libavutil/aes.c - third_party/ffmpeg - Git at Google

 /*
  * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
  *
  * some optimization ideas from aes128.c by Reimar Doeffinger
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 #include "common.h"
 #include "aes.h"

 typedef union {
     uint64_t u64[2];
     uint32_t u32[4];
     uint8_t u8x4[4][4];
     uint8_t u8[16];
 } av_aes_block;

 typedef struct AVAES{
     // Note: round_key[16] is accessed in the init code, but this only
     // overwrites state, which does not matter (see also r7471).
     av_aes_block round_key[15];
     av_aes_block state[2];
     int rounds;
 }AVAES;

 const int av_aes_size= sizeof(AVAES);

 static const uint8_t rcon[10] = {
   0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
 };

 static uint8_t     sbox[256];
 static uint8_t inv_sbox[256];
 #if CONFIG_SMALL
 static uint32_t enc_multbl[1][256];
 static uint32_t dec_multbl[1][256];
 #else
 static uint32_t enc_multbl[4][256];
 static uint32_t dec_multbl[4][256];
 #endif

 static inline void addkey(av_aes_block *dst, const av_aes_block *src, const av_aes_block *round_key){
     dst->u64[0] = src->u64[0] ^ round_key->u64[0];
     dst->u64[1] = src->u64[1] ^ round_key->u64[1];
 }

 static void subshift(av_aes_block s0[2], int s, const uint8_t *box){
     av_aes_block *s1= (av_aes_block *)(s0[0].u8 - s);
     av_aes_block *s3= (av_aes_block *)(s0[0].u8 + s);
     s0[0].u8[0]=box[s0[1].u8[ 0]]; s0[0].u8[ 4]=box[s0[1].u8[ 4]]; s0[0].u8[ 8]=box[s0[1].u8[ 8]]; s0[0].u8[12]=box[s0[1].u8[12]];
     s1[0].u8[3]=box[s1[1].u8[ 7]]; s1[0].u8[ 7]=box[s1[1].u8[11]]; s1[0].u8[11]=box[s1[1].u8[15]]; s1[0].u8[15]=box[s1[1].u8[ 3]];
     s0[0].u8[2]=box[s0[1].u8[10]]; s0[0].u8[10]=box[s0[1].u8[ 2]]; s0[0].u8[ 6]=box[s0[1].u8[14]]; s0[0].u8[14]=box[s0[1].u8[ 6]];
     s3[0].u8[1]=box[s3[1].u8[13]]; s3[0].u8[13]=box[s3[1].u8[ 9]]; s3[0].u8[ 9]=box[s3[1].u8[ 5]]; s3[0].u8[ 5]=box[s3[1].u8[ 1]];
 }

 static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
 #if CONFIG_SMALL
 #define ROT(x,s) ((x<<s)|(x>>(32-s)))
     return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
 #else
     return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
 #endif
 }

 static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){
     uint8_t (*src)[4] = state[1].u8x4;
     state[0].u32[0] = mix_core(multbl, src[0][0], src[s1  ][1], src[2][2], src[s3  ][3]);
     state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]);
     state[0].u32[2] = mix_core(multbl, src[2][0], src[s3  ][1], src[0][2], src[s1  ][3]);
     state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]);
 }

 static inline void crypt(AVAES *a, int s, const uint8_t *sbox, uint32_t multbl[][256]){
     int r;

     for(r=a->rounds-1; r>0; r--){
         mix(a->state, multbl, 3-s, 1+s);
         addkey(&a->state[1], &a->state[0], &a->round_key[r]);
     }
     subshift(&a->state[0], s, sbox);
 }

 void av_aes_crypt(AVAES *a, uint8_t *dst_, const uint8_t *src_, int count, uint8_t *iv_, int decrypt){
     av_aes_block *dst = (av_aes_block *)dst_;
     const av_aes_block *src = (const av_aes_block *)src_;
     av_aes_block *iv = (av_aes_block *)iv_;
     while(count--){
         addkey(&a->state[1], src, &a->round_key[a->rounds]);
         if(decrypt) {
             crypt(a, 0, inv_sbox, dec_multbl);
             if(iv){
                 addkey(&a->state[0], &a->state[0], iv);
                 memcpy(iv, src, 16);
             }
             addkey(dst, &a->state[0], &a->round_key[0]);
         }else{
             if(iv) addkey(&a->state[1], &a->state[1], iv);
             crypt(a, 2,     sbox, enc_multbl);
             addkey(dst, &a->state[0], &a->round_key[0]);
             if(iv) memcpy(iv, dst, 16);
         }
         src++;
         dst++;
     }
 }

 static void init_multbl2(uint8_t tbl[1024], const int c[4], const uint8_t *log8, const uint8_t *alog8, const uint8_t *sbox){
     int i, j;
     for(i=0; i<1024; i++){
         int x= sbox[i>>2];
         if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
     }
 #if !CONFIG_SMALL
     for(j=256; j<1024; j++)
         for(i=0; i<4; i++)
             tbl[4*j+i]= tbl[4*j + ((i-1)&3) - 1024];
 #endif
 }

 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
 int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt) {
     int i, j, t, rconpointer = 0;
     uint8_t tk[8][4];
     int KC= key_bits>>5;
     int rounds= KC + 6;
     uint8_t  log8[256];
     uint8_t alog8[512];

     if(!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]){
         j=1;
         for(i=0; i<255; i++){
             alog8[i]=
             alog8[i+255]= j;
             log8[j]= i;
             j^= j+j;
             if(j>255) j^= 0x11B;
         }
         for(i=0; i<256; i++){
             j= i ? alog8[255-log8[i]] : 0;
             j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4);
             j = (j ^ (j>>8) ^ 99) & 255;
             inv_sbox[j]= i;
             sbox    [i]= j;
         }
         init_multbl2(dec_multbl[0], (const int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
         init_multbl2(enc_multbl[0], (const int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
     }

     if(key_bits!=128 && key_bits!=192 && key_bits!=256)
         return -1;

     a->rounds= rounds;

     memcpy(tk, key, KC*4);

     for(t= 0; t < (rounds+1)*16;) {
         memcpy(a->round_key[0].u8+t, tk, KC*4);
         t+= KC*4;

         for(i = 0; i < 4; i++)
             tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]];
         tk[0][0] ^= rcon[rconpointer++];

         for(j = 1; j < KC; j++){
             if(KC != 8 || j != KC>>1)
                 for(i = 0; i < 4; i++) tk[j][i] ^=      tk[j-1][i];
             else
                 for(i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j-1][i]];
         }
     }

     if(decrypt){
         for(i=1; i<rounds; i++){
             av_aes_block tmp[3];
             memcpy(&tmp[2], &a->round_key[i], 16);
             subshift(&tmp[1], 0, sbox);
             mix(tmp, dec_multbl, 1, 3);
             memcpy(&a->round_key[i], &tmp[0], 16);
         }
     }else{
         for(i=0; i<(rounds+1)>>1; i++){
             for(j=0; j<16; j++)
                 FFSWAP(int, a->round_key[i].u8[j], a->round_key[rounds-i].u8[j]);
         }
     }

     return 0;
 }

 #ifdef TEST
 #include "lfg.h"
 #include "log.h"

 int main(void){
     int i,j;
     AVAES ae, ad, b;
     uint8_t rkey[2][16]= {
         {0},
         {0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59}};
     uint8_t pt[16], rpt[2][16]= {
         {0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3},
         {0}};
     uint8_t rct[2][16]= {
         {0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf},
         {0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65}};
     uint8_t temp[16];
     AVLFG prng;

     av_aes_init(&ae, "PI=3.141592654..", 128, 0);
     av_aes_init(&ad, "PI=3.141592654..", 128, 1);
     av_log_set_level(AV_LOG_DEBUG);
     av_lfg_init(&prng, 1);

     for(i=0; i<2; i++){
         av_aes_init(&b, rkey[i], 128, 1);
         av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
         for(j=0; j<16; j++)
             if(rpt[i][j] != temp[j])
                 av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], temp[j]);
     }

     for(i=0; i<10000; i++){
         for(j=0; j<16; j++){
             pt[j] = av_lfg_get(&prng);
         }
 {START_TIMER
         av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
         if(!(i&(i-1)))
             av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", temp[0], temp[5], temp[10], temp[15]);
         av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
 STOP_TIMER("aes")}
         for(j=0; j<16; j++){
             if(pt[j] != temp[j]){
                 av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], temp[j]);
             }
         }
     }
     return 0;
 }
 #endif
	/*
	* copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
	*
	* some optimization ideas from aes128.c by Reimar Doeffinger
	*
	* This file is part of FFmpeg.
	*
	* FFmpeg is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* FFmpeg is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with FFmpeg; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include "common.h"
	#include "aes.h"

	typedef union {
	uint64_t u64[2];
	uint32_t u32[4];
	uint8_t u8x4[4][4];
	uint8_t u8[16];
	} av_aes_block;

	typedef struct AVAES{
	// Note: round_key[16] is accessed in the init code, but this only
	// overwrites state, which does not matter (see also r7471).
	av_aes_block round_key[15];
	av_aes_block state[2];
	int rounds;
	}AVAES;

	const int av_aes_size= sizeof(AVAES);

	static const uint8_t rcon[10] = {
	0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
	};

	static uint8_t sbox[256];
	static uint8_t inv_sbox[256];
	#if CONFIG_SMALL
	static uint32_t enc_multbl[1][256];
	static uint32_t dec_multbl[1][256];
	#else
	static uint32_t enc_multbl[4][256];
	static uint32_t dec_multbl[4][256];
	#endif

	static inline void addkey(av_aes_block dst, const av_aes_block src, const av_aes_block *round_key){
	dst->u64[0] = src->u64[0] ^ round_key->u64[0];
	dst->u64[1] = src->u64[1] ^ round_key->u64[1];
	}

	static void subshift(av_aes_block s0[2], int s, const uint8_t *box){
	av_aes_block s1= (av_aes_block )(s0[0].u8 - s);
	av_aes_block s3= (av_aes_block )(s0[0].u8 + s);
	s0[0].u8[0]=box[s0[1].u8[ 0]]; s0[0].u8[ 4]=box[s0[1].u8[ 4]]; s0[0].u8[ 8]=box[s0[1].u8[ 8]]; s0[0].u8[12]=box[s0[1].u8[12]];
	s1[0].u8[3]=box[s1[1].u8[ 7]]; s1[0].u8[ 7]=box[s1[1].u8[11]]; s1[0].u8[11]=box[s1[1].u8[15]]; s1[0].u8[15]=box[s1[1].u8[ 3]];
	s0[0].u8[2]=box[s0[1].u8[10]]; s0[0].u8[10]=box[s0[1].u8[ 2]]; s0[0].u8[ 6]=box[s0[1].u8[14]]; s0[0].u8[14]=box[s0[1].u8[ 6]];
	s3[0].u8[1]=box[s3[1].u8[13]]; s3[0].u8[13]=box[s3[1].u8[ 9]]; s3[0].u8[ 9]=box[s3[1].u8[ 5]]; s3[0].u8[ 5]=box[s3[1].u8[ 1]];
	}

	static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
	#if CONFIG_SMALL
	#define ROT(x,s) ((x<<s)\|(x>>(32-s)))
	return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
	#else
	return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
	#endif
	}

	static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){
	uint8_t (*src)[4] = state[1].u8x4;
	state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
	state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]);
	state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
	state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]);
	}

	static inline void crypt(AVAES a, int s, const uint8_t sbox, uint32_t multbl[][256]){
	int r;

	for(r=a->rounds-1; r>0; r--){
	mix(a->state, multbl, 3-s, 1+s);
	addkey(&a->state[1], &a->state[0], &a->round_key[r]);
	}
	subshift(&a->state[0], s, sbox);
	}

	void av_aes_crypt(AVAES a, uint8_t dst_, const uint8_t src_, int count, uint8_t iv_, int decrypt){
	av_aes_block dst = (av_aes_block )dst_;
	const av_aes_block src = (const av_aes_block )src_;
	av_aes_block iv = (av_aes_block )iv_;
	while(count--){
	addkey(&a->state[1], src, &a->round_key[a->rounds]);
	if(decrypt) {
	crypt(a, 0, inv_sbox, dec_multbl);
	if(iv){
	addkey(&a->state[0], &a->state[0], iv);
	memcpy(iv, src, 16);
	}
	addkey(dst, &a->state[0], &a->round_key[0]);
	}else{
	if(iv) addkey(&a->state[1], &a->state[1], iv);
	crypt(a, 2, sbox, enc_multbl);
	addkey(dst, &a->state[0], &a->round_key[0]);
	if(iv) memcpy(iv, dst, 16);
	}
	src++;
	dst++;
	}
	}

	static void init_multbl2(uint8_t tbl[1024], const int c[4], const uint8_t log8, const uint8_t alog8, const uint8_t *sbox){
	int i, j;
	for(i=0; i<1024; i++){
	int x= sbox[i>>2];
	if(x) tbl[i]= alog8[ log8[x] + log8[c[i&3]] ];
	}
	#if !CONFIG_SMALL
	for(j=256; j<1024; j++)
	for(i=0; i<4; i++)
	tbl[4j+i]= tbl[4j + ((i-1)&3) - 1024];
	#endif
	}

	// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
	int av_aes_init(AVAES a, const uint8_t key, int key_bits, int decrypt) {
	int i, j, t, rconpointer = 0;
	uint8_t tk[8][4];
	int KC= key_bits>>5;
	int rounds= KC + 6;
	uint8_t log8[256];
	uint8_t alog8[512];

	if(!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]){
	j=1;
	for(i=0; i<255; i++){
	alog8[i]=
	alog8[i+255]= j;
	log8[j]= i;
	j^= j+j;
	if(j>255) j^= 0x11B;
	}
	for(i=0; i<256; i++){
	j= i ? alog8[255-log8[i]] : 0;
	j ^= (j<<1) ^ (j<<2) ^ (j<<3) ^ (j<<4);
	j = (j ^ (j>>8) ^ 99) & 255;
	inv_sbox[j]= i;
	sbox [i]= j;
	}
	init_multbl2(dec_multbl[0], (const int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
	init_multbl2(enc_multbl[0], (const int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
	}

	if(key_bits!=128 && key_bits!=192 && key_bits!=256)
	return -1;

	a->rounds= rounds;

	memcpy(tk, key, KC*4);

	for(t= 0; t < (rounds+1)*16;) {
	memcpy(a->round_key[0].u8+t, tk, KC*4);
	t+= KC*4;

	for(i = 0; i < 4; i++)
	tk[0][i] ^= sbox[tk[KC-1][(i+1)&3]];
	tk[0][0] ^= rcon[rconpointer++];

	for(j = 1; j < KC; j++){
	if(KC != 8 \|\| j != KC>>1)
	for(i = 0; i < 4; i++) tk[j][i] ^= tk[j-1][i];
	else
	for(i = 0; i < 4; i++) tk[j][i] ^= sbox[tk[j-1][i]];
	}
	}

	if(decrypt){
	for(i=1; i<rounds; i++){
	av_aes_block tmp[3];
	memcpy(&tmp[2], &a->round_key[i], 16);
	subshift(&tmp[1], 0, sbox);
	mix(tmp, dec_multbl, 1, 3);
	memcpy(&a->round_key[i], &tmp[0], 16);
	}
	}else{
	for(i=0; i<(rounds+1)>>1; i++){
	for(j=0; j<16; j++)
	FFSWAP(int, a->round_key[i].u8[j], a->round_key[rounds-i].u8[j]);
	}
	}

	return 0;
	}

	#ifdef TEST
	#include "lfg.h"
	#include "log.h"

	int main(void){
	int i,j;
	AVAES ae, ad, b;
	uint8_t rkey[2][16]= {
	{0},
	{0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3, 0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59}};
	uint8_t pt[16], rpt[2][16]= {
	{0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad, 0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3},
	{0}};
	uint8_t rct[2][16]= {
	{0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7, 0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf},
	{0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0, 0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65}};
	uint8_t temp[16];
	AVLFG prng;

	av_aes_init(&ae, "PI=3.141592654..", 128, 0);
	av_aes_init(&ad, "PI=3.141592654..", 128, 1);
	av_log_set_level(AV_LOG_DEBUG);
	av_lfg_init(&prng, 1);

	for(i=0; i<2; i++){
	av_aes_init(&b, rkey[i], 128, 1);
	av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
	for(j=0; j<16; j++)
	if(rpt[i][j] != temp[j])
	av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n", j, rpt[i][j], temp[j]);
	}

	for(i=0; i<10000; i++){
	for(j=0; j<16; j++){
	pt[j] = av_lfg_get(&prng);
	}
	{START_TIMER
	av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
	if(!(i&(i-1)))
	av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n", temp[0], temp[5], temp[10], temp[15]);
	av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
	STOP_TIMER("aes")}
	for(j=0; j<16; j++){
	if(pt[j] != temp[j]){
	av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n", i,j, pt[j], temp[j]);
	}
	}
	}
	return 0;
	}
	#endif