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
|
// Copyright 2007,2008 Segher Boessenkool <segher@kernel.crashing.org>
// SPDX-License-Identifier: GPL-2.0-or-later
#include "Common/Crypto/bn.h"
#include <cstddef>
#include <cstdio>
#include <cstring>
#include "Common/CommonTypes.h"
static void bn_zero(u8* d, const size_t n)
{
std::memset(d, 0, n);
}
static void bn_copy(u8* d, const u8* a, const size_t n)
{
std::memcpy(d, a, n);
}
int bn_compare(const u8* a, const u8* b, const size_t n)
{
return std::memcmp(a, b, n);
}
void bn_sub_modulus(u8* a, const u8* N, const size_t n)
{
u8 c = 0;
for (size_t i = n; i > 0;)
{
--i;
u32 dig = N[i] + c;
c = (a[i] < dig);
a[i] -= dig;
}
}
void bn_add(u8* d, const u8* a, const u8* b, const u8* N, const size_t n)
{
u8 c = 0;
for (size_t i = n; i > 0;)
{
--i;
u32 dig = a[i] + b[i] + c;
c = (dig >= 0x100);
d[i] = dig;
}
if (c)
bn_sub_modulus(d, N, n);
if (bn_compare(d, N, n) >= 0)
bn_sub_modulus(d, N, n);
}
void bn_mul(u8* d, const u8* a, const u8* b, const u8* N, const size_t n)
{
bn_zero(d, n);
for (size_t i = 0; i < n; i++)
{
for (u8 mask = 0x80; mask != 0; mask >>= 1)
{
bn_add(d, d, d, N, n);
if ((a[i] & mask) != 0)
bn_add(d, d, b, N, n);
}
}
}
void bn_exp(u8* d, const u8* a, const u8* N, const size_t n, const u8* e, const size_t en)
{
u8 t[512];
bn_zero(d, n);
d[n - 1] = 1;
for (size_t i = 0; i < en; i++)
{
for (u8 mask = 0x80; mask != 0; mask >>= 1)
{
bn_mul(t, d, d, N, n);
if ((e[i] & mask) != 0)
bn_mul(d, t, a, N, n);
else
bn_copy(d, t, n);
}
}
}
// only for prime N -- stupid but lazy, see if I care
void bn_inv(u8* d, const u8* a, const u8* N, const size_t n)
{
u8 t[512], s[512];
bn_copy(t, N, n);
bn_zero(s, n);
s[n - 1] = 2;
bn_sub_modulus(t, s, n);
bn_exp(d, a, N, n, t, n);
}
|
