encrypt.c

/*
 *
 * University of Luxembourg
 * Laboratory of Algorithmics, Cryptology and Security (LACS)
 *
 * FELICS - Fair Evaluation of Lightweight Cryptographic Systems
 *
 * Copyright (C) 2015 University of Luxembourg
 *
 * Written in 2015 by Daniel Dinu <dumitru-daniel.dinu@uni.lu>
 *
 * This file is part of FELICS.
 *
 * FELICS 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.
 *
 * FELICS 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/>.
 *
 */

#include <stdint.h>

#include "cipher.h"
#include "constants.h"

void Encrypt(uint8_t *block, uint8_t *roundKeys)
{
	uint32_t *block32 = (uint32_t*)block;
	uint32_t *roundKeys32 = (uint32_t*)roundKeys;

	uint16_t w0, w1, w2, w3;
	uint16_t sbox0, sbox1;
	int8_t i;
	
	for (i = NUMBER_OF_ROUNDS; i > 0 ; i--) {
		/* AddRoundKey */
		block32[0] ^= roundKeys32[0];
		block32[1] ^= roundKeys32[1];
		roundKeys32 += 2;
		
		/* Change to 16 bits */
		w0 = (uint16_t)block32[0];
		w1 = (uint16_t)(block32[0]>>16);
		w2 = (uint16_t)block32[1];
		w3 = (uint16_t)(block32[1]>>16);

		/* SubColumn */	
		sbox1 = ~w1;
		sbox0 = sbox1 | w3;
		sbox0 ^= w0;
		w0 &= sbox1;
		sbox1 = w2 ^ w3;
		w0 ^= sbox1;
		w3 = w1 ^ w2;
		w1 = w2 ^ sbox0;
		sbox1 &= sbox0;
		w3 ^= sbox1;
		w2 = w0 | w3;
		w2 ^= sbox0;

		/* ShiftRow */
		w1 = (w1<<1  | w1 >> 15);
		w2 = (w2<<12 | w2 >> 4);
		w3 = (w3<<13 | w3 >> 3);

		/* Back to 32 bits */
		block32[0] = w0 | (w1 << 16);
		block32[1] = w2 | (w3 << 16);
	}

	/* Last Round Add Key */
	block32[0] ^= roundKeys32[0];
	block32[1] ^= roundKeys32[1];
}