17 EVP_CIPHER_CTX_set_key_length,
29 EVP_CIPHER_block_size,
30 EVP_CIPHER_key_length,
35 EVP_CIPHER_CTX_cipher,
37 EVP_CIPHER_CTX_block_size,
38 EVP_CIPHER_CTX_key_length,
39 EVP_CIPHER_CTX_iv_length,
40 EVP_CIPHER_CTX_get_app_data,
41 EVP_CIPHER_CTX_set_app_data,
45 EVP_CIPHER_param_to_asn1,
46 EVP_CIPHER_asn1_to_param,
47 EVP_CIPHER_CTX_set_padding,
55 #include <openssl/evp.h>
57 EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void);
58 int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx);
59 void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx);
61 int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
62 ENGINE *impl, unsigned char *key, unsigned char *iv);
63 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
64 int *outl, unsigned char *in, int inl);
65 int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
67 int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
68 ENGINE *impl, unsigned char *key, unsigned char *iv);
69 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
70 int *outl, unsigned char *in, int inl);
71 int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
73 int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
74 ENGINE *impl, unsigned char *key, unsigned char *iv, int enc);
75 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
76 int *outl, unsigned char *in, int inl);
77 int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
79 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
80 unsigned char *key, unsigned char *iv);
81 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
83 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
84 unsigned char *key, unsigned char *iv);
85 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
87 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
88 unsigned char *key, unsigned char *iv, int enc);
89 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
91 int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding);
92 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen);
93 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr);
95 const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
96 const EVP_CIPHER *EVP_get_cipherbynid(int nid);
97 const EVP_CIPHER *EVP_get_cipherbyobj(const ASN1_OBJECT *a);
99 int EVP_CIPHER_nid(const EVP_CIPHER *e);
100 int EVP_CIPHER_block_size(const EVP_CIPHER *e);
101 int EVP_CIPHER_key_length(const EVP_CIPHER *e)
102 int EVP_CIPHER_key_length(const EVP_CIPHER *e);
103 int EVP_CIPHER_iv_length(const EVP_CIPHER *e);
104 unsigned long EVP_CIPHER_flags(const EVP_CIPHER *e);
105 unsigned long EVP_CIPHER_mode(const EVP_CIPHER *e);
106 int EVP_CIPHER_type(const EVP_CIPHER *ctx);
108 const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx);
109 int EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx);
110 int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx);
111 int EVP_CIPHER_CTX_key_length(const EVP_CIPHER_CTX *ctx);
112 int EVP_CIPHER_CTX_iv_length(const EVP_CIPHER_CTX *ctx);
113 void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx);
114 void EVP_CIPHER_CTX_set_app_data(const EVP_CIPHER_CTX *ctx, void *data);
115 int EVP_CIPHER_CTX_type(const EVP_CIPHER_CTX *ctx);
116 int EVP_CIPHER_CTX_mode(const EVP_CIPHER_CTX *ctx);
118 int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
119 int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
123 The EVP cipher routines are a high level interface to certain
126 EVP_CIPHER_CTX_new() creates a cipher context.
128 EVP_CIPHER_CTX_free() clears all information from a cipher context
129 and free up any allocated memory associate with it, including B<ctx>
130 itself. This function should be called after all operations using a
131 cipher are complete so sensitive information does not remain in
134 EVP_EncryptInit_ex() sets up cipher context B<ctx> for encryption
135 with cipher B<type> from ENGINE B<impl>. B<ctx> must be created
136 before calling this function. B<type> is normally supplied
137 by a function such as EVP_aes_256_cbc(). If B<impl> is NULL then the
138 default implementation is used. B<key> is the symmetric key to use
139 and B<iv> is the IV to use (if necessary), the actual number of bytes
140 used for the key and IV depends on the cipher. It is possible to set
141 all parameters to NULL except B<type> in an initial call and supply
142 the remaining parameters in subsequent calls, all of which have B<type>
143 set to NULL. This is done when the default cipher parameters are not
146 EVP_EncryptUpdate() encrypts B<inl> bytes from the buffer B<in> and
147 writes the encrypted version to B<out>. This function can be called
148 multiple times to encrypt successive blocks of data. The amount
149 of data written depends on the block alignment of the encrypted data:
150 as a result the amount of data written may be anything from zero bytes
151 to (inl + cipher_block_size - 1) so B<out> should contain sufficient
152 room. The actual number of bytes written is placed in B<outl>. It also
153 checks if B<in> and B<out> are partially overlapping, and if they are
154 0 is returned to indicate failure.
156 If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts
157 the "final" data, that is any data that remains in a partial block.
158 It uses standard block padding (aka PKCS padding) as described in
159 the NOTES section, below. The encrypted
160 final data is written to B<out> which should have sufficient space for
161 one cipher block. The number of bytes written is placed in B<outl>. After
162 this function is called the encryption operation is finished and no further
163 calls to EVP_EncryptUpdate() should be made.
165 If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more
166 data and it will return an error if any data remains in a partial block:
167 that is if the total data length is not a multiple of the block size.
169 EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are the
170 corresponding decryption operations. EVP_DecryptFinal() will return an
171 error code if padding is enabled and the final block is not correctly
172 formatted. The parameters and restrictions are identical to the encryption
173 operations except that if padding is enabled the decrypted data buffer B<out>
174 passed to EVP_DecryptUpdate() should have sufficient room for
175 (B<inl> + cipher_block_size) bytes unless the cipher block size is 1 in
176 which case B<inl> bytes is sufficient.
178 EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are
179 functions that can be used for decryption or encryption. The operation
180 performed depends on the value of the B<enc> parameter. It should be set
181 to 1 for encryption, 0 for decryption and -1 to leave the value unchanged
182 (the actual value of 'enc' being supplied in a previous call).
184 EVP_CIPHER_CTX_reset() clears all information from a cipher context
185 and free up any allocated memory associate with it, except the B<ctx>
186 itself. This function should be called anytime B<ctx> is to be reused
187 for another EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal()
190 EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a
191 similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and
192 EVP_CipherInit_ex() except the B<ctx> parameter does not need to be
193 initialized and they always use the default cipher implementation.
195 EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are
196 identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
197 EVP_CipherFinal_ex(). In previous releases they also cleaned up
198 the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean()
199 must be called to free any context resources.
201 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
202 return an EVP_CIPHER structure when passed a cipher name, a NID or an
203 ASN1_OBJECT structure.
205 EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return the NID of a cipher when
206 passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> structure. The actual NID
207 value is an internal value which may not have a corresponding OBJECT
210 EVP_CIPHER_CTX_set_padding() enables or disables padding. This
211 function should be called after the context is set up for encryption
212 or decryption with EVP_EncryptInit_ex(), EVP_DecryptInit_ex() or
213 EVP_CipherInit_ex(). By default encryption operations are padded using
214 standard block padding and the padding is checked and removed when
215 decrypting. If the B<pad> parameter is zero then no padding is
216 performed, the total amount of data encrypted or decrypted must then
217 be a multiple of the block size or an error will occur.
219 EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
220 length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
221 structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length
222 for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a
223 given cipher, the value of EVP_CIPHER_CTX_key_length() may be different
224 for variable key length ciphers.
226 EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx.
227 If the cipher is a fixed length cipher then attempting to set the key
228 length to any value other than the fixed value is an error.
230 EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
231 length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>.
232 It will return zero if the cipher does not use an IV. The constant
233 B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers.
235 EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block
236 size of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
237 structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the maximum block
238 length for all ciphers.
240 EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the type of the passed
241 cipher or context. This "type" is the actual NID of the cipher OBJECT
242 IDENTIFIER as such it ignores the cipher parameters and 40 bit RC2 and
243 128 bit RC2 have the same NID. If the cipher does not have an object
244 identifier or does not have ASN1 support this function will return
247 EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed
248 an B<EVP_CIPHER_CTX> structure.
250 EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher mode:
251 EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE,
252 EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE,
253 EVP_CIPH_WRAP_MODE or EVP_CIPH_OCB_MODE. If the cipher is a stream cipher then
254 EVP_CIPH_STREAM_CIPHER is returned.
256 EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based
257 on the passed cipher. This will typically include any parameters and an
258 IV. The cipher IV (if any) must be set when this call is made. This call
259 should be made before the cipher is actually "used" (before any
260 EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This function
261 may fail if the cipher does not have any ASN1 support.
263 EVP_CIPHER_asn1_to_param() sets the cipher parameters based on an ASN1
264 AlgorithmIdentifier "parameter". The precise effect depends on the cipher
265 In the case of RC2, for example, it will set the IV and effective key length.
266 This function should be called after the base cipher type is set but before
267 the key is set. For example EVP_CipherInit() will be called with the IV and
268 key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally
269 EVP_CipherInit() again with all parameters except the key set to NULL. It is
270 possible for this function to fail if the cipher does not have any ASN1 support
271 or the parameters cannot be set (for example the RC2 effective key length
274 EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be determined
279 EVP_CIPHER_CTX_new() returns a pointer to a newly created
280 B<EVP_CIPHER_CTX> for success and B<NULL> for failure.
282 EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex()
283 return 1 for success and 0 for failure.
285 EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
286 EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success.
288 EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0 for failure.
289 EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
291 EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure.
293 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
294 return an B<EVP_CIPHER> structure or NULL on error.
296 EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return a NID.
298 EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block
301 EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
304 EVP_CIPHER_CTX_set_padding() always returns 1.
306 EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
307 length or zero if the cipher does not use an IV.
309 EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the cipher's
310 OBJECT IDENTIFIER or NID_undef if it has no defined OBJECT IDENTIFIER.
312 EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure.
314 EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater
315 than zero for success and zero or a negative number.
317 =head1 CIPHER LISTING
319 All algorithms have a fixed key length unless otherwise stated.
321 Refer to L<SEE ALSO> for the full list of ciphers available through the EVP
328 Null cipher: does nothing.
332 =head1 AEAD Interface
334 The EVP interface for Authenticated Encryption with Associated Data (AEAD)
335 modes are subtly altered and several additional I<ctrl> operations are supported
336 depending on the mode specified.
338 To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(),
339 EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output
340 parameter B<out> set to B<NULL>.
342 When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal()
343 indicates whether the operation was successful. If it does not indicate success,
344 the authentication operation has failed and any output data B<MUST NOT> be used
347 =head2 GCM and OCB Modes
349 The following I<ctrl>s are supported in GCM and OCB modes.
353 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
355 Sets the IV length. This call can only be made before specifying an IV. If
356 not called a default IV length is used.
358 For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the
361 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
363 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
364 This call can only be made when encrypting data and B<after> all data has been
365 processed (e.g. after an EVP_EncryptFinal() call).
367 For OCB, C<taglen> must either be 16 or the value previously set via
368 B<EVP_CTRL_AEAD_SET_TAG>.
370 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
372 Sets the expected tag to C<taglen> bytes from C<tag>.
373 The tag length can only be set before specifying an IV.
374 C<taglen> must be between 1 and 16 inclusive.
376 For GCM, this call is only valid when decrypting data.
378 For OCB, this call is valid when decrypting data to set the expected tag,
379 and before encryption to set the desired tag length.
381 In OCB mode, calling this before encryption with C<tag> set to C<NULL> sets the
382 tag length. If this is not called prior to encryption, a default tag length is
385 For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the
386 maximum tag length for OCB.
392 The EVP interface for CCM mode is similar to that of the GCM mode but with a
393 few additional requirements and different I<ctrl> values.
395 For CCM mode, the total plaintext or ciphertext length B<MUST> be passed to
396 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output
397 and input parameters (B<in> and B<out>) set to B<NULL> and the length passed in
398 the B<inl> parameter.
400 The following I<ctrl>s are supported in CCM mode.
404 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
406 This call is made to set the expected B<CCM> tag value when decrypting or
407 the length of the tag (with the C<tag> parameter set to NULL) when encrypting.
408 The tag length is often referred to as B<M>. If not set a default value is
411 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL)
413 Sets the CCM B<L> value. If not set a default is used (8 for AES).
415 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
417 Sets the CCM nonce (IV) length. This call can only be made before specifying an
418 nonce value. The nonce length is given by B<15 - L> so it is 7 by default for
423 =head2 ChaCha20-Poly1305
425 The following I<ctrl>s are supported for the ChaCha20-Poly1305 AEAD algorithm.
429 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
431 Sets the nonce length. This call can only be made before specifying the nonce.
432 If not called a default nonce length of 12 (i.e. 96 bits) is used. The maximum
433 nonce length is 16 (B<CHACHA_CTR_SIZE>, i.e. 128-bits).
435 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
437 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
438 This call can only be made when encrypting data and B<after> all data has been
439 processed (e.g. after an EVP_EncryptFinal() call).
441 C<taglen> specified here must be 16 (B<POLY1305_BLOCK_SIZE>, i.e. 128-bits) or
444 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
446 Sets the expected tag to C<taglen> bytes from C<tag>.
447 The tag length can only be set before specifying an IV.
448 C<taglen> must be between 1 and 16 (B<POLY1305_BLOCK_SIZE>) inclusive.
449 This call is only valid when decrypting data.
455 Where possible the B<EVP> interface to symmetric ciphers should be used in
456 preference to the low level interfaces. This is because the code then becomes
457 transparent to the cipher used and much more flexible. Additionally, the
458 B<EVP> interface will ensure the use of platform specific cryptographic
459 acceleration such as AES-NI (the low level interfaces do not provide the
462 PKCS padding works by adding B<n> padding bytes of value B<n> to make the total
463 length of the encrypted data a multiple of the block size. Padding is always
464 added so if the data is already a multiple of the block size B<n> will equal
465 the block size. For example if the block size is 8 and 11 bytes are to be
466 encrypted then 5 padding bytes of value 5 will be added.
468 When decrypting the final block is checked to see if it has the correct form.
470 Although the decryption operation can produce an error if padding is enabled,
471 it is not a strong test that the input data or key is correct. A random block
472 has better than 1 in 256 chance of being of the correct format and problems with
473 the input data earlier on will not produce a final decrypt error.
475 If padding is disabled then the decryption operation will always succeed if
476 the total amount of data decrypted is a multiple of the block size.
478 The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(),
479 EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained for
480 compatibility with existing code. New code should use EVP_EncryptInit_ex(),
481 EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(),
482 EVP_CipherInit_ex() and EVP_CipherFinal_ex() because they can reuse an
483 existing context without allocating and freeing it up on each call.
485 EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros.
489 B<EVP_MAX_KEY_LENGTH> and B<EVP_MAX_IV_LENGTH> only refer to the internal
490 ciphers with default key lengths. If custom ciphers exceed these values the
491 results are unpredictable. This is because it has become standard practice to
492 define a generic key as a fixed unsigned char array containing
493 B<EVP_MAX_KEY_LENGTH> bytes.
495 The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested
496 for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode.
500 Encrypt a string using IDEA:
502 int do_crypt(char *outfile)
504 unsigned char outbuf[1024];
507 * Bogus key and IV: we'd normally set these from
510 unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
511 unsigned char iv[] = {1,2,3,4,5,6,7,8};
512 char intext[] = "Some Crypto Text";
516 ctx = EVP_CIPHER_CTX_new();
517 EVP_EncryptInit_ex(ctx, EVP_idea_cbc(), NULL, key, iv);
519 if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) {
521 EVP_CIPHER_CTX_free(ctx);
525 * Buffer passed to EVP_EncryptFinal() must be after data just
526 * encrypted to avoid overwriting it.
528 if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) {
530 EVP_CIPHER_CTX_free(ctx);
534 EVP_CIPHER_CTX_free(ctx);
536 * Need binary mode for fopen because encrypted data is
537 * binary data. Also cannot use strlen() on it because
538 * it won't be NUL terminated and may contain embedded
541 out = fopen(outfile, "wb");
546 fwrite(outbuf, 1, outlen, out);
551 The ciphertext from the above example can be decrypted using the B<openssl>
552 utility with the command line (shown on two lines for clarity):
555 -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename
557 General encryption and decryption function example using FILE I/O and AES128
560 int do_crypt(FILE *in, FILE *out, int do_encrypt)
562 /* Allow enough space in output buffer for additional block */
563 unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
567 * Bogus key and IV: we'd normally set these from
570 unsigned char key[] = "0123456789abcdeF";
571 unsigned char iv[] = "1234567887654321";
573 /* Don't set key or IV right away; we want to check lengths */
574 ctx = EVP_CIPHER_CTX_new();
575 EVP_CipherInit_ex(&ctx, EVP_aes_128_cbc(), NULL, NULL, NULL,
577 OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16);
578 OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16);
580 /* Now we can set key and IV */
581 EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, do_encrypt);
584 inlen = fread(inbuf, 1, 1024, in);
587 if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) {
589 EVP_CIPHER_CTX_free(ctx);
592 fwrite(outbuf, 1, outlen, out);
594 if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) {
596 EVP_CIPHER_CTX_free(ctx);
599 fwrite(outbuf, 1, outlen, out);
601 EVP_CIPHER_CTX_free(ctx);
610 Supported ciphers are listed in:
629 Support for OCB mode was added in OpenSSL 1.1.0
631 B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result,
632 EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup()
633 disappeared. EVP_CIPHER_CTX_init() remains as an alias for
634 EVP_CIPHER_CTX_reset().
638 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
640 Licensed under the OpenSSL license (the "License"). You may not use
641 this file except in compliance with the License. You can obtain a copy
642 in the file LICENSE in the source distribution or at
643 L<https://www.openssl.org/source/license.html>.