forked from etc/pineapple-src
268 lines
8.2 KiB
C
Executable file
268 lines
8.2 KiB
C
Executable file
/*
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* copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
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*
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* some optimization ideas from aes128.c by Reimar Doeffinger
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "common.h"
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#include "aes.h"
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#include "aes_internal.h"
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#include "intreadwrite.h"
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#include "timer.h"
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const int av_aes_size= sizeof(AVAES);
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struct AVAES *av_aes_alloc(void)
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{
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return av_mallocz(sizeof(struct AVAES));
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}
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static const uint8_t rcon[10] = {
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
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};
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static uint8_t sbox[256];
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static uint8_t inv_sbox[256];
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#if CONFIG_SMALL
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static uint32_t enc_multbl[1][256];
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static uint32_t dec_multbl[1][256];
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#else
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static uint32_t enc_multbl[4][256];
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static uint32_t dec_multbl[4][256];
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#endif
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#if HAVE_BIGENDIAN
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# define ROT(x, s) (((x) >> (s)) | ((x) << (32-(s))))
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#else
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# define ROT(x, s) (((x) << (s)) | ((x) >> (32-(s))))
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#endif
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static inline void addkey(av_aes_block *dst, const av_aes_block *src,
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const av_aes_block *round_key)
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{
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dst->u64[0] = src->u64[0] ^ round_key->u64[0];
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dst->u64[1] = src->u64[1] ^ round_key->u64[1];
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}
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static inline void addkey_s(av_aes_block *dst, const uint8_t *src,
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const av_aes_block *round_key)
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{
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dst->u64[0] = AV_RN64(src) ^ round_key->u64[0];
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dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1];
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}
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static inline void addkey_d(uint8_t *dst, const av_aes_block *src,
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const av_aes_block *round_key)
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{
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AV_WN64(dst, src->u64[0] ^ round_key->u64[0]);
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AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]);
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}
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static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
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{
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av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s);
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av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s);
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s0[0].u8[ 0] = box[s0[1].u8[ 0]];
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s0[0].u8[ 4] = box[s0[1].u8[ 4]];
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s0[0].u8[ 8] = box[s0[1].u8[ 8]];
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s0[0].u8[12] = box[s0[1].u8[12]];
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s1[0].u8[ 3] = box[s1[1].u8[ 7]];
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s1[0].u8[ 7] = box[s1[1].u8[11]];
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s1[0].u8[11] = box[s1[1].u8[15]];
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s1[0].u8[15] = box[s1[1].u8[ 3]];
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s0[0].u8[ 2] = box[s0[1].u8[10]];
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s0[0].u8[10] = box[s0[1].u8[ 2]];
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s0[0].u8[ 6] = box[s0[1].u8[14]];
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s0[0].u8[14] = box[s0[1].u8[ 6]];
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s3[0].u8[ 1] = box[s3[1].u8[13]];
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s3[0].u8[13] = box[s3[1].u8[ 9]];
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s3[0].u8[ 9] = box[s3[1].u8[ 5]];
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s3[0].u8[ 5] = box[s3[1].u8[ 1]];
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}
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static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d)
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{
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#if CONFIG_SMALL
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return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
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#else
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return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
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#endif
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}
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static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3)
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{
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uint8_t (*src)[4] = state[1].u8x4;
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state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
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state[0].u32[1] = mix_core(multbl, src[1][0], src[s3 - 1][1], src[3][2], src[s1 - 1][3]);
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state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
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state[0].u32[3] = mix_core(multbl, src[3][0], src[s1 - 1][1], src[1][2], src[s3 - 1][3]);
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}
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static inline void aes_crypt(AVAES *a, int s, const uint8_t *sbox,
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uint32_t multbl[][256])
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{
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int r;
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for (r = a->rounds - 1; r > 0; r--) {
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mix(a->state, multbl, 3 - s, 1 + s);
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addkey(&a->state[1], &a->state[0], &a->round_key[r]);
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}
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subshift(&a->state[0], s, sbox);
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}
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static void aes_encrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
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int count, uint8_t *iv, int rounds)
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{
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while (count--) {
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addkey_s(&a->state[1], src, &a->round_key[rounds]);
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if (iv)
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addkey_s(&a->state[1], iv, &a->state[1]);
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aes_crypt(a, 2, sbox, enc_multbl);
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addkey_d(dst, &a->state[0], &a->round_key[0]);
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if (iv)
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memcpy(iv, dst, 16);
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src += 16;
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dst += 16;
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}
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}
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static void aes_decrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
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int count, uint8_t *iv, int rounds)
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{
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while (count--) {
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addkey_s(&a->state[1], src, &a->round_key[rounds]);
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aes_crypt(a, 0, inv_sbox, dec_multbl);
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if (iv) {
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addkey_s(&a->state[0], iv, &a->state[0]);
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memcpy(iv, src, 16);
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}
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addkey_d(dst, &a->state[0], &a->round_key[0]);
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src += 16;
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dst += 16;
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}
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}
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void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
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int count, uint8_t *iv, int decrypt)
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{
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a->crypt(a, dst, src, count, iv, a->rounds);
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}
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static void init_multbl2(uint32_t tbl[][256], const int c[4],
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const uint8_t *log8, const uint8_t *alog8,
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const uint8_t *sbox)
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{
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int i;
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for (i = 0; i < 256; i++) {
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int x = sbox[i];
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if (x) {
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int k, l, m, n;
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x = log8[x];
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k = alog8[x + log8[c[0]]];
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l = alog8[x + log8[c[1]]];
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m = alog8[x + log8[c[2]]];
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n = alog8[x + log8[c[3]]];
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tbl[0][i] = AV_NE(MKBETAG(k, l, m, n), MKTAG(k, l, m, n));
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#if !CONFIG_SMALL
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tbl[1][i] = ROT(tbl[0][i], 8);
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tbl[2][i] = ROT(tbl[0][i], 16);
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tbl[3][i] = ROT(tbl[0][i], 24);
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#endif
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}
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}
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}
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// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
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int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
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{
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int i, j, t, rconpointer = 0;
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uint8_t tk[8][4];
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int KC = key_bits >> 5;
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int rounds = KC + 6;
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uint8_t log8[256];
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uint8_t alog8[512];
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a->crypt = decrypt ? aes_decrypt : aes_encrypt;
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if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl) - 1][FF_ARRAY_ELEMS(enc_multbl[0]) - 1]) {
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j = 1;
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for (i = 0; i < 255; i++) {
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alog8[i] = alog8[i + 255] = j;
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log8[j] = i;
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j ^= j + j;
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if (j > 255)
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j ^= 0x11B;
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}
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for (i = 0; i < 256; i++) {
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j = i ? alog8[255 - log8[i]] : 0;
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j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4);
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j = (j ^ (j >> 8) ^ 99) & 255;
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inv_sbox[j] = i;
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sbox[i] = j;
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}
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init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb },
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log8, alog8, inv_sbox);
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init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
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log8, alog8, sbox);
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}
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if (key_bits != 128 && key_bits != 192 && key_bits != 256)
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return AVERROR(EINVAL);
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a->rounds = rounds;
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memcpy(tk, key, KC * 4);
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memcpy(a->round_key[0].u8, key, KC * 4);
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for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) {
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for (i = 0; i < 4; i++)
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tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
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tk[0][0] ^= rcon[rconpointer++];
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for (j = 1; j < KC; j++) {
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if (KC != 8 || j != KC >> 1)
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for (i = 0; i < 4; i++)
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tk[j][i] ^= tk[j - 1][i];
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else
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for (i = 0; i < 4; i++)
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tk[j][i] ^= sbox[tk[j - 1][i]];
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}
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memcpy(a->round_key[0].u8 + t, tk, KC * 4);
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}
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if (decrypt) {
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for (i = 1; i < rounds; i++) {
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av_aes_block tmp[3];
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tmp[2] = a->round_key[i];
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subshift(&tmp[1], 0, sbox);
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mix(tmp, dec_multbl, 1, 3);
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a->round_key[i] = tmp[0];
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}
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} else {
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for (i = 0; i < (rounds + 1) >> 1; i++)
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FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds - i]);
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}
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return 0;
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}
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