Statistics
| Branch: | Revision:

ffmpeg / libavutil / aes.c @ 80a07f6e

History | View | Annotate | Download (8.08 KB)

1 3306dfd5 Michael Niedermayer
/*
2 034f5fba Michael Niedermayer
 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
3 3306dfd5 Michael Niedermayer
 *
4 2eb697a4 Diego Biurrun
 * some optimization ideas from aes128.c by Reimar Doeffinger
5
 *
6 3306dfd5 Michael Niedermayer
 * 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
26
typedef struct AVAES{
27 ef0d7a0d Reimar Döffinger
    // Note: round_key[16] is accessed in the init code, but this only
28
    // overwrites state, which does not matter (see also r7471).
29 954bd264 Michael Niedermayer
    uint8_t round_key[15][4][4];
30 298dd6b7 Michael Niedermayer
    uint8_t state[2][4][4];
31 3306dfd5 Michael Niedermayer
    int rounds;
32
}AVAES;
33
34 6572e1a4 Michael Niedermayer
const int av_aes_size= sizeof(AVAES);
35
36 a6e923c9 Michael Niedermayer
static const uint8_t rcon[10] = {
37
  0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
38 3306dfd5 Michael Niedermayer
};
39
40
static uint8_t     sbox[256];
41
static uint8_t inv_sbox[256];
42 b250f9c6 Aurelien Jacobs
#if CONFIG_SMALL
43 cd0968c4 Michael Niedermayer
static uint32_t enc_multbl[1][256];
44
static uint32_t dec_multbl[1][256];
45
#else
46
static uint32_t enc_multbl[4][256];
47
static uint32_t dec_multbl[4][256];
48
#endif
49 3306dfd5 Michael Niedermayer
50 7b484a7a Reimar Döffinger
static inline void addkey(uint64_t dst[2], const uint64_t src[2], const uint64_t round_key[2]){
51 7465619a Michael Niedermayer
    dst[0] = src[0] ^ round_key[0];
52
    dst[1] = src[1] ^ round_key[1];
53 3306dfd5 Michael Niedermayer
}
54
55 7b484a7a Reimar Döffinger
static void subshift(uint8_t s0[2][16], int s, const uint8_t *box){
56 b0642c74 Michael Niedermayer
    uint8_t (*s1)[16]= s0[0] - s;
57
    uint8_t (*s3)[16]= s0[0] + s;
58 298dd6b7 Michael Niedermayer
    s0[0][0]=box[s0[1][ 0]]; s0[0][ 4]=box[s0[1][ 4]]; s0[0][ 8]=box[s0[1][ 8]]; s0[0][12]=box[s0[1][12]];
59 b0642c74 Michael Niedermayer
    s1[0][3]=box[s1[1][ 7]]; s1[0][ 7]=box[s1[1][11]]; s1[0][11]=box[s1[1][15]]; s1[0][15]=box[s1[1][ 3]];
60 298dd6b7 Michael Niedermayer
    s0[0][2]=box[s0[1][10]]; s0[0][10]=box[s0[1][ 2]]; s0[0][ 6]=box[s0[1][14]]; s0[0][14]=box[s0[1][ 6]];
61 b0642c74 Michael Niedermayer
    s3[0][1]=box[s3[1][13]]; s3[0][13]=box[s3[1][ 9]]; s3[0][ 9]=box[s3[1][ 5]]; s3[0][ 5]=box[s3[1][ 1]];
62 1aa72a70 Michael Niedermayer
}
63 0458e790 Michael Niedermayer
64 97f6d154 Michael Niedermayer
static inline int mix_core(uint32_t multbl[4][256], int a, int b, int c, int d){
65 b250f9c6 Aurelien Jacobs
#if CONFIG_SMALL
66 97f6d154 Michael Niedermayer
#define ROT(x,s) ((x<<s)|(x>>(32-s)))
67
    return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
68 cd0968c4 Michael Niedermayer
#else
69 97f6d154 Michael Niedermayer
    return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
70 cd0968c4 Michael Niedermayer
#endif
71 3306dfd5 Michael Niedermayer
}
72 298dd6b7 Michael Niedermayer
73
static inline void mix(uint8_t state[2][4][4], uint32_t multbl[4][256], int s1, int s3){
74 97f6d154 Michael Niedermayer
    ((uint32_t *)(state))[0] = mix_core(multbl, state[1][0][0], state[1][s1  ][1], state[1][2][2], state[1][s3  ][3]);
75
    ((uint32_t *)(state))[1] = mix_core(multbl, state[1][1][0], state[1][s3-1][1], state[1][3][2], state[1][s1-1][3]);
76
    ((uint32_t *)(state))[2] = mix_core(multbl, state[1][2][0], state[1][s3  ][1], state[1][0][2], state[1][s1  ][3]);
77
    ((uint32_t *)(state))[3] = mix_core(multbl, state[1][3][0], state[1][s1-1][1], state[1][1][2], state[1][s3-1][3]);
78 1aa72a70 Michael Niedermayer
}
79 3306dfd5 Michael Niedermayer
80 7b484a7a Reimar Döffinger
static inline void crypt(AVAES *a, int s, const uint8_t *sbox, const uint32_t *multbl){
81 14bc3849 Michael Niedermayer
    int r;
82 3306dfd5 Michael Niedermayer
83 7465619a Michael Niedermayer
    for(r=a->rounds-1; r>0; r--){
84 298dd6b7 Michael Niedermayer
        mix(a->state, multbl, 3-s, 1+s);
85 7465619a Michael Niedermayer
        addkey(a->state[1], a->state[0], a->round_key[r]);
86 3306dfd5 Michael Niedermayer
    }
87 b0642c74 Michael Niedermayer
    subshift(a->state[0][0], s, sbox);
88 3306dfd5 Michael Niedermayer
}
89
90 7b484a7a Reimar Döffinger
void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt){
91 97e3458c Michael Niedermayer
    while(count--){
92
        addkey(a->state[1], src, a->round_key[a->rounds]);
93
        if(decrypt) {
94
            crypt(a, 0, inv_sbox, dec_multbl);
95
            if(iv){
96
                addkey(a->state[0], a->state[0], iv);
97
                memcpy(iv, src, 16);
98
            }
99
            addkey(dst, a->state[0], a->round_key[0]);
100
        }else{
101
            if(iv) addkey(a->state[1], a->state[1], iv);
102
            crypt(a, 2,     sbox, enc_multbl);
103
            addkey(dst, a->state[0], a->round_key[0]);
104
            if(iv) memcpy(iv, dst, 16);
105
        }
106
        src+=16;
107
        dst+=16;
108
    }
109 ff8f6594 Michael Niedermayer
}
110
111 7b484a7a Reimar Döffinger
static void init_multbl2(uint8_t tbl[1024], const int c[4], const uint8_t *log8, const uint8_t *alog8, const uint8_t *sbox){
112 597e3232 Michael Niedermayer
    int i, j;
113 0458e790 Michael Niedermayer
    for(i=0; i<1024; i++){
114 96b10308 Michael Niedermayer
        int x= sbox[i>>2];
115 0458e790 Michael Niedermayer
        if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
116
    }
117 b250f9c6 Aurelien Jacobs
#if !CONFIG_SMALL
118 597e3232 Michael Niedermayer
    for(j=256; j<1024; j++)
119
        for(i=0; i<4; i++)
120
            tbl[4*j+i]= tbl[4*j + ((i-1)&3) - 1024];
121 7200f5d0 Michael Niedermayer
#endif
122 0458e790 Michael Niedermayer
}
123
124 3306dfd5 Michael Niedermayer
// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
125 57d7b036 Baptiste Coudurier
int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt) {
126 3306dfd5 Michael Niedermayer
    int i, j, t, rconpointer = 0;
127
    uint8_t tk[8][4];
128 96b10308 Michael Niedermayer
    int KC= key_bits>>5;
129 d43a2975 Michael Niedermayer
    int rounds= KC + 6;
130 cd0968c4 Michael Niedermayer
    uint8_t  log8[256];
131
    uint8_t alog8[512];
132 3306dfd5 Michael Niedermayer
133 79d4c96a Michael Niedermayer
    if(!enc_multbl[0][sizeof(enc_multbl)/sizeof(enc_multbl[0][0])-1]){
134 3306dfd5 Michael Niedermayer
        j=1;
135
        for(i=0; i<255; i++){
136
            alog8[i]=
137
            alog8[i+255]= j;
138
            log8[j]= i;
139
            j^= j+j;
140
            if(j>255) j^= 0x11B;
141
        }
142
        for(i=0; i<256; i++){
143
            j= i ? alog8[255-log8[i]] : 0;
144 2c3427eb Michael Niedermayer
            j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4);
145
            j = (j ^ (j>>8) ^ 99) & 255;
146 3306dfd5 Michael Niedermayer
            inv_sbox[j]= i;
147
            sbox    [i]= j;
148
        }
149 7b484a7a Reimar Döffinger
        init_multbl2(dec_multbl[0], (const int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
150
        init_multbl2(enc_multbl[0], (const int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
151 3306dfd5 Michael Niedermayer
    }
152
153 d43a2975 Michael Niedermayer
    if(key_bits!=128 && key_bits!=192 && key_bits!=256)
154 6572e1a4 Michael Niedermayer
        return -1;
155 3306dfd5 Michael Niedermayer
156 d43a2975 Michael Niedermayer
    a->rounds= rounds;
157 eade86e2 Michael Niedermayer
158 3306dfd5 Michael Niedermayer
    memcpy(tk, key, KC*4);
159
160 5d1b5393 Michael Niedermayer
    for(t= 0; t < (rounds+1)*16;) {
161
        memcpy(a->round_key[0][0]+t, tk, KC*4);
162
        t+= KC*4;
163 3306dfd5 Michael Niedermayer
164
        for(i = 0; i < 4; i++)
165 84c72fb1 Michael Niedermayer
            tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]];
166 3306dfd5 Michael Niedermayer
        tk[0][0] ^= rcon[rconpointer++];
167
168
        for(j = 1; j < KC; j++){
169 96b10308 Michael Niedermayer
            if(KC != 8 || j != KC>>1)
170 b1e5c294 Michael Niedermayer
                for(i = 0; i < 4; i++) tk[j][i] ^=      tk[j-1][i];
171 3306dfd5 Michael Niedermayer
            else
172 b1e5c294 Michael Niedermayer
                for(i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j-1][i]];
173 3306dfd5 Michael Niedermayer
        }
174
    }
175 f12cf3d2 Michael Niedermayer
176 954bd264 Michael Niedermayer
    if(decrypt){
177 28b51235 Michael Niedermayer
        for(i=1; i<rounds; i++){
178 2d3475ae Michael Niedermayer
            uint8_t tmp[3][16];
179
            memcpy(tmp[2], a->round_key[i][0], 16);
180
            subshift(tmp[1], 0, sbox);
181 298dd6b7 Michael Niedermayer
            mix(tmp, dec_multbl, 1, 3);
182
            memcpy(a->round_key[i][0], tmp[0], 16);
183 28b51235 Michael Niedermayer
        }
184 f25b650a Michael Niedermayer
    }else{
185 96b10308 Michael Niedermayer
        for(i=0; i<(rounds+1)>>1; i++){
186 f25b650a Michael Niedermayer
            for(j=0; j<16; j++)
187
                FFSWAP(int, a->round_key[i][0][j], a->round_key[rounds-i][0][j]);
188
        }
189 cc858970 Michael Niedermayer
    }
190 f12cf3d2 Michael Niedermayer
191 6572e1a4 Michael Niedermayer
    return 0;
192 3306dfd5 Michael Niedermayer
}
193
194
#ifdef TEST
195 294eaa26 Diego Biurrun
#include "lfg.h"
196 0d80bd2f Michael Niedermayer
#include "log.h"
197 3306dfd5 Michael Niedermayer
198 f8a80fd6 Diego Biurrun
int main(void){
199 1b105243 Michael Niedermayer
    int i,j;
200 6572e1a4 Michael Niedermayer
    AVAES ae, ad, b;
201 d65dc0cd Michael Niedermayer
    uint8_t rkey[2][16]= {
202
        {0},
203
        {0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59}};
204
    uint8_t pt[16], rpt[2][16]= {
205
        {0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3},
206
        {0}};
207
    uint8_t rct[2][16]= {
208
        {0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf},
209
        {0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65}};
210 7465619a Michael Niedermayer
    uint8_t temp[16];
211 64bde197 Diego Biurrun
    AVLFG prng;
212 3306dfd5 Michael Niedermayer
213 6572e1a4 Michael Niedermayer
    av_aes_init(&ae, "PI=3.141592654..", 128, 0);
214
    av_aes_init(&ad, "PI=3.141592654..", 128, 1);
215 b56e34c5 Diego Biurrun
    av_log_set_level(AV_LOG_DEBUG);
216 64bde197 Diego Biurrun
    av_lfg_init(&prng, 1);
217 cf5773e9 Michael Niedermayer
218 d65dc0cd Michael Niedermayer
    for(i=0; i<2; i++){
219 6572e1a4 Michael Niedermayer
        av_aes_init(&b, rkey[i], 128, 1);
220 ca2560df Michael Niedermayer
        av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
221 d65dc0cd Michael Niedermayer
        for(j=0; j<16; j++)
222 7465619a Michael Niedermayer
            if(rpt[i][j] != temp[j])
223
                av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], temp[j]);
224 d65dc0cd Michael Niedermayer
    }
225 0458e790 Michael Niedermayer
226 3306dfd5 Michael Niedermayer
    for(i=0; i<10000; i++){
227 ff8f6594 Michael Niedermayer
        for(j=0; j<16; j++){
228 64bde197 Diego Biurrun
            pt[j] = av_lfg_get(&prng);
229 ff8f6594 Michael Niedermayer
        }
230 cf5773e9 Michael Niedermayer
{START_TIMER
231 ca2560df Michael Niedermayer
        av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
232 ff8f6594 Michael Niedermayer
        if(!(i&(i-1)))
233 7465619a Michael Niedermayer
            av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", temp[0], temp[5], temp[10], temp[15]);
234 ca2560df Michael Niedermayer
        av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
235 cf5773e9 Michael Niedermayer
STOP_TIMER("aes")}
236 ff8f6594 Michael Niedermayer
        for(j=0; j<16; j++){
237 7465619a Michael Niedermayer
            if(pt[j] != temp[j]){
238
                av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], temp[j]);
239 ff8f6594 Michael Niedermayer
            }
240
        }
241 3306dfd5 Michael Niedermayer
    }
242
    return 0;
243
}
244
#endif