c2df3b23e6e94797d531c24bcb4a475a27b0e94f
[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 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 // Note: round_key[16] is accessed in the init code, but this only
28 // overwrites state, which does not matter (see also r7471).
29 uint8_t round_key[15][4][4];
30 uint8_t state[2][4][4];
31 int rounds;
32 }AVAES;
33
34 const int av_aes_size= sizeof(AVAES);
35
36 static const uint8_t rcon[10] = {
37 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
38 };
39
40 static uint8_t sbox[256];
41 static uint8_t inv_sbox[256];
42 #ifdef CONFIG_SMALL
43 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
50 static inline void addkey(uint64_t dst[2], uint64_t src[2], uint64_t round_key[2]){
51 dst[0] = src[0] ^ round_key[0];
52 dst[1] = src[1] ^ round_key[1];
53 }
54
55 static void subshift(uint8_t s0[2][16], int s, uint8_t *box){
56 uint8_t (*s1)[16]= s0[0] - s;
57 uint8_t (*s3)[16]= s0[0] + s;
58 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 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 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 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 }
63
64 static inline int mix_core(uint32_t multbl[4][256], int a, int b, int c, int d){
65 #ifdef CONFIG_SMALL
66 #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 #else
69 return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
70 #endif
71 }
72
73 static inline void mix(uint8_t state[2][4][4], uint32_t multbl[4][256], int s1, int s3){
74 ((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 }
79
80 static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
81 int r;
82
83 for(r=a->rounds-1; r>0; r--){
84 mix(a->state, multbl, 3-s, 1+s);
85 addkey(a->state[1], a->state[0], a->round_key[r]);
86 }
87 subshift(a->state[0][0], s, sbox);
88 }
89
90 void av_aes_crypt(AVAES *a, uint8_t *dst, uint8_t *src, int count, uint8_t *iv, int decrypt){
91 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 }
110
111 static void init_multbl2(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8, uint8_t *sbox){
112 int i, j;
113 for(i=0; i<1024; i++){
114 int x= sbox[i>>2];
115 if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
116 }
117 #ifndef CONFIG_SMALL
118 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 #endif
122 }
123
124 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
125 int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt) {
126 int i, j, t, rconpointer = 0;
127 uint8_t tk[8][4];
128 int KC= key_bits>>5;
129 int rounds= KC + 6;
130 uint8_t log8[256];
131 uint8_t alog8[512];
132
133 if(!enc_multbl[0][sizeof(enc_multbl)/sizeof(enc_multbl[0][0])-1]){
134 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 j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4);
145 j = (j ^ (j>>8) ^ 99) & 255;
146 inv_sbox[j]= i;
147 sbox [i]= j;
148 }
149 init_multbl2(dec_multbl[0], (int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
150 init_multbl2(enc_multbl[0], (int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
151 }
152
153 if(key_bits!=128 && key_bits!=192 && key_bits!=256)
154 return -1;
155
156 a->rounds= rounds;
157
158 memcpy(tk, key, KC*4);
159
160 for(t= 0; t < (rounds+1)*16;) {
161 memcpy(a->round_key[0][0]+t, tk, KC*4);
162 t+= KC*4;
163
164 for(i = 0; i < 4; i++)
165 tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]];
166 tk[0][0] ^= rcon[rconpointer++];
167
168 for(j = 1; j < KC; j++){
169 if(KC != 8 || j != KC>>1)
170 for(i = 0; i < 4; i++) tk[j][i] ^= tk[j-1][i];
171 else
172 for(i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j-1][i]];
173 }
174 }
175
176 if(decrypt){
177 for(i=1; i<rounds; i++){
178 uint8_t tmp[3][16];
179 memcpy(tmp[2], a->round_key[i][0], 16);
180 subshift(tmp[1], 0, sbox);
181 mix(tmp, dec_multbl, 1, 3);
182 memcpy(a->round_key[i][0], tmp[0], 16);
183 }
184 }else{
185 for(i=0; i<(rounds+1)>>1; i++){
186 for(j=0; j<16; j++)
187 FFSWAP(int, a->round_key[i][0][j], a->round_key[rounds-i][0][j]);
188 }
189 }
190
191 return 0;
192 }
193
194 #ifdef TEST
195 #include "log.h"
196
197 int main(void){
198 int i,j;
199 AVAES ae, ad, b;
200 uint8_t rkey[2][16]= {
201 {0},
202 {0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59}};
203 uint8_t pt[16], rpt[2][16]= {
204 {0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3},
205 {0}};
206 uint8_t rct[2][16]= {
207 {0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf},
208 {0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65}};
209 uint8_t temp[16];
210
211 av_aes_init(&ae, "PI=3.141592654..", 128, 0);
212 av_aes_init(&ad, "PI=3.141592654..", 128, 1);
213 av_log_level= AV_LOG_DEBUG;
214
215 for(i=0; i<2; i++){
216 av_aes_init(&b, rkey[i], 128, 1);
217 av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
218 for(j=0; j<16; j++)
219 if(rpt[i][j] != temp[j])
220 av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], temp[j]);
221 }
222
223 for(i=0; i<10000; i++){
224 for(j=0; j<16; j++){
225 pt[j]= random();
226 }
227 {START_TIMER
228 av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
229 if(!(i&(i-1)))
230 av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", temp[0], temp[5], temp[10], temp[15]);
231 av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
232 STOP_TIMER("aes")}
233 for(j=0; j<16; j++){
234 if(pt[j] != temp[j]){
235 av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], temp[j]);
236 }
237 }
238 }
239 return 0;
240 }
241 #endif