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use 2 state arrays so that fewer temporary variables are needed

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Originally committed as revision 7545 to svn://svn.ffmpeg.org/ffmpeg/trunk
pull/126/head
Michael Niedermayer 18 years ago
parent cc6b4da83a
commit 298dd6b7c8
1 changed files with 32 additions and 33 deletions
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  1. 65
      libavutil/aes.c

65
libavutil/aes.c
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@ -25,7 +25,7 @@
typedef struct AVAES{
uint8_t round_key[15][4][4];
uint8_t state[4][4];
uint8_t state[2][4][4];
int rounds;
}AVAES;
@ -46,16 +46,15 @@ static uint32_t dec_multbl[4][256];
#endif
static inline void addkey(uint64_t state[2], uint64_t round_key[2]){
state[0] ^= round_key[0];
state[1] ^= round_key[1];
state[2] = state[0] ^ round_key[0];
state[3] = state[1] ^ round_key[1];
}
static void subshift(uint8_t s0[4], uint8_t s1[4], uint8_t s3[4], uint8_t *box){
int t;
s0[0]=box[s0[ 0]]; s0[ 4]=box[s0[ 4]]; s0[ 8]=box[s0[ 8]]; s0[12]=box[s0[12]];
t=s1[0]; s1[0]=box[s1[ 4]]; s1[ 4]=box[s1[ 8]]; s1[ 8]=box[s1[12]]; s1[12]=box[t];
t=s0[2]; s0[2]=box[s0[10]]; s0[10]=box[ t]; t=s0[ 6]; s0[ 6]=box[s0[14]]; s0[14]=box[t];
t=s3[0]; s3[0]=box[s3[12]]; s3[12]=box[s3[ 8]]; s3[ 8]=box[s3[ 4]]; s3[ 4]=box[t];
static void subshift(uint8_t s0[2][16], uint8_t s1[2][16], uint8_t s3[2][16], uint8_t *box){
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]];
s1[0][0]=box[s1[1][ 4]]; s1[0][ 4]=box[s1[1][ 8]]; s1[0][ 8]=box[s1[1][12]]; s1[0][12]=box[s1[1][ 0]];
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]];
s3[0][0]=box[s3[1][12]]; s3[0][12]=box[s3[1][ 8]]; s3[0][ 8]=box[s3[1][ 4]]; s3[0][ 4]=box[s3[1][ 0]];
}
#define ROT(x,s) ((x<<s)|(x>>(32-s)))
@ -72,20 +71,16 @@ static inline void mix(uint8_t state[4][4], uint32_t multbl[4][256]){
#endif
}
#endif
static inline void mix2(uint8_t state[4][4], uint32_t multbl[4][256], int s1, int s3){
int a = multbl[0][state[0][0]] ^ multbl[1][state[s1 ][1]]
^multbl[2][state[2][2]] ^ multbl[3][state[s3 ][3]];
int b = multbl[0][state[1][0]] ^ multbl[1][state[s3-1][1]]
^multbl[2][state[3][2]] ^ multbl[3][state[s1-1][3]];
int c = multbl[0][state[2][0]] ^ multbl[1][state[s3 ][1]]
^multbl[2][state[0][2]] ^ multbl[3][state[s1 ][3]];
int d = multbl[0][state[3][0]] ^ multbl[1][state[s1-1][1]]
^multbl[2][state[1][2]] ^ multbl[3][state[s3-1][3]];
((uint32_t *)(state))[0]=a;
((uint32_t *)(state))[1]=b;
((uint32_t *)(state))[2]=c;
((uint32_t *)(state))[3]=d;
static inline void mix(uint8_t state[2][4][4], uint32_t multbl[4][256], int s1, int s3){
((uint32_t *)(state))[0] = multbl[0][state[1][0][0]] ^ multbl[1][state[1][s1 ][1]]
^multbl[2][state[1][2][2]] ^ multbl[3][state[1][s3 ][3]];
((uint32_t *)(state))[1] = multbl[0][state[1][1][0]] ^ multbl[1][state[1][s3-1][1]]
^multbl[2][state[1][3][2]] ^ multbl[3][state[1][s1-1][3]];
((uint32_t *)(state))[2] = multbl[0][state[1][2][0]] ^ multbl[1][state[1][s3 ][1]]
^multbl[2][state[1][0][2]] ^ multbl[3][state[1][s1 ][3]];
((uint32_t *)(state))[3] = multbl[0][state[1][3][0]] ^ multbl[1][state[1][s1-1][1]]
^multbl[2][state[1][1][2]] ^ multbl[3][state[1][s3-1][3]];
}
static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
@ -93,10 +88,10 @@ static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
for(r=a->rounds; r>1; r--){
addkey(a->state, a->round_key[r]);
mix2(a->state, multbl, 3-s, 1+s);
mix(a->state, multbl, 3-s, 1+s);
}
addkey(a->state, a->round_key[1]);
subshift(a->state[0], a->state[0]+3-s, a->state[0]+1+s, sbox);
subshift(a->state[0][0], a->state[0][0]+3-s, a->state[0][0]+1+s, sbox);
addkey(a->state, a->round_key[0]);
}
@ -175,8 +170,12 @@ int av_aes_init(AVAES *a, uint8_t *key, int key_bits, int decrypt) {
if(decrypt){
for(i=1; i<rounds; i++){
subshift(a->round_key[i][0], a->round_key[i][0]+3, a->round_key[i][0]+1, sbox);
mix2(a->round_key[i], dec_multbl, 1, 3);
uint8_t tmp[2][16];
memcpy(tmp[1], a->round_key[i][0], 16);
subshift(tmp[0], tmp[0]+3, tmp[0]+1, sbox);
memcpy(tmp[1], tmp[0], 16);
mix(tmp, dec_multbl, 1, 3);
memcpy(a->round_key[i][0], tmp[0], 16);
}
}else{
for(i=0; i<(rounds+1)>>1; i++){
@ -213,8 +212,8 @@ int main(){
memcpy(b.state, rct[i], 16);
aes_decrypt(&b);
for(j=0; j<16; j++)
if(rpt[i][j] != b.state[0][j])
av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], b.state[0][j]);
if(rpt[i][j] != b.state[1][0][j])
av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], b.state[1][0][j]);
}
for(i=0; i<10000; i++){
@ -225,13 +224,13 @@ int main(){
{START_TIMER
aes_encrypt(&ae);
if(!(i&(i-1)))
av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", ae.state[0][0], ae.state[1][1], ae.state[2][2], ae.state[3][3]);
memcpy(ad.state, ae.state, 16);
av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", ae.state[1][0][0], ae.state[1][1][1], ae.state[1][2][2], ae.state[1][3][3]);
memcpy(ad.state[0], ae.state[1], 16);
aes_decrypt(&ad);
STOP_TIMER("aes")}
for(j=0; j<16; j++){
if(pt[j] != ad.state[0][j]){
av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], ad.state[0][j]);
if(pt[j] != ad.state[1][0][j]){
av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], ad.state[1][0][j]);
}
}
}

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