1 /*
2 * An 32-bit implementation of the XTEA algorithm
3 *
4 * Copyright The Mbed TLS Contributors
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
20 #include "common.h"
21
22 #if defined(MBEDTLS_XTEA_C)
23
24 #include "mbedtls/xtea.h"
25 #include "mbedtls/platform_util.h"
26
27 #include <string.h>
28
29 #if defined(MBEDTLS_SELF_TEST)
30 #if defined(MBEDTLS_PLATFORM_C)
31 #include "mbedtls/platform.h"
32 #else
33 #include <stdio.h>
34 #define mbedtls_printf printf
35 #endif /* MBEDTLS_PLATFORM_C */
36 #endif /* MBEDTLS_SELF_TEST */
37
38 #if !defined(MBEDTLS_XTEA_ALT)
39
mbedtls_xtea_init(mbedtls_xtea_context * ctx)40 void mbedtls_xtea_init( mbedtls_xtea_context *ctx )
41 {
42 memset( ctx, 0, sizeof( mbedtls_xtea_context ) );
43 }
44
mbedtls_xtea_free(mbedtls_xtea_context * ctx)45 void mbedtls_xtea_free( mbedtls_xtea_context *ctx )
46 {
47 if( ctx == NULL )
48 return;
49
50 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_xtea_context ) );
51 }
52
53 /*
54 * XTEA key schedule
55 */
mbedtls_xtea_setup(mbedtls_xtea_context * ctx,const unsigned char key[16])56 void mbedtls_xtea_setup( mbedtls_xtea_context *ctx, const unsigned char key[16] )
57 {
58 int i;
59
60 memset( ctx, 0, sizeof(mbedtls_xtea_context) );
61
62 for( i = 0; i < 4; i++ )
63 {
64 ctx->k[i] = MBEDTLS_GET_UINT32_BE( key, i << 2 );
65 }
66 }
67
68 /*
69 * XTEA encrypt function
70 */
mbedtls_xtea_crypt_ecb(mbedtls_xtea_context * ctx,int mode,const unsigned char input[8],unsigned char output[8])71 int mbedtls_xtea_crypt_ecb( mbedtls_xtea_context *ctx, int mode,
72 const unsigned char input[8], unsigned char output[8])
73 {
74 uint32_t *k, v0, v1, i;
75
76 k = ctx->k;
77
78 v0 = MBEDTLS_GET_UINT32_BE( input, 0 );
79 v1 = MBEDTLS_GET_UINT32_BE( input, 4 );
80
81 if( mode == MBEDTLS_XTEA_ENCRYPT )
82 {
83 uint32_t sum = 0, delta = 0x9E3779B9;
84
85 for( i = 0; i < 32; i++ )
86 {
87 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
88 sum += delta;
89 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
90 }
91 }
92 else /* MBEDTLS_XTEA_DECRYPT */
93 {
94 uint32_t delta = 0x9E3779B9, sum = delta * 32;
95
96 for( i = 0; i < 32; i++ )
97 {
98 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
99 sum -= delta;
100 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
101 }
102 }
103
104 MBEDTLS_PUT_UINT32_BE( v0, output, 0 );
105 MBEDTLS_PUT_UINT32_BE( v1, output, 4 );
106
107 return( 0 );
108 }
109
110 #if defined(MBEDTLS_CIPHER_MODE_CBC)
111 /*
112 * XTEA-CBC buffer encryption/decryption
113 */
mbedtls_xtea_crypt_cbc(mbedtls_xtea_context * ctx,int mode,size_t length,unsigned char iv[8],const unsigned char * input,unsigned char * output)114 int mbedtls_xtea_crypt_cbc( mbedtls_xtea_context *ctx, int mode, size_t length,
115 unsigned char iv[8], const unsigned char *input,
116 unsigned char *output)
117 {
118 int i;
119 unsigned char temp[8];
120
121 if( length % 8 )
122 return( MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH );
123
124 if( mode == MBEDTLS_XTEA_DECRYPT )
125 {
126 while( length > 0 )
127 {
128 memcpy( temp, input, 8 );
129 mbedtls_xtea_crypt_ecb( ctx, mode, input, output );
130
131 for( i = 0; i < 8; i++ )
132 output[i] = (unsigned char)( output[i] ^ iv[i] );
133
134 memcpy( iv, temp, 8 );
135
136 input += 8;
137 output += 8;
138 length -= 8;
139 }
140 }
141 else
142 {
143 while( length > 0 )
144 {
145 for( i = 0; i < 8; i++ )
146 output[i] = (unsigned char)( input[i] ^ iv[i] );
147
148 mbedtls_xtea_crypt_ecb( ctx, mode, output, output );
149 memcpy( iv, output, 8 );
150
151 input += 8;
152 output += 8;
153 length -= 8;
154 }
155 }
156
157 return( 0 );
158 }
159 #endif /* MBEDTLS_CIPHER_MODE_CBC */
160 #endif /* !MBEDTLS_XTEA_ALT */
161
162 #if defined(MBEDTLS_SELF_TEST)
163
164 /*
165 * XTEA tests vectors (non-official)
166 */
167
168 static const unsigned char xtea_test_key[6][16] =
169 {
170 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
171 0x0c, 0x0d, 0x0e, 0x0f },
172 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
173 0x0c, 0x0d, 0x0e, 0x0f },
174 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
175 0x0c, 0x0d, 0x0e, 0x0f },
176 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
177 0x00, 0x00, 0x00, 0x00 },
178 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
179 0x00, 0x00, 0x00, 0x00 },
180 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
181 0x00, 0x00, 0x00, 0x00 }
182 };
183
184 static const unsigned char xtea_test_pt[6][8] =
185 {
186 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
187 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
188 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
189 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
190 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
191 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
192 };
193
194 static const unsigned char xtea_test_ct[6][8] =
195 {
196 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
197 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
198 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
199 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
200 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
201 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
202 };
203
204 /*
205 * Checkup routine
206 */
mbedtls_xtea_self_test(int verbose)207 int mbedtls_xtea_self_test( int verbose )
208 {
209 int i, ret = 0;
210 unsigned char buf[8];
211 mbedtls_xtea_context ctx;
212
213 mbedtls_xtea_init( &ctx );
214 for( i = 0; i < 6; i++ )
215 {
216 if( verbose != 0 )
217 mbedtls_printf( " XTEA test #%d: ", i + 1 );
218
219 memcpy( buf, xtea_test_pt[i], 8 );
220
221 mbedtls_xtea_setup( &ctx, xtea_test_key[i] );
222 mbedtls_xtea_crypt_ecb( &ctx, MBEDTLS_XTEA_ENCRYPT, buf, buf );
223
224 if( memcmp( buf, xtea_test_ct[i], 8 ) != 0 )
225 {
226 if( verbose != 0 )
227 mbedtls_printf( "failed\n" );
228
229 ret = 1;
230 goto exit;
231 }
232
233 if( verbose != 0 )
234 mbedtls_printf( "passed\n" );
235 }
236
237 if( verbose != 0 )
238 mbedtls_printf( "\n" );
239
240 exit:
241 mbedtls_xtea_free( &ctx );
242
243 return( ret );
244 }
245
246 #endif /* MBEDTLS_SELF_TEST */
247
248 #endif /* MBEDTLS_XTEA_C */
249