using System; using System.Diagnostics; using Org.BouncyCastle.Crypto.Utilities; using Org.BouncyCastle.Math.Raw; using Org.BouncyCastle.Security; namespace Org.BouncyCastle.Math.EC.Custom.GM { internal class SM2P256V1Field { // 2^256 - 2^224 - 2^96 + 2^64 - 1 internal static readonly uint[] P = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE }; private static readonly uint[] PExt = new uint[]{ 00000001, 0x00000000, 0xFFFFFFFE, 0x00000001, 0x00000001, 0xFFFFFFFE, 0x00000000, 0x00000002, 0xFFFFFFFE, 0xFFFFFFFD, 0x00000003, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0xFFFFFFFE }; private const uint P7 = 0xFFFFFFFE; private const uint PExt15 = 0xFFFFFFFE; public static void Add(uint[] x, uint[] y, uint[] z) { uint c = Nat256.Add(x, y, z); if (c != 0 || (z[7] >= P7 && Nat256.Gte(z, P))) { AddPInvTo(z); } } public static void AddExt(uint[] xx, uint[] yy, uint[] zz) { uint c = Nat.Add(16, xx, yy, zz); if (c != 0 || (zz[15] >= PExt15 && Nat.Gte(16, zz, PExt))) { Nat.SubFrom(16, PExt, zz); } } public static void AddOne(uint[] x, uint[] z) { uint c = Nat.Inc(8, x, z); if (c != 0 || (z[7] >= P7 && Nat256.Gte(z, P))) { AddPInvTo(z); } } public static uint[] FromBigInteger(BigInteger x) { uint[] z = Nat.FromBigInteger(256, x); if (z[7] >= P7 && Nat256.Gte(z, P)) { Nat256.SubFrom(P, z, 0); } return z; } public static void Inv(uint[] x, uint[] z) { Mod.CheckedModOddInverse(P, x, z); } public static void Half(uint[] x, uint[] z) { if ((x[0] & 1) == 0) { Nat.ShiftDownBit(8, x, 0, z); } else { uint c = Nat256.Add(x, P, z); Nat.ShiftDownBit(8, z, c); } } public static int IsZero(uint[] x) { uint d = 0; for (int i = 0; i < 8; ++i) { d |= x[i]; } d = (d >> 1) | (d & 1); return ((int)d - 1) >> 31; } public static void Multiply(uint[] x, uint[] y, uint[] z) { uint[] tt = Nat256.CreateExt(); Nat256.Mul(x, y, tt); Reduce(tt, z); } public static void MultiplyAddToExt(uint[] x, uint[] y, uint[] zz) { uint c = Nat256.MulAddTo(x, y, zz); if (c != 0 || (zz[15] >= PExt15 && Nat.Gte(16, zz, PExt))) { Nat.SubFrom(16, PExt, zz); } } public static void Negate(uint[] x, uint[] z) { if (0 != IsZero(x)) { Nat256.Sub(P, P, z); } else { Nat256.Sub(P, x, z); } } public static void Random(SecureRandom r, uint[] z) { byte[] bb = new byte[8 * 4]; do { r.NextBytes(bb); Pack.LE_To_UInt32(bb, 0, z, 0, 8); } while (0 == Nat.LessThan(8, z, P)); } public static void RandomMult(SecureRandom r, uint[] z) { do { Random(r, z); } while (0 != IsZero(z)); } public static void Reduce(uint[] xx, uint[] z) { long xx08 = xx[8], xx09 = xx[9], xx10 = xx[10], xx11 = xx[11]; long xx12 = xx[12], xx13 = xx[13], xx14 = xx[14], xx15 = xx[15]; long t0 = xx08 + xx09; long t1 = xx10 + xx11; long t2 = xx12 + xx15; long t3 = xx13 + xx14; long t4 = t3 + (xx15 << 1); long ts = t0 + t3; long tt = t1 + t2 + ts; long cc = 0; cc += (long)xx[0] + tt + xx13 + xx14 + xx15; z[0] = (uint)cc; cc >>= 32; cc += (long)xx[1] + tt - xx08 + xx14 + xx15; z[1] = (uint)cc; cc >>= 32; cc += (long)xx[2] - ts; z[2] = (uint)cc; cc >>= 32; cc += (long)xx[3] + tt - xx09 - xx10 + xx13; z[3] = (uint)cc; cc >>= 32; cc += (long)xx[4] + tt - t1 - xx08 + xx14; z[4] = (uint)cc; cc >>= 32; cc += (long)xx[5] + t4 + xx10; z[5] = (uint)cc; cc >>= 32; cc += (long)xx[6] + xx11 + xx14 + xx15; z[6] = (uint)cc; cc >>= 32; cc += (long)xx[7] + tt + t4 + xx12; z[7] = (uint)cc; cc >>= 32; Debug.Assert(cc >= 0); Reduce32((uint)cc, z); } public static void Reduce32(uint x, uint[] z) { long cc = 0; if (x != 0) { long xx08 = x; cc += (long)z[0] + xx08; z[0] = (uint)cc; cc >>= 32; if (cc != 0) { cc += (long)z[1]; z[1] = (uint)cc; cc >>= 32; } cc += (long)z[2] - xx08; z[2] = (uint)cc; cc >>= 32; cc += (long)z[3] + xx08; z[3] = (uint)cc; cc >>= 32; if (cc != 0) { cc += (long)z[4]; z[4] = (uint)cc; cc >>= 32; cc += (long)z[5]; z[5] = (uint)cc; cc >>= 32; cc += (long)z[6]; z[6] = (uint)cc; cc >>= 32; } cc += (long)z[7] + xx08; z[7] = (uint)cc; cc >>= 32; Debug.Assert(cc == 0 || cc == 1); } if (cc != 0 || (z[7] >= P7 && Nat256.Gte(z, P))) { AddPInvTo(z); } } public static void Square(uint[] x, uint[] z) { uint[] tt = Nat256.CreateExt(); Nat256.Square(x, tt); Reduce(tt, z); } public static void SquareN(uint[] x, int n, uint[] z) { Debug.Assert(n > 0); uint[] tt = Nat256.CreateExt(); Nat256.Square(x, tt); Reduce(tt, z); while (--n > 0) { Nat256.Square(z, tt); Reduce(tt, z); } } public static void Subtract(uint[] x, uint[] y, uint[] z) { int c = Nat256.Sub(x, y, z); if (c != 0) { SubPInvFrom(z); } } public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz) { int c = Nat.Sub(16, xx, yy, zz); if (c != 0) { Nat.AddTo(16, PExt, zz); } } public static void Twice(uint[] x, uint[] z) { uint c = Nat.ShiftUpBit(8, x, 0, z); if (c != 0 || (z[7] >= P7 && Nat256.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] - 1; z[2] = (uint)c; c >>= 32; c += (long)z[3] + 1; z[3] = (uint)c; c >>= 32; if (c != 0) { c += (long)z[4]; z[4] = (uint)c; c >>= 32; c += (long)z[5]; z[5] = (uint)c; c >>= 32; c += (long)z[6]; z[6] = (uint)c; c >>= 32; } c += (long)z[7] + 1; z[7] = (uint)c; //c >>= 32; } 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] + 1; z[2] = (uint)c; c >>= 32; c += (long)z[3] - 1; z[3] = (uint)c; c >>= 32; if (c != 0) { c += (long)z[4]; z[4] = (uint)c; c >>= 32; c += (long)z[5]; z[5] = (uint)c; c >>= 32; c += (long)z[6]; z[6] = (uint)c; c >>= 32; } c += (long)z[7] - 1; z[7] = (uint)c; //c >>= 32; } } }