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
|
/*
* Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <dev/random/chacha20.h>
static const char sigma[16] = "expand 32-byte k";
void chacha20_init(uint32_t state[16], const uint8_t key[32],
const uint8_t nonce[12], uint32_t counter)
{
state[0] = ((uint32_t *)sigma)[0];
state[1] = ((uint32_t *)sigma)[1];
state[2] = ((uint32_t *)sigma)[2];
state[3] = ((uint32_t *)sigma)[3];
for (int i = 0; i < 8; ++i) {
state[4 + i] = ((uint32_t *)key)[i];
}
state[12] = counter;
state[13] = ((uint32_t *)nonce)[0];
state[14] = ((uint32_t *)nonce)[1];
state[15] = ((uint32_t *)nonce)[2];
}
void
chacha20_block(uint32_t state[16], uint8_t out[64])
{
uint32_t x[16];
memcpy(x, state, sizeof(x));
for (int i = 0; i < 10; i++) {
QR(x[0], x[4], x[8], x[12]);
QR(x[1], x[5], x[9], x[13]);
QR(x[2], x[6], x[10], x[14]);
QR(x[3], x[7], x[11], x[15]);
QR(x[0], x[5], x[10], x[15]);
QR(x[1], x[6], x[11], x[12]);
QR(x[2], x[7], x[8], x[13]);
QR(x[3], x[4], x[9], x[14]);
}
for (int i = 0; i < 16; ++i) {
x[i] += state[i];
((uint32_t *)out)[i] = x[i];
}
state[12]++;
}
void
chacha20_encrypt(uint32_t state[16], uint8_t *in,
uint8_t *out, size_t len)
{
uint8_t block[64];
size_t offset = 0;
while (len > 0) {
chacha20_block(state, block);
size_t n = len > 64 ? 64 : len;
for (size_t i = 0; i < n; ++i) {
out[offset + i] = in ? in[offset + i] ^ block[i] : block[i];
}
offset += n;
len -= n;
}
}
|
