big bug fixed, still some problems with flow control

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

diff --git a/aes_enc.c b/aes_enc.c
index 7932e528d48218511191ee51cbf024a9b8c19798..dadf9f45a63d7d875e2bde7441a8741469392278 100644 (file)
--- a/aes_enc.c
+++ b/aes_enc.c
@@ -1,6 +1,6 @@
 /* aes_enc.c */
 /*
-    This file is part of the Crypto-avr-lib/microcrypt-lib.
+    This file is part of the AVR-Crypto-Lib.
     Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
 
     This program is free software: you can redistribute it and/or modify
@@ -33,14 +33,16 @@
 #include "aes_enc.h"
 #include <avr/pgmspace.h>
 
-
-void aes_shiftrow(void* data, uint8_t shift){
+void aes_shiftcol(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);
+       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[(shift+0)&3];
+       ((uint8_t*)data)[ 4] = tmp[(shift+1)&3];
+       ((uint8_t*)data)[ 8] = tmp[(shift+2)&3];
+       ((uint8_t*)data)[12] = tmp[(shift+3)&3];
 }
 
 #define GF256MUL_1(a) (a)
@@ -49,38 +51,35 @@ void aes_shiftrow(void* data, uint8_t shift){
 
 static
 void aes_enc_round(aes_cipher_state_t* state, const aes_roundkey_t* k){
-       uint8_t tmp[16];
+       uint8_t tmp[16], t;
        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);
+       aes_shiftcol(tmp+1, 1);
+       aes_shiftcol(tmp+2, 2);
+       aes_shiftcol(tmp+3, 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]);               
+               t = tmp[4*i+0] ^ tmp[4*i+1] ^ tmp[4*i+2] ^ tmp[4*i+3];
+               state->s[4*i+0] =
+                         GF256MUL_2(tmp[4*i+0]^tmp[4*i+1])
+                       ^ tmp[4*i+0]
+                       ^ t;
+               state->s[4*i+1] =
+                         GF256MUL_2(tmp[4*i+1]^tmp[4*i+2])
+                       ^ tmp[4*i+1]
+                       ^ t;
+               state->s[4*i+2] =
+                         GF256MUL_2(tmp[4*i+2]^tmp[4*i+3])
+                       ^ tmp[4*i+2]
+                       ^ t;
+               state->s[4*i+3] =
+                         GF256MUL_2(tmp[4*i+3]^tmp[4*i+0])
+                       ^ tmp[4*i+3]
+                       ^ t;
        }
 
        /* addKey */
@@ -98,9 +97,9 @@ void aes_enc_lastround(aes_cipher_state_t* state,const aes_roundkey_t* k){
                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);
+       aes_shiftcol(state->s+1, 1);
+       aes_shiftcol(state->s+2, 2);
+       aes_shiftcol(state->s+3, 3);
        /* keyAdd */
        for(i=0; i<16; ++i){
                state->s[i] ^= k->ks[i];