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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 FFmpeg. | |
7 | * | |
8 | * FFmpeg 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 | * FFmpeg 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 FFmpeg; 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 | #include "timer.h" | |
27 | ||
28 | typedef union { | |
29 | uint64_t u64[2]; | |
30 | uint32_t u32[4]; | |
31 | uint8_t u8x4[4][4]; | |
32 | uint8_t u8[16]; | |
33 | } av_aes_block; | |
34 | ||
35 | typedef struct AVAES { | |
36 | // Note: round_key[16] is accessed in the init code, but this only | |
37 | // overwrites state, which does not matter (see also commit ba554c0). | |
38 | av_aes_block round_key[15]; | |
39 | av_aes_block state[2]; | |
40 | int rounds; | |
41 | } AVAES; | |
42 | ||
43 | const int av_aes_size= sizeof(AVAES); | |
44 | ||
45 | struct AVAES *av_aes_alloc(void) | |
46 | { | |
47 | return av_mallocz(sizeof(struct AVAES)); | |
48 | } | |
49 | ||
50 | static const uint8_t rcon[10] = { | |
51 | 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 | |
52 | }; | |
53 | ||
54 | static uint8_t sbox[256]; | |
55 | static uint8_t inv_sbox[256]; | |
56 | #if CONFIG_SMALL | |
57 | static uint32_t enc_multbl[1][256]; | |
58 | static uint32_t dec_multbl[1][256]; | |
59 | #else | |
60 | static uint32_t enc_multbl[4][256]; | |
61 | static uint32_t dec_multbl[4][256]; | |
62 | #endif | |
63 | ||
64 | #if HAVE_BIGENDIAN | |
65 | # define ROT(x, s) ((x >> s) | (x << (32-s))) | |
66 | #else | |
67 | # define ROT(x, s) ((x << s) | (x >> (32-s))) | |
68 | #endif | |
69 | ||
70 | static inline void addkey(av_aes_block *dst, const av_aes_block *src, | |
71 | const av_aes_block *round_key) | |
72 | { | |
73 | dst->u64[0] = src->u64[0] ^ round_key->u64[0]; | |
74 | dst->u64[1] = src->u64[1] ^ round_key->u64[1]; | |
75 | } | |
76 | ||
77 | static inline void addkey_s(av_aes_block *dst, const uint8_t *src, | |
78 | const av_aes_block *round_key) | |
79 | { | |
80 | dst->u64[0] = AV_RN64(src) ^ round_key->u64[0]; | |
81 | dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1]; | |
82 | } | |
83 | ||
84 | static inline void addkey_d(uint8_t *dst, const av_aes_block *src, | |
85 | const av_aes_block *round_key) | |
86 | { | |
87 | AV_WN64(dst, src->u64[0] ^ round_key->u64[0]); | |
88 | AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]); | |
89 | } | |
90 | ||
91 | static void subshift(av_aes_block s0[2], int s, const uint8_t *box) | |
92 | { | |
93 | av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s); | |
94 | av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s); | |
95 | ||
96 | s0[0].u8[ 0] = box[s0[1].u8[ 0]]; | |
97 | s0[0].u8[ 4] = box[s0[1].u8[ 4]]; | |
98 | s0[0].u8[ 8] = box[s0[1].u8[ 8]]; | |
99 | s0[0].u8[12] = box[s0[1].u8[12]]; | |
100 | s1[0].u8[ 3] = box[s1[1].u8[ 7]]; | |
101 | s1[0].u8[ 7] = box[s1[1].u8[11]]; | |
102 | s1[0].u8[11] = box[s1[1].u8[15]]; | |
103 | s1[0].u8[15] = box[s1[1].u8[ 3]]; | |
104 | s0[0].u8[ 2] = box[s0[1].u8[10]]; | |
105 | s0[0].u8[10] = box[s0[1].u8[ 2]]; | |
106 | s0[0].u8[ 6] = box[s0[1].u8[14]]; | |
107 | s0[0].u8[14] = box[s0[1].u8[ 6]]; | |
108 | s3[0].u8[ 1] = box[s3[1].u8[13]]; | |
109 | s3[0].u8[13] = box[s3[1].u8[ 9]]; | |
110 | s3[0].u8[ 9] = box[s3[1].u8[ 5]]; | |
111 | s3[0].u8[ 5] = box[s3[1].u8[ 1]]; | |
112 | } | |
113 | ||
114 | static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){ | |
115 | #if CONFIG_SMALL | |
116 | return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24); | |
117 | #else | |
118 | return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d]; | |
119 | #endif | |
120 | } | |
121 | ||
122 | static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){ | |
123 | uint8_t (*src)[4] = state[1].u8x4; | |
124 | state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]); | |
125 | state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]); | |
126 | state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]); | |
127 | state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]); | |
128 | } | |
129 | ||
130 | static inline void crypt(AVAES *a, int s, const uint8_t *sbox, | |
131 | uint32_t multbl[][256]) | |
132 | { | |
133 | int r; | |
134 | ||
135 | for (r = a->rounds - 1; r > 0; r--) { | |
136 | mix(a->state, multbl, 3 - s, 1 + s); | |
137 | addkey(&a->state[1], &a->state[0], &a->round_key[r]); | |
138 | } | |
139 | ||
140 | subshift(&a->state[0], s, sbox); | |
141 | } | |
142 | ||
143 | void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src, | |
144 | int count, uint8_t *iv, int decrypt) | |
145 | { | |
146 | while (count--) { | |
147 | addkey_s(&a->state[1], src, &a->round_key[a->rounds]); | |
148 | if (decrypt) { | |
149 | crypt(a, 0, inv_sbox, dec_multbl); | |
150 | if (iv) { | |
151 | addkey_s(&a->state[0], iv, &a->state[0]); | |
152 | memcpy(iv, src, 16); | |
153 | } | |
154 | addkey_d(dst, &a->state[0], &a->round_key[0]); | |
155 | } else { | |
156 | if (iv) | |
157 | addkey_s(&a->state[1], iv, &a->state[1]); | |
158 | crypt(a, 2, sbox, enc_multbl); | |
159 | addkey_d(dst, &a->state[0], &a->round_key[0]); | |
160 | if (iv) | |
161 | memcpy(iv, dst, 16); | |
162 | } | |
163 | src += 16; | |
164 | dst += 16; | |
165 | } | |
166 | } | |
167 | ||
168 | static void init_multbl2(uint32_t tbl[][256], const int c[4], | |
169 | const uint8_t *log8, const uint8_t *alog8, | |
170 | const uint8_t *sbox) | |
171 | { | |
172 | int i; | |
173 | ||
174 | for (i = 0; i < 256; i++) { | |
175 | int x = sbox[i]; | |
176 | if (x) { | |
177 | int k, l, m, n; | |
178 | x = log8[x]; | |
179 | k = alog8[x + log8[c[0]]]; | |
180 | l = alog8[x + log8[c[1]]]; | |
181 | m = alog8[x + log8[c[2]]]; | |
182 | n = alog8[x + log8[c[3]]]; | |
183 | tbl[0][i] = AV_NE(MKBETAG(k,l,m,n), MKTAG(k,l,m,n)); | |
184 | #if !CONFIG_SMALL | |
185 | tbl[1][i] = ROT(tbl[0][i], 8); | |
186 | tbl[2][i] = ROT(tbl[0][i], 16); | |
187 | tbl[3][i] = ROT(tbl[0][i], 24); | |
188 | #endif | |
189 | } | |
190 | } | |
191 | } | |
192 | ||
193 | // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen | |
194 | int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt) | |
195 | { | |
196 | int i, j, t, rconpointer = 0; | |
197 | uint8_t tk[8][4]; | |
198 | int KC = key_bits >> 5; | |
199 | int rounds = KC + 6; | |
200 | uint8_t log8[256]; | |
201 | uint8_t alog8[512]; | |
202 | ||
203 | if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) { | |
204 | j = 1; | |
205 | for (i = 0; i < 255; i++) { | |
206 | alog8[i] = alog8[i + 255] = j; | |
207 | log8[j] = i; | |
208 | j ^= j + j; | |
209 | if (j > 255) | |
210 | j ^= 0x11B; | |
211 | } | |
212 | for (i = 0; i < 256; i++) { | |
213 | j = i ? alog8[255 - log8[i]] : 0; | |
214 | j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4); | |
215 | j = (j ^ (j >> 8) ^ 99) & 255; | |
216 | inv_sbox[j] = i; | |
217 | sbox[i] = j; | |
218 | } | |
219 | init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb }, | |
220 | log8, alog8, inv_sbox); | |
221 | init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 }, | |
222 | log8, alog8, sbox); | |
223 | } | |
224 | ||
225 | if (key_bits != 128 && key_bits != 192 && key_bits != 256) | |
226 | return -1; | |
227 | ||
228 | a->rounds = rounds; | |
229 | ||
230 | memcpy(tk, key, KC * 4); | |
231 | memcpy(a->round_key[0].u8, key, KC * 4); | |
232 | ||
233 | for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) { | |
234 | for (i = 0; i < 4; i++) | |
235 | tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]]; | |
236 | tk[0][0] ^= rcon[rconpointer++]; | |
237 | ||
238 | for (j = 1; j < KC; j++) { | |
239 | if (KC != 8 || j != KC >> 1) | |
240 | for (i = 0; i < 4; i++) | |
241 | tk[j][i] ^= tk[j - 1][i]; | |
242 | else | |
243 | for (i = 0; i < 4; i++) | |
244 | tk[j][i] ^= sbox[tk[j - 1][i]]; | |
245 | } | |
246 | ||
247 | memcpy(a->round_key[0].u8 + t, tk, KC * 4); | |
248 | } | |
249 | ||
250 | if (decrypt) { | |
251 | for (i = 1; i < rounds; i++) { | |
252 | av_aes_block tmp[3]; | |
253 | tmp[2] = a->round_key[i]; | |
254 | subshift(&tmp[1], 0, sbox); | |
255 | mix(tmp, dec_multbl, 1, 3); | |
256 | a->round_key[i] = tmp[0]; | |
257 | } | |
258 | } else { | |
259 | for (i = 0; i < (rounds + 1) >> 1; i++) { | |
260 | FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds-i]); | |
261 | } | |
262 | } | |
263 | ||
264 | return 0; | |
265 | } | |
266 | ||
267 | #ifdef TEST | |
268 | // LCOV_EXCL_START | |
269 | #include <string.h> | |
270 | #include "lfg.h" | |
271 | #include "log.h" | |
272 | ||
273 | int main(int argc, char **argv) | |
274 | { | |
275 | int i, j; | |
276 | AVAES b; | |
277 | uint8_t rkey[2][16] = { | |
278 | { 0 }, | |
279 | { 0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, | |
280 | 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59 } | |
281 | }; | |
282 | uint8_t pt[16], rpt[2][16]= { | |
283 | { 0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, | |
284 | 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3 }, | |
285 | { 0 } | |
286 | }; | |
287 | uint8_t rct[2][16]= { | |
288 | { 0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, | |
289 | 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf }, | |
290 | { 0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, | |
291 | 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65 } | |
292 | }; | |
293 | uint8_t temp[16]; | |
294 | int err = 0; | |
295 | ||
296 | av_log_set_level(AV_LOG_DEBUG); | |
297 | ||
298 | for (i = 0; i < 2; i++) { | |
299 | av_aes_init(&b, rkey[i], 128, 1); | |
300 | av_aes_crypt(&b, temp, rct[i], 1, NULL, 1); | |
301 | for (j = 0; j < 16; j++) { | |
302 | if (rpt[i][j] != temp[j]) { | |
303 | av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", | |
304 | j, rpt[i][j], temp[j]); | |
305 | err = 1; | |
306 | } | |
307 | } | |
308 | } | |
309 | ||
310 | if (argc > 1 && !strcmp(argv[1], "-t")) { | |
311 | AVAES ae, ad; | |
312 | AVLFG prng; | |
313 | ||
314 | av_aes_init(&ae, "PI=3.141592654..", 128, 0); | |
315 | av_aes_init(&ad, "PI=3.141592654..", 128, 1); | |
316 | av_lfg_init(&prng, 1); | |
317 | ||
318 | for (i = 0; i < 10000; i++) { | |
319 | for (j = 0; j < 16; j++) { | |
320 | pt[j] = av_lfg_get(&prng); | |
321 | } | |
322 | { | |
323 | START_TIMER; | |
324 | av_aes_crypt(&ae, temp, pt, 1, NULL, 0); | |
325 | if (!(i & (i - 1))) | |
326 | av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", | |
327 | temp[0], temp[5], temp[10], temp[15]); | |
328 | av_aes_crypt(&ad, temp, temp, 1, NULL, 1); | |
329 | STOP_TIMER("aes"); | |
330 | } | |
331 | for (j = 0; j < 16; j++) { | |
332 | if (pt[j] != temp[j]) { | |
333 | av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", | |
334 | i, j, pt[j], temp[j]); | |
335 | } | |
336 | } | |
337 | } | |
338 | } | |
339 | return err; | |
340 | } | |
341 | // LCOV_EXCL_STOP | |
342 | #endif |