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
|
/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see bearssl_block.h */
uint32_t
br_chacha20_ct_run(const void *key,
const void *iv, uint32_t cc, void *data, size_t len)
{
unsigned char *buf;
uint32_t kw[8], ivw[3];
size_t u;
static const uint32_t CW[] = {
0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
};
buf = data;
for (u = 0; u < 8; u ++) {
kw[u] = br_dec32le((const unsigned char *)key + (u << 2));
}
for (u = 0; u < 3; u ++) {
ivw[u] = br_dec32le((const unsigned char *)iv + (u << 2));
}
while (len > 0) {
uint32_t state[16];
int i;
size_t clen;
unsigned char tmp[64];
memcpy(&state[0], CW, sizeof CW);
memcpy(&state[4], kw, sizeof kw);
state[12] = cc;
memcpy(&state[13], ivw, sizeof ivw);
for (i = 0; i < 10; i ++) {
#define QROUND(a, b, c, d) do { \
state[a] += state[b]; \
state[d] ^= state[a]; \
state[d] = (state[d] << 16) | (state[d] >> 16); \
state[c] += state[d]; \
state[b] ^= state[c]; \
state[b] = (state[b] << 12) | (state[b] >> 20); \
state[a] += state[b]; \
state[d] ^= state[a]; \
state[d] = (state[d] << 8) | (state[d] >> 24); \
state[c] += state[d]; \
state[b] ^= state[c]; \
state[b] = (state[b] << 7) | (state[b] >> 25); \
} while (0)
QROUND( 0, 4, 8, 12);
QROUND( 1, 5, 9, 13);
QROUND( 2, 6, 10, 14);
QROUND( 3, 7, 11, 15);
QROUND( 0, 5, 10, 15);
QROUND( 1, 6, 11, 12);
QROUND( 2, 7, 8, 13);
QROUND( 3, 4, 9, 14);
#undef QROUND
}
for (u = 0; u < 4; u ++) {
br_enc32le(&tmp[u << 2], state[u] + CW[u]);
}
for (u = 4; u < 12; u ++) {
br_enc32le(&tmp[u << 2], state[u] + kw[u - 4]);
}
br_enc32le(&tmp[48], state[12] + cc);
for (u = 13; u < 16; u ++) {
br_enc32le(&tmp[u << 2], state[u] + ivw[u - 13]);
}
clen = len < 64 ? len : 64;
for (u = 0; u < clen; u ++) {
buf[u] ^= tmp[u];
}
buf += clen;
len -= clen;
cc ++;
}
return cc;
}
|
