/* aes.c */
/*
- This file is part of the Crypto-avr-lib/microcrypt-lib.
+ 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
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+1], 0x1b)
^ gf256mul(0x9, tmp[4*i+2], 0x1b)
^ gf256mul(0xe, tmp[4*i+3], 0x1b);
+ */
}
/* shiftRows */
aes_invshiftcol(state->s+1, 1);