a first look at aes assembly

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

diff --git a/aes_keyschedule.c b/aes_keyschedule.c
index d53c406cf27e48e798ea940f2d0da56f1a00ccc8..cd92c9ccbb57b1c779135d497e11f2cd01031328 100644 (file)
--- a/aes_keyschedule.c
+++ b/aes_keyschedule.c
@@ -1,7 +1,7 @@
 /* aes_keyschedule.c */
 /*
     This file is part of the Crypto-avr-lib/microcrypt-lib.
-    Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
+    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
@@ -26,7 +26,6 @@
  */
 
 #include <stdint.h>
-#include "gf256mul.h"
 #include "aes.h"
 #include "aes_keyschedule.h"
 #include "aes_sbox.h"
@@ -43,9 +42,13 @@ void aes_rotword(void* a){
        ((uint8_t*)a)[3] = t;
 }
 
+uint8_t rc_tab[] PROGMEM = { 0x01, 0x02, 0x04, 0x08,
+                             0x10, 0x20, 0x40, 0x80,
+                             0x1b, 0x36 };
+
 void aes_init(const void* key, uint16_t keysize_b, aes_genctx_t* ctx){
        uint8_t hi,i,nk, next_nk;
-       uint8_t rc=1;
+       uint8_t rc=0;
        uint8_t tmp[4];
        nk=keysize_b>>5; /* 4, 6, 8 */
        hi=4*(nk+6+1);
@@ -67,8 +70,8 @@ void aes_init(const void* key, uint16_t keysize_b, aes_genctx_t* ctx){
                        tmp[1] = pgm_read_byte(aes_sbox+tmp[1]);
                        tmp[2] = pgm_read_byte(aes_sbox+tmp[2]);
                        tmp[3] = pgm_read_byte(aes_sbox+tmp[3]);
-                       tmp[0] ^= rc;
-                       rc = gf256mul(2,rc,0x1b);
+                       tmp[0] ^= pgm_read_byte(rc_tab+rc);
+                       rc++;
                }
                ((uint32_t*)(ctx->key[0].ks))[i] = ((uint32_t*)(ctx->key[0].ks))[i-nk]
                                                   ^ *((uint32_t*)tmp);