h264: remove assert() immediately following return statement
[libav.git] / libavutil / aes.c
CommitLineData
3306dfd5 1/*
034f5fba 2 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
3306dfd5 3 *
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4 * some optimization ideas from aes128.c by Reimar Doeffinger
5 *
2912e87a 6 * This file is part of Libav.
3306dfd5 7 *
2912e87a 8 * Libav is free software; you can redistribute it and/or
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9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
2912e87a 13 * Libav is distributed in the hope that it will be useful,
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14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
2912e87a 19 * License along with Libav; if not, write to the Free Software
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20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "common.h"
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24#include "aes.h"
25
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26typedef union {
27 uint64_t u64[2];
28 uint32_t u32[4];
29 uint8_t u8x4[4][4];
30 uint8_t u8[16];
31} av_aes_block;
32
4bfe0644 33typedef struct AVAES {
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34 // Note: round_key[16] is accessed in the init code, but this only
35 // overwrites state, which does not matter (see also r7471).
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36 av_aes_block round_key[15];
37 av_aes_block state[2];
3306dfd5 38 int rounds;
4bfe0644 39} AVAES;
3306dfd5 40
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41const int av_aes_size= sizeof(AVAES);
42
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43static const uint8_t rcon[10] = {
44 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
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45};
46
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47static uint8_t sbox[256];
48static uint8_t inv_sbox[256];
b250f9c6 49#if CONFIG_SMALL
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50static uint32_t enc_multbl[1][256];
51static uint32_t dec_multbl[1][256];
52#else
53static uint32_t enc_multbl[4][256];
54static uint32_t dec_multbl[4][256];
55#endif
3306dfd5 56
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57static inline void addkey(av_aes_block *dst, const av_aes_block *src,
58 const av_aes_block *round_key)
59{
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60 dst->u64[0] = src->u64[0] ^ round_key->u64[0];
61 dst->u64[1] = src->u64[1] ^ round_key->u64[1];
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62}
63
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64static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
65{
66 av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s);
67 av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s);
68
69 s0[0].u8[ 0] = box[s0[1].u8[ 0]];
70 s0[0].u8[ 4] = box[s0[1].u8[ 4]];
71 s0[0].u8[ 8] = box[s0[1].u8[ 8]];
72 s0[0].u8[12] = box[s0[1].u8[12]];
73 s1[0].u8[ 3] = box[s1[1].u8[ 7]];
74 s1[0].u8[ 7] = box[s1[1].u8[11]];
75 s1[0].u8[11] = box[s1[1].u8[15]];
76 s1[0].u8[15] = box[s1[1].u8[ 3]];
77 s0[0].u8[ 2] = box[s0[1].u8[10]];
78 s0[0].u8[10] = box[s0[1].u8[ 2]];
79 s0[0].u8[ 6] = box[s0[1].u8[14]];
80 s0[0].u8[14] = box[s0[1].u8[ 6]];
81 s3[0].u8[ 1] = box[s3[1].u8[13]];
82 s3[0].u8[13] = box[s3[1].u8[ 9]];
83 s3[0].u8[ 9] = box[s3[1].u8[ 5]];
84 s3[0].u8[ 5] = box[s3[1].u8[ 1]];
1aa72a70 85}
0458e790 86
17c78b08 87static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
b250f9c6 88#if CONFIG_SMALL
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89#define ROT(x,s) ((x<<s)|(x>>(32-s)))
90 return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
cd0968c4 91#else
97f6d154 92 return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
cd0968c4 93#endif
3306dfd5 94}
298dd6b7 95
dd025f25 96static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){
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97 uint8_t (*src)[4] = state[1].u8x4;
98 state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
99 state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]);
100 state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
101 state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]);
1aa72a70 102}
3306dfd5 103
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104static inline void crypt(AVAES *a, int s, const uint8_t *sbox,
105 uint32_t multbl[][256])
106{
14bc3849 107 int r;
3306dfd5 108
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109 for (r = a->rounds - 1; r > 0; r--) {
110 mix(a->state, multbl, 3 - s, 1 + s);
dd025f25 111 addkey(&a->state[1], &a->state[0], &a->round_key[r]);
3306dfd5 112 }
4bfe0644 113
dd025f25 114 subshift(&a->state[0], s, sbox);
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115}
116
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117void av_aes_crypt(AVAES *a, uint8_t *dst_, const uint8_t *src_,
118 int count, uint8_t *iv_, int decrypt)
119{
120 av_aes_block *dst = (av_aes_block *) dst_;
121 const av_aes_block *src = (const av_aes_block *) src_;
122 av_aes_block *iv = (av_aes_block *) iv_;
123
124 while (count--) {
dd025f25 125 addkey(&a->state[1], src, &a->round_key[a->rounds]);
4bfe0644 126 if (decrypt) {
97e3458c 127 crypt(a, 0, inv_sbox, dec_multbl);
4bfe0644 128 if (iv) {
dd025f25 129 addkey(&a->state[0], &a->state[0], iv);
af2ea724 130 *iv = *src;
97e3458c 131 }
dd025f25 132 addkey(dst, &a->state[0], &a->round_key[0]);
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133 } else {
134 if (iv)
135 addkey(&a->state[1], &a->state[1], iv);
136 crypt(a, 2, sbox, enc_multbl);
dd025f25 137 addkey(dst, &a->state[0], &a->round_key[0]);
4bfe0644 138 if (iv)
af2ea724 139 *iv = *dst;
97e3458c 140 }
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141 src++;
142 dst++;
97e3458c 143 }
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144}
145
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146static void init_multbl2(uint8_t tbl[1024], const int c[4],
147 const uint8_t *log8, const uint8_t *alog8,
148 const uint8_t *sbox)
149{
597e3232 150 int i, j;
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151
152 for (i = 0; i < 1024; i++) {
153 int x = sbox[i >> 2];
154 if (x)
155 tbl[i] = alog8[log8[x] + log8[c[i & 3]]];
0458e790 156 }
b250f9c6 157#if !CONFIG_SMALL
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158 for (j = 256; j < 1024; j++)
159 for (i = 0; i < 4; i++)
160 tbl[4*j + i] = tbl[4*j + ((i - 1) & 3) - 1024];
7200f5d0 161#endif
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162}
163
3306dfd5 164// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
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165int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
166{
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167 int i, j, t, rconpointer = 0;
168 uint8_t tk[8][4];
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169 int KC = key_bits >> 5;
170 int rounds = KC + 6;
171 uint8_t log8[256];
cd0968c4 172 uint8_t alog8[512];
3306dfd5 173
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174 if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) {
175 j = 1;
176 for (i = 0; i < 255; i++) {
177 alog8[i] = alog8[i + 255] = j;
178 log8[j] = i;
179 j ^= j + j;
180 if (j > 255)
181 j ^= 0x11B;
3306dfd5 182 }
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183 for (i = 0; i < 256; i++) {
184 j = i ? alog8[255 - log8[i]] : 0;
185 j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4);
186 j = (j ^ (j >> 8) ^ 99) & 255;
187 inv_sbox[j] = i;
188 sbox[i] = j;
3306dfd5 189 }
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190 init_multbl2(dec_multbl[0], (const int[4]) { 0xe, 0x9, 0xd, 0xb },
191 log8, alog8, inv_sbox);
192 init_multbl2(enc_multbl[0], (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
193 log8, alog8, sbox);
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194 }
195
4bfe0644 196 if (key_bits != 128 && key_bits != 192 && key_bits != 256)
6572e1a4 197 return -1;
3306dfd5 198
4bfe0644 199 a->rounds = rounds;
eade86e2 200
4bfe0644 201 memcpy(tk, key, KC * 4);
3306dfd5 202
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203 for (t = 0; t < (rounds + 1) * 16;) {
204 memcpy(a->round_key[0].u8 + t, tk, KC * 4);
205 t += KC * 4;
3306dfd5 206
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207 for (i = 0; i < 4; i++)
208 tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
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209 tk[0][0] ^= rcon[rconpointer++];
210
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211 for (j = 1; j < KC; j++) {
212 if (KC != 8 || j != KC >> 1)
213 for (i = 0; i < 4; i++)
214 tk[j][i] ^= tk[j - 1][i];
3306dfd5 215 else
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216 for (i = 0; i < 4; i++)
217 tk[j][i] ^= sbox[tk[j - 1][i]];
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218 }
219 }
f12cf3d2 220
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221 if (decrypt) {
222 for (i = 1; i < rounds; i++) {
dd025f25 223 av_aes_block tmp[3];
af2ea724 224 tmp[2] = a->round_key[i];
2ad4a3bc 225 subshift(&tmp[1], 0, sbox);
298dd6b7 226 mix(tmp, dec_multbl, 1, 3);
af2ea724 227 a->round_key[i] = tmp[0];
28b51235 228 }
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229 } else {
230 for (i = 0; i < (rounds + 1) >> 1; i++) {
af2ea724 231 FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds-i]);
f25b650a 232 }
cc858970 233 }
f12cf3d2 234
6572e1a4 235 return 0;
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236}
237
238#ifdef TEST
744765a9 239#include <string.h>
294eaa26 240#include "lfg.h"
0d80bd2f 241#include "log.h"
3306dfd5 242
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243int main(int argc, char **argv)
244{
4bfe0644 245 int i, j;
744765a9 246 AVAES b;
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247 uint8_t rkey[2][16] = {
248 { 0 },
249 { 0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3,
250 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59 }
251 };
d65dc0cd 252 uint8_t pt[16], rpt[2][16]= {
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253 { 0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad,
254 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3 },
255 { 0 }
256 };
d65dc0cd 257 uint8_t rct[2][16]= {
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258 { 0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7,
259 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf },
260 { 0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0,
261 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65 }
262 };
7465619a 263 uint8_t temp[16];
744765a9 264 int err = 0;
3306dfd5 265
b56e34c5 266 av_log_set_level(AV_LOG_DEBUG);
cf5773e9 267
4bfe0644 268 for (i = 0; i < 2; i++) {
6572e1a4 269 av_aes_init(&b, rkey[i], 128, 1);
ca2560df 270 av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
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271 for (j = 0; j < 16; j++) {
272 if (rpt[i][j] != temp[j]) {
273 av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n",
274 j, rpt[i][j], temp[j]);
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275 err = 1;
276 }
4bfe0644 277 }
d65dc0cd 278 }
0458e790 279
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280 if (argc > 1 && !strcmp(argv[1], "-t")) {
281 AVAES ae, ad;
282 AVLFG prng;
283
284 av_aes_init(&ae, "PI=3.141592654..", 128, 0);
285 av_aes_init(&ad, "PI=3.141592654..", 128, 1);
286 av_lfg_init(&prng, 1);
287
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288 for (i = 0; i < 10000; i++) {
289 for (j = 0; j < 16; j++) {
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290 pt[j] = av_lfg_get(&prng);
291 }
292 {
293 START_TIMER;
294 av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
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295 if (!(i & (i - 1)))
296 av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n",
297 temp[0], temp[5], temp[10], temp[15]);
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298 av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
299 STOP_TIMER("aes");
300 }
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301 for (j = 0; j < 16; j++) {
302 if (pt[j] != temp[j]) {
303 av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n",
304 i, j, pt[j], temp[j]);
744765a9 305 }
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306 }
307 }
3306dfd5 308 }
744765a9 309 return err;
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310}
311#endif