diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP128R1Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP128R1Field.cs | 218 |
1 files changed, 218 insertions, 0 deletions
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; + } + } +} |