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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2012 Amaury Pouly
*
* 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 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "crypto.h"
#include <stdlib.h>
#include "misc.h"
static uint32_t do_round(union xorcrypt_key_t *key)
{
uint32_t k7 = key->k[7];
uint32_t k2 = key->k[2];
uint32_t k5_3_1 = key->k[5] ^ key->k[3] ^ key->k[1];
key->k[1] = k2;
uint32_t k_11_7_5_3_1 = key->k[11] ^ k7 ^ k5_3_1;
key->k[2] = key->k[3] ^ k2;
key->k[3] = key->k[4];
key->k[4] = key->k[5];
key->k[5] = key->k[6];
uint32_t k0 = key->k[0];
key->k[7] = k7 ^ key->k[8];
uint32_t k13 = key->k[13];
key->k[8] = key->k[9];
uint32_t k10 = key->k[10];
key->k[6] = k7;
key->k[9] = k10;
uint32_t k11 = key->k[11];
key->k[0] = k0 ^ k13 ^ k_11_7_5_3_1;
key->k[10] = (k11 >> 1) | (k11 << 31);
uint32_t k11_12 = k11 ^ key->k[12];
uint32_t k14 = key->k[14];
key->k[12] = k13;
key->k[13] = k14;
uint32_t k15 = key->k[15];
key->k[15] = k0;
key->k[11] = k11_12;
key->k[14] = k15;
return key->k[0];
}
uint32_t xor_encrypt(union xorcrypt_key_t keys[2], void *_data, int size)
{
if(size % 4)
bugp("xor_encrypt: size is not a multiple of 4 !\n");
size /= 4;
uint32_t *data = _data;
uint32_t final_xor = 0;
for(int i = 0; i < size; i += 4)
{
uint32_t x = do_round(&keys[1]);
/* xor first key's first word with data (at most 4 words of data) */
for(int j = i; j < i + 4 && j < size; j++)
{
keys[0].k[0] ^= data[j];
data[j] ^= x;
}
final_xor = do_round(&keys[0]);
}
return final_xor ^ do_round(&keys[1]);
}
uint32_t xor_decrypt(union xorcrypt_key_t keys[2], void *_data, int size)
{
if(size % 4)
bugp("xor_decrypt: size is not a multiple of 4 !\n");
size /= 4;
uint32_t *data = _data;
uint32_t final_xor = 0;
for(int i = 0; i < size; i += 4)
{
uint32_t x = do_round(&keys[1]);
/* xor first key's first word with data (at most 4 words of data) */
for(int j = i; j < i + 4 && j < size; j++)
{
data[j] ^= x;
keys[0].k[0] ^= data[j];
}
final_xor = do_round(&keys[0]);
}
return final_xor ^ do_round(&keys[1]);
}
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