diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT113Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecT113Field.cs | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT113Field.cs b/crypto/src/math/ec/custom/sec/SecT113Field.cs new file mode 100644 index 000000000..dbb645e6f --- /dev/null +++ b/crypto/src/math/ec/custom/sec/SecT113Field.cs @@ -0,0 +1,180 @@ +using System; +using System.Diagnostics; + +using Org.BouncyCastle.Math.Raw; + +namespace Org.BouncyCastle.Math.EC.Custom.Sec +{ + internal class SecT113Field + { + private const ulong M49 = ulong.MaxValue >> 15; + private const ulong M57 = ulong.MaxValue >> 7; + + public static void Add(ulong[] x, ulong[] y, ulong[] z) + { + z[0] = x[0] ^ y[0]; + z[1] = x[1] ^ y[1]; + } + + public static void AddExt(ulong[] xx, ulong[] yy, ulong[] zz) + { + zz[0] = xx[0] ^ yy[0]; + zz[1] = xx[1] ^ yy[1]; + zz[2] = xx[2] ^ yy[2]; + zz[3] = xx[3] ^ yy[3]; + } + + public static void AddOne(ulong[] x, ulong[] z) + { + z[0] = x[0] ^ 1UL; + z[1] = x[1]; + } + + public static ulong[] FromBigInteger(BigInteger x) + { + ulong[] z = Nat128.FromBigInteger64(x); + Reduce15(z, 0); + return z; + } + + public static void Multiply(ulong[] x, ulong[] y, ulong[] z) + { + ulong[] tt = Nat128.CreateExt64(); + ImplMultiply(x, y, tt); + Reduce(tt, z); + } + + public static void MultiplyAddToExt(ulong[] x, ulong[] y, ulong[] zz) + { + ulong[] tt = Nat128.CreateExt64(); + ImplMultiply(x, y, tt); + AddExt(zz, tt, zz); + } + + public static void Reduce(ulong[] xx, ulong[] z) + { + ulong x0 = xx[0], x1 = xx[1], x2 = xx[2], x3 = xx[3]; + + x1 ^= (x3 << 15) ^ (x3 << 24); + x2 ^= (x3 >> 49) ^ (x3 >> 40); + + x0 ^= (x2 << 15) ^ (x2 << 24); + x1 ^= (x2 >> 49) ^ (x2 >> 40); + + ulong t = x1 >> 49; + z[0] = x0 ^ t ^ (t << 9); + z[1] = x1 & M49; + } + + public static void Reduce15(ulong[] z, int zOff) + { + ulong z1 = z[zOff + 1], t = z1 >> 49; + z[zOff ] ^= t ^ (t << 9); + z[zOff + 1] = z1 & M49; + } + + public static void Square(ulong[] x, ulong[] z) + { + ulong[] tt = Nat128.CreateExt64(); + ImplSquare(x, tt); + Reduce(tt, z); + } + + public static void SquareAddToExt(ulong[] x, ulong[] zz) + { + ulong[] tt = Nat128.CreateExt64(); + ImplSquare(x, tt); + AddExt(zz, tt, zz); + } + + public static void SquareN(ulong[] x, int n, ulong[] z) + { + Debug.Assert(n > 0); + + ulong[] tt = Nat128.CreateExt64(); + ImplSquare(x, tt); + Reduce(tt, z); + + while (--n > 0) + { + ImplSquare(z, tt); + Reduce(tt, z); + } + } + + protected static void ImplMultiply(ulong[] x, ulong[] y, ulong[] zz) + { + /* + * "Three-way recursion" as described in "Batch binary Edwards", Daniel J. Bernstein. + */ + + ulong f0 = x[0], f1 = x[1]; + f1 = ((f0 >> 57) ^ (f1 << 7)) & M57; + f0 &= M57; + + ulong g0 = y[0], g1 = y[1]; + g1 = ((g0 >> 57) ^ (g1 << 7)) & M57; + g0 &= M57; + + ulong[] H = new ulong[6]; + + ImplMulw(f0, g0, H, 0); // H(0) 57/56 bits + ImplMulw(f1, g1, H, 2); // H(INF) 57/54 bits + ImplMulw(f0 ^ f1, g0 ^ g1, H, 4); // H(1) 57/56 bits + + ulong r = H[1] ^ H[2]; + ulong z0 = H[0], + z3 = H[3], + z1 = H[4] ^ z0 ^ r, + z2 = H[5] ^ z3 ^ r; + + zz[0] = z0 ^ (z1 << 57); + zz[1] = (z1 >> 7) ^ (z2 << 50); + zz[2] = (z2 >> 14) ^ (z3 << 43); + zz[3] = (z3 >> 21); + } + + protected static void ImplMulw(ulong x, ulong y, ulong[] z, int zOff) + { + Debug.Assert(x >> 57 == 0); + Debug.Assert(y >> 57 == 0); + + ulong[] u = new ulong[8]; + //u[0] = 0; + u[1] = y; + u[2] = u[1] << 1; + u[3] = u[2] ^ y; + u[4] = u[2] << 1; + u[5] = u[4] ^ y; + u[6] = u[3] << 1; + u[7] = u[6] ^ y; + + uint j = (uint)x; + ulong g, h = 0, l = u[j & 7]; + int k = 48; + do + { + j = (uint)(x >> k); + g = u[j & 7] + ^ u[(j >> 3) & 7] << 3 + ^ u[(j >> 6) & 7] << 6; + l ^= (g << k); + h ^= (g >> -k); + } + while ((k -= 9) > 0); + + h ^= ((x & 0x0100804020100800UL) & (ulong)(((long)y << 7) >> 63)) >> 8; + + Debug.Assert(h >> 49 == 0); + + z[zOff ] = l & M57; + z[zOff + 1] = (l >> 57) ^ (h << 7); + } + + protected static void ImplSquare(ulong[] x, ulong[] zz) + { + Interleave.Expand64To128(x[0], zz, 0); + Interleave.Expand64To128(x[1], zz, 2); + } + } +} |