2 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
4 * some optimization ideas from aes128.c by Reimar Doeffinger
6 * This file is part of FFmpeg.
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.
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.
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
25 #include "intreadwrite.h"
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 commit ba554c0).
37 av_aes_block round_key[15];
38 av_aes_block state[2];
42 #if FF_API_CONTEXT_SIZE
43 const int av_aes_size= sizeof(AVAES);
46 struct AVAES *av_aes_alloc(void)
48 return av_mallocz(sizeof(struct AVAES));
51 static const uint8_t rcon[10] = {
52 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
55 static uint8_t sbox[256];
56 static uint8_t inv_sbox[256];
58 static uint32_t enc_multbl[1][256];
59 static uint32_t dec_multbl[1][256];
61 static uint32_t enc_multbl[4][256];
62 static uint32_t dec_multbl[4][256];
66 # define ROT(x, s) ((x >> s) | (x << (32-s)))
68 # define ROT(x, s) ((x << s) | (x >> (32-s)))
71 static inline void addkey(av_aes_block *dst, const av_aes_block *src,
72 const av_aes_block *round_key)
74 dst->u64[0] = src->u64[0] ^ round_key->u64[0];
75 dst->u64[1] = src->u64[1] ^ round_key->u64[1];
78 static inline void addkey_s(av_aes_block *dst, const uint8_t *src,
79 const av_aes_block *round_key)
81 dst->u64[0] = AV_RN64(src) ^ round_key->u64[0];
82 dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1];
85 static inline void addkey_d(uint8_t *dst, const av_aes_block *src,
86 const av_aes_block *round_key)
88 AV_WN64(dst, src->u64[0] ^ round_key->u64[0]);
89 AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]);
92 static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
94 av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s);
95 av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s);
97 s0[0].u8[ 0] = box[s0[1].u8[ 0]];
98 s0[0].u8[ 4] = box[s0[1].u8[ 4]];
99 s0[0].u8[ 8] = box[s0[1].u8[ 8]];
100 s0[0].u8[12] = box[s0[1].u8[12]];
101 s1[0].u8[ 3] = box[s1[1].u8[ 7]];
102 s1[0].u8[ 7] = box[s1[1].u8[11]];
103 s1[0].u8[11] = box[s1[1].u8[15]];
104 s1[0].u8[15] = box[s1[1].u8[ 3]];
105 s0[0].u8[ 2] = box[s0[1].u8[10]];
106 s0[0].u8[10] = box[s0[1].u8[ 2]];
107 s0[0].u8[ 6] = box[s0[1].u8[14]];
108 s0[0].u8[14] = box[s0[1].u8[ 6]];
109 s3[0].u8[ 1] = box[s3[1].u8[13]];
110 s3[0].u8[13] = box[s3[1].u8[ 9]];
111 s3[0].u8[ 9] = box[s3[1].u8[ 5]];
112 s3[0].u8[ 5] = box[s3[1].u8[ 1]];
115 static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
117 return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
119 return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
123 static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){
124 uint8_t (*src)[4] = state[1].u8x4;
125 state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
126 state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]);
127 state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
128 state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]);
131 static inline void crypt(AVAES *a, int s, const uint8_t *sbox,
132 uint32_t multbl[][256])
136 for (r = a->rounds - 1; r > 0; r--) {
137 mix(a->state, multbl, 3 - s, 1 + s);
138 addkey(&a->state[1], &a->state[0], &a->round_key[r]);
141 subshift(&a->state[0], s, sbox);
144 void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
145 int count, uint8_t *iv, int decrypt)
148 addkey_s(&a->state[1], src, &a->round_key[a->rounds]);
150 crypt(a, 0, inv_sbox, dec_multbl);
152 addkey_s(&a->state[0], iv, &a->state[0]);
155 addkey_d(dst, &a->state[0], &a->round_key[0]);
158 addkey_s(&a->state[1], iv, &a->state[1]);
159 crypt(a, 2, sbox, enc_multbl);
160 addkey_d(dst, &a->state[0], &a->round_key[0]);
169 static void init_multbl2(uint32_t tbl[][256], const int c[4],
170 const uint8_t *log8, const uint8_t *alog8,
175 for (i = 0; i < 256; i++) {
180 k = alog8[x + log8[c[0]]];
181 l = alog8[x + log8[c[1]]];
182 m = alog8[x + log8[c[2]]];
183 n = alog8[x + log8[c[3]]];
184 tbl[0][i] = AV_NE(MKBETAG(k,l,m,n), MKTAG(k,l,m,n));
186 tbl[1][i] = ROT(tbl[0][i], 8);
187 tbl[2][i] = ROT(tbl[0][i], 16);
188 tbl[3][i] = ROT(tbl[0][i], 24);
194 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
195 int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
197 int i, j, t, rconpointer = 0;
199 int KC = key_bits >> 5;
204 if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) {
206 for (i = 0; i < 255; i++) {
207 alog8[i] = alog8[i + 255] = j;
213 for (i = 0; i < 256; i++) {
214 j = i ? alog8[255 - log8[i]] : 0;
215 j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4);
216 j = (j ^ (j >> 8) ^ 99) & 255;
220 init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb },
221 log8, alog8, inv_sbox);
222 init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
226 if (key_bits != 128 && key_bits != 192 && key_bits != 256)
231 memcpy(tk, key, KC * 4);
232 memcpy(a->round_key[0].u8, key, KC * 4);
234 for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) {
235 for (i = 0; i < 4; i++)
236 tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
237 tk[0][0] ^= rcon[rconpointer++];
239 for (j = 1; j < KC; j++) {
240 if (KC != 8 || j != KC >> 1)
241 for (i = 0; i < 4; i++)
242 tk[j][i] ^= tk[j - 1][i];
244 for (i = 0; i < 4; i++)
245 tk[j][i] ^= sbox[tk[j - 1][i]];
248 memcpy(a->round_key[0].u8 + t, tk, KC * 4);
252 for (i = 1; i < rounds; i++) {
254 tmp[2] = a->round_key[i];
255 subshift(&tmp[1], 0, sbox);
256 mix(tmp, dec_multbl, 1, 3);
257 a->round_key[i] = tmp[0];
260 for (i = 0; i < (rounds + 1) >> 1; i++) {
261 FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds-i]);
274 int main(int argc, char **argv)
278 uint8_t rkey[2][16] = {
280 { 0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3,
281 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59 }
283 uint8_t pt[16], rpt[2][16]= {
284 { 0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad,
285 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3 },
288 uint8_t rct[2][16]= {
289 { 0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7,
290 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf },
291 { 0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0,
292 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65 }
297 av_log_set_level(AV_LOG_DEBUG);
299 for (i = 0; i < 2; i++) {
300 av_aes_init(&b, rkey[i], 128, 1);
301 av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
302 for (j = 0; j < 16; j++) {
303 if (rpt[i][j] != temp[j]) {
304 av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n",
305 j, rpt[i][j], temp[j]);
311 if (argc > 1 && !strcmp(argv[1], "-t")) {
315 av_aes_init(&ae, "PI=3.141592654..", 128, 0);
316 av_aes_init(&ad, "PI=3.141592654..", 128, 1);
317 av_lfg_init(&prng, 1);
319 for (i = 0; i < 10000; i++) {
320 for (j = 0; j < 16; j++) {
321 pt[j] = av_lfg_get(&prng);
325 av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
327 av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n",
328 temp[0], temp[5], temp[10], temp[15]);
329 av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
332 for (j = 0; j < 16; j++) {
333 if (pt[j] != temp[j]) {
334 av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n",
335 i, j, pt[j], temp[j]);