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simplify special round 

Originally committed as revision 7481 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2007-01-14 16:49:35 +00:00
parent cf5773e95f
commit 388b5e69ec
1 changed files with 4 additions and 6 deletions
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10
libavutil/aes.c
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@ -70,10 +70,9 @@ static inline void mix(uint8_t state[4][4], uint32_t multbl[4][256]){
void av_aes_decrypt(AVAES *a){ void av_aes_decrypt(AVAES *a){
int t, r; int t, r;
addkey(a->state, a->round_key[a->rounds]);
for(r=a->rounds-1; r>=0; r--){ for(r=a->rounds-1; r>=0; r--){
if(r==a->rounds-1) if(r!=a->rounds-1)
addkey(a->state, a->round_key[r+1]);
else
mix(a->state, dec_multbl); mix(a->state, dec_multbl);
SUBSHIFT0((a->state[0]+0), inv_sbox) SUBSHIFT0((a->state[0]+0), inv_sbox)
SUBSHIFT3((a->state[0]+1), inv_sbox) SUBSHIFT3((a->state[0]+1), inv_sbox)
@ -92,11 +91,10 @@ void av_aes_encrypt(AVAES *a){
SUBSHIFT1((a->state[0]+1), sbox) SUBSHIFT1((a->state[0]+1), sbox)
SUBSHIFT2((a->state[0]+2), sbox) SUBSHIFT2((a->state[0]+2), sbox)
SUBSHIFT3((a->state[0]+3), sbox) SUBSHIFT3((a->state[0]+3), sbox)
if(r==a->rounds-1) if(r!=a->rounds-1)
addkey(a->state, a->round_key[r+1]);
else
mix(a->state, enc_multbl); //FIXME replace log8 by const / optimze mix as this can be simplified alot mix(a->state, enc_multbl); //FIXME replace log8 by const / optimze mix as this can be simplified alot
} }
addkey(a->state, a->round_key[r]);
} }
static init_multbl(uint8_t tbl[256], int c[4], uint8_t *log8, uint8_t *alog8){ static init_multbl(uint8_t tbl[256], int c[4], uint8_t *log8, uint8_t *alog8){