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, const unsigned char *key, const unsigned char *iv);
63 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
64 int *outl, const 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, const unsigned char *key, const unsigned char *iv);
69 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
70 int *outl, const 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, const unsigned char *key, const unsigned char *iv, int enc);
75 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
76 int *outl, const 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 const unsigned char *key, const 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 const unsigned char *key, const 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 const unsigned char *key, const 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);
94 int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key);
96 const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
97 const EVP_CIPHER *EVP_get_cipherbynid(int nid);
98 const EVP_CIPHER *EVP_get_cipherbyobj(const ASN1_OBJECT *a);
100 int EVP_CIPHER_nid(const EVP_CIPHER *e);
101 int EVP_CIPHER_block_size(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 For most ciphers and modes, the amount of data written can be anything
151 from zero bytes to (inl + cipher_block_size - 1) bytes.
152 For wrap cipher modes, the amount of data written can be anything
153 from zero bytes to (inl + cipher_block_size) bytes.
154 For stream ciphers, the amount of data written can be anything from zero
156 Thus, B<out> should contain sufficient room for the operation being performed.
157 The actual number of bytes written is placed in B<outl>. It also
158 checks if B<in> and B<out> are partially overlapping, and if they are
159 0 is returned to indicate failure.
161 If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts
162 the "final" data, that is any data that remains in a partial block.
163 It uses standard block padding (aka PKCS padding) as described in
164 the NOTES section, below. The encrypted
165 final data is written to B<out> which should have sufficient space for
166 one cipher block. The number of bytes written is placed in B<outl>. After
167 this function is called the encryption operation is finished and no further
168 calls to EVP_EncryptUpdate() should be made.
170 If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more
171 data and it will return an error if any data remains in a partial block:
172 that is if the total data length is not a multiple of the block size.
174 EVP_DecryptInit_ex(), EVP_DecryptUpdate() and EVP_DecryptFinal_ex() are the
175 corresponding decryption operations. EVP_DecryptFinal() will return an
176 error code if padding is enabled and the final block is not correctly
177 formatted. The parameters and restrictions are identical to the encryption
178 operations except that if padding is enabled the decrypted data buffer B<out>
179 passed to EVP_DecryptUpdate() should have sufficient room for
180 (B<inl> + cipher_block_size) bytes unless the cipher block size is 1 in
181 which case B<inl> bytes is sufficient.
183 EVP_CipherInit_ex(), EVP_CipherUpdate() and EVP_CipherFinal_ex() are
184 functions that can be used for decryption or encryption. The operation
185 performed depends on the value of the B<enc> parameter. It should be set
186 to 1 for encryption, 0 for decryption and -1 to leave the value unchanged
187 (the actual value of 'enc' being supplied in a previous call).
189 EVP_CIPHER_CTX_reset() clears all information from a cipher context
190 and free up any allocated memory associate with it, except the B<ctx>
191 itself. This function should be called anytime B<ctx> is to be reused
192 for another EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal()
195 EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit() behave in a
196 similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and
197 EVP_CipherInit_ex() except they always use the default cipher implementation.
199 EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal() are
200 identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
201 EVP_CipherFinal_ex(). In previous releases they also cleaned up
202 the B<ctx>, but this is no longer done and EVP_CIPHER_CTX_clean()
203 must be called to free any context resources.
205 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
206 return an EVP_CIPHER structure when passed a cipher name, a NID or an
207 ASN1_OBJECT structure.
209 EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return the NID of a cipher when
210 passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX> structure. The actual NID
211 value is an internal value which may not have a corresponding OBJECT
214 EVP_CIPHER_CTX_set_padding() enables or disables padding. This
215 function should be called after the context is set up for encryption
216 or decryption with EVP_EncryptInit_ex(), EVP_DecryptInit_ex() or
217 EVP_CipherInit_ex(). By default encryption operations are padded using
218 standard block padding and the padding is checked and removed when
219 decrypting. If the B<pad> parameter is zero then no padding is
220 performed, the total amount of data encrypted or decrypted must then
221 be a multiple of the block size or an error will occur.
223 EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
224 length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
225 structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum key length
226 for all ciphers. Note: although EVP_CIPHER_key_length() is fixed for a
227 given cipher, the value of EVP_CIPHER_CTX_key_length() may be different
228 for variable key length ciphers.
230 EVP_CIPHER_CTX_set_key_length() sets the key length of the cipher ctx.
231 If the cipher is a fixed length cipher then attempting to set the key
232 length to any value other than the fixed value is an error.
234 EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
235 length of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>.
236 It will return zero if the cipher does not use an IV. The constant
237 B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers.
239 EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block
240 size of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
241 structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the maximum block
242 length for all ciphers.
244 EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the type of the passed
245 cipher or context. This "type" is the actual NID of the cipher OBJECT
246 IDENTIFIER as such it ignores the cipher parameters and 40 bit RC2 and
247 128 bit RC2 have the same NID. If the cipher does not have an object
248 identifier or does not have ASN1 support this function will return
251 EVP_CIPHER_CTX_cipher() returns the B<EVP_CIPHER> structure when passed
252 an B<EVP_CIPHER_CTX> structure.
254 EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return the block cipher mode:
255 EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE,
256 EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE,
257 EVP_CIPH_WRAP_MODE or EVP_CIPH_OCB_MODE. If the cipher is a stream cipher then
258 EVP_CIPH_STREAM_CIPHER is returned.
260 EVP_CIPHER_param_to_asn1() sets the AlgorithmIdentifier "parameter" based
261 on the passed cipher. This will typically include any parameters and an
262 IV. The cipher IV (if any) must be set when this call is made. This call
263 should be made before the cipher is actually "used" (before any
264 EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example). This function
265 may fail if the cipher does not have any ASN1 support.
267 EVP_CIPHER_asn1_to_param() sets the cipher parameters based on an ASN1
268 AlgorithmIdentifier "parameter". The precise effect depends on the cipher
269 In the case of RC2, for example, it will set the IV and effective key length.
270 This function should be called after the base cipher type is set but before
271 the key is set. For example EVP_CipherInit() will be called with the IV and
272 key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally
273 EVP_CipherInit() again with all parameters except the key set to NULL. It is
274 possible for this function to fail if the cipher does not have any ASN1 support
275 or the parameters cannot be set (for example the RC2 effective key length
278 EVP_CIPHER_CTX_ctrl() allows various cipher specific parameters to be determined
281 EVP_CIPHER_CTX_rand_key() generates a random key of the appropriate length
282 based on the cipher context. The EVP_CIPHER can provide its own random key
283 generation routine to support keys of a specific form. B<Key> must point to a
284 buffer at least as big as the value returned by EVP_CIPHER_CTX_key_length().
288 EVP_CIPHER_CTX_new() returns a pointer to a newly created
289 B<EVP_CIPHER_CTX> for success and B<NULL> for failure.
291 EVP_EncryptInit_ex(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex()
292 return 1 for success and 0 for failure.
294 EVP_DecryptInit_ex() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
295 EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success.
297 EVP_CipherInit_ex() and EVP_CipherUpdate() return 1 for success and 0 for failure.
298 EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
300 EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure.
302 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
303 return an B<EVP_CIPHER> structure or NULL on error.
305 EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return a NID.
307 EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block
310 EVP_CIPHER_key_length() and EVP_CIPHER_CTX_key_length() return the key
313 EVP_CIPHER_CTX_set_padding() always returns 1.
315 EVP_CIPHER_iv_length() and EVP_CIPHER_CTX_iv_length() return the IV
316 length or zero if the cipher does not use an IV.
318 EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the cipher's
319 OBJECT IDENTIFIER or NID_undef if it has no defined OBJECT IDENTIFIER.
321 EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure.
323 EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater
324 than zero for success and zero or a negative number on failure.
326 EVP_CIPHER_CTX_rand_key() returns 1 for success.
328 =head1 CIPHER LISTING
330 All algorithms have a fixed key length unless otherwise stated.
332 Refer to L<SEE ALSO> for the full list of ciphers available through the EVP
339 Null cipher: does nothing.
343 =head1 AEAD Interface
345 The EVP interface for Authenticated Encryption with Associated Data (AEAD)
346 modes are subtly altered and several additional I<ctrl> operations are supported
347 depending on the mode specified.
349 To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(),
350 EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output
351 parameter B<out> set to B<NULL>.
353 When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal()
354 indicates whether the operation was successful. If it does not indicate success,
355 the authentication operation has failed and any output data B<MUST NOT> be used
358 =head2 GCM and OCB Modes
360 The following I<ctrl>s are supported in GCM and OCB modes.
364 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
366 Sets the IV length. This call can only be made before specifying an IV. If
367 not called a default IV length is used.
369 For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the
372 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
374 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
375 This call can only be made when encrypting data and B<after> all data has been
376 processed (e.g. after an EVP_EncryptFinal() call).
378 For OCB, C<taglen> must either be 16 or the value previously set via
379 B<EVP_CTRL_AEAD_SET_TAG>.
381 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
383 Sets the expected tag to C<taglen> bytes from C<tag>.
384 The tag length can only be set before specifying an IV.
385 C<taglen> must be between 1 and 16 inclusive.
387 For GCM, this call is only valid when decrypting data.
389 For OCB, this call is valid when decrypting data to set the expected tag,
390 and before encryption to set the desired tag length.
392 In OCB mode, calling this before encryption with C<tag> set to C<NULL> sets the
393 tag length. If this is not called prior to encryption, a default tag length is
396 For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the
397 maximum tag length for OCB.
403 The EVP interface for CCM mode is similar to that of the GCM mode but with a
404 few additional requirements and different I<ctrl> values.
406 For CCM mode, the total plaintext or ciphertext length B<MUST> be passed to
407 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output
408 and input parameters (B<in> and B<out>) set to B<NULL> and the length passed in
409 the B<inl> parameter.
411 The following I<ctrl>s are supported in CCM mode.
415 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
417 This call is made to set the expected B<CCM> tag value when decrypting or
418 the length of the tag (with the C<tag> parameter set to NULL) when encrypting.
419 The tag length is often referred to as B<M>. If not set a default value is
420 used (12 for AES). When decrypting, the tag needs to be set before passing
421 in data to be decrypted, but as in GCM and OCB mode, it can be set after
422 passing additional authenticated data (see L<AEAD Interface>).
424 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL)
426 Sets the CCM B<L> value. If not set a default is used (8 for AES).
428 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
430 Sets the CCM nonce (IV) length. This call can only be made before specifying
431 a nonce value. The nonce length is given by B<15 - L> so it is 7 by default for
436 =head2 ChaCha20-Poly1305
438 The following I<ctrl>s are supported for the ChaCha20-Poly1305 AEAD algorithm.
442 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
444 Sets the nonce length. This call can only be made before specifying the nonce.
445 If not called a default nonce length of 12 (i.e. 96 bits) is used. The maximum
446 nonce length is 12 bytes (i.e. 96-bits). If a nonce of less than 12 bytes is set
447 then the nonce is automatically padded with leading 0 bytes to make it 12 bytes
450 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
452 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
453 This call can only be made when encrypting data and B<after> all data has been
454 processed (e.g. after an EVP_EncryptFinal() call).
456 C<taglen> specified here must be 16 (B<POLY1305_BLOCK_SIZE>, i.e. 128-bits) or
459 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
461 Sets the expected tag to C<taglen> bytes from C<tag>.
462 The tag length can only be set before specifying an IV.
463 C<taglen> must be between 1 and 16 (B<POLY1305_BLOCK_SIZE>) inclusive.
464 This call is only valid when decrypting data.
470 Where possible the B<EVP> interface to symmetric ciphers should be used in
471 preference to the low-level interfaces. This is because the code then becomes
472 transparent to the cipher used and much more flexible. Additionally, the
473 B<EVP> interface will ensure the use of platform specific cryptographic
474 acceleration such as AES-NI (the low-level interfaces do not provide the
477 PKCS padding works by adding B<n> padding bytes of value B<n> to make the total
478 length of the encrypted data a multiple of the block size. Padding is always
479 added so if the data is already a multiple of the block size B<n> will equal
480 the block size. For example if the block size is 8 and 11 bytes are to be
481 encrypted then 5 padding bytes of value 5 will be added.
483 When decrypting the final block is checked to see if it has the correct form.
485 Although the decryption operation can produce an error if padding is enabled,
486 it is not a strong test that the input data or key is correct. A random block
487 has better than 1 in 256 chance of being of the correct format and problems with
488 the input data earlier on will not produce a final decrypt error.
490 If padding is disabled then the decryption operation will always succeed if
491 the total amount of data decrypted is a multiple of the block size.
493 The functions EVP_EncryptInit(), EVP_EncryptFinal(), EVP_DecryptInit(),
494 EVP_CipherInit() and EVP_CipherFinal() are obsolete but are retained for
495 compatibility with existing code. New code should use EVP_EncryptInit_ex(),
496 EVP_EncryptFinal_ex(), EVP_DecryptInit_ex(), EVP_DecryptFinal_ex(),
497 EVP_CipherInit_ex() and EVP_CipherFinal_ex() because they can reuse an
498 existing context without allocating and freeing it up on each call.
500 There are some differences between functions EVP_CipherInit() and
501 EVP_CipherInit_ex(), significant in some circumstances. EVP_CipherInit() fills
502 the passed context object with zeros. As a consequence, EVP_CipherInit() does
503 not allow step-by-step initialization of the ctx when the I<key> and I<iv> are
504 passed in separate calls. It also means that the flags set for the CTX are
505 removed, and it is especially important for the
506 B<EVP_CIPHER_CTX_FLAG_WRAP_ALLOW> flag treated specially in
509 EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros.
513 B<EVP_MAX_KEY_LENGTH> and B<EVP_MAX_IV_LENGTH> only refer to the internal
514 ciphers with default key lengths. If custom ciphers exceed these values the
515 results are unpredictable. This is because it has become standard practice to
516 define a generic key as a fixed unsigned char array containing
517 B<EVP_MAX_KEY_LENGTH> bytes.
519 The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested
520 for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode.
524 Encrypt a string using IDEA:
526 int do_crypt(char *outfile)
528 unsigned char outbuf[1024];
531 * Bogus key and IV: we'd normally set these from
534 unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
535 unsigned char iv[] = {1,2,3,4,5,6,7,8};
536 char intext[] = "Some Crypto Text";
540 ctx = EVP_CIPHER_CTX_new();
541 EVP_EncryptInit_ex(ctx, EVP_idea_cbc(), NULL, key, iv);
543 if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) {
545 EVP_CIPHER_CTX_free(ctx);
549 * Buffer passed to EVP_EncryptFinal() must be after data just
550 * encrypted to avoid overwriting it.
552 if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) {
554 EVP_CIPHER_CTX_free(ctx);
558 EVP_CIPHER_CTX_free(ctx);
560 * Need binary mode for fopen because encrypted data is
561 * binary data. Also cannot use strlen() on it because
562 * it won't be NUL terminated and may contain embedded
565 out = fopen(outfile, "wb");
570 fwrite(outbuf, 1, outlen, out);
575 The ciphertext from the above example can be decrypted using the B<openssl>
576 utility with the command line (shown on two lines for clarity):
579 -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename
581 General encryption and decryption function example using FILE I/O and AES128
584 int do_crypt(FILE *in, FILE *out, int do_encrypt)
586 /* Allow enough space in output buffer for additional block */
587 unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
591 * Bogus key and IV: we'd normally set these from
594 unsigned char key[] = "0123456789abcdeF";
595 unsigned char iv[] = "1234567887654321";
597 /* Don't set key or IV right away; we want to check lengths */
598 ctx = EVP_CIPHER_CTX_new();
599 EVP_CipherInit_ex(ctx, EVP_aes_128_cbc(), NULL, NULL, NULL,
601 OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16);
602 OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16);
604 /* Now we can set key and IV */
605 EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, do_encrypt);
608 inlen = fread(inbuf, 1, 1024, in);
611 if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) {
613 EVP_CIPHER_CTX_free(ctx);
616 fwrite(outbuf, 1, outlen, out);
618 if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) {
620 EVP_CIPHER_CTX_free(ctx);
623 fwrite(outbuf, 1, outlen, out);
625 EVP_CIPHER_CTX_free(ctx);
634 Supported ciphers are listed in:
653 Support for OCB mode was added in OpenSSL 1.1.0.
655 B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result,
656 EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup()
657 disappeared. EVP_CIPHER_CTX_init() remains as an alias for
658 EVP_CIPHER_CTX_reset().
662 Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
664 Licensed under the OpenSSL license (the "License"). You may not use
665 this file except in compliance with the License. You can obtain a copy
666 in the file LICENSE in the source distribution or at
667 L<https://www.openssl.org/source/license.html>.