SecP128R1Field
class SecP128R1Field
using Org.BouncyCastle.Crypto.Utilities;
using Org.BouncyCastle.Math.Raw;
using Org.BouncyCastle.Security;
namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
internal class SecP128R1Field
{
internal static readonly uint[] P = new uint[4] {
uint.MaxValue,
uint.MaxValue,
uint.MaxValue,
4294967293
};
private static readonly uint[] PExt = new uint[8] {
1,
0,
0,
4,
4294967294,
uint.MaxValue,
3,
4294967292
};
private static readonly uint[] PExtInv = new uint[8] {
uint.MaxValue,
uint.MaxValue,
uint.MaxValue,
4294967291,
1,
0,
4294967292,
3
};
private const uint P3 = 4294967293;
private const uint PExt7 = 4294967292;
public static void Add(uint[] x, uint[] y, uint[] z)
{
if (Nat128.Add(x, y, z) != 0 || (z[3] >= 4294967293 && Nat128.Gte(z, P)))
AddPInvTo(z);
}
public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
{
if (Nat256.Add(xx, yy, zz) != 0 || (zz[7] >= 4294967292 && Nat256.Gte(zz, PExt)))
Nat.AddTo(PExtInv.Length, PExtInv, zz);
}
public static void AddOne(uint[] x, uint[] z)
{
if (Nat.Inc(4, x, z) != 0 || (z[3] >= 4294967293 && Nat128.Gte(z, P)))
AddPInvTo(z);
}
public static uint[] FromBigInteger(BigInteger x)
{
uint[] array = Nat.FromBigInteger(128, x);
if (array[3] >= 4294967293 && Nat128.Gte(array, P))
Nat128.SubFrom(P, array);
return array;
}
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 Inv(uint[] x, uint[] z)
{
Mod.CheckedModOddInverse(P, x, z);
}
public static int IsZero(uint[] x)
{
uint num = 0;
for (int i = 0; i < 4; i++) {
num |= x[i];
}
num = ((num >> 1) | (num & 1));
return (int)(num - 1) >> 31;
}
public static void Multiply(uint[] x, uint[] y, uint[] z)
{
uint[] array = Nat128.CreateExt();
Nat128.Mul(x, y, array);
Reduce(array, z);
}
public static void MultiplyAddToExt(uint[] x, uint[] y, uint[] zz)
{
if (Nat128.MulAddTo(x, y, zz) != 0 || (zz[7] >= 4294967292 && Nat256.Gte(zz, PExt)))
Nat.AddTo(PExtInv.Length, PExtInv, zz);
}
public static void Negate(uint[] x, uint[] z)
{
if (IsZero(x) != 0)
Nat128.Sub(P, P, z);
else
Nat128.Sub(P, x, z);
}
public static void Random(SecureRandom r, uint[] z)
{
byte[] array = new byte[16];
do {
r.NextBytes(array);
Pack.LE_To_UInt32(array, 0, z, 0, 4);
} while (Nat.LessThan(4, z, P) == 0);
}
public static void RandomMult(SecureRandom r, uint[] z)
{
do {
Random(r, z);
} while (IsZero(z) != 0);
}
public static void Reduce(uint[] xx, uint[] z)
{
ulong num = xx[0];
ulong num2 = xx[1];
ulong num3 = xx[2];
ulong num4 = xx[3];
ulong num5 = xx[4];
ulong num6 = xx[5];
ulong num7 = xx[6];
ulong num8 = xx[7];
num4 += num8;
num7 += num8 << 1;
num3 += num7;
num6 += num7 << 1;
num2 += num6;
num5 += num6 << 1;
num += num5;
num4 += num5 << 1;
z[0] = (uint)num;
num2 += num >> 32;
z[1] = (uint)num2;
num3 += num2 >> 32;
z[2] = (uint)num3;
num4 += num3 >> 32;
z[3] = (uint)num4;
Reduce32((uint)(num4 >> 32), z);
}
public static void Reduce32(uint x, uint[] z)
{
while (x != 0) {
ulong num = x;
ulong num2 = z[0] + num;
z[0] = (uint)num2;
num2 >>= 32;
if (num2 != 0) {
num2 += z[1];
z[1] = (uint)num2;
num2 >>= 32;
num2 += z[2];
z[2] = (uint)num2;
num2 >>= 32;
}
num2 += z[3] + (num << 1);
z[3] = (uint)num2;
num2 >>= 32;
x = (uint)num2;
}
if (z[3] >= 4294967293 && Nat128.Gte(z, P))
AddPInvTo(z);
}
public static void Square(uint[] x, uint[] z)
{
uint[] array = Nat128.CreateExt();
Nat128.Square(x, array);
Reduce(array, z);
}
public static void SquareN(uint[] x, int n, uint[] z)
{
uint[] array = Nat128.CreateExt();
Nat128.Square(x, array);
Reduce(array, z);
while (--n > 0) {
Nat128.Square(z, array);
Reduce(array, z);
}
}
public static void Subtract(uint[] x, uint[] y, uint[] z)
{
if (Nat128.Sub(x, y, z) != 0)
SubPInvFrom(z);
}
public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
{
if (Nat.Sub(10, xx, yy, zz) != 0)
Nat.SubFrom(PExtInv.Length, PExtInv, zz);
}
public static void Twice(uint[] x, uint[] z)
{
if (Nat.ShiftUpBit(4, x, 0, z) != 0 || (z[3] >= 4294967293 && Nat128.Gte(z, P)))
AddPInvTo(z);
}
private static void AddPInvTo(uint[] z)
{
long num = (long)z[0] + 1;
z[0] = (uint)num;
num >>= 32;
if (num != 0) {
num += z[1];
z[1] = (uint)num;
num >>= 32;
num += z[2];
z[2] = (uint)num;
num >>= 32;
}
num += (long)z[3] + 2;
z[3] = (uint)num;
}
private static void SubPInvFrom(uint[] z)
{
long num = (long)z[0] - 1;
z[0] = (uint)num;
num >>= 32;
if (num != 0) {
num += z[1];
z[1] = (uint)num;
num >>= 32;
num += z[2];
z[2] = (uint)num;
num >>= 32;
}
num += (long)z[3] - 2;
z[3] = (uint)num;
}
}
}