1EVP_EncryptInit(3) OpenSSL EVP_EncryptInit(3)
2
6 EVP_CIPHER_CTX_init, EVP_EncryptInit_ex, EVP_EncryptUpdate,
7 EVP_EncryptFinal_ex, EVP_DecryptInit_ex, EVP_DecryptUpdate,
8 EVP_DecryptFinal_ex, EVP_CipherInit_ex, EVP_CipherUpdate,
9 EVP_CipherFinal_ex, EVP_CIPHER_CTX_set_key_length, EVP_CIPHER_CTX_ctrl,
10 EVP_CIPHER_CTX_cleanup, EVP_EncryptInit, EVP_EncryptFinal,
11 EVP_DecryptInit, EVP_DecryptFinal, EVP_CipherInit, EVP_CipherFinal,
12 EVP_get_cipherbyname, EVP_get_cipherbynid, EVP_get_cipherbyobj,
13 EVP_CIPHER_nid, EVP_CIPHER_block_size, EVP_CIPHER_key_length,
14 EVP_CIPHER_iv_length, EVP_CIPHER_flags, EVP_CIPHER_mode,
15 EVP_CIPHER_type, EVP_CIPHER_CTX_cipher, EVP_CIPHER_CTX_nid,
16 EVP_CIPHER_CTX_block_size, EVP_CIPHER_CTX_key_length,
17 EVP_CIPHER_CTX_iv_length, EVP_CIPHER_CTX_get_app_data,
18 EVP_CIPHER_CTX_set_app_data, EVP_CIPHER_CTX_type, EVP_CIPHER_CTX_flags,
19 EVP_CIPHER_CTX_mode, EVP_CIPHER_param_to_asn1,
20 EVP_CIPHER_asn1_to_param, EVP_CIPHER_CTX_set_padding - EVP cipher
21 routines
22
24 #include <openssl/evp.h>
25 void EVP_CIPHER_CTX_init(EVP_CIPHER_CTX *a);
27 int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
29 ENGINE *impl, unsigned char *key, unsigned char *iv);
30 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
31 int *outl, unsigned char *in, int inl);
32 int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out,
33 int *outl);
34 int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
36 ENGINE *impl, unsigned char *key, unsigned char *iv);
37 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
38 int *outl, unsigned char *in, int inl);
39 int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm,
40 int *outl);
41 int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
43 ENGINE *impl, unsigned char *key, unsigned char *iv, int enc);
44 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
45 int *outl, unsigned char *in, int inl);
46 int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm,
47 int *outl);
48 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
50 unsigned char *key, unsigned char *iv);
51 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out,
52 int *outl);
53 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
55 unsigned char *key, unsigned char *iv);
56 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
57 int *outl);
58 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
60 unsigned char *key, unsigned char *iv, int enc);
61 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm,
62 int *outl);
63 int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding);
65 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen);
66 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr);
67 int EVP_CIPHER_CTX_cleanup(EVP_CIPHER_CTX *a);
68 const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
70 #define EVP_get_cipherbynid(a) EVP_get_cipherbyname(OBJ_nid2sn(a))
71 #define EVP_get_cipherbyobj(a) EVP_get_cipherbynid(OBJ_obj2nid(a))
72 #define EVP_CIPHER_nid(e) ((e)->nid)
74 #define EVP_CIPHER_block_size(e) ((e)->block_size)
75 #define EVP_CIPHER_key_length(e) ((e)->key_len)
76 #define EVP_CIPHER_iv_length(e) ((e)->iv_len)
77 #define EVP_CIPHER_flags(e) ((e)->flags)
78 #define EVP_CIPHER_mode(e) ((e)->flags) & EVP_CIPH_MODE)
79 int EVP_CIPHER_type(const EVP_CIPHER *ctx);
80 #define EVP_CIPHER_CTX_cipher(e) ((e)->cipher)
82 #define EVP_CIPHER_CTX_nid(e) ((e)->cipher->nid)
83 #define EVP_CIPHER_CTX_block_size(e) ((e)->cipher->block_size)
84 #define EVP_CIPHER_CTX_key_length(e) ((e)->key_len)
85 #define EVP_CIPHER_CTX_iv_length(e) ((e)->cipher->iv_len)
86 #define EVP_CIPHER_CTX_get_app_data(e) ((e)->app_data)
87 #define EVP_CIPHER_CTX_set_app_data(e,d) ((e)->app_data=(char *)(d))
88 #define EVP_CIPHER_CTX_type(c) EVP_CIPHER_type(EVP_CIPHER_CTX_cipher(c))
89 #define EVP_CIPHER_CTX_flags(e) ((e)->cipher->flags)
90 #define EVP_CIPHER_CTX_mode(e) ((e)->cipher->flags & EVP_CIPH_MODE)
91 int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
93 int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
94 const EVP_CIPHER *EVP_des_ede3(void);
96 const EVP_CIPHER *EVP_des_ede3_ecb(void);
97 const EVP_CIPHER *EVP_des_ede3_cfb64(void);
98 const EVP_CIPHER *EVP_des_ede3_cfb1(void);
99 const EVP_CIPHER *EVP_des_ede3_cfb8(void);
100 const EVP_CIPHER *EVP_des_ede3_ofb(void);
101 const EVP_CIPHER *EVP_des_ede3_cbc(void);
102 const EVP_CIPHER *EVP_aes_128_ecb(void);
103 const EVP_CIPHER *EVP_aes_128_cbc(void);
104 const EVP_CIPHER *EVP_aes_128_cfb1(void);
105 const EVP_CIPHER *EVP_aes_128_cfb8(void);
106 const EVP_CIPHER *EVP_aes_128_cfb128(void);
107 const EVP_CIPHER *EVP_aes_128_ofb(void);
108 const EVP_CIPHER *EVP_aes_192_ecb(void);
109 const EVP_CIPHER *EVP_aes_192_cbc(void);
110 const EVP_CIPHER *EVP_aes_192_cfb1(void);
111 const EVP_CIPHER *EVP_aes_192_cfb8(void);
112 const EVP_CIPHER *EVP_aes_192_cfb128(void);
113 const EVP_CIPHER *EVP_aes_192_ofb(void);
114 const EVP_CIPHER *EVP_aes_256_ecb(void);
115 const EVP_CIPHER *EVP_aes_256_cbc(void);
116 const EVP_CIPHER *EVP_aes_256_cfb1(void);
117 const EVP_CIPHER *EVP_aes_256_cfb8(void);
118 const EVP_CIPHER *EVP_aes_256_cfb128(void);
119 const EVP_CIPHER *EVP_aes_256_ofb(void);
120
122 The EVP cipher routines are a high level interface to certain symmetric
123 ciphers.
124 EVP_CIPHER_CTX_init() initializes cipher contex ctx.
126 EVP_EncryptInit_ex() sets up cipher context ctx for encryption with
128 cipher type from ENGINE impl. ctx must be initialized before calling
129 this function. type is normally supplied by a function such as
130 EVP_des_cbc(). If impl is NULL then the default implementation is used.
131 key is the symmetric key to use and iv is the IV to use (if necessary),
132 the actual number of bytes used for the key and IV depends on the
133 cipher. It is possible to set all parameters to NULL except type in an
134 initial call and supply the remaining parameters in subsequent calls,
135 all of which have type set to NULL. This is done when the default
136 cipher parameters are not appropriate.
137 EVP_EncryptUpdate() encrypts inl bytes from the buffer in and writes
139 the encrypted version to out. This function can be called multiple
140 times to encrypt successive blocks of data. The amount of data written
141 depends on the block alignment of the encrypted data: as a result the
142 amount of data written may be anything from zero bytes to (inl +
143 cipher_block_size - 1) so outl should contain sufficient room. The
144 actual number of bytes written is placed in outl.
145 If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts
147 the "final" data, that is any data that remains in a partial block. It
148 uses standard block padding (aka PKCS padding). The encrypted final
149 data is written to out which should have sufficient space for one
150 cipher block. The number of bytes written is placed in outl. After this
151 function is called the encryption operation is finished and no further
152 calls to EVP_EncryptUpdate() should be made.
153 If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any
155 more data and it will return an error if any data remains in a partial
156 block: that is if the total data length is not a multiple of the block
157 size.
158 EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are
160 the corresponding decryption operations. EVP_DecryptFinal() will return
161 an error code if padding is enabled and the final block is not
162 correctly formatted. The parameters and restrictions are identical to
163 the encryption operations except that if padding is enabled the
164 decrypted data buffer out passed to EVP_DecryptUpdate() should have
165 sufficient room for (inl + cipher_block_size) bytes unless the cipher
166 block size is 1 in which case inl bytes is sufficient.
167 EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are
169 functions that can be used for decryption or encryption. The operation
170 performed depends on the value of the enc parameter. It should be set
171 to 1 for encryption, 0 for decryption and -1 to leave the value
172 unchanged (the actual value of 'enc' being supplied in a previous
173 call).
174 EVP_CIPHER_CTX_cleanup() clears all information from a cipher context
176 and free up any allocated memory associate with it. It should be called
177 after all operations using a cipher are complete so sensitive
178 information does not remain in memory.
179 EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a
181 similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex and
182 EVP_CipherInit_ex() except the ctx paramter does not need to be
183 initialized and they always use the default cipher implementation.
184 EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() behave in
186 a similar way to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
187 EVP_CipherFinal_ex() except ctx is automatically cleaned up after the
188 call.
189 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
191 return an EVP_CIPHER structure when passed a cipher name, a NID or an
192 ASN1_OBJECT structure.
193 EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return the NID of a cipher
195 when passed an EVP_CIPHER or EVP_CIPHER_CTX structure. The actual NID
196 value is an internal value which may not have a corresponding OBJECT
197 IDENTIFIER.
198 EVP_CIPHER_CTX_set_padding() enables or disables padding. By default
200 encryption operations are padded using standard block padding and the
201 padding is checked and removed when decrypting. If the pad parameter is
202 zero then no padding is performed, the total amount of data encrypted
203 or decrypted must then be a multiple of the block size or an error will
204 occur.
205 EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
207 length of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX
208 structure. The constant EVP_MAX_KEY_LENGTH is the maximum key length
209 for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a
210 given cipher, the value of EVP_CIPHER_CTX_key_length() may be different
211 for variable key length ciphers.
212 EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx.
214 If the cipher is a fixed length cipher then attempting to set the key
215 length to any value other than the fixed value is an error.
216 EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
218 length of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX. It
219 will return zero if the cipher does not use an IV. The constant
220 EVP_MAX_IV_LENGTH is the maximum IV length for all ciphers.
221 EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the
223 block size of a cipher when passed an EVP_CIPHER or EVP_CIPHER_CTX
224 structure. The constant EVP_MAX_IV_LENGTH is also the maximum block
225 length for all ciphers.
226 EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the type of the
228 passed cipher or context. This "type" is the actual NID of the cipher
229 OBJECT IDENTIFIER as such it ignores the cipher parameters and 40 bit
230 RC2 and 128 bit RC2 have the same NID. If the cipher does not have an
231 object identifier or does not have ASN1 support this function will
232 return NID_undef.
233 EVP_CIPHER_CTX_cipher() returns the EVP_CIPHER structure when passed an
235 EVP_CIPHER_CTX structure.
236 EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher
238 mode: EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE or
239 EVP_CIPH_OFB_MODE. If the cipher is a stream cipher then
240 EVP_CIPH_STREAM_CIPHER is returned.
241 EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter"
243 based on the passed cipher. This will typically include any parameters
244 and an IV. The cipher IV (if any) must be set when this call is made.
245 This call should be made before the cipher is actually "used" (before
246 any EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This
247 function may fail if the cipher does not have any ASN1 support.
248 EVP_CIPHER_asn1_to_param() sets the cipher parameters based on an ASN1
250 AlgorithmIdentifier "parameter". The precise effect depends on the
251 cipher In the case of RC2, for example, it will set the IV and
252 effective key length. This function should be called after the base
253 cipher type is set but before the key is set. For example
254 EVP_CipherInit() will be called with the IV and key set to NULL,
255 EVP_CIPHER_asn1_to_param() will be called and finally EVP_CipherInit()
256 again with all parameters except the key set to NULL. It is possible
257 for this function to fail if the cipher does not have any ASN1 support
258 or the parameters cannot be set (for example the RC2 effective key
259 length is not supported.
260 EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be
262 determined and set. Currently only the RC2 effective key length and the
263 number of rounds of RC5 can be set.
264
266 EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex()
267 return 1 for success and 0 for failure.
268 EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0
270 for failure. EVP_DecryptFinal_ex() returns 0 if the decrypt failed or
271 1 for success.
272 EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0
274 for failure. EVP_CipherFinal_ex() returns 0 for a decryption failure
275 or 1 for success.
276 EVP_CIPHER_CTX_cleanup() returns 1 for success and 0 for failure.
278 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
280 return an EVP_CIPHER structure or NULL on error.
281 EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return a NID.
283 EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the
285 block size.
286 EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
288 length.
289 EVP_CIPHER_CTX_set_padding() always returns 1.
291 EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
293 length or zero if the cipher does not use an IV.
294 EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the
296 cipher's OBJECT IDENTIFIER or NID_undef if it has no defined OBJECT
297 IDENTIFIER.
298 EVP_CIPHER_CTX_cipher() returns an EVP_CIPHER structure.
300 EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return 1 for
302 success or zero for failure.
303
305 All algorithms have a fixed key length unless otherwise stated.
306 EVP_enc_null()
308 Null cipher: does nothing.
309 EVP_des_cbc(void), EVP_des_ecb(void), EVP_des_cfb(void),
311 EVP_des_ofb(void)
312 DES in CBC, ECB, CFB and OFB modes respectively.
313 EVP_des_ede_cbc(void), EVP_des_ede(), EVP_des_ede_ofb(void),
315 EVP_des_ede_cfb(void)
316 Two key triple DES in CBC, ECB, CFB and OFB modes respectively.
317 EVP_des_ede3_cbc(void), EVP_des_ede3(), EVP_des_ede3_ofb(void),
319 EVP_des_ede3_cfb(void)
320 Three key triple DES in CBC, ECB, CFB and OFB modes respectively.
321 EVP_desx_cbc(void)
323 DESX algorithm in CBC mode.
324 EVP_aes_128_cbc(void), EVP_aes_128_ecb(), EVP_aes_128_ofb(void),
326 EVP_aes_128_cfb1(void), EVP_aes_128_cfb8(void),
327 EVP_aes_128_cfb128(void)
328 AES with 128 bit key length in CBC, ECB, OFB and CFB modes
329 respectively.
330 EVP_aes_192_cbc(void), EVP_aes_192_ecb(), EVP_aes_192_ofb(void),
332 EVP_aes_192_cfb1(void), EVP_aes_192_cfb8(void),
333 EVP_aes_192_cfb128(void)
334 AES with 192 bit key length in CBC, ECB, OFB and CFB modes
335 respectively.
336 EVP_aes_256_cbc(void), EVP_aes_256_ecb(), EVP_aes_256_ofb(void),
338 EVP_aes_256_cfb1(void), EVP_aes_256_cfb8(void),
339 EVP_aes_256_cfb128(void)
340 AES with 256 bit key length in CBC, ECB, OFB and CFB modes
341 respectively.
342 EVP_rc4(void)
344 RC4 stream cipher. This is a variable key length cipher with
345 default key length 128 bits.
346 EVP_rc4_40(void)
348 RC4 stream cipher with 40 bit key length. This is obsolete and new
349 code should use EVP_rc4() and the EVP_CIPHER_CTX_set_key_length()
350 function.
351 EVP_idea_cbc() EVP_idea_ecb(void), EVP_idea_cfb(void),
353 EVP_idea_ofb(void), EVP_idea_cbc(void)
354 IDEA encryption algorithm in CBC, ECB, CFB and OFB modes
355 respectively.
356 EVP_rc2_cbc(void), EVP_rc2_ecb(void), EVP_rc2_cfb(void),
358 EVP_rc2_ofb(void)
359 RC2 encryption algorithm in CBC, ECB, CFB and OFB modes
360 respectively. This is a variable key length cipher with an
361 additional parameter called "effective key bits" or "effective key
362 length". By default both are set to 128 bits.
363 EVP_rc2_40_cbc(void), EVP_rc2_64_cbc(void)
365 RC2 algorithm in CBC mode with a default key length and effective
366 key length of 40 and 64 bits. These are obsolete and new code
367 should use EVP_rc2_cbc(), EVP_CIPHER_CTX_set_key_length() and
368 EVP_CIPHER_CTX_ctrl() to set the key length and effective key
369 length.
370 EVP_bf_cbc(void), EVP_bf_ecb(void), EVP_bf_cfb(void), EVP_bf_ofb(void);
372 Blowfish encryption algorithm in CBC, ECB, CFB and OFB modes
373 respectively. This is a variable key length cipher.
374 EVP_cast5_cbc(void), EVP_cast5_ecb(void), EVP_cast5_cfb(void),
376 EVP_cast5_ofb(void)
377 CAST encryption algorithm in CBC, ECB, CFB and OFB modes
378 respectively. This is a variable key length cipher.
379 EVP_rc5_32_12_16_cbc(void), EVP_rc5_32_12_16_ecb(void),
381 EVP_rc5_32_12_16_cfb(void), EVP_rc5_32_12_16_ofb(void)
382 RC5 encryption algorithm in CBC, ECB, CFB and OFB modes
383 respectively. This is a variable key length cipher with an
384 additional "number of rounds" parameter. By default the key length
385 is set to 128 bits and 12 rounds.
386
388 Where possible the EVP interface to symmetric ciphers should be used in
389 preference to the low level interfaces. This is because the code then
390 becomes transparent to the cipher used and much more flexible.
391 PKCS padding works by adding n padding bytes of value n to make the
393 total length of the encrypted data a multiple of the block size.
394 Padding is always added so if the data is already a multiple of the
395 block size n will equal the block size. For example if the block size
396 is 8 and 11 bytes are to be encrypted then 5 padding bytes of value 5
397 will be added.
398 When decrypting the final block is checked to see if it has the correct
400 form.
401 Although the decryption operation can produce an error if padding is
403 enabled, it is not a strong test that the input data or key is correct.
404 A random block has better than 1 in 256 chance of being of the correct
405 format and problems with the input data earlier on will not produce a
406 final decrypt error.
407 If padding is disabled then the decryption operation will always
409 succeed if the total amount of data decrypted is a multiple of the
410 block size.
411 The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(),
413 EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained
414 for compatibility with existing code. New code should use
415 EVP_EncryptInit_ex(), EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(),
416 EVP_DecryptFinal_ex(), EVP_CipherInit_ex() and EVP_CipherFinal_ex()
417 because they can reuse an existing context without allocating and
418 freeing it up on each call.
419
421 For RC5 the number of rounds can currently only be set to 8, 12 or 16.
422 This is a limitation of the current RC5 code rather than the EVP
423 interface.
424 EVP_MAX_KEY_LENGTH and EVP_MAX_IV_LENGTH only refer to the internal
426 ciphers with default key lengths. If custom ciphers exceed these values
427 the results are unpredictable. This is because it has become standard
428 practice to define a generic key as a fixed unsigned char array
429 containing EVP_MAX_KEY_LENGTH bytes.
430 The ASN1 code is incomplete (and sometimes inaccurate) it has only been
432 tested for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC
433 mode.
434
436 Get the number of rounds used in RC5:
437 int nrounds;
439 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_RC5_ROUNDS, 0, &nrounds);
440 Get the RC2 effective key length:
442 int key_bits;
444 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GET_RC2_KEY_BITS, 0, &key_bits);
445 Set the number of rounds used in RC5:
447 int nrounds;
449 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC5_ROUNDS, nrounds, NULL);
450 Set the effective key length used in RC2:
452 int key_bits;
454 EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_SET_RC2_KEY_BITS, key_bits, NULL);
455 Encrypt a string using blowfish:
457 int do_crypt(char *outfile)
459 {
460 unsigned char outbuf[1024];
461 int outlen, tmplen;
462 /* Bogus key and IV: we'd normally set these from
463 * another source.
464 */
465 unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
466 unsigned char iv[] = {1,2,3,4,5,6,7,8};
467 char intext[] = "Some Crypto Text";
468 EVP_CIPHER_CTX ctx;
469 FILE *out;
470 EVP_CIPHER_CTX_init(&ctx);
471 EVP_EncryptInit_ex(&ctx, EVP_bf_cbc(), NULL, key, iv);
472 if(!EVP_EncryptUpdate(&ctx, outbuf, &outlen, intext, strlen(intext)))
474 {
475 /* Error */
476 return 0;
477 }
478 /* Buffer passed to EVP_EncryptFinal() must be after data just
479 * encrypted to avoid overwriting it.
480 */
481 if(!EVP_EncryptFinal_ex(&ctx, outbuf + outlen, &tmplen))
482 {
483 /* Error */
484 return 0;
485 }
486 outlen += tmplen;
487 EVP_CIPHER_CTX_cleanup(&ctx);
488 /* Need binary mode for fopen because encrypted data is
489 * binary data. Also cannot use strlen() on it because
490 * it wont be null terminated and may contain embedded
491 * nulls.
492 */
493 out = fopen(outfile, "wb");
494 fwrite(outbuf, 1, outlen, out);
495 fclose(out);
496 return 1;
497 }
498 The ciphertext from the above example can be decrypted using the
500 openssl utility with the command line:
501 S<openssl bf -in cipher.bin -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 -d>
503 General encryption, decryption function example using FILE I/O and RC2
505 with an 80 bit key:
506 int do_crypt(FILE *in, FILE *out, int do_encrypt)
508 {
509 /* Allow enough space in output buffer for additional block */
510 inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
511 int inlen, outlen;
512 /* Bogus key and IV: we'd normally set these from
513 * another source.
514 */
515 unsigned char key[] = "0123456789";
516 unsigned char iv[] = "12345678";
517 /* Don't set key or IV because we will modify the parameters */
518 EVP_CIPHER_CTX_init(&ctx);
519 EVP_CipherInit_ex(&ctx, EVP_rc2(), NULL, NULL, NULL, do_encrypt);
520 EVP_CIPHER_CTX_set_key_length(&ctx, 10);
521 /* We finished modifying parameters so now we can set key and IV */
522 EVP_CipherInit_ex(&ctx, NULL, NULL, key, iv, do_encrypt);
523 for(;;)
525 {
526 inlen = fread(inbuf, 1, 1024, in);
527 if(inlen <= 0) break;
528 if(!EVP_CipherUpdate(&ctx, outbuf, &outlen, inbuf, inlen))
529 {
530 /* Error */
531 EVP_CIPHER_CTX_cleanup(&ctx);
532 return 0;
533 }
534 fwrite(outbuf, 1, outlen, out);
535 }
536 if(!EVP_CipherFinal_ex(&ctx, outbuf, &outlen))
537 {
538 /* Error */
539 EVP_CIPHER_CTX_cleanup(&ctx);
540 return 0;
541 }
542 fwrite(outbuf, 1, outlen, out);
543 EVP_CIPHER_CTX_cleanup(&ctx);
545 return 1;
546 }
547
549 evp(3)
550
552 EVP_CIPHER_CTX_init(), EVP_EncryptInit_ex(), EVP_EncryptFinal_ex(),
553 EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(), EVP_CipherInit_ex(),
554 EVP_CipherFinal_ex() and EVP_CIPHER_CTX_set_padding() appeared in
555 OpenSSL 0.9.7.
5561.0.0e 2011-09-07 EVP_EncryptInit(3)