diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP160R1Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP160R1Field.cs | 186 |
1 files changed, 186 insertions, 0 deletions
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); + } + } + } +} |