[] xx, uint[] z)
+        {
+            ulong cc = Nat160.Mul33Add(PInv33, xx, 5, xx, 0, z, 0);
+            uint c = Nat160.Mul33DWordAdd(PInv33, cc, z, 0);
+
+            Debug.Assert(c == 0 || c == 1);
+
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.Add33To(5, PInv33, z);
+            }
+        }
+
+        public static void Reduce32(uint x, uint[] z)
+        {
+            if ((x != 0 && Nat160.Mul33WordAdd(PInv33, x, z, 0) != 0)
+                || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.Add33To(5, PInv33, z);
+            }
+        }
+
+        public static void Square(uint[] x, uint[] z)
+        {
+            uint[] tt = Nat160.CreateExt();
+            Nat160.Square(x, tt);
+            Reduce(tt, z);
+        }
+
+        public static void SquareN(uint[] x, int n, uint[] z)
+        {
+            Debug.Assert(n > 0);
+
+            uint[] tt = Nat160.CreateExt();
+            Nat160.Square(x, tt);
+            Reduce(tt, z);
+
+            while (--n > 0)
+            {
+                Nat160.Square(z, tt);
+                Reduce(tt, z);
+            }
+        }
+
+        public static void Subtract(uint[] x, uint[] y, uint[] z)
+        {
+            int c = Nat160.Sub(x, y, z);
+            if (c != 0)
+            {
+                Nat.Sub33From(5, PInv33, z);
+            }
+        }
+
+        public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
+        {
+            int c = Nat.Sub(10, xx, yy, zz);
+            if (c != 0)
+            {
+                if (Nat.SubFrom(PExtInv.Length, PExtInv, zz) != 0)
+                {
+                    Nat.DecAt(10, zz, PExtInv.Length);
+                }
+            }
+        }
+
+        public static void Twice(uint[] x, uint[] z)
+        {
+            uint c = Nat.ShiftUpBit(5, x, 0, z);
+            if (c != 0 || (z[4] == P4 && Nat160.Gte(z, P)))
+            {
+                Nat.Add33To(5, PInv33, z);
+            }
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs b/crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs
new file mode 100644
index 000000000..bdb5245b2
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs
@@ -0,0 +1,218 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R2FieldElement
+        : ECFieldElement
+    {
+        public static readonly BigInteger Q = SecP160R2Curve.q;
+
+        protected internal readonly uint[] x;
+
+        public SecP160R2FieldElement(BigInteger x)
+        {
+            if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0)
+                throw new ArgumentException("value invalid for SecP160R2FieldElement", "x");
+
+            this.x = SecP160R2Field.FromBigInteger(x);
+        }
+
+        public SecP160R2FieldElement()
+        {
+            this.x = Nat160.Create();
+        }
+
+        protected internal SecP160R2FieldElement(uint[] x)
+        {
+            this.x = x;
+        }
+
+        public override bool IsZero
+        {
+            get { return Nat160.IsZero(x); }
+        }
+
+        public override bool IsOne
+        {
+            get { return Nat160.IsOne(x); }
+        }
+
+        public override bool TestBitZero()
+        {
+            return Nat160.GetBit(x, 0) == 1;
+        }
+
+        public override BigInteger ToBigInteger()
+        {
+            return Nat160.ToBigInteger(x);
+        }
+
+        public override string FieldName
+        {
+            get { return "SecP160R2Field"; }
+        }
+
+        public override int FieldSize
+        {
+            get { return Q.BitLength; }
+        }
+
+        public override ECFieldElement Add(ECFieldElement b)
+        {
+            uint[] z = Nat160.Create();
+            SecP160R2Field.Add(x, ((SecP160R2FieldElement)b).x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement AddOne()
+        {
+            uint[] z = Nat160.Create();
+            SecP160R2Field.AddOne(x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement Subtract(ECFieldElement b)
+        {
+            uint[] z = Nat160.Create();
+            SecP160R2Field.Subtract(x, ((SecP160R2FieldElement)b).x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement Multiply(ECFieldElement b)
+        {
+            uint[] z = Nat160.Create();
+            SecP160R2Field.Multiply(x, ((SecP160R2FieldElement)b).x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement Divide(ECFieldElement b)
+        {
+    //        return Multiply(b.invert());
+            uint[] z = Nat160.Create();
+            Mod.Invert(SecP160R2Field.P, ((SecP160R2FieldElement)b).x, z);
+            SecP160R2Field.Multiply(z, x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement Negate()
+        {
+            uint[] z = Nat160.Create();
+            SecP160R2Field.Negate(x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement Square()
+        {
+            uint[] z = Nat160.Create();
+            SecP160R2Field.Square(x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        public override ECFieldElement Invert()
+        {
+    //        return new SecP160R2FieldElement(ToBigInteger().modInverse(Q));
+            uint[] z = Nat160.Create();
+            Mod.Invert(SecP160R2Field.P, x, z);
+            return new SecP160R2FieldElement(z);
+        }
+
+        // D.1.4 91
+        /**
+         * return a sqrt root - the routine verifies that the calculation returns the right value - if
+         * none exists it returns null.
+         */
+        public override ECFieldElement Sqrt()
+        {
+            /*
+             * Raise this element to the exponent 2^158 - 2^30 - 2^12 - 2^10 - 2^7 - 2^6 - 2^5 - 2^1 - 2^0
+             * 
+             * Breaking up the exponent's binary representation into "repunits", we get: { 127 1s } { 1
+             * 0s } { 17 1s } { 1 0s } { 1 1s } { 1 0s } { 2 1s } { 3 0s } { 3 1s } { 1 0s } { 1 1s }
+             * 
+             * Therefore we need an Addition chain containing 1, 2, 3, 17, 127 (the lengths of the repunits)
+             * We use: [1], [2], [3], 4, 7, 14, [17], 31, 62, 124, [127]
+             */
+
+            uint[] x1 = this.x;
+            if (Nat160.IsZero(x1) || Nat160.IsOne(x1))
+            {
+                return this;
+            }
+
+            uint[] x2 = Nat160.Create();
+            SecP160R2Field.Square(x1, x2);
+            SecP160R2Field.Multiply(x2, x1, x2);
+            uint[] x3 = Nat160.Create();
+            SecP160R2Field.Square(x2, x3);
+            SecP160R2Field.Multiply(x3, x1, x3);
+            uint[] x4 = Nat160.Create();
+            SecP160R2Field.Square(x3, x4);
+            SecP160R2Field.Multiply(x4, x1, x4);
+            uint[] x7 = Nat160.Create();
+            SecP160R2Field.SquareN(x4, 3, x7);
+            SecP160R2Field.Multiply(x7, x3, x7);
+            uint[] x14 = x4;
+            SecP160R2Field.SquareN(x7, 7, x14);
+            SecP160R2Field.Multiply(x14, x7, x14);
+            uint[] x17 = x7;
+            SecP160R2Field.SquareN(x14, 3, x17);
+            SecP160R2Field.Multiply(x17, x3, x17);
+            uint[] x31 = Nat160.Create();
+            SecP160R2Field.SquareN(x17, 14, x31);
+            SecP160R2Field.Multiply(x31, x14, x31);
+            uint[] x62 = x14;
+            SecP160R2Field.SquareN(x31, 31, x62);
+            SecP160R2Field.Multiply(x62, x31, x62);
+            uint[] x124 = x31;
+            SecP160R2Field.SquareN(x62, 62, x124);
+            SecP160R2Field.Multiply(x124, x62, x124);
+            uint[] x127 = x62;
+            SecP160R2Field.SquareN(x124, 3, x127);
+            SecP160R2Field.Multiply(x127, x3, x127);
+
+            uint[] t1 = x127;
+            SecP160R2Field.SquareN(t1, 18, t1);
+            SecP160R2Field.Multiply(t1, x17, t1);
+            SecP160R2Field.SquareN(t1, 2, t1);
+            SecP160R2Field.Multiply(t1, x1, t1);
+            SecP160R2Field.SquareN(t1, 3, t1);
+            SecP160R2Field.Multiply(t1, x2, t1);
+            SecP160R2Field.SquareN(t1, 6, t1);
+            SecP160R2Field.Multiply(t1, x3, t1);
+            SecP160R2Field.SquareN(t1, 2, t1);
+            SecP160R2Field.Multiply(t1, x1, t1);
+
+            uint[] t2 = x2;
+            SecP160R2Field.Square(t1, t2);
+
+            return Nat160.Eq(x1, t2) ? new SecP160R2FieldElement(t1) : null;        
+        }
+
+        public override bool Equals(object obj)
+        {
+            return Equals(obj as SecP160R2FieldElement);
+        }
+
+        public override bool Equals(ECFieldElement other)
+        {
+            return Equals(other as SecP160R2FieldElement);
+        }
+
+        public virtual bool Equals(SecP160R2FieldElement other)
+        {
+            if (this == other)
+                return true;
+            if (null == other)
+                return false;
+            return Nat160.Eq(x, other.x);
+        }
+
+        public override int GetHashCode()
+        {
+            return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 5);
+        }
+    }
+}
diff --git a/crypto/src/math/ec/custom/sec/SecP160R2Point.cs b/crypto/src/math/ec/custom/sec/SecP160R2Point.cs
new file mode 100644
index 000000000..343cf8c16
--- /dev/null
+++ b/crypto/src/math/ec/custom/sec/SecP160R2Point.cs
@@ -0,0 +1,279 @@
+using System;
+
+using Org.BouncyCastle.Math.Raw;
+
+namespace Org.BouncyCastle.Math.EC.Custom.Sec
+{
+    internal class SecP160R2Point
+        : AbstractFpPoint
+    {
+        /**
+         * Create a point which encodes with point compression.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * 
+         * @deprecated Use ECCurve.CreatePoint to construct points
+         */
+        public SecP160R2Point(ECCurve curve, ECFieldElement x, ECFieldElement y)
+            : this(curve, x, y, false)
+        {
+        }
+
+        /**
+         * Create a point that encodes with or without point compresion.
+         * 
+         * @param curve
+         *            the curve to use
+         * @param x
+         *            affine x co-ordinate
+         * @param y
+         *            affine y co-ordinate
+         * @param withCompression
+         *            if true encode with point compression
+         * 
+         * @deprecated per-point compression property will be removed, refer
+         *             {@link #getEncoded(bool)}
+         */
+        public SecP160R2Point(ECCurve curve, ECFieldElement x, ECFieldElement y, bool withCompression)
+            : base(curve, x, y, withCompression)
+        {
+            if ((x == null) != (y == null))
+                throw new ArgumentException("Exactly one of the field elements is null");
+        }
+
+        internal SecP160R2Point(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
+            : base(curve, x, y, zs, withCompression)
+        {
+        }
+
+        protected override ECPoint Detach()
+        {
+            return new SecP160R2Point(null, AffineXCoord, AffineYCoord);
+        }
+
+        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;
+
+            SecP160R2FieldElement X1 = (SecP160R2FieldElement)this.RawXCoord, Y1 = (SecP160R2FieldElement)this.RawYCoord;
+            SecP160R2FieldElement X2 = (SecP160R2FieldElement)b.RawXCoord, Y2 = (SecP160R2FieldElement)b.RawYCoord;
+
+            SecP160R2FieldElement Z1 = (SecP160R2FieldElement)this.RawZCoords[0];
+            SecP160R2FieldElement Z2 = (SecP160R2FieldElement)b.RawZCoords[0];
+
+            uint c;
+            uint[] tt1 = Nat160.CreateExt();
+            uint[] t2 = Nat160.Create();
+            uint[] t3 = Nat160.Create();
+            uint[] t4 = Nat160.Create();
+
+            bool Z1IsOne = Z1.IsOne;
+            uint[] U2, S2;
+            if (Z1IsOne)
+            {
+                U2 = X2.x;
+                S2 = Y2.x;
+            }
+            else
+            {
+                S2 = t3;
+                SecP160R2Field.Square(Z1.x, S2);
+
+                U2 = t2;
+                SecP160R2Field.Multiply(S2, X2.x, U2);
+
+                SecP160R2Field.Multiply(S2, Z1.x, S2);
+                SecP160R2Field.Multiply(S2, Y2.x, S2);
+            }
+
+            bool Z2IsOne = Z2.IsOne;
+            uint[] U1, S1;
+            if (Z2IsOne)
+            {
+                U1 = X1.x;
+                S1 = Y1.x;
+            }
+            else
+            {
+                S1 = t4;
+                SecP160R2Field.Square(Z2.x, S1);
+
+                U1 = tt1;
+                SecP160R2Field.Multiply(S1, X1.x, U1);
+
+                SecP160R2Field.Multiply(S1, Z2.x, S1);
+                SecP160R2Field.Multiply(S1, Y1.x, S1);
+            }
+
+            uint[] H = Nat160.Create();
+            SecP160R2Field.Subtract(U1, U2, H);
+
+            uint[] R = t2;
+            SecP160R2Field.Subtract(S1, S2, R);
+
+            // Check if b == this or b == -this
+            if (Nat160.IsZero(H))
+            {
+                if (Nat160.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;
+            SecP160R2Field.Square(H, HSquared);
+
+            uint[] G = Nat160.Create();
+            SecP160R2Field.Multiply(HSquared, H, G);
+
+            uint[] V = t3;
+            SecP160R2Field.Multiply(HSquared, U1, V);
+
+            SecP160R2Field.Negate(G, G);
+            Nat160.Mul(S1, G, tt1);
+
+            c = Nat160.AddBothTo(V, V, G);
+            SecP160R2Field.Reduce32(c, G);
+
+            SecP160R2FieldElement X3 = new SecP160R2FieldElement(t4);
+            SecP160R2Field.Square(R, X3.x);
+            SecP160R2Field.Subtract(X3.x, G, X3.x);
+
+            SecP160R2FieldElement Y3 = new SecP160R2FieldElement(G);
+            SecP160R2Field.Subtract(V, X3.x, Y3.x);
+            SecP160R2Field.MultiplyAddToExt(Y3.x, R, tt1);
+            SecP160R2Field.Reduce(tt1, Y3.x);
+
+            SecP160R2FieldElement Z3 = new SecP160R2FieldElement(H);
+            if (!Z1IsOne)
+            {
+                SecP160R2Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+            if (!Z2IsOne)
+            {
+                SecP160R2Field.Multiply(Z3.x, Z2.x, Z3.x);
+            }
+
+            ECFieldElement[] zs = new ECFieldElement[]{ Z3 };
+
+            return new SecP160R2Point(curve, X3, Y3, zs, IsCompressed);
+        }
+
+        public override ECPoint Twice()
+        {
+            if (this.IsInfinity)
+                return this;
+
+            ECCurve curve = this.Curve;
+
+            SecP160R2FieldElement Y1 = (SecP160R2FieldElement)this.RawYCoord;
+            if (Y1.IsZero)
+                return curve.Infinity;
+
+            SecP160R2FieldElement X1 = (SecP160R2FieldElement)this.RawXCoord, Z1 = (SecP160R2FieldElement)this.RawZCoords[0];
+
+            uint c;
+            uint[] t1 = Nat160.Create();
+            uint[] t2 = Nat160.Create();
+
+            uint[] Y1Squared = Nat160.Create();
+            SecP160R2Field.Square(Y1.x, Y1Squared);
+
+            uint[] T = Nat160.Create();
+            SecP160R2Field.Square(Y1Squared, T);
+
+            bool Z1IsOne = Z1.IsOne;
+
+            uint[] Z1Squared = Z1.x;
+            if (!Z1IsOne)
+            {
+                Z1Squared = t2;
+                SecP160R2Field.Square(Z1.x, Z1Squared);
+            }
+
+            SecP160R2Field.Subtract(X1.x, Z1Squared, t1);
+
+            uint[] M = t2;
+            SecP160R2Field.Add(X1.x, Z1Squared, M);
+            SecP160R2Field.Multiply(M, t1, M);
+            c = Nat160.AddBothTo(M, M, M);
+            SecP160R2Field.Reduce32(c, M);
+
+            uint[] S = Y1Squared;
+            SecP160R2Field.Multiply(Y1Squared, X1.x, S);
+            c = Nat.ShiftUpBits(5, S, 2, 0);
+            SecP160R2Field.Reduce32(c, S);
+
+            c = Nat.ShiftUpBits(5, T, 3, 0, t1);
+            SecP160R2Field.Reduce32(c, t1);
+
+            SecP160R2FieldElement X3 = new SecP160R2FieldElement(T);
+            SecP160R2Field.Square(M, X3.x);
+            SecP160R2Field.Subtract(X3.x, S, X3.x);
+            SecP160R2Field.Subtract(X3.x, S, X3.x);
+
+            SecP160R2FieldElement Y3 = new SecP160R2FieldElement(S);
+            SecP160R2Field.Subtract(S, X3.x, Y3.x);
+            SecP160R2Field.Multiply(Y3.x, M, Y3.x);
+            SecP160R2Field.Subtract(Y3.x, t1, Y3.x);
+
+            SecP160R2FieldElement Z3 = new SecP160R2FieldElement(M);
+            SecP160R2Field.Twice(Y1.x, Z3.x);
+            if (!Z1IsOne)
+            {
+                SecP160R2Field.Multiply(Z3.x, Z1.x, Z3.x);
+            }
+
+            return new SecP160R2Point(curve, X3, Y3, new ECFieldElement[]{ Z3 }, IsCompressed);
+        }
+
+        public override ECPoint TwicePlus(ECPoint b)
+        {
+            if (this == b)
+                return ThreeTimes();
+            if (this.IsInfinity)
+                return b;
+            if (b.IsInfinity)
+                return Twice();
+
+            ECFieldElement Y1 = this.RawYCoord;
+            if (Y1.IsZero)
+                return b;
+
+            return Twice().Add(b);
+        }
+
+        public override ECPoint ThreeTimes()
+        {
+            if (this.IsInfinity || this.RawYCoord.IsZero)
+                return this;
+
+            // NOTE: Be careful about recursions between TwicePlus and ThreeTimes
+            return Twice().Add(this);
+        }
+
+        public override ECPoint Negate()
+        {
+            if (IsInfinity)
+                return this;
+
+            return new SecP160R2Point(Curve, this.RawXCoord, this.RawYCoord.Negate(), this.RawZCoords, IsCompressed);
+        }
+    }
+}