+++ /dev/null
-/* aes.c */
-/*
- This file is part of the AVR-Crypto-Lib.
- Copyright (C) 2008, 2009 Daniel Otte (daniel.otte@rub.de)
-
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
- (at your option) any later version.
-
- This program 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 General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
-*/
-
-#include <stdint.h>
-#include <string.h>
-#include "gf256mul.h"
-#include "aes.h"
-#include "aes_invsbox.h"
-#include "aes_dec.h"
-#include <avr/pgmspace.h>
-
-void aes_invshiftrow(void* data, uint8_t shift){
- uint8_t tmp[4];
- tmp[0] = ((uint8_t*)data)[(4+0-shift)&3];
- tmp[1] = ((uint8_t*)data)[(4+1-shift)&3];
- tmp[2] = ((uint8_t*)data)[(4+2-shift)&3];
- tmp[3] = ((uint8_t*)data)[(4+3-shift)&3];
- memcpy(data, tmp, 4);
-}
-
-void aes_invshiftcol(void* data, uint8_t shift){
- uint8_t tmp[4];
- tmp[0] = ((uint8_t*)data)[ 0];
- tmp[1] = ((uint8_t*)data)[ 4];
- tmp[2] = ((uint8_t*)data)[ 8];
- tmp[3] = ((uint8_t*)data)[12];
- ((uint8_t*)data)[ 0] = tmp[(4-shift+0)&3];
- ((uint8_t*)data)[ 4] = tmp[(4-shift+1)&3];
- ((uint8_t*)data)[ 8] = tmp[(4-shift+2)&3];
- ((uint8_t*)data)[12] = tmp[(4-shift+3)&3];
-}
-static
-void aes_dec_round(aes_cipher_state_t* state, const aes_roundkey_t* k){
- uint8_t tmp[16];
- uint8_t i;
- uint8_t t,u,v,w;
- /* keyAdd */
- for(i=0; i<16; ++i){
- tmp[i] = state->s[i] ^ k->ks[i];
- }
- /* mixColums */
- for(i=0; i<4; ++i){
- t = tmp[4*i+3] ^ tmp[4*i+2];
- u = tmp[4*i+1] ^ tmp[4*i+0];
- v = t ^ u;
- v = gf256mul(0x09, v, 0x1b);
- w = v ^ gf256mul(0x04, tmp[4*i+2] ^ tmp[4*i+0], 0x1b);
- v = v ^ gf256mul(0x04, tmp[4*i+3] ^ tmp[4*i+1], 0x1b);
- state->s[4*i+3] = tmp[4*i+3] ^ v ^ gf256mul(0x02, tmp[4*i+0] ^ tmp[4*i+3], 0x1b);
- state->s[4*i+2] = tmp[4*i+2] ^ w ^ gf256mul(0x02, t, 0x1b);
- state->s[4*i+1] = tmp[4*i+1] ^ v ^ gf256mul(0x02, tmp[4*i+2] ^ tmp[4*i+1], 0x1b);
- state->s[4*i+0] = tmp[4*i+0] ^ w ^ gf256mul(0x02, u, 0x1b);
-
- /*
- state->s[4*i+0] =
- gf256mul(0xe, tmp[4*i+0], 0x1b)
- ^ gf256mul(0xb, tmp[4*i+1], 0x1b)
- ^ gf256mul(0xd, tmp[4*i+2], 0x1b)
- ^ gf256mul(0x9, tmp[4*i+3], 0x1b);
- state->s[4*i+1] =
- gf256mul(0x9, tmp[4*i+0], 0x1b)
- ^ gf256mul(0xe, tmp[4*i+1], 0x1b)
- ^ gf256mul(0xb, tmp[4*i+2], 0x1b)
- ^ gf256mul(0xd, tmp[4*i+3], 0x1b);
- state->s[4*i+2] =
- gf256mul(0xd, tmp[4*i+0], 0x1b)
- ^ gf256mul(0x9, tmp[4*i+1], 0x1b)
- ^ gf256mul(0xe, tmp[4*i+2], 0x1b)
- ^ gf256mul(0xb, tmp[4*i+3], 0x1b);
- state->s[4*i+3] =
- gf256mul(0xb, tmp[4*i+0], 0x1b)
- ^ gf256mul(0xd, tmp[4*i+1], 0x1b)
- ^ gf256mul(0x9, tmp[4*i+2], 0x1b)
- ^ gf256mul(0xe, tmp[4*i+3], 0x1b);
- */
- }
- /* shiftRows */
- aes_invshiftcol(state->s+1, 1);
- aes_invshiftcol(state->s+2, 2);
- aes_invshiftcol(state->s+3, 3);
- /* subBytes */
- for(i=0; i<16; ++i){
- state->s[i] = pgm_read_byte(aes_invsbox+state->s[i]);
- }
-}
-
-
-static
-void aes_dec_firstround(aes_cipher_state_t* state, const aes_roundkey_t* k){
- uint8_t i;
- /* keyAdd */
- for(i=0; i<16; ++i){
- state->s[i] ^= k->ks[i];
- }
- /* shiftRows */
- aes_invshiftcol(state->s+1, 1);
- aes_invshiftcol(state->s+2, 2);
- aes_invshiftcol(state->s+3, 3);
- /* subBytes */
- for(i=0; i<16; ++i){
- state->s[i] = pgm_read_byte(aes_invsbox+state->s[i]);
- }
-}
-
-void aes_decrypt_core(aes_cipher_state_t* state, const aes_genctx_t* ks, uint8_t rounds){
- uint8_t i;
- aes_dec_firstround(state, &(ks->key[i=rounds]));
- for(;rounds>1;--rounds){
- --i;
- aes_dec_round(state, &(ks->key[i]));
- }
- for(i=0; i<16; ++i){
- state->s[i] ^= ks->key[0].ks[i];
- }
-}