1 /*
2 * An 32-bit implementation of the XTEA algorithm
3 *
4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 * This file is part of mbed TLS (https://tls.mbed.org)
20 */
21
22 #if !defined(MBEDTLS_CONFIG_FILE)
23 #include "mbedtls/config.h"
24 #else
25 #include MBEDTLS_CONFIG_FILE
26 #endif
27
28 #if defined(MBEDTLS_XTEA_C)
29
30 #include "mbedtls/xtea.h"
31 #include "mbedtls/platform_util.h"
32
33 #include <string.h>
34
35 #if defined(MBEDTLS_SELF_TEST)
36 #if defined(MBEDTLS_PLATFORM_C)
37 #include "mbedtls/platform.h"
38 #else
39 #include <stdio.h>
40 #define mbedtls_printf printf
41 #endif /* MBEDTLS_PLATFORM_C */
42 #endif /* MBEDTLS_SELF_TEST */
43
44 #if !defined(MBEDTLS_XTEA_ALT)
45
46 /*
47 * 32-bit integer manipulation macros (big endian)
48 */
49 #ifndef GET_UINT32_BE
50 #define GET_UINT32_BE(n,b,i) \
51 { \
52 (n) = ( (uint32_t) (b)[(i) ] << 24 ) \
53 | ( (uint32_t) (b)[(i) + 1] << 16 ) \
54 | ( (uint32_t) (b)[(i) + 2] << 8 ) \
55 | ( (uint32_t) (b)[(i) + 3] ); \
56 }
57 #endif
58
59 #ifndef PUT_UINT32_BE
60 #define PUT_UINT32_BE(n,b,i) \
61 { \
62 (b)[(i) ] = (unsigned char) ( (n) >> 24 ); \
63 (b)[(i) + 1] = (unsigned char) ( (n) >> 16 ); \
64 (b)[(i) + 2] = (unsigned char) ( (n) >> 8 ); \
65 (b)[(i) + 3] = (unsigned char) ( (n) ); \
66 }
67 #endif
68
mbedtls_xtea_init(mbedtls_xtea_context * ctx)69 void mbedtls_xtea_init( mbedtls_xtea_context *ctx )
70 {
71 memset( ctx, 0, sizeof( mbedtls_xtea_context ) );
72 }
73
mbedtls_xtea_free(mbedtls_xtea_context * ctx)74 void mbedtls_xtea_free( mbedtls_xtea_context *ctx )
75 {
76 if( ctx == NULL )
77 return;
78
79 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_xtea_context ) );
80 }
81
82 /*
83 * XTEA key schedule
84 */
mbedtls_xtea_setup(mbedtls_xtea_context * ctx,const unsigned char key[16])85 void mbedtls_xtea_setup( mbedtls_xtea_context *ctx, const unsigned char key[16] )
86 {
87 int i;
88
89 memset( ctx, 0, sizeof(mbedtls_xtea_context) );
90
91 for( i = 0; i < 4; i++ )
92 {
93 GET_UINT32_BE( ctx->k[i], key, i << 2 );
94 }
95 }
96
97 /*
98 * XTEA encrypt function
99 */
mbedtls_xtea_crypt_ecb(mbedtls_xtea_context * ctx,int mode,const unsigned char input[8],unsigned char output[8])100 int mbedtls_xtea_crypt_ecb( mbedtls_xtea_context *ctx, int mode,
101 const unsigned char input[8], unsigned char output[8])
102 {
103 uint32_t *k, v0, v1, i;
104
105 k = ctx->k;
106
107 GET_UINT32_BE( v0, input, 0 );
108 GET_UINT32_BE( v1, input, 4 );
109
110 if( mode == MBEDTLS_XTEA_ENCRYPT )
111 {
112 uint32_t sum = 0, delta = 0x9E3779B9;
113
114 for( i = 0; i < 32; i++ )
115 {
116 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
117 sum += delta;
118 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
119 }
120 }
121 else /* MBEDTLS_XTEA_DECRYPT */
122 {
123 uint32_t delta = 0x9E3779B9, sum = delta * 32;
124
125 for( i = 0; i < 32; i++ )
126 {
127 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
128 sum -= delta;
129 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
130 }
131 }
132
133 PUT_UINT32_BE( v0, output, 0 );
134 PUT_UINT32_BE( v1, output, 4 );
135
136 return( 0 );
137 }
138
139 #if defined(MBEDTLS_CIPHER_MODE_CBC)
140 /*
141 * XTEA-CBC buffer encryption/decryption
142 */
mbedtls_xtea_crypt_cbc(mbedtls_xtea_context * ctx,int mode,size_t length,unsigned char iv[8],const unsigned char * input,unsigned char * output)143 int mbedtls_xtea_crypt_cbc( mbedtls_xtea_context *ctx, int mode, size_t length,
144 unsigned char iv[8], const unsigned char *input,
145 unsigned char *output)
146 {
147 int i;
148 unsigned char temp[8];
149
150 if( length % 8 )
151 return( MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH );
152
153 if( mode == MBEDTLS_XTEA_DECRYPT )
154 {
155 while( length > 0 )
156 {
157 memcpy( temp, input, 8 );
158 mbedtls_xtea_crypt_ecb( ctx, mode, input, output );
159
160 for( i = 0; i < 8; i++ )
161 output[i] = (unsigned char)( output[i] ^ iv[i] );
162
163 memcpy( iv, temp, 8 );
164
165 input += 8;
166 output += 8;
167 length -= 8;
168 }
169 }
170 else
171 {
172 while( length > 0 )
173 {
174 for( i = 0; i < 8; i++ )
175 output[i] = (unsigned char)( input[i] ^ iv[i] );
176
177 mbedtls_xtea_crypt_ecb( ctx, mode, output, output );
178 memcpy( iv, output, 8 );
179
180 input += 8;
181 output += 8;
182 length -= 8;
183 }
184 }
185
186 return( 0 );
187 }
188 #endif /* MBEDTLS_CIPHER_MODE_CBC */
189 #endif /* !MBEDTLS_XTEA_ALT */
190
191 #if defined(MBEDTLS_SELF_TEST)
192
193 /*
194 * XTEA tests vectors (non-official)
195 */
196
197 static const unsigned char xtea_test_key[6][16] =
198 {
199 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
200 0x0c, 0x0d, 0x0e, 0x0f },
201 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
202 0x0c, 0x0d, 0x0e, 0x0f },
203 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
204 0x0c, 0x0d, 0x0e, 0x0f },
205 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
206 0x00, 0x00, 0x00, 0x00 },
207 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
208 0x00, 0x00, 0x00, 0x00 },
209 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
210 0x00, 0x00, 0x00, 0x00 }
211 };
212
213 static const unsigned char xtea_test_pt[6][8] =
214 {
215 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
216 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
217 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
218 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
219 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
220 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
221 };
222
223 static const unsigned char xtea_test_ct[6][8] =
224 {
225 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
226 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
227 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
228 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
229 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
230 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
231 };
232
233 /*
234 * Checkup routine
235 */
mbedtls_xtea_self_test(int verbose)236 int mbedtls_xtea_self_test( int verbose )
237 {
238 int i, ret = 0;
239 unsigned char buf[8];
240 mbedtls_xtea_context ctx;
241
242 mbedtls_xtea_init( &ctx );
243 for( i = 0; i < 6; i++ )
244 {
245 if( verbose != 0 )
246 mbedtls_printf( " XTEA test #%d: ", i + 1 );
247
248 memcpy( buf, xtea_test_pt[i], 8 );
249
250 mbedtls_xtea_setup( &ctx, xtea_test_key[i] );
251 mbedtls_xtea_crypt_ecb( &ctx, MBEDTLS_XTEA_ENCRYPT, buf, buf );
252
253 if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
254 {
255 if( verbose != 0 )
256 mbedtls_printf( "failed\n" );
257
258 ret = 1;
259 goto exit;
260 }
261
262 if( verbose != 0 )
263 mbedtls_printf( "passed\n" );
264 }
265
266 if( verbose != 0 )
267 mbedtls_printf( "\n" );
268
269 exit:
270 mbedtls_xtea_free( &ctx );
271
272 return( ret );
273 }
274
275 #endif /* MBEDTLS_SELF_TEST */
276
277 #endif /* MBEDTLS_XTEA_C */
278