PolarSSL v1.2.9
xtea.c
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1 /*
2  * An 32-bit implementation of the XTEA algorithm
3  *
4  * Copyright (C) 2006-2013, Brainspark B.V.
5  *
6  * This file is part of PolarSSL (http://www.polarssl.org)
7  * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
8  *
9  * All rights reserved.
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License along
22  * with this program; if not, write to the Free Software Foundation, Inc.,
23  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24  */
25 
26 #include "polarssl/config.h"
27 
28 #if defined(POLARSSL_XTEA_C)
29 
30 #include "polarssl/xtea.h"
31 
32 #if !defined(POLARSSL_XTEA_ALT)
33 
34 /*
35  * 32-bit integer manipulation macros (big endian)
36  */
37 #ifndef GET_UINT32_BE
38 #define GET_UINT32_BE(n,b,i) \
39 { \
40  (n) = ( (uint32_t) (b)[(i) ] << 24 ) \
41  | ( (uint32_t) (b)[(i) + 1] << 16 ) \
42  | ( (uint32_t) (b)[(i) + 2] << 8 ) \
43  | ( (uint32_t) (b)[(i) + 3] ); \
44 }
45 #endif
46 
47 #ifndef PUT_UINT32_BE
48 #define PUT_UINT32_BE(n,b,i) \
49 { \
50  (b)[(i) ] = (unsigned char) ( (n) >> 24 ); \
51  (b)[(i) + 1] = (unsigned char) ( (n) >> 16 ); \
52  (b)[(i) + 2] = (unsigned char) ( (n) >> 8 ); \
53  (b)[(i) + 3] = (unsigned char) ( (n) ); \
54 }
55 #endif
56 
57 /*
58  * XTEA key schedule
59  */
60 void xtea_setup( xtea_context *ctx, unsigned char key[16] )
61 {
62  int i;
63 
64  memset(ctx, 0, sizeof(xtea_context));
65 
66  for( i = 0; i < 4; i++ )
67  {
68  GET_UINT32_BE( ctx->k[i], key, i << 2 );
69  }
70 }
71 
72 /*
73  * XTEA encrypt function
74  */
75 int xtea_crypt_ecb( xtea_context *ctx, int mode, unsigned char input[8],
76  unsigned char output[8])
77 {
78  uint32_t *k, v0, v1, i;
79 
80  k = ctx->k;
81 
82  GET_UINT32_BE( v0, input, 0 );
83  GET_UINT32_BE( v1, input, 4 );
84 
85  if( mode == XTEA_ENCRYPT )
86  {
87  uint32_t sum = 0, delta = 0x9E3779B9;
88 
89  for( i = 0; i < 32; i++ )
90  {
91  v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
92  sum += delta;
93  v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
94  }
95  }
96  else /* XTEA_DECRYPT */
97  {
98  uint32_t delta = 0x9E3779B9, sum = delta * 32;
99 
100  for( i = 0; i < 32; i++ )
101  {
102  v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
103  sum -= delta;
104  v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
105  }
106  }
107 
108  PUT_UINT32_BE( v0, output, 0 );
109  PUT_UINT32_BE( v1, output, 4 );
110 
111  return( 0 );
112 }
113 
114 /*
115  * XTEA-CBC buffer encryption/decryption
116  */
117 int xtea_crypt_cbc( xtea_context *ctx,
118  int mode,
119  size_t length,
120  unsigned char iv[8],
121  unsigned char *input,
122  unsigned char *output)
123 {
124  int i;
125  unsigned char temp[8];
126 
127  if(length % 8)
129 
130  if( mode == XTEA_DECRYPT )
131  {
132  while( length > 0 )
133  {
134  memcpy( temp, input, 8 );
135  xtea_crypt_ecb( ctx, mode, input, output );
136 
137  for(i = 0; i < 8; i++)
138  output[i] = (unsigned char)( output[i] ^ iv[i] );
139 
140  memcpy( iv, temp, 8 );
141 
142  input += 8;
143  output += 8;
144  length -= 8;
145  }
146  }
147  else
148  {
149  while( length > 0 )
150  {
151  for( i = 0; i < 8; i++ )
152  output[i] = (unsigned char)( input[i] ^ iv[i] );
153 
154  xtea_crypt_ecb( ctx, mode, output, output );
155  memcpy( iv, output, 8 );
156 
157  input += 8;
158  output += 8;
159  length -= 8;
160  }
161  }
162 
163  return( 0 );
164 }
165 #endif /* !POLARSSL_XTEA_ALT */
166 
167 #if defined(POLARSSL_SELF_TEST)
168 
169 #include <string.h>
170 #include <stdio.h>
171 
172 /*
173  * XTEA tests vectors (non-official)
174  */
175 
176 static const unsigned char xtea_test_key[6][16] =
177 {
178  { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
179  0x0c, 0x0d, 0x0e, 0x0f },
180  { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
181  0x0c, 0x0d, 0x0e, 0x0f },
182  { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
183  0x0c, 0x0d, 0x0e, 0x0f },
184  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
185  0x00, 0x00, 0x00, 0x00 },
186  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
187  0x00, 0x00, 0x00, 0x00 },
188  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
189  0x00, 0x00, 0x00, 0x00 }
190 };
191 
192 static const unsigned char xtea_test_pt[6][8] =
193 {
194  { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
195  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
196  { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
197  { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
198  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
199  { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
200 };
201 
202 static const unsigned char xtea_test_ct[6][8] =
203 {
204  { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
205  { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
206  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
207  { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
208  { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
209  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
210 };
211 
212 /*
213  * Checkup routine
214  */
215 int xtea_self_test( int verbose )
216 {
217  int i;
218  unsigned char buf[8];
219  xtea_context ctx;
220 
221  for( i = 0; i < 6; i++ )
222  {
223  if( verbose != 0 )
224  printf( " XTEA test #%d: ", i + 1 );
225 
226  memcpy( buf, xtea_test_pt[i], 8 );
227 
228  xtea_setup( &ctx, (unsigned char *) xtea_test_key[i] );
229  xtea_crypt_ecb( &ctx, XTEA_ENCRYPT, buf, buf );
230 
231  if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
232  {
233  if( verbose != 0 )
234  printf( "failed\n" );
235 
236  return( 1 );
237  }
238 
239  if( verbose != 0 )
240  printf( "passed\n" );
241  }
242 
243  if( verbose != 0 )
244  printf( "\n" );
245 
246  return( 0 );
247 }
248 
249 #endif
250 
251 #endif