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351 lines
9.3 KiB
351 lines
9.3 KiB
2 months ago
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using System;
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using System.Diagnostics;
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using Org.BouncyCastle.Crypto.Utilities;
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using Org.BouncyCastle.Math.Raw;
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using Org.BouncyCastle.Security;
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namespace Org.BouncyCastle.Math.EC.Custom.Sec
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{
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internal class SecP256R1Field
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{
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// 2^256 - 2^224 + 2^192 + 2^96 - 1
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internal static readonly uint[] P = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000000,
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0x00000000, 0x00000001, 0xFFFFFFFF };
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private static readonly uint[] PExt = new uint[]{ 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF,
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0xFFFFFFFF, 0xFFFFFFFE, 0x00000001, 0xFFFFFFFE, 0x00000001, 0xFFFFFFFE, 0x00000001, 0x00000001, 0xFFFFFFFE,
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0x00000002, 0xFFFFFFFE };
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private const uint P7 = 0xFFFFFFFF;
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private const uint PExt15 = 0xFFFFFFFE;
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public static void Add(uint[] x, uint[] y, uint[] z)
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{
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uint c = Nat256.Add(x, y, z);
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if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
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{
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AddPInvTo(z);
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}
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}
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public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
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{
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uint c = Nat.Add(16, xx, yy, zz);
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if (c != 0 || (zz[15] >= PExt15 && Nat.Gte(16, zz, PExt)))
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{
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Nat.SubFrom(16, PExt, zz);
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}
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}
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public static void AddOne(uint[] x, uint[] z)
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{
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uint c = Nat.Inc(8, x, z);
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if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
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{
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AddPInvTo(z);
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}
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}
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public static uint[] FromBigInteger(BigInteger x)
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{
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uint[] z = Nat.FromBigInteger(256, x);
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if (z[7] == P7 && Nat256.Gte(z, P))
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{
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Nat256.SubFrom(P, z);
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}
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return z;
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}
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public static void Half(uint[] x, uint[] z)
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{
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if ((x[0] & 1) == 0)
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{
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Nat.ShiftDownBit(8, x, 0, z);
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}
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else
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{
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uint c = Nat256.Add(x, P, z);
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Nat.ShiftDownBit(8, z, c);
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}
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}
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public static void Inv(uint[] x, uint[] z)
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{
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Mod.CheckedModOddInverse(P, x, z);
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}
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public static int IsZero(uint[] x)
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{
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uint d = 0;
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for (int i = 0; i < 8; ++i)
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{
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d |= x[i];
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}
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d = (d >> 1) | (d & 1);
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return ((int)d - 1) >> 31;
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}
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public static void Multiply(uint[] x, uint[] y, uint[] z)
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{
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uint[] tt = Nat256.CreateExt();
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Nat256.Mul(x, y, tt);
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Reduce(tt, z);
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}
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public static void MultiplyAddToExt(uint[] x, uint[] y, uint[] zz)
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{
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uint c = Nat256.MulAddTo(x, y, zz);
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if (c != 0 || (zz[15] >= PExt15 && Nat.Gte(16, zz, PExt)))
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{
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Nat.SubFrom(16, PExt, zz);
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}
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}
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public static void Negate(uint[] x, uint[] z)
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{
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if (0 != IsZero(x))
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{
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Nat256.Sub(P, P, z);
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}
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else
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{
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Nat256.Sub(P, x, z);
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}
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}
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public static void Random(SecureRandom r, uint[] z)
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{
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byte[] bb = new byte[8 * 4];
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do
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{
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r.NextBytes(bb);
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Pack.LE_To_UInt32(bb, 0, z, 0, 8);
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}
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while (0 == Nat.LessThan(8, z, P));
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}
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public static void RandomMult(SecureRandom r, uint[] z)
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{
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do
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{
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Random(r, z);
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}
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while (0 != IsZero(z));
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}
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public static void Reduce(uint[] xx, uint[] z)
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{
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long xx08 = xx[8], xx09 = xx[9], xx10 = xx[10], xx11 = xx[11];
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long xx12 = xx[12], xx13 = xx[13], xx14 = xx[14], xx15 = xx[15];
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const long n = 6;
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xx08 -= n;
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long t0 = xx08 + xx09;
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long t1 = xx09 + xx10;
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long t2 = xx10 + xx11 - xx15;
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long t3 = xx11 + xx12;
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long t4 = xx12 + xx13;
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long t5 = xx13 + xx14;
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long t6 = xx14 + xx15;
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long t7 = t5 - t0;
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long cc = 0;
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cc += (long)xx[0] - t3 - t7;
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z[0] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[1] + t1 - t4 - t6;
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z[1] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[2] + t2 - t5;
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z[2] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[3] + (t3 << 1) + t7 - t6;
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z[3] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[4] + (t4 << 1) + xx14 - t1;
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z[4] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[5] + (t5 << 1) - t2;
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z[5] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[6] + (t6 << 1) + t7;
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z[6] = (uint)cc;
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cc >>= 32;
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cc += (long)xx[7] + (xx15 << 1) + xx08 - t2 - t4;
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z[7] = (uint)cc;
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cc >>= 32;
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cc += n;
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Debug.Assert(cc >= 0);
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Reduce32((uint)cc, z);
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}
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public static void Reduce32(uint x, uint[] z)
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{
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long cc = 0;
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if (x != 0)
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{
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long xx08 = x;
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cc += (long)z[0] + xx08;
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z[0] = (uint)cc;
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cc >>= 32;
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if (cc != 0)
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{
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cc += (long)z[1];
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z[1] = (uint)cc;
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cc >>= 32;
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cc += (long)z[2];
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z[2] = (uint)cc;
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cc >>= 32;
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}
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cc += (long)z[3] - xx08;
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z[3] = (uint)cc;
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cc >>= 32;
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if (cc != 0)
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{
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cc += (long)z[4];
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z[4] = (uint)cc;
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cc >>= 32;
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cc += (long)z[5];
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z[5] = (uint)cc;
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cc >>= 32;
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}
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cc += (long)z[6] - xx08;
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z[6] = (uint)cc;
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cc >>= 32;
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cc += (long)z[7] + xx08;
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z[7] = (uint)cc;
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cc >>= 32;
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Debug.Assert(cc == 0 || cc == 1);
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}
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if (cc != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
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{
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AddPInvTo(z);
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}
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}
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public static void Square(uint[] x, uint[] z)
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{
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uint[] tt = Nat256.CreateExt();
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Nat256.Square(x, tt);
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Reduce(tt, z);
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}
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public static void SquareN(uint[] x, int n, uint[] z)
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{
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Debug.Assert(n > 0);
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uint[] tt = Nat256.CreateExt();
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Nat256.Square(x, tt);
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Reduce(tt, z);
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while (--n > 0)
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{
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Nat256.Square(z, tt);
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Reduce(tt, z);
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}
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}
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public static void Subtract(uint[] x, uint[] y, uint[] z)
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{
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int c = Nat256.Sub(x, y, z);
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if (c != 0)
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{
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SubPInvFrom(z);
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}
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}
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public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
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{
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int c = Nat.Sub(16, xx, yy, zz);
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if (c != 0)
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{
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Nat.AddTo(16, PExt, zz);
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}
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}
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public static void Twice(uint[] x, uint[] z)
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{
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uint c = Nat.ShiftUpBit(8, x, 0, z);
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if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
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{
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AddPInvTo(z);
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}
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}
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private static void AddPInvTo(uint[] z)
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{
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long c = (long)z[0] + 1;
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z[0] = (uint)c;
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c >>= 32;
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if (c != 0)
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{
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c += (long)z[1];
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z[1] = (uint)c;
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c >>= 32;
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c += (long)z[2];
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z[2] = (uint)c;
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c >>= 32;
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}
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c += (long)z[3] - 1;
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z[3] = (uint)c;
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c >>= 32;
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if (c != 0)
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{
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c += (long)z[4];
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z[4] = (uint)c;
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c >>= 32;
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c += (long)z[5];
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z[5] = (uint)c;
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c >>= 32;
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}
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c += (long)z[6] - 1;
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z[6] = (uint)c;
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c >>= 32;
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c += (long)z[7] + 1;
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z[7] = (uint)c;
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//c >>= 32;
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}
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private static void SubPInvFrom(uint[] z)
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{
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long c = (long)z[0] - 1;
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z[0] = (uint)c;
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c >>= 32;
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if (c != 0)
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{
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c += (long)z[1];
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z[1] = (uint)c;
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c >>= 32;
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c += (long)z[2];
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z[2] = (uint)c;
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c >>= 32;
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}
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c += (long)z[3] + 1;
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z[3] = (uint)c;
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c >>= 32;
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if (c != 0)
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{
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c += (long)z[4];
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z[4] = (uint)c;
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c >>= 32;
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c += (long)z[5];
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z[5] = (uint)c;
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c >>= 32;
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}
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c += (long)z[6] + 1;
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z[6] = (uint)c;
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c >>= 32;
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c += (long)z[7] - 1;
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z[7] = (uint)c;
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//c >>= 32;
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}
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}
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}
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