1 /* aes_keyschedule.c */
3 This file is part of the AVR-Crypto-Lib.
4 Copyright (C) 2008, 2009 Daniel Otte (daniel.otte@rub.de)
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 * \file aes_keyschedule.c
21 * \email daniel.otte@rub.de
24 * \license GPLv3 or later
30 #include "aes_keyschedule.h"
33 #include <avr/pgmspace.h>
36 void aes_rotword(void* a){
39 ((uint8_t*)a)[0] = ((uint8_t*)a)[1];
40 ((uint8_t*)a)[1] = ((uint8_t*)a)[2];
41 ((uint8_t*)a)[2] = ((uint8_t*)a)[3];
45 const uint8_t rc_tab[] PROGMEM = { 0x01, 0x02, 0x04, 0x08,
46 0x10, 0x20, 0x40, 0x80,
49 void aes_init(const void* key, uint16_t keysize_b, aes_genctx_t* ctx){
50 uint8_t hi,i,nk, next_nk;
56 nk=keysize_b>>5; /* 4, 6, 8 */
58 memcpy(ctx, key, keysize_b/8);
61 tmp.v32 = ((uint32_t*)(ctx->key[0].ks))[i-1];
64 tmp.v8[0] = pgm_read_byte(aes_sbox+tmp.v8[0]);
65 tmp.v8[1] = pgm_read_byte(aes_sbox+tmp.v8[1]);
66 tmp.v8[2] = pgm_read_byte(aes_sbox+tmp.v8[2]);
67 tmp.v8[3] = pgm_read_byte(aes_sbox+tmp.v8[3]);
71 aes_rotword(&(tmp.v32));
72 tmp.v8[0] = pgm_read_byte(aes_sbox+tmp.v8[0]);
73 tmp.v8[1] = pgm_read_byte(aes_sbox+tmp.v8[1]);
74 tmp.v8[2] = pgm_read_byte(aes_sbox+tmp.v8[2]);
75 tmp.v8[3] = pgm_read_byte(aes_sbox+tmp.v8[3]);
76 tmp.v8[0] ^= pgm_read_byte(rc_tab+rc);
79 ((uint32_t*)(ctx->key[0].ks))[i] = ((uint32_t*)(ctx->key[0].ks))[i-nk]
84 void aes128_init(const void* key, aes128_ctx_t* ctx){
85 aes_init(key, 128, (aes_genctx_t*)ctx);
88 void aes192_init(const void* key, aes192_ctx_t* ctx){
89 aes_init(key, 192, (aes_genctx_t*)ctx);
92 void aes256_init(const void* key, aes256_ctx_t* ctx){
93 aes_init(key, 256, (aes_genctx_t*)ctx);