new AES in C, happy new year

[avr-crypto-lib.git] / aes_enc.c

diff --git a/aes_enc.c b/aes_enc.c
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+/* aes_enc.c */
+/*
+    This file is part of the Crypto-avr-lib/microcrypt-lib.
+    Copyright (C) 2008  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/>.
+*/
+/**
+ * \file     aes_enc.c
+ * \email    daniel.otte@rub.de
+ * \author   Daniel Otte 
+ * \date     2008-12-30
+ * \license  GPLv3 or later
+ * 
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include "aes.h"
+#include "gf256mul.h"
+#include "aes_sbox.h"
+#include "aes_enc.h"
+#include <avr/pgmspace.h>
+
+
+void aes_shiftrow(void* data, uint8_t shift){
+       uint8_t tmp[4];
+       tmp[0] = ((uint8_t*)data)[(0+shift)&3];
+       tmp[1] = ((uint8_t*)data)[(1+shift)&3];
+       tmp[2] = ((uint8_t*)data)[(2+shift)&3];
+       tmp[3] = ((uint8_t*)data)[(3+shift)&3];
+       memcpy(data, tmp, 4);
+}
+
+#define GF256MUL_1(a) (a)
+#define GF256MUL_2(a) (gf256mul(2, (a), 0x1b))
+#define GF256MUL_3(a) (gf256mul(3, (a), 0x1b))
+
+
+
+static
+void aes_enc_round(aes_cipher_state_t* state, const aes_roundkey_t* k){
+       uint8_t tmp[16];
+       uint8_t i;
+       /* subBytes */
+       for(i=0; i<16; ++i){
+               tmp[i] = pgm_read_byte(aes_sbox+state->s[i]);
+       }
+       /* shiftRows */
+       aes_shiftrow(tmp+4, 1);
+       aes_shiftrow(tmp+8, 2);
+       aes_shiftrow(tmp+12, 3);
+       /* mixColums */
+       for(i=0; i<4; ++i){
+               state->s[4*0+i] =
+                         GF256MUL_2(tmp[4*0+i])
+                       ^ GF256MUL_3(tmp[4*1+i])
+                       ^ GF256MUL_1(tmp[4*2+i])
+                       ^ GF256MUL_1(tmp[4*3+i]);
+               state->s[4*1+i] =
+                         GF256MUL_1(tmp[4*0+i])
+                       ^ GF256MUL_2(tmp[4*1+i])
+                       ^ GF256MUL_3(tmp[4*2+i])
+                       ^ GF256MUL_1(tmp[4*3+i]);
+               state->s[4*2+i] =
+                         GF256MUL_1(tmp[4*0+i])
+                       ^ GF256MUL_1(tmp[4*1+i])
+                       ^ GF256MUL_2(tmp[4*2+i])
+                       ^ GF256MUL_3(tmp[4*3+i]);
+               state->s[4*3+i] =
+                         GF256MUL_3(tmp[4*0+i])
+                       ^ GF256MUL_1(tmp[4*1+i])
+                       ^ GF256MUL_1(tmp[4*2+i])
+                       ^ GF256MUL_2(tmp[4*3+i]);               
+       }
+
+       /* addKey */
+       for(i=0; i<16; ++i){
+               state->s[i] ^= k->ks[i];
+       }
+}
+
+
+static
+void aes_enc_lastround(aes_cipher_state_t* state,const aes_roundkey_t* k){
+       uint8_t i;
+       /* subBytes */
+       for(i=0; i<16; ++i){
+               state->s[i] = pgm_read_byte(aes_sbox+state->s[i]);
+       }
+       /* shiftRows */
+       aes_shiftrow(state->s+4, 1);
+       aes_shiftrow(state->s+8, 2);
+       aes_shiftrow(state->s+12, 3);
+       /* keyAdd */
+       for(i=0; i<16; ++i){
+               state->s[i] ^= k->ks[i];
+       }
+}
+
+void aes_encrypt_core(aes_cipher_state_t* state, const aes_genctx_t* ks, uint8_t rounds){
+       uint8_t i;
+       for(i=0; i<16; ++i){
+               state->s[i] ^= ks->key[0].ks[i];
+       }
+       i=1;
+       for(;rounds>1;--rounds){
+               aes_enc_round(state, &(ks->key[i]));
+               ++i;
+       }
+       aes_enc_lastround(state, &(ks->key[i]));
+}