From 298dd6b7c8231a25fe79de682cce4e7330500fcf Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 16 Jan 2007 17:17:05 +0000 Subject: use 2 state arrays so that fewer temporary variables are needed Originally committed as revision 7545 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavutil/aes.c | 65 ++++++++++++++++++++++++++++----------------------------- 1 file changed, 32 insertions(+), 33 deletions(-) (limited to 'libavutil') diff --git a/libavutil/aes.c b/libavutil/aes.c index fa07bc83e6..c2ba0d2db7 100644 --- a/libavutil/aes.c +++ b/libavutil/aes.c @@ -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<>(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; iround_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]); } } } -- cgit v1.2.3