1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
using System;
using System.Diagnostics;
namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
internal class SecP256K1Field
{
// 2^256 - 2^32 - 2^9 - 2^8 - 2^7 - 2^6 - 2^4 - 1
internal static readonly uint[] P = new uint[]{ 0xFFFFFC2F, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF };
private const uint P7 = 0xFFFFFFFF;
private static readonly uint[] PExt = new uint[]{ 0x000E90A1, 0x000007A2, 0x00000001, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0xFFFFF85E, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF,
0xFFFFFFFF, 0xFFFFFFFF };
private const uint PExt15 = 0xFFFFFFFF;
private static readonly ulong PInv = 0x00000001000003D1UL;
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)))
{
Nat256.AddDWord(PInv, z, 0);
}
}
public static void AddExt(uint[] xx, uint[] yy, uint[] zz)
{
uint c = Nat256.AddExt(xx, yy, zz);
if (c != 0 || (zz[15] == PExt15 && Nat256.GteExt(zz, PExt)))
{
Nat256.SubExt(zz, PExt, zz);
}
}
public static void AddOne(uint[] x, uint[] z)
{
Array.Copy(x, 0, z, 0, 8);
uint c = Nat256.Inc(z, 0);
if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
{
Nat256.AddDWord(PInv, z, 0);
}
}
public static uint[] FromBigInteger(BigInteger x)
{
uint[] z = Nat256.FromBigInteger(x);
if (z[7] == P7 && Nat256.Gte(z, P))
{
Nat256.AddDWord(PInv, z, 0);
}
return z;
}
public static void Half(uint[] x, uint[] z)
{
if ((x[0] & 1) == 0)
{
Nat256.ShiftDownBit(x, 0, z);
}
else
{
uint c = Nat256.Add(x, P, z);
Nat256.ShiftDownBit(z, c, z);
}
}
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 Negate(uint[] x, uint[] z)
{
if (Nat256.IsZero(x))
{
Nat256.Zero(z);
}
else
{
Nat256.Sub(P, x, z);
}
}
public static void Reduce(uint[] tt, uint[] z)
{
long extra = -(long)tt[8];
extra += (long)Nat256.MulWordAddExt((uint)PInv, tt, 8, tt, 0);
extra += (long)Nat256.AddToExt(tt, 8, tt, 1) << 32;
extra += (long)tt[8];
ulong c = Nat256.MulWordDwordAdd((uint)PInv, (ulong)extra, tt, 0);
c += Nat256.AddDWord((ulong)extra, tt, 1);
Debug.Assert(c == 0 || c == 1);
if (c != 0 || (tt[7] == P7 && Nat256.Gte(tt, P)))
{
Nat256.AddDWord(PInv, tt, 0);
}
Array.Copy(tt, 0, z, 0, 8);
}
public static void Square(uint[] x, uint[] z)
{
uint[] tt = Nat256.CreateExt();
Nat256.Square(x, tt);
Reduce(tt, z);
}
public static void Subtract(uint[] x, uint[] y, uint[] z)
{
int c = Nat256.Sub(x, y, z);
if (c != 0)
{
Nat256.SubDWord(PInv, z);
}
}
public static void SubtractExt(uint[] xx, uint[] yy, uint[] zz)
{
int c = Nat256.SubExt(xx, yy, zz);
if (c != 0)
{
Nat256.AddExt(zz, PExt, zz);
}
}
public static void Twice(uint[] x, uint[] z)
{
uint c = Nat256.ShiftUpBit(x, 0, z);
if (c != 0 || (z[7] == P7 && Nat256.Gte(z, P)))
{
Nat256.AddDWord(PInv, z, 0);
}
}
}
}
|
