1*0957b409SSimon J. Gerraty /*
2*0957b409SSimon J. Gerraty * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3*0957b409SSimon J. Gerraty *
4*0957b409SSimon J. Gerraty * Permission is hereby granted, free of charge, to any person obtaining
5*0957b409SSimon J. Gerraty * a copy of this software and associated documentation files (the
6*0957b409SSimon J. Gerraty * "Software"), to deal in the Software without restriction, including
7*0957b409SSimon J. Gerraty * without limitation the rights to use, copy, modify, merge, publish,
8*0957b409SSimon J. Gerraty * distribute, sublicense, and/or sell copies of the Software, and to
9*0957b409SSimon J. Gerraty * permit persons to whom the Software is furnished to do so, subject to
10*0957b409SSimon J. Gerraty * the following conditions:
11*0957b409SSimon J. Gerraty *
12*0957b409SSimon J. Gerraty * The above copyright notice and this permission notice shall be
13*0957b409SSimon J. Gerraty * included in all copies or substantial portions of the Software.
14*0957b409SSimon J. Gerraty *
15*0957b409SSimon J. Gerraty * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*0957b409SSimon J. Gerraty * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*0957b409SSimon J. Gerraty * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18*0957b409SSimon J. Gerraty * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19*0957b409SSimon J. Gerraty * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20*0957b409SSimon J. Gerraty * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21*0957b409SSimon J. Gerraty * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22*0957b409SSimon J. Gerraty * SOFTWARE.
23*0957b409SSimon J. Gerraty */
24*0957b409SSimon J. Gerraty
25*0957b409SSimon J. Gerraty #include "inner.h"
26*0957b409SSimon J. Gerraty
27*0957b409SSimon J. Gerraty /* see bearssl_block.h */
28*0957b409SSimon J. Gerraty uint32_t
br_chacha20_ct_run(const void * key,const void * iv,uint32_t cc,void * data,size_t len)29*0957b409SSimon J. Gerraty br_chacha20_ct_run(const void *key,
30*0957b409SSimon J. Gerraty const void *iv, uint32_t cc, void *data, size_t len)
31*0957b409SSimon J. Gerraty {
32*0957b409SSimon J. Gerraty unsigned char *buf;
33*0957b409SSimon J. Gerraty uint32_t kw[8], ivw[3];
34*0957b409SSimon J. Gerraty size_t u;
35*0957b409SSimon J. Gerraty
36*0957b409SSimon J. Gerraty static const uint32_t CW[] = {
37*0957b409SSimon J. Gerraty 0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
38*0957b409SSimon J. Gerraty };
39*0957b409SSimon J. Gerraty
40*0957b409SSimon J. Gerraty buf = data;
41*0957b409SSimon J. Gerraty for (u = 0; u < 8; u ++) {
42*0957b409SSimon J. Gerraty kw[u] = br_dec32le((const unsigned char *)key + (u << 2));
43*0957b409SSimon J. Gerraty }
44*0957b409SSimon J. Gerraty for (u = 0; u < 3; u ++) {
45*0957b409SSimon J. Gerraty ivw[u] = br_dec32le((const unsigned char *)iv + (u << 2));
46*0957b409SSimon J. Gerraty }
47*0957b409SSimon J. Gerraty while (len > 0) {
48*0957b409SSimon J. Gerraty uint32_t state[16];
49*0957b409SSimon J. Gerraty int i;
50*0957b409SSimon J. Gerraty size_t clen;
51*0957b409SSimon J. Gerraty unsigned char tmp[64];
52*0957b409SSimon J. Gerraty
53*0957b409SSimon J. Gerraty memcpy(&state[0], CW, sizeof CW);
54*0957b409SSimon J. Gerraty memcpy(&state[4], kw, sizeof kw);
55*0957b409SSimon J. Gerraty state[12] = cc;
56*0957b409SSimon J. Gerraty memcpy(&state[13], ivw, sizeof ivw);
57*0957b409SSimon J. Gerraty for (i = 0; i < 10; i ++) {
58*0957b409SSimon J. Gerraty
59*0957b409SSimon J. Gerraty #define QROUND(a, b, c, d) do { \
60*0957b409SSimon J. Gerraty state[a] += state[b]; \
61*0957b409SSimon J. Gerraty state[d] ^= state[a]; \
62*0957b409SSimon J. Gerraty state[d] = (state[d] << 16) | (state[d] >> 16); \
63*0957b409SSimon J. Gerraty state[c] += state[d]; \
64*0957b409SSimon J. Gerraty state[b] ^= state[c]; \
65*0957b409SSimon J. Gerraty state[b] = (state[b] << 12) | (state[b] >> 20); \
66*0957b409SSimon J. Gerraty state[a] += state[b]; \
67*0957b409SSimon J. Gerraty state[d] ^= state[a]; \
68*0957b409SSimon J. Gerraty state[d] = (state[d] << 8) | (state[d] >> 24); \
69*0957b409SSimon J. Gerraty state[c] += state[d]; \
70*0957b409SSimon J. Gerraty state[b] ^= state[c]; \
71*0957b409SSimon J. Gerraty state[b] = (state[b] << 7) | (state[b] >> 25); \
72*0957b409SSimon J. Gerraty } while (0)
73*0957b409SSimon J. Gerraty
74*0957b409SSimon J. Gerraty QROUND( 0, 4, 8, 12);
75*0957b409SSimon J. Gerraty QROUND( 1, 5, 9, 13);
76*0957b409SSimon J. Gerraty QROUND( 2, 6, 10, 14);
77*0957b409SSimon J. Gerraty QROUND( 3, 7, 11, 15);
78*0957b409SSimon J. Gerraty QROUND( 0, 5, 10, 15);
79*0957b409SSimon J. Gerraty QROUND( 1, 6, 11, 12);
80*0957b409SSimon J. Gerraty QROUND( 2, 7, 8, 13);
81*0957b409SSimon J. Gerraty QROUND( 3, 4, 9, 14);
82*0957b409SSimon J. Gerraty
83*0957b409SSimon J. Gerraty #undef QROUND
84*0957b409SSimon J. Gerraty
85*0957b409SSimon J. Gerraty }
86*0957b409SSimon J. Gerraty for (u = 0; u < 4; u ++) {
87*0957b409SSimon J. Gerraty br_enc32le(&tmp[u << 2], state[u] + CW[u]);
88*0957b409SSimon J. Gerraty }
89*0957b409SSimon J. Gerraty for (u = 4; u < 12; u ++) {
90*0957b409SSimon J. Gerraty br_enc32le(&tmp[u << 2], state[u] + kw[u - 4]);
91*0957b409SSimon J. Gerraty }
92*0957b409SSimon J. Gerraty br_enc32le(&tmp[48], state[12] + cc);
93*0957b409SSimon J. Gerraty for (u = 13; u < 16; u ++) {
94*0957b409SSimon J. Gerraty br_enc32le(&tmp[u << 2], state[u] + ivw[u - 13]);
95*0957b409SSimon J. Gerraty }
96*0957b409SSimon J. Gerraty
97*0957b409SSimon J. Gerraty clen = len < 64 ? len : 64;
98*0957b409SSimon J. Gerraty for (u = 0; u < clen; u ++) {
99*0957b409SSimon J. Gerraty buf[u] ^= tmp[u];
100*0957b409SSimon J. Gerraty }
101*0957b409SSimon J. Gerraty buf += clen;
102*0957b409SSimon J. Gerraty len -= clen;
103*0957b409SSimon J. Gerraty cc ++;
104*0957b409SSimon J. Gerraty }
105*0957b409SSimon J. Gerraty return cc;
106*0957b409SSimon J. Gerraty }
107