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/*
* An 32-bit implementation of the XTEA algorithm
*
* Copyright (C) 2006-2010, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* 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 program 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "polarssl/config.h"
#if defined(POLARSSL_XTEA_C)
#include "polarssl/xtea.h"
/*
* 32-bit integer manipulation macros (big endian)
*/
#ifndef GET_ULONG_BE
#define GET_ULONG_BE(n,b,i) \
{ \
(n) = ( (unsigned long) (b)[(i) ] << 24 ) \
| ( (unsigned long) (b)[(i) + 1] << 16 ) \
| ( (unsigned long) (b)[(i) + 2] << 8 ) \
| ( (unsigned long) (b)[(i) + 3] ); \
}
#endif
#ifndef PUT_ULONG_BE
#define PUT_ULONG_BE(n,b,i) \
{ \
(b)[(i) ] = (unsigned char) ( (n) >> 24 ); \
(b)[(i) + 1] = (unsigned char) ( (n) >> 16 ); \
(b)[(i) + 2] = (unsigned char) ( (n) >> 8 ); \
(b)[(i) + 3] = (unsigned char) ( (n) ); \
}
#endif
/*
* XTEA key schedule
*/
void xtea_setup( xtea_context *ctx, unsigned char key[16] )
{
int i;
memset(ctx, 0, sizeof(xtea_context));
for( i = 0; i < 4; i++ )
{
GET_ULONG_BE( ctx->k[i], key, i << 2 );
}
}
/*
* XTEA encrypt function
*/
int xtea_crypt_ecb( xtea_context *ctx, int mode, unsigned char input[8],
unsigned char output[8])
{
uint32_t *k, v0, v1, i;
k = ctx->k;
GET_ULONG_BE( v0, input, 0 );
GET_ULONG_BE( v1, input, 4 );
if( mode == XTEA_ENCRYPT )
{
uint32_t sum = 0, delta = 0x9E3779B9;
for( i = 0; i < 32; i++ )
{
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
}
}
else /* XTEA_DECRYPT */
{
uint32_t delta = 0x9E3779B9, sum = delta * 32;
for( i = 0; i < 32; i++ )
{
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
}
}
PUT_ULONG_BE( v0, output, 0 );
PUT_ULONG_BE( v1, output, 4 );
return( 0 );
}
/*
* XTEA-CBC buffer encryption/decryption
*/
int xtea_crypt_cbc( xtea_context *ctx,
int mode,
size_t length,
unsigned char iv[8],
unsigned char *input,
unsigned char *output)
{
int i;
unsigned char temp[8];
if(length % 8)
return( POLARSSL_ERR_XTEA_INVALID_INPUT_LENGTH );
if( mode == XTEA_DECRYPT )
{
while( length > 0 )
{
memcpy( temp, input, 8 );
xtea_crypt_ecb( ctx, mode, input, output );
for(i = 0; i < 8; i++)
output[i] = (unsigned char)( output[i] ^ iv[i] );
memcpy( iv, temp, 8 );
input += 8;
output += 8;
length -= 8;
}
}
else
{
while( length > 0 )
{
for( i = 0; i < 8; i++ )
output[i] = (unsigned char)( input[i] ^ iv[i] );
xtea_crypt_ecb( ctx, mode, output, output );
memcpy( iv, output, 8 );
input += 8;
output += 8;
length -= 8;
}
}
return( 0 );
}
#if defined(POLARSSL_SELF_TEST)
#include <string.h>
#include <stdio.h>
/*
* XTEA tests vectors (non-official)
*/
static const unsigned char xtea_test_key[6][16] =
{
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
0x0c, 0x0d, 0x0e, 0x0f },
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
0x0c, 0x0d, 0x0e, 0x0f },
{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
0x0c, 0x0d, 0x0e, 0x0f },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00 },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00 },
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00 }
};
static const unsigned char xtea_test_pt[6][8] =
{
{ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
{ 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
{ 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
{ 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
};
static const unsigned char xtea_test_ct[6][8] =
{
{ 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
{ 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
{ 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
{ 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
{ 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
};
/*
* Checkup routine
*/
int xtea_self_test( int verbose )
{
int i;
unsigned char buf[8];
xtea_context ctx;
for( i = 0; i < 6; i++ )
{
if( verbose != 0 )
printf( " XTEA test #%d: ", i + 1 );
memcpy( buf, xtea_test_pt[i], 8 );
xtea_setup( &ctx, (unsigned char *) xtea_test_key[i] );
xtea_crypt_ecb( &ctx, XTEA_ENCRYPT, buf, buf );
if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
{
if( verbose != 0 )
printf( "failed\n" );
return( 1 );
}
if( verbose != 0 )
printf( "passed\n" );
}
if( verbose != 0 )
printf( "\n" );
return( 0 );
}
#endif
#endif
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