1 /* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
3 *
4 * Rights for redistribution and usage in source and binary
5 * forms are granted according to the OpenSSL license.
6 */
7
8 #include <openssl/crypto.h>
9 #include "modes_lcl.h"
10 #include <string.h>
11
12 #ifndef MODES_DEBUG
13 # ifndef NDEBUG
14 # define NDEBUG
15 # endif
16 #endif
17 #include <assert.h>
18
19 /*
20 * Trouble with Ciphertext Stealing, CTS, mode is that there is no
21 * common official specification, but couple of cipher/application
22 * specific ones: RFC2040 and RFC3962. Then there is 'Proposal to
23 * Extend CBC Mode By "Ciphertext Stealing"' at NIST site, which
24 * deviates from mentioned RFCs. Most notably it allows input to be
25 * of block length and it doesn't flip the order of the last two
26 * blocks. CTS is being discussed even in ECB context, but it's not
27 * adopted for any known application. This implementation provides
28 * two interfaces: one compliant with above mentioned RFCs and one
29 * compliant with the NIST proposal, both extending CBC mode.
30 */
31
32 size_t CRYPTO_cts128_encrypt_block(const unsigned char *in, unsigned char *out,
33 size_t len, const void *key,
34 unsigned char ivec[16], block128_f block)
35 { size_t residue, n;
36
37 assert (in && out && key && ivec);
38
39 if (len <= 16) return 0;
40
41 if ((residue=len%16) == 0) residue = 16;
42
43 len -= residue;
44
45 CRYPTO_cbc128_encrypt(in,out,len,key,ivec,block);
46
47 in += len;
48 out += len;
49
50 for (n=0; n<residue; ++n)
51 ivec[n] ^= in[n];
52 (*block)(ivec,ivec,key);
53 memcpy(out,out-16,residue);
54 memcpy(out-16,ivec,16);
55
56 return len+residue;
57 }
58
59 size_t CRYPTO_nistcts128_encrypt_block(const unsigned char *in, unsigned char *out,
60 size_t len, const void *key,
61 unsigned char ivec[16], block128_f block)
62 { size_t residue, n;
63
64 assert (in && out && key && ivec);
65
66 if (len < 16) return 0;
67
68 residue=len%16;
69
70 len -= residue;
71
72 CRYPTO_cbc128_encrypt(in,out,len,key,ivec,block);
73
74 if (residue==0) return len;
75
76 in += len;
77 out += len;
78
79 for (n=0; n<residue; ++n)
80 ivec[n] ^= in[n];
81 (*block)(ivec,ivec,key);
82 memcpy(out-16+residue,ivec,16);
83
84 return len+residue;
85 }
86
87 size_t CRYPTO_cts128_encrypt(const unsigned char *in, unsigned char *out,
88 size_t len, const void *key,
89 unsigned char ivec[16], cbc128_f cbc)
90 { size_t residue;
91 union { size_t align; unsigned char c[16]; } tmp;
92
93 assert (in && out && key && ivec);
94
95 if (len <= 16) return 0;
96
97 if ((residue=len%16) == 0) residue = 16;
98
99 len -= residue;
100
101 (*cbc)(in,out,len,key,ivec,1);
102
103 in += len;
104 out += len;
105
106 #if defined(CBC_HANDLES_TRUNCATED_IO)
107 memcpy(tmp.c,out-16,16);
108 (*cbc)(in,out-16,residue,key,ivec,1);
109 memcpy(out,tmp.c,residue);
110 #else
111 memset(tmp.c,0,sizeof(tmp));
112 memcpy(tmp.c,in,residue);
113 memcpy(out,out-16,residue);
114 (*cbc)(tmp.c,out-16,16,key,ivec,1);
115 #endif
116 return len+residue;
117 }
118
119 size_t CRYPTO_nistcts128_encrypt(const unsigned char *in, unsigned char *out,
120 size_t len, const void *key,
121 unsigned char ivec[16], cbc128_f cbc)
122 { size_t residue;
123 union { size_t align; unsigned char c[16]; } tmp;
124
125 assert (in && out && key && ivec);
126
127 if (len < 16) return 0;
128
129 residue=len%16;
130
131 len -= residue;
132
133 (*cbc)(in,out,len,key,ivec,1);
134
135 if (residue==0) return len;
136
137 in += len;
138 out += len;
139
140 #if defined(CBC_HANDLES_TRUNCATED_IO)
141 (*cbc)(in,out-16+residue,residue,key,ivec,1);
142 #else
143 memset(tmp.c,0,sizeof(tmp));
144 memcpy(tmp.c,in,residue);
145 (*cbc)(tmp.c,out-16+residue,16,key,ivec,1);
146 #endif
147 return len+residue;
148 }
149
150 size_t CRYPTO_cts128_decrypt_block(const unsigned char *in, unsigned char *out,
151 size_t len, const void *key,
152 unsigned char ivec[16], block128_f block)
153 { size_t residue, n;
154 union { size_t align; unsigned char c[32]; } tmp;
155
156 assert (in && out && key && ivec);
157
158 if (len<=16) return 0;
159
160 if ((residue=len%16) == 0) residue = 16;
161
162 len -= 16+residue;
163
164 if (len) {
165 CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block);
166 in += len;
167 out += len;
168 }
169
170 (*block)(in,tmp.c+16,key);
171
172 memcpy(tmp.c,tmp.c+16,16);
173 memcpy(tmp.c,in+16,residue);
174 (*block)(tmp.c,tmp.c,key);
175
176 for(n=0; n<16; ++n) {
177 unsigned char c = in[n];
178 out[n] = tmp.c[n] ^ ivec[n];
179 ivec[n] = c;
180 }
181 for(residue+=16; n<residue; ++n)
182 out[n] = tmp.c[n] ^ in[n];
183
184 return 16+len+residue;
185 }
186
187 size_t CRYPTO_nistcts128_decrypt_block(const unsigned char *in, unsigned char *out,
188 size_t len, const void *key,
189 unsigned char ivec[16], block128_f block)
190 { size_t residue, n;
191 union { size_t align; unsigned char c[32]; } tmp;
192
193 assert (in && out && key && ivec);
194
195 if (len<16) return 0;
196
197 residue=len%16;
198
199 if (residue==0) {
200 CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block);
201 return len;
202 }
203
204 len -= 16+residue;
205
206 if (len) {
207 CRYPTO_cbc128_decrypt(in,out,len,key,ivec,block);
208 in += len;
209 out += len;
210 }
211
212 (*block)(in+residue,tmp.c+16,key);
213
214 memcpy(tmp.c,tmp.c+16,16);
215 memcpy(tmp.c,in,residue);
216 (*block)(tmp.c,tmp.c,key);
217
218 for(n=0; n<16; ++n) {
219 unsigned char c = in[n];
220 out[n] = tmp.c[n] ^ ivec[n];
221 ivec[n] = in[n+residue];
222 tmp.c[n] = c;
223 }
224 for(residue+=16; n<residue; ++n)
225 out[n] = tmp.c[n] ^ tmp.c[n-16];
226
227 return 16+len+residue;
228 }
229
230 size_t CRYPTO_cts128_decrypt(const unsigned char *in, unsigned char *out,
231 size_t len, const void *key,
232 unsigned char ivec[16], cbc128_f cbc)
233 { size_t residue;
234 union { size_t align; unsigned char c[32]; } tmp;
235
236 assert (in && out && key && ivec);
237
238 if (len<=16) return 0;
239
240 if ((residue=len%16) == 0) residue = 16;
241
242 len -= 16+residue;
243
244 if (len) {
245 (*cbc)(in,out,len,key,ivec,0);
246 in += len;
247 out += len;
248 }
249
250 memset(tmp.c,0,sizeof(tmp));
251 /* this places in[16] at &tmp.c[16] and decrypted block at &tmp.c[0] */
252 (*cbc)(in,tmp.c,16,key,tmp.c+16,0);
253
254 memcpy(tmp.c,in+16,residue);
255 #if defined(CBC_HANDLES_TRUNCATED_IO)
256 (*cbc)(tmp.c,out,16+residue,key,ivec,0);
257 #else
258 (*cbc)(tmp.c,tmp.c,32,key,ivec,0);
259 memcpy(out,tmp.c,16+residue);
260 #endif
261 return 16+len+residue;
262 }
263
264 size_t CRYPTO_nistcts128_decrypt(const unsigned char *in, unsigned char *out,
265 size_t len, const void *key,
266 unsigned char ivec[16], cbc128_f cbc)
267 { size_t residue;
268 union { size_t align; unsigned char c[32]; } tmp;
269
270 assert (in && out && key && ivec);
271
272 if (len<16) return 0;
273
274 residue=len%16;
275
276 if (residue==0) {
277 (*cbc)(in,out,len,key,ivec,0);
278 return len;
279 }
280
281 len -= 16+residue;
282
283 if (len) {
284 (*cbc)(in,out,len,key,ivec,0);
285 in += len;
286 out += len;
287 }
288
289 memset(tmp.c,0,sizeof(tmp));
290 /* this places in[16] at &tmp.c[16] and decrypted block at &tmp.c[0] */
291 (*cbc)(in+residue,tmp.c,16,key,tmp.c+16,0);
292
293 memcpy(tmp.c,in,residue);
294 #if defined(CBC_HANDLES_TRUNCATED_IO)
295 (*cbc)(tmp.c,out,16+residue,key,ivec,0);
296 #else
297 (*cbc)(tmp.c,tmp.c,32,key,ivec,0);
298 memcpy(out,tmp.c,16+residue);
299 #endif
300 return 16+len+residue;
301 }
302
303 #if defined(SELFTEST)
304 #include <stdio.h>
305 #include <openssl/aes.h>
306
307 /* test vectors from RFC 3962 */
308 static const unsigned char test_key[16] = "chicken teriyaki";
309 static const unsigned char test_input[64] =
310 "I would like the" " General Gau's C"
311 "hicken, please, " "and wonton soup.";
312 static const unsigned char test_iv[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
313
314 static const unsigned char vector_17[17] =
315 {0xc6,0x35,0x35,0x68,0xf2,0xbf,0x8c,0xb4, 0xd8,0xa5,0x80,0x36,0x2d,0xa7,0xff,0x7f,
316 0x97};
317 static const unsigned char vector_31[31] =
318 {0xfc,0x00,0x78,0x3e,0x0e,0xfd,0xb2,0xc1, 0xd4,0x45,0xd4,0xc8,0xef,0xf7,0xed,0x22,
319 0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5};
320 static const unsigned char vector_32[32] =
321 {0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8,
322 0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84};
323 static const unsigned char vector_47[47] =
324 {0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84,
325 0xb3,0xff,0xfd,0x94,0x0c,0x16,0xa1,0x8c, 0x1b,0x55,0x49,0xd2,0xf8,0x38,0x02,0x9e,
326 0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5};
327 static const unsigned char vector_48[48] =
328 {0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84,
329 0x9d,0xad,0x8b,0xbb,0x96,0xc4,0xcd,0xc0, 0x3b,0xc1,0x03,0xe1,0xa1,0x94,0xbb,0xd8,
330 0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8};
331 static const unsigned char vector_64[64] =
332 {0x97,0x68,0x72,0x68,0xd6,0xec,0xcc,0xc0, 0xc0,0x7b,0x25,0xe2,0x5e,0xcf,0xe5,0x84,
333 0x39,0x31,0x25,0x23,0xa7,0x86,0x62,0xd5, 0xbe,0x7f,0xcb,0xcc,0x98,0xeb,0xf5,0xa8,
334 0x48,0x07,0xef,0xe8,0x36,0xee,0x89,0xa5, 0x26,0x73,0x0d,0xbc,0x2f,0x7b,0xc8,0x40,
335 0x9d,0xad,0x8b,0xbb,0x96,0xc4,0xcd,0xc0, 0x3b,0xc1,0x03,0xe1,0xa1,0x94,0xbb,0xd8};
336
337 static AES_KEY encks, decks;
338
339 void test_vector(const unsigned char *vector,size_t len)
340 { unsigned char iv[sizeof(test_iv)];
341 unsigned char cleartext[64],ciphertext[64];
342 size_t tail;
343
344 printf("vector_%d\n",len); fflush(stdout);
345
346 if ((tail=len%16) == 0) tail = 16;
347 tail += 16;
348
349 /* test block-based encryption */
350 memcpy(iv,test_iv,sizeof(test_iv));
351 CRYPTO_cts128_encrypt_block(test_input,ciphertext,len,&encks,iv,(block128_f)AES_encrypt);
352 if (memcmp(ciphertext,vector,len))
353 fprintf(stderr,"output_%d mismatch\n",len), exit(1);
354 if (memcmp(iv,vector+len-tail,sizeof(iv)))
355 fprintf(stderr,"iv_%d mismatch\n",len), exit(1);
356
357 /* test block-based decryption */
358 memcpy(iv,test_iv,sizeof(test_iv));
359 CRYPTO_cts128_decrypt_block(ciphertext,cleartext,len,&decks,iv,(block128_f)AES_decrypt);
360 if (memcmp(cleartext,test_input,len))
361 fprintf(stderr,"input_%d mismatch\n",len), exit(2);
362 if (memcmp(iv,vector+len-tail,sizeof(iv)))
363 fprintf(stderr,"iv_%d mismatch\n",len), exit(2);
364
365 /* test streamed encryption */
366 memcpy(iv,test_iv,sizeof(test_iv));
367 CRYPTO_cts128_encrypt(test_input,ciphertext,len,&encks,iv,(cbc128_f)AES_cbc_encrypt);
368 if (memcmp(ciphertext,vector,len))
369 fprintf(stderr,"output_%d mismatch\n",len), exit(3);
370 if (memcmp(iv,vector+len-tail,sizeof(iv)))
371 fprintf(stderr,"iv_%d mismatch\n",len), exit(3);
372
373 /* test streamed decryption */
374 memcpy(iv,test_iv,sizeof(test_iv));
375 CRYPTO_cts128_decrypt(ciphertext,cleartext,len,&decks,iv,(cbc128_f)AES_cbc_encrypt);
376 if (memcmp(cleartext,test_input,len))
377 fprintf(stderr,"input_%d mismatch\n",len), exit(4);
378 if (memcmp(iv,vector+len-tail,sizeof(iv)))
379 fprintf(stderr,"iv_%d mismatch\n",len), exit(4);
380 }
381
382 void test_nistvector(const unsigned char *vector,size_t len)
383 { unsigned char iv[sizeof(test_iv)];
384 unsigned char cleartext[64],ciphertext[64],nistvector[64];
385 size_t tail;
386
387 printf("nistvector_%d\n",len); fflush(stdout);
388
389 if ((tail=len%16) == 0) tail = 16;
390
391 len -= 16 + tail;
392 memcpy(nistvector,vector,len);
393 /* flip two last blocks */
394 memcpy(nistvector+len,vector+len+16,tail);
395 memcpy(nistvector+len+tail,vector+len,16);
396 len += 16 + tail;
397 tail = 16;
398
399 /* test block-based encryption */
400 memcpy(iv,test_iv,sizeof(test_iv));
401 CRYPTO_nistcts128_encrypt_block(test_input,ciphertext,len,&encks,iv,(block128_f)AES_encrypt);
402 if (memcmp(ciphertext,nistvector,len))
403 fprintf(stderr,"output_%d mismatch\n",len), exit(1);
404 if (memcmp(iv,nistvector+len-tail,sizeof(iv)))
405 fprintf(stderr,"iv_%d mismatch\n",len), exit(1);
406
407 /* test block-based decryption */
408 memcpy(iv,test_iv,sizeof(test_iv));
409 CRYPTO_nistcts128_decrypt_block(ciphertext,cleartext,len,&decks,iv,(block128_f)AES_decrypt);
410 if (memcmp(cleartext,test_input,len))
411 fprintf(stderr,"input_%d mismatch\n",len), exit(2);
412 if (memcmp(iv,nistvector+len-tail,sizeof(iv)))
413 fprintf(stderr,"iv_%d mismatch\n",len), exit(2);
414
415 /* test streamed encryption */
416 memcpy(iv,test_iv,sizeof(test_iv));
417 CRYPTO_nistcts128_encrypt(test_input,ciphertext,len,&encks,iv,(cbc128_f)AES_cbc_encrypt);
418 if (memcmp(ciphertext,nistvector,len))
419 fprintf(stderr,"output_%d mismatch\n",len), exit(3);
420 if (memcmp(iv,nistvector+len-tail,sizeof(iv)))
421 fprintf(stderr,"iv_%d mismatch\n",len), exit(3);
422
423 /* test streamed decryption */
424 memcpy(iv,test_iv,sizeof(test_iv));
425 CRYPTO_nistcts128_decrypt(ciphertext,cleartext,len,&decks,iv,(cbc128_f)AES_cbc_encrypt);
426 if (memcmp(cleartext,test_input,len))
427 fprintf(stderr,"input_%d mismatch\n",len), exit(4);
428 if (memcmp(iv,nistvector+len-tail,sizeof(iv)))
429 fprintf(stderr,"iv_%d mismatch\n",len), exit(4);
430 }
431
432 int main()
433 {
434 AES_set_encrypt_key(test_key,128,&encks);
435 AES_set_decrypt_key(test_key,128,&decks);
436
437 test_vector(vector_17,sizeof(vector_17));
438 test_vector(vector_31,sizeof(vector_31));
439 test_vector(vector_32,sizeof(vector_32));
440 test_vector(vector_47,sizeof(vector_47));
441 test_vector(vector_48,sizeof(vector_48));
442 test_vector(vector_64,sizeof(vector_64));
443
444 test_nistvector(vector_17,sizeof(vector_17));
445 test_nistvector(vector_31,sizeof(vector_31));
446 test_nistvector(vector_32,sizeof(vector_32));
447 test_nistvector(vector_47,sizeof(vector_47));
448 test_nistvector(vector_48,sizeof(vector_48));
449 test_nistvector(vector_64,sizeof(vector_64));
450
451 return 0;
452 }
453 #endif