b29e735d497295c3cb781204e401553d9b173ede
[libav.git] / libavutil / aes.c
1 /*
2 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 *
20 * some optimization ideas from aes128.c by Reimar Doeffinger
21 */
22
23 #include "common.h"
24 #include "aes.h"
25
26 typedef struct AVAES{
27 uint8_t round_key[15][4][4];
28 uint8_t state[2][4][4];
29 int rounds;
30 }AVAES;
31
32 const int av_aes_size= sizeof(AVAES);
33
34 static const uint8_t rcon[10] = {
35 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
36 };
37
38 static uint8_t sbox[256];
39 static uint8_t inv_sbox[256];
40 #ifdef CONFIG_SMALL
41 static uint32_t enc_multbl[1][256];
42 static uint32_t dec_multbl[1][256];
43 #else
44 static uint32_t enc_multbl[4][256];
45 static uint32_t dec_multbl[4][256];
46 #endif
47
48 static inline void addkey(uint64_t dst[2], uint64_t src[2], uint64_t round_key[2]){
49 dst[0] = src[0] ^ round_key[0];
50 dst[1] = src[1] ^ round_key[1];
51 }
52
53 static void subshift(uint8_t s0[2][16], int s, uint8_t *box){
54 uint8_t (*s1)[16]= s0[0] - s;
55 uint8_t (*s3)[16]= s0[0] + s;
56 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]];
57 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]];
58 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]];
59 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]];
60 }
61
62 static inline int mix_core(uint32_t multbl[4][256], int a, int b, int c, int d){
63 #ifdef CONFIG_SMALL
64 #define ROT(x,s) ((x<<s)|(x>>(32-s)))
65 return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
66 #else
67 return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
68 #endif
69 }
70
71 static inline void mix(uint8_t state[2][4][4], uint32_t multbl[4][256], int s1, int s3){
72 ((uint32_t *)(state))[0] = mix_core(multbl, state[1][0][0], state[1][s1 ][1], state[1][2][2], state[1][s3 ][3]);
73 ((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]);
74 ((uint32_t *)(state))[2] = mix_core(multbl, state[1][2][0], state[1][s3 ][1], state[1][0][2], state[1][s1 ][3]);
75 ((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]);
76 }
77
78 static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
79 int r;
80
81 for(r=a->rounds-1; r>0; r--){
82 mix(a->state, multbl, 3-s, 1+s);
83 addkey(a->state[1], a->state[0], a->round_key[r]);
84 }
85 subshift(a->state[0][0], s, sbox);
86 }
87
88 void av_aes_crypt(AVAES *a, uint8_t *dst, uint8_t *src, int count, uint8_t *iv, int decrypt){
89 while(count--){
90 addkey(a->state[1], src, a->round_key[a->rounds]);
91 if(decrypt) {
92 crypt(a, 0, inv_sbox, dec_multbl);
93 if(iv){
94 addkey(a->state[0], a->state[0], iv);
95 memcpy(iv, src, 16);
96 }
97 addkey(dst, a->state[0], a->round_key[0]);
98 }else{
99 if(iv) addkey(a->state[1], a->state[1], iv);
100 crypt(a, 2, sbox, enc_multbl);
101 addkey(dst, a->state[0], a->round_key[0]);
102 if(iv) memcpy(iv, dst, 16);
103 }
104 src+=16;
105 dst+=16;
106 }
107 }
108
109 static void init_multbl2(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8, uint8_t *sbox){
110 int i, j;
111 for(i=0; i<1024; i++){
112 int x= sbox[i>>2];
113 if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
114 }
115 #ifndef CONFIG_SMALL
116 for(j=256; j<1024; j++)
117 for(i=0; i<4; i++)
118 tbl[4*j+i]= tbl[4*j + ((i-1)&3) - 1024];
119 #endif
120 }
121
122 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
123 int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt) {
124 int i, j, t, rconpointer = 0;
125 uint8_t tk[8][4];
126 int KC= key_bits>>5;
127 int rounds= KC + 6;
128 uint8_t log8[256];
129 uint8_t alog8[512];
130
131 if(!enc_multbl[0][sizeof(enc_multbl)/sizeof(enc_multbl[0][0])-1]){
132 j=1;
133 for(i=0; i<255; i++){
134 alog8[i]=
135 alog8[i+255]= j;
136 log8[j]= i;
137 j^= j+j;
138 if(j>255) j^= 0x11B;
139 }
140 for(i=0; i<256; i++){
141 j= i ? alog8[255-log8[i]] : 0;
142 j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4);
143 j = (j ^ (j>>8) ^ 99) & 255;
144 inv_sbox[j]= i;
145 sbox [i]= j;
146 }
147 init_multbl2(dec_multbl[0], (int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
148 init_multbl2(enc_multbl[0], (int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
149 }
150
151 if(key_bits!=128 && key_bits!=192 && key_bits!=256)
152 return -1;
153
154 a->rounds= rounds;
155
156 memcpy(tk, key, KC*4);
157
158 for(t= 0; t < (rounds+1)*16;) {
159 memcpy(a->round_key[0][0]+t, tk, KC*4);
160 t+= KC*4;
161
162 for(i = 0; i < 4; i++)
163 tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]];
164 tk[0][0] ^= rcon[rconpointer++];
165
166 for(j = 1; j < KC; j++){
167 if(KC != 8 || j != KC>>1)
168 for(i = 0; i < 4; i++) tk[j][i] ^= tk[j-1][i];
169 else
170 for(i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j-1][i]];
171 }
172 }
173
174 if(decrypt){
175 for(i=1; i<rounds; i++){
176 uint8_t tmp[3][16];
177 memcpy(tmp[2], a->round_key[i][0], 16);
178 subshift(tmp[1], 0, sbox);
179 mix(tmp, dec_multbl, 1, 3);
180 memcpy(a->round_key[i][0], tmp[0], 16);
181 }
182 }else{
183 for(i=0; i<(rounds+1)>>1; i++){
184 for(j=0; j<16; j++)
185 FFSWAP(int, a->round_key[i][0][j], a->round_key[rounds-i][0][j]);
186 }
187 }
188
189 return 0;
190 }
191
192 #ifdef TEST
193 #include "log.h"
194
195 int main(){
196 int i,j;
197 AVAES ae, ad, b;
198 uint8_t rkey[2][16]= {
199 {0},
200 {0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59}};
201 uint8_t pt[16], rpt[2][16]= {
202 {0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3},
203 {0}};
204 uint8_t rct[2][16]= {
205 {0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf},
206 {0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65}};
207 uint8_t temp[16];
208
209 av_aes_init(&ae, "PI=3.141592654..", 128, 0);
210 av_aes_init(&ad, "PI=3.141592654..", 128, 1);
211 av_log_level= AV_LOG_DEBUG;
212
213 for(i=0; i<2; i++){
214 av_aes_init(&b, rkey[i], 128, 1);
215 av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
216 for(j=0; j<16; j++)
217 if(rpt[i][j] != temp[j])
218 av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], temp[j]);
219 }
220
221 for(i=0; i<10000; i++){
222 for(j=0; j<16; j++){
223 pt[j]= random();
224 }
225 {START_TIMER
226 av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
227 if(!(i&(i-1)))
228 av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", temp[0], temp[5], temp[10], temp[15]);
229 av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
230 STOP_TIMER("aes")}
231 for(j=0; j<16; j++){
232 if(pt[j] != temp[j]){
233 av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], temp[j]);
234 }
235 }
236 }
237 return 0;
238 }
239 #endif