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
32 #include <string.h>
33
34 #if defined(MBEDTLS_SELF_TEST)
35 #if defined(MBEDTLS_PLATFORM_C)
36 #include "mbedtls/platform.h"
37 #else
38 #include <stdio.h>
39 #define mbedtls_printf printf
40 #endif /* MBEDTLS_PLATFORM_C */
41 #endif /* MBEDTLS_SELF_TEST */
42
43 #if !defined(MBEDTLS_XTEA_ALT)
44
45 /* Implementation that should never be optimized out by the compiler */
mbedtls_zeroize(void * v,size_t n)46 static void mbedtls_zeroize( void *v, size_t n ) {
47 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
48 }
49
50 /*
51 * 32-bit integer manipulation macros (big endian)
52 */
53 #ifndef GET_UINT32_BE
54 #define GET_UINT32_BE(n,b,i) \
55 { \
56 (n) = ( (uint32_t) (b)[(i) ] << 24 ) \
57 | ( (uint32_t) (b)[(i) + 1] << 16 ) \
58 | ( (uint32_t) (b)[(i) + 2] << 8 ) \
59 | ( (uint32_t) (b)[(i) + 3] ); \
60 }
61 #endif
62
63 #ifndef PUT_UINT32_BE
64 #define PUT_UINT32_BE(n,b,i) \
65 { \
66 (b)[(i) ] = (unsigned char) ( (n) >> 24 ); \
67 (b)[(i) + 1] = (unsigned char) ( (n) >> 16 ); \
68 (b)[(i) + 2] = (unsigned char) ( (n) >> 8 ); \
69 (b)[(i) + 3] = (unsigned char) ( (n) ); \
70 }
71 #endif
72
mbedtls_xtea_init(mbedtls_xtea_context * ctx)73 void mbedtls_xtea_init( mbedtls_xtea_context *ctx )
74 {
75 memset( ctx, 0, sizeof( mbedtls_xtea_context ) );
76 }
77
mbedtls_xtea_free(mbedtls_xtea_context * ctx)78 void mbedtls_xtea_free( mbedtls_xtea_context *ctx )
79 {
80 if( ctx == NULL )
81 return;
82
83 mbedtls_zeroize( ctx, sizeof( mbedtls_xtea_context ) );
84 }
85
86 /*
87 * XTEA key schedule
88 */
mbedtls_xtea_setup(mbedtls_xtea_context * ctx,const unsigned char key[16])89 void mbedtls_xtea_setup( mbedtls_xtea_context *ctx, const unsigned char key[16] )
90 {
91 int i;
92
93 memset( ctx, 0, sizeof(mbedtls_xtea_context) );
94
95 for( i = 0; i < 4; i++ )
96 {
97 GET_UINT32_BE( ctx->k[i], key, i << 2 );
98 }
99 }
100
101 /*
102 * XTEA encrypt function
103 */
mbedtls_xtea_crypt_ecb(mbedtls_xtea_context * ctx,int mode,const unsigned char input[8],unsigned char output[8])104 int mbedtls_xtea_crypt_ecb( mbedtls_xtea_context *ctx, int mode,
105 const unsigned char input[8], unsigned char output[8])
106 {
107 uint32_t *k, v0, v1, i;
108
109 k = ctx->k;
110
111 GET_UINT32_BE( v0, input, 0 );
112 GET_UINT32_BE( v1, input, 4 );
113
114 if( mode == MBEDTLS_XTEA_ENCRYPT )
115 {
116 uint32_t sum = 0, delta = 0x9E3779B9;
117
118 for( i = 0; i < 32; i++ )
119 {
120 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
121 sum += delta;
122 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
123 }
124 }
125 else /* MBEDTLS_XTEA_DECRYPT */
126 {
127 uint32_t delta = 0x9E3779B9, sum = delta * 32;
128
129 for( i = 0; i < 32; i++ )
130 {
131 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
132 sum -= delta;
133 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
134 }
135 }
136
137 PUT_UINT32_BE( v0, output, 0 );
138 PUT_UINT32_BE( v1, output, 4 );
139
140 return( 0 );
141 }
142
143 #if defined(MBEDTLS_CIPHER_MODE_CBC)
144 /*
145 * XTEA-CBC buffer encryption/decryption
146 */
mbedtls_xtea_crypt_cbc(mbedtls_xtea_context * ctx,int mode,size_t length,unsigned char iv[8],const unsigned char * input,unsigned char * output)147 int mbedtls_xtea_crypt_cbc( mbedtls_xtea_context *ctx, int mode, size_t length,
148 unsigned char iv[8], const unsigned char *input,
149 unsigned char *output)
150 {
151 int i;
152 unsigned char temp[8];
153
154 if( length % 8 )
155 return( MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH );
156
157 if( mode == MBEDTLS_XTEA_DECRYPT )
158 {
159 while( length > 0 )
160 {
161 memcpy( temp, input, 8 );
162 mbedtls_xtea_crypt_ecb( ctx, mode, input, output );
163
164 for( i = 0; i < 8; i++ )
165 output[i] = (unsigned char)( output[i] ^ iv[i] );
166
167 memcpy( iv, temp, 8 );
168
169 input += 8;
170 output += 8;
171 length -= 8;
172 }
173 }
174 else
175 {
176 while( length > 0 )
177 {
178 for( i = 0; i < 8; i++ )
179 output[i] = (unsigned char)( input[i] ^ iv[i] );
180
181 mbedtls_xtea_crypt_ecb( ctx, mode, output, output );
182 memcpy( iv, output, 8 );
183
184 input += 8;
185 output += 8;
186 length -= 8;
187 }
188 }
189
190 return( 0 );
191 }
192 #endif /* MBEDTLS_CIPHER_MODE_CBC */
193 #endif /* !MBEDTLS_XTEA_ALT */
194
195 #if defined(MBEDTLS_SELF_TEST)
196
197 /*
198 * XTEA tests vectors (non-official)
199 */
200
201 static const unsigned char xtea_test_key[6][16] =
202 {
203 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
204 0x0c, 0x0d, 0x0e, 0x0f },
205 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
206 0x0c, 0x0d, 0x0e, 0x0f },
207 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
208 0x0c, 0x0d, 0x0e, 0x0f },
209 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
210 0x00, 0x00, 0x00, 0x00 },
211 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
212 0x00, 0x00, 0x00, 0x00 },
213 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
214 0x00, 0x00, 0x00, 0x00 }
215 };
216
217 static const unsigned char xtea_test_pt[6][8] =
218 {
219 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
220 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
221 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
222 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
223 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
224 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
225 };
226
227 static const unsigned char xtea_test_ct[6][8] =
228 {
229 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
230 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
231 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
232 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
233 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
234 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
235 };
236
237 /*
238 * Checkup routine
239 */
mbedtls_xtea_self_test(int verbose)240 int mbedtls_xtea_self_test( int verbose )
241 {
242 int i, ret = 0;
243 unsigned char buf[8];
244 mbedtls_xtea_context ctx;
245
246 mbedtls_xtea_init( &ctx );
247 for( i = 0; i < 6; i++ )
248 {
249 if( verbose != 0 )
250 mbedtls_printf( " XTEA test #%d: ", i + 1 );
251
252 memcpy( buf, xtea_test_pt[i], 8 );
253
254 mbedtls_xtea_setup( &ctx, xtea_test_key[i] );
255 mbedtls_xtea_crypt_ecb( &ctx, MBEDTLS_XTEA_ENCRYPT, buf, buf );
256
257 if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
258 {
259 if( verbose != 0 )
260 mbedtls_printf( "failed\n" );
261
262 ret = 1;
263 goto exit;
264 }
265
266 if( verbose != 0 )
267 mbedtls_printf( "passed\n" );
268 }
269
270 if( verbose != 0 )
271 mbedtls_printf( "\n" );
272
273 exit:
274 mbedtls_xtea_free( &ctx );
275
276 return( ret );
277 }
278
279 #endif /* MBEDTLS_SELF_TEST */
280
281 #endif /* MBEDTLS_XTEA_C */
282
