0301e0395c6894f0934ce9291b5df3abc0945b27
[libav.git] / libavutil / aes.c
1 /*
2 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * some optimization ideas from aes128.c by Reimar Doeffinger
5 *
6 * This file is part of Libav.
7 *
8 * Libav is free software; you can redistribute it and/or
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 *
13 * Libav is distributed in the hope that it will be useful,
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
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include "common.h"
24 #include "aes.h"
25 #include "intreadwrite.h"
26
27 typedef union {
28 uint64_t u64[2];
29 uint32_t u32[4];
30 uint8_t u8x4[4][4];
31 uint8_t u8[16];
32 } av_aes_block;
33
34 typedef struct AVAES {
35 // Note: round_key[16] is accessed in the init code, but this only
36 // overwrites state, which does not matter (see also r7471).
37 av_aes_block round_key[15];
38 av_aes_block state[2];
39 int rounds;
40 } AVAES;
41
42 const int av_aes_size= sizeof(AVAES);
43
44 static const uint8_t rcon[10] = {
45 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
46 };
47
48 static uint8_t sbox[256];
49 static uint8_t inv_sbox[256];
50 #if CONFIG_SMALL
51 static uint32_t enc_multbl[1][256];
52 static uint32_t dec_multbl[1][256];
53 #else
54 static uint32_t enc_multbl[4][256];
55 static uint32_t dec_multbl[4][256];
56 #endif
57
58 #if HAVE_BIGENDIAN
59 # define ROT(x, s) ((x >> s) | (x << (32-s)))
60 #else
61 # define ROT(x, s) ((x << s) | (x >> (32-s)))
62 #endif
63
64 static inline void addkey(av_aes_block *dst, const av_aes_block *src,
65 const av_aes_block *round_key)
66 {
67 dst->u64[0] = src->u64[0] ^ round_key->u64[0];
68 dst->u64[1] = src->u64[1] ^ round_key->u64[1];
69 }
70
71 static inline void addkey_s(av_aes_block *dst, const uint8_t *src,
72 const av_aes_block *round_key)
73 {
74 dst->u64[0] = AV_RN64(src) ^ round_key->u64[0];
75 dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1];
76 }
77
78 static inline void addkey_d(uint8_t *dst, const av_aes_block *src,
79 const av_aes_block *round_key)
80 {
81 AV_WN64(dst, src->u64[0] ^ round_key->u64[0]);
82 AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]);
83 }
84
85 static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
86 {
87 av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s);
88 av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s);
89
90 s0[0].u8[ 0] = box[s0[1].u8[ 0]];
91 s0[0].u8[ 4] = box[s0[1].u8[ 4]];
92 s0[0].u8[ 8] = box[s0[1].u8[ 8]];
93 s0[0].u8[12] = box[s0[1].u8[12]];
94 s1[0].u8[ 3] = box[s1[1].u8[ 7]];
95 s1[0].u8[ 7] = box[s1[1].u8[11]];
96 s1[0].u8[11] = box[s1[1].u8[15]];
97 s1[0].u8[15] = box[s1[1].u8[ 3]];
98 s0[0].u8[ 2] = box[s0[1].u8[10]];
99 s0[0].u8[10] = box[s0[1].u8[ 2]];
100 s0[0].u8[ 6] = box[s0[1].u8[14]];
101 s0[0].u8[14] = box[s0[1].u8[ 6]];
102 s3[0].u8[ 1] = box[s3[1].u8[13]];
103 s3[0].u8[13] = box[s3[1].u8[ 9]];
104 s3[0].u8[ 9] = box[s3[1].u8[ 5]];
105 s3[0].u8[ 5] = box[s3[1].u8[ 1]];
106 }
107
108 static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
109 #if CONFIG_SMALL
110 return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
111 #else
112 return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
113 #endif
114 }
115
116 static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){
117 uint8_t (*src)[4] = state[1].u8x4;
118 state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
119 state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]);
120 state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
121 state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]);
122 }
123
124 static inline void crypt(AVAES *a, int s, const uint8_t *sbox,
125 uint32_t multbl[][256])
126 {
127 int r;
128
129 for (r = a->rounds - 1; r > 0; r--) {
130 mix(a->state, multbl, 3 - s, 1 + s);
131 addkey(&a->state[1], &a->state[0], &a->round_key[r]);
132 }
133
134 subshift(&a->state[0], s, sbox);
135 }
136
137 void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
138 int count, uint8_t *iv, int decrypt)
139 {
140 while (count--) {
141 addkey_s(&a->state[1], src, &a->round_key[a->rounds]);
142 if (decrypt) {
143 crypt(a, 0, inv_sbox, dec_multbl);
144 if (iv) {
145 addkey_s(&a->state[0], iv, &a->state[0]);
146 memcpy(iv, src, 16);
147 }
148 addkey_d(dst, &a->state[0], &a->round_key[0]);
149 } else {
150 if (iv)
151 addkey_s(&a->state[1], iv, &a->state[1]);
152 crypt(a, 2, sbox, enc_multbl);
153 addkey_d(dst, &a->state[0], &a->round_key[0]);
154 if (iv)
155 memcpy(iv, dst, 16);
156 }
157 src += 16;
158 dst += 16;
159 }
160 }
161
162 static void init_multbl2(uint32_t tbl[][256], const int c[4],
163 const uint8_t *log8, const uint8_t *alog8,
164 const uint8_t *sbox)
165 {
166 int i;
167
168 for (i = 0; i < 256; i++) {
169 int x = sbox[i];
170 if (x) {
171 int k, l, m, n;
172 x = log8[x];
173 k = alog8[x + log8[c[0]]];
174 l = alog8[x + log8[c[1]]];
175 m = alog8[x + log8[c[2]]];
176 n = alog8[x + log8[c[3]]];
177 tbl[0][i] = AV_NE(MKBETAG(k,l,m,n), MKTAG(k,l,m,n));
178 #if !CONFIG_SMALL
179 tbl[1][i] = ROT(tbl[0][i], 8);
180 tbl[2][i] = ROT(tbl[0][i], 16);
181 tbl[3][i] = ROT(tbl[0][i], 24);
182 #endif
183 }
184 }
185 }
186
187 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
188 int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
189 {
190 int i, j, t, rconpointer = 0;
191 uint8_t tk[8][4];
192 int KC = key_bits >> 5;
193 int rounds = KC + 6;
194 uint8_t log8[256];
195 uint8_t alog8[512];
196
197 if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) {
198 j = 1;
199 for (i = 0; i < 255; i++) {
200 alog8[i] = alog8[i + 255] = j;
201 log8[j] = i;
202 j ^= j + j;
203 if (j > 255)
204 j ^= 0x11B;
205 }
206 for (i = 0; i < 256; i++) {
207 j = i ? alog8[255 - log8[i]] : 0;
208 j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4);
209 j = (j ^ (j >> 8) ^ 99) & 255;
210 inv_sbox[j] = i;
211 sbox[i] = j;
212 }
213 init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb },
214 log8, alog8, inv_sbox);
215 init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
216 log8, alog8, sbox);
217 }
218
219 if (key_bits != 128 && key_bits != 192 && key_bits != 256)
220 return -1;
221
222 a->rounds = rounds;
223
224 memcpy(tk, key, KC * 4);
225 memcpy(a->round_key[0].u8, key, KC * 4);
226
227 for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) {
228 for (i = 0; i < 4; i++)
229 tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
230 tk[0][0] ^= rcon[rconpointer++];
231
232 for (j = 1; j < KC; j++) {
233 if (KC != 8 || j != KC >> 1)
234 for (i = 0; i < 4; i++)
235 tk[j][i] ^= tk[j - 1][i];
236 else
237 for (i = 0; i < 4; i++)
238 tk[j][i] ^= sbox[tk[j - 1][i]];
239 }
240
241 memcpy(a->round_key[0].u8 + t, tk, KC * 4);
242 }
243
244 if (decrypt) {
245 for (i = 1; i < rounds; i++) {
246 av_aes_block tmp[3];
247 tmp[2] = a->round_key[i];
248 subshift(&tmp[1], 0, sbox);
249 mix(tmp, dec_multbl, 1, 3);
250 a->round_key[i] = tmp[0];
251 }
252 } else {
253 for (i = 0; i < (rounds + 1) >> 1; i++) {
254 FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds-i]);
255 }
256 }
257
258 return 0;
259 }
260
261 #ifdef TEST
262 #include <string.h>
263 #include "lfg.h"
264 #include "log.h"
265
266 int main(int argc, char **argv)
267 {
268 int i, j;
269 AVAES b;
270 uint8_t rkey[2][16] = {
271 { 0 },
272 { 0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3,
273 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59 }
274 };
275 uint8_t pt[16], rpt[2][16]= {
276 { 0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad,
277 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3 },
278 { 0 }
279 };
280 uint8_t rct[2][16]= {
281 { 0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7,
282 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf },
283 { 0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0,
284 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65 }
285 };
286 uint8_t temp[16];
287 int err = 0;
288
289 av_log_set_level(AV_LOG_DEBUG);
290
291 for (i = 0; i < 2; i++) {
292 av_aes_init(&b, rkey[i], 128, 1);
293 av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
294 for (j = 0; j < 16; j++) {
295 if (rpt[i][j] != temp[j]) {
296 av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n",
297 j, rpt[i][j], temp[j]);
298 err = 1;
299 }
300 }
301 }
302
303 if (argc > 1 && !strcmp(argv[1], "-t")) {
304 AVAES ae, ad;
305 AVLFG prng;
306
307 av_aes_init(&ae, "PI=3.141592654..", 128, 0);
308 av_aes_init(&ad, "PI=3.141592654..", 128, 1);
309 av_lfg_init(&prng, 1);
310
311 for (i = 0; i < 10000; i++) {
312 for (j = 0; j < 16; j++) {
313 pt[j] = av_lfg_get(&prng);
314 }
315 {
316 START_TIMER;
317 av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
318 if (!(i & (i - 1)))
319 av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n",
320 temp[0], temp[5], temp[10], temp[15]);
321 av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
322 STOP_TIMER("aes");
323 }
324 for (j = 0; j < 16; j++) {
325 if (pt[j] != temp[j]) {
326 av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n",
327 i, j, pt[j], temp[j]);
328 }
329 }
330 }
331 }
332 return err;
333 }
334 #endif