25 EVP_CIPHER_CTX_set_key_length,
39 EVP_CIPHER_get0_description,
40 EVP_CIPHER_names_do_all,
41 EVP_CIPHER_get0_provider,
43 EVP_CIPHER_get_params,
44 EVP_CIPHER_gettable_params,
45 EVP_CIPHER_get_block_size,
46 EVP_CIPHER_get_key_length,
47 EVP_CIPHER_get_iv_length,
51 EVP_CIPHER_CTX_cipher,
52 EVP_CIPHER_CTX_get0_cipher,
53 EVP_CIPHER_CTX_get1_cipher,
54 EVP_CIPHER_CTX_get0_name,
55 EVP_CIPHER_CTX_get_nid,
56 EVP_CIPHER_CTX_get_params,
57 EVP_CIPHER_gettable_ctx_params,
58 EVP_CIPHER_CTX_gettable_params,
59 EVP_CIPHER_CTX_set_params,
60 EVP_CIPHER_settable_ctx_params,
61 EVP_CIPHER_CTX_settable_params,
62 EVP_CIPHER_CTX_get_block_size,
63 EVP_CIPHER_CTX_get_key_length,
64 EVP_CIPHER_CTX_get_iv_length,
65 EVP_CIPHER_CTX_get_tag_length,
66 EVP_CIPHER_CTX_get_app_data,
67 EVP_CIPHER_CTX_set_app_data,
69 EVP_CIPHER_CTX_set_flags,
70 EVP_CIPHER_CTX_clear_flags,
71 EVP_CIPHER_CTX_test_flags,
72 EVP_CIPHER_CTX_get_type,
73 EVP_CIPHER_CTX_get_mode,
74 EVP_CIPHER_CTX_get_num,
75 EVP_CIPHER_CTX_set_num,
76 EVP_CIPHER_CTX_is_encrypting,
77 EVP_CIPHER_param_to_asn1,
78 EVP_CIPHER_asn1_to_param,
79 EVP_CIPHER_CTX_set_padding,
81 EVP_CIPHER_do_all_provided,
84 EVP_CIPHER_block_size,
85 EVP_CIPHER_key_length,
90 EVP_CIPHER_CTX_encrypting,
92 EVP_CIPHER_CTX_block_size,
93 EVP_CIPHER_CTX_key_length,
94 EVP_CIPHER_CTX_iv_length,
95 EVP_CIPHER_CTX_tag_length,
105 #include <openssl/evp.h>
107 EVP_CIPHER *EVP_CIPHER_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
108 const char *properties);
109 int EVP_CIPHER_up_ref(EVP_CIPHER *cipher);
110 void EVP_CIPHER_free(EVP_CIPHER *cipher);
111 EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void);
112 int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx);
113 void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx);
114 EVP_CIPHER_CTX *EVP_CIPHER_CTX_dup(const EVP_CIPHER_CTX *in);
115 int EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, const EVP_CIPHER_CTX *in);
117 int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
118 ENGINE *impl, const unsigned char *key, const unsigned char *iv);
119 int EVP_EncryptInit_ex2(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
120 const unsigned char *key, const unsigned char *iv,
121 const OSSL_PARAM params[]);
122 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
123 int *outl, const unsigned char *in, int inl);
124 int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
126 int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
127 ENGINE *impl, const unsigned char *key, const unsigned char *iv);
128 int EVP_DecryptInit_ex2(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
129 const unsigned char *key, const unsigned char *iv,
130 const OSSL_PARAM params[]);
131 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
132 int *outl, const unsigned char *in, int inl);
133 int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
135 int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
136 ENGINE *impl, const unsigned char *key, const unsigned char *iv, int enc);
137 int EVP_CipherInit_ex2(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
138 const unsigned char *key, const unsigned char *iv,
139 int enc, const OSSL_PARAM params[]);
140 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out,
141 int *outl, const unsigned char *in, int inl);
142 int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
144 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
145 const unsigned char *key, const unsigned char *iv);
146 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);
148 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
149 const unsigned char *key, const unsigned char *iv);
150 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
152 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type,
153 const unsigned char *key, const unsigned char *iv, int enc);
154 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);
156 int EVP_Cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
157 const unsigned char *in, unsigned int inl);
159 int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *x, int padding);
160 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *x, int keylen);
161 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int cmd, int p1, void *p2);
162 int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key);
163 void EVP_CIPHER_CTX_set_flags(EVP_CIPHER_CTX *ctx, int flags);
164 void EVP_CIPHER_CTX_clear_flags(EVP_CIPHER_CTX *ctx, int flags);
165 int EVP_CIPHER_CTX_test_flags(const EVP_CIPHER_CTX *ctx, int flags);
167 const EVP_CIPHER *EVP_get_cipherbyname(const char *name);
168 const EVP_CIPHER *EVP_get_cipherbynid(int nid);
169 const EVP_CIPHER *EVP_get_cipherbyobj(const ASN1_OBJECT *a);
171 int EVP_CIPHER_get_nid(const EVP_CIPHER *e);
172 int EVP_CIPHER_is_a(const EVP_CIPHER *cipher, const char *name);
173 int EVP_CIPHER_names_do_all(const EVP_CIPHER *cipher,
174 void (*fn)(const char *name, void *data),
176 const char *EVP_CIPHER_get0_name(const EVP_CIPHER *cipher);
177 const char *EVP_CIPHER_get0_description(const EVP_CIPHER *cipher);
178 const OSSL_PROVIDER *EVP_CIPHER_get0_provider(const EVP_CIPHER *cipher);
179 int EVP_CIPHER_get_block_size(const EVP_CIPHER *e);
180 int EVP_CIPHER_get_key_length(const EVP_CIPHER *e);
181 int EVP_CIPHER_get_iv_length(const EVP_CIPHER *e);
182 unsigned long EVP_CIPHER_get_flags(const EVP_CIPHER *e);
183 unsigned long EVP_CIPHER_get_mode(const EVP_CIPHER *e);
184 int EVP_CIPHER_get_type(const EVP_CIPHER *cipher);
186 const EVP_CIPHER *EVP_CIPHER_CTX_get0_cipher(const EVP_CIPHER_CTX *ctx);
187 EVP_CIPHER *EVP_CIPHER_CTX_get1_cipher(const EVP_CIPHER_CTX *ctx);
188 int EVP_CIPHER_CTX_get_nid(const EVP_CIPHER_CTX *ctx);
189 const char *EVP_CIPHER_CTX_get0_name(const EVP_CIPHER_CTX *ctx);
191 int EVP_CIPHER_get_params(EVP_CIPHER *cipher, OSSL_PARAM params[]);
192 int EVP_CIPHER_CTX_set_params(EVP_CIPHER_CTX *ctx, const OSSL_PARAM params[]);
193 int EVP_CIPHER_CTX_get_params(EVP_CIPHER_CTX *ctx, OSSL_PARAM params[]);
194 const OSSL_PARAM *EVP_CIPHER_gettable_params(const EVP_CIPHER *cipher);
195 const OSSL_PARAM *EVP_CIPHER_settable_ctx_params(const EVP_CIPHER *cipher);
196 const OSSL_PARAM *EVP_CIPHER_gettable_ctx_params(const EVP_CIPHER *cipher);
197 const OSSL_PARAM *EVP_CIPHER_CTX_settable_params(EVP_CIPHER_CTX *ctx);
198 const OSSL_PARAM *EVP_CIPHER_CTX_gettable_params(EVP_CIPHER_CTX *ctx);
199 int EVP_CIPHER_CTX_get_block_size(const EVP_CIPHER_CTX *ctx);
200 int EVP_CIPHER_CTX_get_key_length(const EVP_CIPHER_CTX *ctx);
201 int EVP_CIPHER_CTX_get_iv_length(const EVP_CIPHER_CTX *ctx);
202 int EVP_CIPHER_CTX_get_tag_length(const EVP_CIPHER_CTX *ctx);
203 void *EVP_CIPHER_CTX_get_app_data(const EVP_CIPHER_CTX *ctx);
204 void EVP_CIPHER_CTX_set_app_data(const EVP_CIPHER_CTX *ctx, void *data);
205 int EVP_CIPHER_CTX_get_type(const EVP_CIPHER_CTX *ctx);
206 int EVP_CIPHER_CTX_get_mode(const EVP_CIPHER_CTX *ctx);
207 int EVP_CIPHER_CTX_get_num(const EVP_CIPHER_CTX *ctx);
208 int EVP_CIPHER_CTX_set_num(EVP_CIPHER_CTX *ctx, int num);
209 int EVP_CIPHER_CTX_is_encrypting(const EVP_CIPHER_CTX *ctx);
211 int EVP_CIPHER_param_to_asn1(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
212 int EVP_CIPHER_asn1_to_param(EVP_CIPHER_CTX *c, ASN1_TYPE *type);
214 void EVP_CIPHER_do_all_provided(OSSL_LIB_CTX *libctx,
215 void (*fn)(EVP_CIPHER *cipher, void *arg),
218 #define EVP_CIPHER_nid EVP_CIPHER_get_nid
219 #define EVP_CIPHER_name EVP_CIPHER_get0_name
220 #define EVP_CIPHER_block_size EVP_CIPHER_get_block_size
221 #define EVP_CIPHER_key_length EVP_CIPHER_get_key_length
222 #define EVP_CIPHER_iv_length EVP_CIPHER_get_iv_length
223 #define EVP_CIPHER_flags EVP_CIPHER_get_flags
224 #define EVP_CIPHER_mode EVP_CIPHER_get_mode
225 #define EVP_CIPHER_type EVP_CIPHER_get_type
226 #define EVP_CIPHER_CTX_encrypting EVP_CIPHER_CTX_is_encrypting
227 #define EVP_CIPHER_CTX_nid EVP_CIPHER_CTX_get_nid
228 #define EVP_CIPHER_CTX_block_size EVP_CIPHER_CTX_get_block_size
229 #define EVP_CIPHER_CTX_key_length EVP_CIPHER_CTX_get_key_length
230 #define EVP_CIPHER_CTX_iv_length EVP_CIPHER_CTX_get_iv_length
231 #define EVP_CIPHER_CTX_tag_length EVP_CIPHER_CTX_get_tag_length
232 #define EVP_CIPHER_CTX_num EVP_CIPHER_CTX_get_num
233 #define EVP_CIPHER_CTX_type EVP_CIPHER_CTX_get_type
234 #define EVP_CIPHER_CTX_mode EVP_CIPHER_CTX_get_mode
236 The following function has been deprecated since OpenSSL 3.0, and can be
237 hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
238 see L<openssl_user_macros(7)>:
240 const EVP_CIPHER *EVP_CIPHER_CTX_cipher(const EVP_CIPHER_CTX *ctx);
242 The following function has been deprecated since OpenSSL 1.1.0, and can be
243 hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
244 see L<openssl_user_macros(7)>:
246 int EVP_CIPHER_CTX_flags(const EVP_CIPHER_CTX *ctx);
250 The EVP cipher routines are a high-level interface to certain
253 The B<EVP_CIPHER> type is a structure for cipher method implementation.
257 =item EVP_CIPHER_fetch()
259 Fetches the cipher implementation for the given I<algorithm> from any provider
260 offering it, within the criteria given by the I<properties>.
261 See L<crypto(7)/ALGORITHM FETCHING> for further information.
263 The returned value must eventually be freed with EVP_CIPHER_free().
265 Fetched B<EVP_CIPHER> structures are reference counted.
267 =item EVP_CIPHER_up_ref()
269 Increments the reference count for an B<EVP_CIPHER> structure.
271 =item EVP_CIPHER_free()
273 Decrements the reference count for the fetched B<EVP_CIPHER> structure.
274 If the reference count drops to 0 then the structure is freed.
276 =item EVP_CIPHER_CTX_new()
278 Allocates and returns a cipher context.
280 =item EVP_CIPHER_CTX_free()
282 Clears all information from a cipher context and frees any allocated memory
283 associated with it, including I<ctx> itself. This function should be called after
284 all operations using a cipher are complete so sensitive information does not
287 =item EVP_CIPHER_CTX_dup()
289 Can be used to duplicate the cipher state from I<in>. This is useful
290 to avoid multiple EVP_MD_fetch() calls or if large amounts of data are to be
291 hashed which only differ in the last few bytes.
293 =item EVP_CIPHER_CTX_copy()
295 Can be used to copy the cipher state from I<in> to I<out>.
297 =item EVP_CIPHER_CTX_ctrl()
299 I<This is a legacy method.> EVP_CIPHER_CTX_set_params() and
300 EVP_CIPHER_CTX_get_params() is the mechanism that should be used to set and get
301 parameters that are used by providers.
303 Performs cipher-specific control actions on context I<ctx>. The control command
304 is indicated in I<cmd> and any additional arguments in I<p1> and I<p2>.
305 EVP_CIPHER_CTX_ctrl() must be called after EVP_CipherInit_ex2(). Other restrictions
306 may apply depending on the control type and cipher implementation.
308 If this function happens to be used with a fetched B<EVP_CIPHER>, it will
309 translate the controls that are known to OpenSSL into L<OSSL_PARAM(3)>
310 parameters with keys defined by OpenSSL and call EVP_CIPHER_CTX_get_params() or
311 EVP_CIPHER_CTX_set_params() as is appropriate for each control command.
313 See L</CONTROLS> below for more information, including what translations are
316 =item EVP_CIPHER_get_params()
318 Retrieves the requested list of algorithm I<params> from a CIPHER I<cipher>.
319 See L</PARAMETERS> below for more information.
321 =item EVP_CIPHER_CTX_get_params()
323 Retrieves the requested list of I<params> from CIPHER context I<ctx>.
324 See L</PARAMETERS> below for more information.
326 =item EVP_CIPHER_CTX_set_params()
328 Sets the list of I<params> into a CIPHER context I<ctx>.
329 See L</PARAMETERS> below for more information.
331 =item EVP_CIPHER_gettable_params()
333 Get a constant B<OSSL_PARAM> array that describes the retrievable parameters
334 that can be used with EVP_CIPHER_get_params(). See L<OSSL_PARAM(3)> for the
335 use of B<OSSL_PARAM> as a parameter descriptor.
337 =item EVP_CIPHER_gettable_ctx_params() and EVP_CIPHER_CTX_gettable_params()
339 Get a constant B<OSSL_PARAM> array that describes the retrievable parameters
340 that can be used with EVP_CIPHER_CTX_get_params().
341 EVP_CIPHER_gettable_ctx_params() returns the parameters that can be retrieved
342 from the algorithm, whereas EVP_CIPHER_CTX_gettable_params() returns the
343 parameters that can be retrieved in the context's current state.
344 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as a parameter descriptor.
346 =item EVP_CIPHER_settable_ctx_params() and EVP_CIPHER_CTX_settable_params()
348 Get a constant B<OSSL_PARAM> array that describes the settable parameters
349 that can be used with EVP_CIPHER_CTX_set_params().
350 EVP_CIPHER_settable_ctx_params() returns the parameters that can be set from the
351 algorithm, whereas EVP_CIPHER_CTX_settable_params() returns the parameters that
352 can be set in the context's current state.
353 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as a parameter descriptor.
355 =item EVP_EncryptInit_ex2()
357 Sets up cipher context I<ctx> for encryption with cipher I<type>. I<type> is
358 typically supplied by calling EVP_CIPHER_fetch(). I<type> may also be set
359 using legacy functions such as EVP_aes_256_cbc(), but this is not recommended
360 for new applications. I<key> is the symmetric key to use and I<iv> is the IV to
361 use (if necessary), the actual number of bytes used for the key and IV depends
362 on the cipher. The parameters I<params> will be set on the context after
363 initialisation. It is possible to set all parameters to NULL except I<type> in
364 an initial call and supply the remaining parameters in subsequent calls, all of
365 which have I<type> set to NULL. This is done when the default cipher parameters
367 For B<EVP_CIPH_GCM_MODE> the IV will be generated internally if it is not
370 =item EVP_EncryptInit_ex()
372 This legacy function is similar to EVP_EncryptInit_ex2() when I<impl> is NULL.
373 The implementation of the I<type> from the I<impl> engine will be used if it
376 =item EVP_EncryptUpdate()
378 Encrypts I<inl> bytes from the buffer I<in> and writes the encrypted version to
379 I<out>. This function can be called multiple times to encrypt successive blocks
380 of data. The amount of data written depends on the block alignment of the
382 For most ciphers and modes, the amount of data written can be anything
383 from zero bytes to (inl + cipher_block_size - 1) bytes.
384 For wrap cipher modes, the amount of data written can be anything
385 from zero bytes to (inl + cipher_block_size) bytes.
386 For stream ciphers, the amount of data written can be anything from zero
388 Thus, I<out> should contain sufficient room for the operation being performed.
389 The actual number of bytes written is placed in I<outl>. It also
390 checks if I<in> and I<out> are partially overlapping, and if they are
391 0 is returned to indicate failure.
393 If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts
394 the "final" data, that is any data that remains in a partial block.
395 It uses standard block padding (aka PKCS padding) as described in
396 the NOTES section, below. The encrypted
397 final data is written to I<out> which should have sufficient space for
398 one cipher block. The number of bytes written is placed in I<outl>. After
399 this function is called the encryption operation is finished and no further
400 calls to EVP_EncryptUpdate() should be made.
402 If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more
403 data and it will return an error if any data remains in a partial block:
404 that is if the total data length is not a multiple of the block size.
406 =item EVP_DecryptInit_ex2(), EVP_DecryptInit_ex(), EVP_DecryptUpdate()
407 and EVP_DecryptFinal_ex()
409 These functions are the corresponding decryption operations.
410 EVP_DecryptFinal() will return an error code if padding is enabled and the
411 final block is not correctly formatted. The parameters and restrictions are
412 identical to the encryption operations except that if padding is enabled the
413 decrypted data buffer I<out> passed to EVP_DecryptUpdate() should have
414 sufficient room for (I<inl> + cipher_block_size) bytes unless the cipher block
415 size is 1 in which case I<inl> bytes is sufficient.
417 =item EVP_CipherInit_ex2(), EVP_CipherInit_ex(), EVP_CipherUpdate() and
420 These functions can be used for decryption or encryption. The operation
421 performed depends on the value of the I<enc> parameter. It should be set to 1
422 for encryption, 0 for decryption and -1 to leave the value unchanged
423 (the actual value of 'enc' being supplied in a previous call).
425 =item EVP_CIPHER_CTX_reset()
427 Clears all information from a cipher context and free up any allocated memory
428 associated with it, except the I<ctx> itself. This function should be called
429 anytime I<ctx> is reused by another
430 EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal() series of calls.
432 =item EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit()
434 Behave in a similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and
435 EVP_CipherInit_ex() except if the I<type> is not a fetched cipher they use the
436 default implementation of the I<type>.
438 =item EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal()
440 Identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
441 EVP_CipherFinal_ex(). In previous releases they also cleaned up
442 the I<ctx>, but this is no longer done and EVP_CIPHER_CTX_cleanup()
443 must be called to free any context resources.
447 Encrypts or decrypts a maximum I<inl> amount of bytes from I<in> and leaves the
450 For legacy ciphers - If the cipher doesn't have the flag
451 B<EVP_CIPH_FLAG_CUSTOM_CIPHER> set, then I<inl> must be a multiple of
452 EVP_CIPHER_get_block_size(). If it isn't, the result is undefined. If the cipher
453 has that flag set, then I<inl> can be any size.
455 Due to the constraints of the API contract of this function it shouldn't be used
456 in applications, please consider using EVP_CipherUpdate() and
457 EVP_CipherFinal_ex() instead.
459 =item EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
461 Returns an B<EVP_CIPHER> structure when passed a cipher name, a cipher B<NID> or
462 an B<ASN1_OBJECT> structure respectively.
464 EVP_get_cipherbyname() will return NULL for algorithms such as "AES-128-SIV",
465 "AES-128-CBC-CTS" and "CAMELLIA-128-CBC-CTS" which were previously only
466 accessible via low level interfaces.
468 The EVP_get_cipherbyname() function is present for backwards compatibility with
469 OpenSSL prior to version 3 and is different to the EVP_CIPHER_fetch() function
470 since it does not attempt to "fetch" an implementation of the cipher.
471 Additionally, it only knows about ciphers that are built-in to OpenSSL and have
472 an associated NID. Similarly EVP_get_cipherbynid() and EVP_get_cipherbyobj()
473 also return objects without an associated implementation.
475 When the cipher objects returned by these functions are used (such as in a call
476 to EVP_EncryptInit_ex()) an implementation of the cipher will be implicitly
477 fetched from the loaded providers. This fetch could fail if no suitable
478 implementation is available. Use EVP_CIPHER_fetch() instead to explicitly fetch
479 the algorithm and an associated implementation from a provider.
481 See L<crypto(7)/ALGORITHM FETCHING> for more information about fetching.
483 The cipher objects returned from these functions do not need to be freed with
486 =item EVP_CIPHER_get_nid() and EVP_CIPHER_CTX_get_nid()
488 Return the NID of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
489 structure. The actual NID value is an internal value which may not have a
490 corresponding OBJECT IDENTIFIER.
492 =item EVP_CIPHER_CTX_set_flags(), EVP_CIPHER_CTX_clear_flags() and EVP_CIPHER_CTX_test_flags()
494 Sets, clears and tests I<ctx> flags. See L</FLAGS> below for more information.
496 For provided ciphers EVP_CIPHER_CTX_set_flags() should be called only after the
497 fetched cipher has been assigned to the I<ctx>. It is recommended to use
498 L</PARAMETERS> instead.
500 =item EVP_CIPHER_CTX_set_padding()
502 Enables or disables padding. This function should be called after the context
503 is set up for encryption or decryption with EVP_EncryptInit_ex2(),
504 EVP_DecryptInit_ex2() or EVP_CipherInit_ex2(). By default encryption operations
505 are padded using standard block padding and the padding is checked and removed
506 when decrypting. If the I<pad> parameter is zero then no padding is
507 performed, the total amount of data encrypted or decrypted must then
508 be a multiple of the block size or an error will occur.
510 =item EVP_CIPHER_get_key_length() and EVP_CIPHER_CTX_get_key_length()
512 Return the key length of a cipher when passed an B<EVP_CIPHER> or
513 B<EVP_CIPHER_CTX> structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum
514 key length for all ciphers. Note: although EVP_CIPHER_get_key_length() is fixed for
515 a given cipher, the value of EVP_CIPHER_CTX_get_key_length() may be different for
516 variable key length ciphers.
518 =item EVP_CIPHER_CTX_set_key_length()
520 Sets the key length of the cipher context.
521 If the cipher is a fixed length cipher then attempting to set the key
522 length to any value other than the fixed value is an error.
524 =item EVP_CIPHER_get_iv_length() and EVP_CIPHER_CTX_get_iv_length()
526 Return the IV length of a cipher when passed an B<EVP_CIPHER> or
527 B<EVP_CIPHER_CTX>. It will return zero if the cipher does not use an IV.
528 The constant B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers.
530 =item EVP_CIPHER_CTX_get_tag_length()
532 Returns the tag length of an AEAD cipher when passed a B<EVP_CIPHER_CTX>. It will
533 return zero if the cipher does not support a tag. It returns a default value if
534 the tag length has not been set.
536 =item EVP_CIPHER_get_block_size() and EVP_CIPHER_CTX_get_block_size()
538 Return the block size of a cipher when passed an B<EVP_CIPHER> or
539 B<EVP_CIPHER_CTX> structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the
540 maximum block length for all ciphers.
542 =item EVP_CIPHER_get_type() and EVP_CIPHER_CTX_get_type()
544 Return the type of the passed cipher or context. This "type" is the actual NID
545 of the cipher OBJECT IDENTIFIER and as such it ignores the cipher parameters
546 (40 bit RC2 and 128 bit RC2 have the same NID). If the cipher does not have an
547 object identifier or does not have ASN1 support this function will return
550 =item EVP_CIPHER_is_a()
552 Returns 1 if I<cipher> is an implementation of an algorithm that's identifiable
553 with I<name>, otherwise 0. If I<cipher> is a legacy cipher (it's the return
554 value from the likes of EVP_aes128() rather than the result of an
555 EVP_CIPHER_fetch()), only cipher names registered with the default library
556 context (see L<OSSL_LIB_CTX(3)>) will be considered.
558 =item EVP_CIPHER_get0_name() and EVP_CIPHER_CTX_get0_name()
560 Return the name of the passed cipher or context. For fetched ciphers with
561 multiple names, only one of them is returned. See also EVP_CIPHER_names_do_all().
563 =item EVP_CIPHER_names_do_all()
565 Traverses all names for the I<cipher>, and calls I<fn> with each name and
566 I<data>. This is only useful with fetched B<EVP_CIPHER>s.
568 =item EVP_CIPHER_get0_description()
570 Returns a description of the cipher, meant for display and human consumption.
571 The description is at the discretion of the cipher implementation.
573 =item EVP_CIPHER_get0_provider()
575 Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
578 =item EVP_CIPHER_CTX_get0_cipher()
580 Returns the B<EVP_CIPHER> structure when passed an B<EVP_CIPHER_CTX> structure.
581 EVP_CIPHER_CTX_get1_cipher() is the same except the ownership is passed to
584 =item EVP_CIPHER_get_mode() and EVP_CIPHER_CTX_get_mode()
586 Return the block cipher mode:
587 EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE,
588 EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE,
589 EVP_CIPH_WRAP_MODE, EVP_CIPH_OCB_MODE or EVP_CIPH_SIV_MODE.
590 If the cipher is a stream cipher then EVP_CIPH_STREAM_CIPHER is returned.
592 =item EVP_CIPHER_get_flags()
594 Returns any flags associated with the cipher. See L</FLAGS>
595 for a list of currently defined flags.
597 =item EVP_CIPHER_CTX_get_num() and EVP_CIPHER_CTX_set_num()
599 Gets or sets the cipher specific "num" parameter for the associated I<ctx>.
600 Built-in ciphers typically use this to track how much of the current underlying block
601 has been "used" already.
603 =item EVP_CIPHER_CTX_is_encrypting()
605 Reports whether the I<ctx> is being used for encryption or decryption.
607 =item EVP_CIPHER_CTX_flags()
609 A deprecated macro calling C<EVP_CIPHER_get_flags(EVP_CIPHER_CTX_get0_cipher(ctx))>.
612 =item EVP_CIPHER_param_to_asn1()
614 Sets the AlgorithmIdentifier "parameter" based on the passed cipher. This will
615 typically include any parameters and an IV. The cipher IV (if any) must be set
616 when this call is made. This call should be made before the cipher is actually
617 "used" (before any EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example).
618 This function may fail if the cipher does not have any ASN1 support.
620 =item EVP_CIPHER_asn1_to_param()
622 Sets the cipher parameters based on an ASN1 AlgorithmIdentifier "parameter".
623 The precise effect depends on the cipher. In the case of B<RC2>, for example,
624 it will set the IV and effective key length.
625 This function should be called after the base cipher type is set but before
626 the key is set. For example EVP_CipherInit() will be called with the IV and
627 key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally
628 EVP_CipherInit() again with all parameters except the key set to NULL. It is
629 possible for this function to fail if the cipher does not have any ASN1 support
630 or the parameters cannot be set (for example the RC2 effective key length
633 =item EVP_CIPHER_CTX_rand_key()
635 Generates a random key of the appropriate length based on the cipher context.
636 The B<EVP_CIPHER> can provide its own random key generation routine to support
637 keys of a specific form. I<key> must point to a buffer at least as big as the
638 value returned by EVP_CIPHER_CTX_get_key_length().
640 =item EVP_CIPHER_do_all_provided()
642 Traverses all ciphers implemented by all activated providers in the given
643 library context I<libctx>, and for each of the implementations, calls the given
644 function I<fn> with the implementation method and the given I<arg> as argument.
650 See L<OSSL_PARAM(3)> for information about passing parameters.
652 =head2 Gettable EVP_CIPHER parameters
654 When EVP_CIPHER_fetch() is called it internally calls EVP_CIPHER_get_params()
655 and caches the results.
657 EVP_CIPHER_get_params() can be used with the following B<OSSL_PARAM> keys:
661 =item "mode" (B<OSSL_CIPHER_PARAM_MODE>) <unsigned integer>
663 Gets the mode for the associated cipher algorithm I<cipher>.
664 See L</EVP_CIPHER_get_mode() and EVP_CIPHER_CTX_get_mode()> for a list of valid modes.
665 Use EVP_CIPHER_get_mode() to retrieve the cached value.
667 =item "keylen" (B<OSSL_CIPHER_PARAM_KEYLEN>) <unsigned integer>
669 Gets the key length for the associated cipher algorithm I<cipher>.
670 Use EVP_CIPHER_get_key_length() to retrieve the cached value.
672 =item "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN>) <unsigned integer>
674 Gets the IV length for the associated cipher algorithm I<cipher>.
675 Use EVP_CIPHER_get_iv_length() to retrieve the cached value.
677 =item "blocksize" (B<OSSL_CIPHER_PARAM_BLOCK_SIZE>) <unsigned integer>
679 Gets the block size for the associated cipher algorithm I<cipher>.
680 The block size should be 1 for stream ciphers.
681 Note that the block size for a cipher may be different to the block size for
682 the underlying encryption/decryption primitive.
683 For example AES in CTR mode has a block size of 1 (because it operates like a
684 stream cipher), even though AES has a block size of 16.
685 Use EVP_CIPHER_get_block_size() to retrieve the cached value.
687 =item "aead" (B<OSSL_CIPHER_PARAM_AEAD>) <integer>
689 Gets 1 if this is an AEAD cipher algorithm, otherwise it gets 0.
690 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) to retrieve the
693 =item "custom-iv" (B<OSSL_CIPHER_PARAM_CUSTOM_IV>) <integer>
695 Gets 1 if the cipher algorithm I<cipher> has a custom IV, otherwise it gets 0.
696 Storing and initializing the IV is left entirely to the implementation, if a
698 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_CUSTOM_IV) to retrieve the
701 =item "cts" (B<OSSL_CIPHER_PARAM_CTS>) <integer>
703 Gets 1 if the cipher algorithm I<cipher> uses ciphertext stealing,
705 This is currently used to indicate that the cipher is a one shot that only
706 allows a single call to EVP_CipherUpdate().
707 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_CTS) to retrieve the
710 =item "tls-multi" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK>) <integer>
712 Gets 1 if the cipher algorithm I<cipher> supports interleaving of crypto blocks,
713 otherwise it gets 0. The interleaving is an optimization only applicable to certain
715 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK) to retrieve the
718 =item "has-randkey" (B<OSSL_CIPHER_PARAM_HAS_RANDKEY>) <integer>
720 Gets 1 if the cipher algorithm I<cipher> supports the gettable EVP_CIPHER_CTX
721 parameter B<OSSL_CIPHER_PARAM_RANDOM_KEY>. Only DES and 3DES set this to 1,
722 all other OpenSSL ciphers return 0.
726 =head2 Gettable and Settable EVP_CIPHER_CTX parameters
728 The following B<OSSL_PARAM> keys can be used with both EVP_CIPHER_CTX_get_params()
729 and EVP_CIPHER_CTX_set_params().
733 =item "padding" (B<OSSL_CIPHER_PARAM_PADDING>) <unsigned integer>
735 Gets or sets the padding mode for the cipher context I<ctx>.
736 Padding is enabled if the value is 1, and disabled if the value is 0.
737 See also EVP_CIPHER_CTX_set_padding().
739 =item "num" (B<OSSL_CIPHER_PARAM_NUM>) <unsigned integer>
741 Gets or sets the cipher specific "num" parameter for the cipher context I<ctx>.
742 Built-in ciphers typically use this to track how much of the current underlying
743 block has been "used" already.
744 See also EVP_CIPHER_CTX_get_num() and EVP_CIPHER_CTX_set_num().
746 =item "keylen" (B<OSSL_CIPHER_PARAM_KEYLEN>) <unsigned integer>
748 Gets or sets the key length for the cipher context I<ctx>.
749 The length of the "keylen" parameter should not exceed that of a B<size_t>.
750 See also EVP_CIPHER_CTX_get_key_length() and EVP_CIPHER_CTX_set_key_length().
752 =item "tag" (B<OSSL_CIPHER_PARAM_AEAD_TAG>) <octet string>
754 Gets or sets the AEAD tag for the associated cipher context I<ctx>.
755 See L<EVP_EncryptInit(3)/AEAD Interface>.
757 =item "keybits" (B<OSSL_CIPHER_PARAM_RC2_KEYBITS>) <unsigned integer>
759 Gets or sets the effective keybits used for a RC2 cipher.
760 The length of the "keybits" parameter should not exceed that of a B<size_t>.
762 =item "rounds" (B<OSSL_CIPHER_PARAM_ROUNDS>) <unsigned integer>
764 Gets or sets the number of rounds to be used for a cipher.
765 This is used by the RC5 cipher.
767 =item "alg_id_param" (B<OSSL_CIPHER_PARAM_ALGORITHM_ID_PARAMS>) <octet string>
769 Used to pass the DER encoded AlgorithmIdentifier parameter to or from
770 the cipher implementation. Functions like L<EVP_CIPHER_param_to_asn1(3)>
771 and L<EVP_CIPHER_asn1_to_param(3)> use this parameter for any implementation
772 that has the flag B<EVP_CIPH_FLAG_CUSTOM_ASN1> set.
774 =item "cts_mode" (B<OSSL_CIPHER_PARAM_CTS_MODE>) <UTF8 string>
776 Gets or sets the cipher text stealing mode. For all modes the output size is the
777 same as the input size. The input length must be greater than or equal to the
778 block size. (The block size for AES and CAMELLIA is 16 bytes).
780 Valid values for the mode are:
786 The NIST variant of cipher text stealing.
787 For input lengths that are multiples of the block size it is equivalent to
788 using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher otherwise the second last
789 cipher text block is a partial block.
793 For input lengths that are multiples of the block size it is equivalent to
794 using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher, otherwise it is the same as
799 The Kerberos5 variant of cipher text stealing which always swaps the last
800 cipher text block with the previous block (which may be a partial or full block
801 depending on the input length). If the input length is exactly one full block
802 then this is equivalent to using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher.
806 The default is "CS1".
807 This is only supported for "AES-128-CBC-CTS", "AES-192-CBC-CTS", "AES-256-CBC-CTS",
808 "CAMELLIA-128-CBC-CTS", "CAMELLIA-192-CBC-CTS" and "CAMELLIA-256-CBC-CTS".
810 =item "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>) <unsigned integer>
812 Sets or gets the number of records being sent in one go for a tls1 multiblock
813 cipher operation (either 4 or 8 records).
817 =head2 Gettable EVP_CIPHER_CTX parameters
819 The following B<OSSL_PARAM> keys can be used with EVP_CIPHER_CTX_get_params():
823 =item "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN> and <B<OSSL_CIPHER_PARAM_AEAD_IVLEN>) <unsigned integer>
825 Gets the IV length for the cipher context I<ctx>.
826 The length of the "ivlen" parameter should not exceed that of a B<size_t>.
827 See also EVP_CIPHER_CTX_get_iv_length().
829 =item "iv" (B<OSSL_CIPHER_PARAM_IV>) <octet string OR octet ptr>
831 Gets the IV used to initialize the associated cipher context I<ctx>.
832 See also EVP_CIPHER_CTX_get_original_iv().
834 =item "updated-iv" (B<OSSL_CIPHER_PARAM_UPDATED_IV>) <octet string OR octet ptr>
836 Gets the updated pseudo-IV state for the associated cipher context, e.g.,
837 the previous ciphertext block for CBC mode or the iteratively encrypted IV
838 value for OFB mode. Note that octet pointer access is deprecated and is
839 provided only for backwards compatibility with historical libcrypto APIs.
840 See also EVP_CIPHER_CTX_get_updated_iv().
842 =item "randkey" (B<OSSL_CIPHER_PARAM_RANDOM_KEY>) <octet string>
844 Gets an implementation specific randomly generated key for the associated
845 cipher context I<ctx>. This is currently only supported by DES and 3DES (which set
846 the key to odd parity).
848 =item "taglen" (B<OSSL_CIPHER_PARAM_AEAD_TAGLEN>) <unsigned integer>
850 Gets the tag length to be used for an AEAD cipher for the associated cipher
851 context I<ctx>. It gets a default value if it has not been set.
852 The length of the "taglen" parameter should not exceed that of a B<size_t>.
853 See also EVP_CIPHER_CTX_get_tag_length().
855 =item "tlsaadpad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD>) <unsigned integer>
857 Gets the length of the tag that will be added to a TLS record for the AEAD
858 tag for the associated cipher context I<ctx>.
859 The length of the "tlsaadpad" parameter should not exceed that of a B<size_t>.
861 =item "tlsivgen" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN>) <octet string>
863 Gets the invocation field generated for encryption.
864 Can only be called after "tlsivfixed" is set.
865 This is only used for GCM mode.
867 =item "tls1multi_enclen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_LEN>) <unsigned integer>
869 Get the total length of the record returned from the "tls1multi_enc" operation.
871 =item "tls1multi_maxbufsz" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_BUFSIZE>) <unsigned integer>
873 Gets the maximum record length for a TLS1 multiblock cipher operation.
874 The length of the "tls1multi_maxbufsz" parameter should not exceed that of a B<size_t>.
876 =item "tls1multi_aadpacklen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD_PACKLEN>) <unsigned integer>
878 Gets the result of running the "tls1multi_aad" operation.
880 =item "tls-mac" (B<OSSL_CIPHER_PARAM_TLS_MAC>) <octet ptr>
882 Used to pass the TLS MAC data.
886 =head2 Settable EVP_CIPHER_CTX parameters
888 The following B<OSSL_PARAM> keys can be used with EVP_CIPHER_CTX_set_params():
892 =item "mackey" (B<OSSL_CIPHER_PARAM_AEAD_MAC_KEY>) <octet string>
894 Sets the MAC key used by composite AEAD ciphers such as AES-CBC-HMAC-SHA256.
896 =item "speed" (B<OSSL_CIPHER_PARAM_SPEED>) <unsigned integer>
898 Sets the speed option for the associated cipher context. This is only supported
899 by AES SIV ciphers which disallow multiple operations by default.
900 Setting "speed" to 1 allows another encrypt or decrypt operation to be
901 performed. This is used for performance testing.
903 =item "use-bits" (B<OSSL_CIPHER_PARAM_USE_BITS>) <unsigned integer>
905 Determines if the input length I<inl> passed to EVP_EncryptUpdate(),
906 EVP_DecryptUpdate() and EVP_CipherUpdate() is the number of bits or number of bytes.
907 Setting "use-bits" to 1 uses bits. The default is in bytes.
908 This is only used for B<CFB1> ciphers.
910 This can be set using EVP_CIPHER_CTX_set_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS).
912 =item "tls-version" (B<OSSL_CIPHER_PARAM_TLS_VERSION>) <integer>
914 Sets the TLS version.
916 =item "tls-mac-size" (B<OSSL_CIPHER_PARAM_TLS_MAC_SIZE>) <unsigned integer>
918 Set the TLS MAC size.
920 =item "tlsaad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD>) <octet string>
922 Sets TLSv1.2 AAD information for the associated cipher context I<ctx>.
923 TLSv1.2 AAD information is always 13 bytes in length and is as defined for the
924 "additional_data" field described in section 6.2.3.3 of RFC5246.
926 =item "tlsivfixed" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED>) <octet string>
928 Sets the fixed portion of an IV for an AEAD cipher used in a TLS record
929 encryption/ decryption for the associated cipher context.
930 TLS record encryption/decryption always occurs "in place" so that the input and
931 output buffers are always the same memory location.
932 AEAD IVs in TLSv1.2 consist of an implicit "fixed" part and an explicit part
933 that varies with every record.
934 Setting a TLS fixed IV changes a cipher to encrypt/decrypt TLS records.
935 TLS records are encrypted/decrypted using a single OSSL_FUNC_cipher_cipher call per
937 For a record decryption the first bytes of the input buffer will be the explicit
938 part of the IV and the final bytes of the input buffer will be the AEAD tag.
939 The length of the explicit part of the IV and the tag length will depend on the
940 cipher in use and will be defined in the RFC for the relevant ciphersuite.
941 In order to allow for "in place" decryption the plaintext output should be
942 written to the same location in the output buffer that the ciphertext payload
943 was read from, i.e. immediately after the explicit IV.
945 When encrypting a record the first bytes of the input buffer should be empty to
946 allow space for the explicit IV, as will the final bytes where the tag will
948 The length of the input buffer will include the length of the explicit IV, the
949 payload, and the tag bytes.
950 The cipher implementation should generate the explicit IV and write it to the
951 beginning of the output buffer, do "in place" encryption of the payload and
952 write that to the output buffer, and finally add the tag onto the end of the
955 Whether encrypting or decrypting the value written to I<*outl> in the
956 OSSL_FUNC_cipher_cipher call should be the length of the payload excluding the explicit
957 IV length and the tag length.
959 =item "tlsivinv" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV>) <octet string>
961 Sets the invocation field used for decryption.
962 Can only be called after "tlsivfixed" is set.
963 This is only used for GCM mode.
965 =item "tls1multi_enc" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC>) <octet string>
967 Triggers a multiblock TLS1 encrypt operation for a TLS1 aware cipher that
968 supports sending 4 or 8 records in one go.
969 The cipher performs both the MAC and encrypt stages and constructs the record
971 "tls1multi_enc" supplies the output buffer for the encrypt operation,
972 "tls1multi_encin" & "tls1multi_interleave" must also be set in order to supply
973 values to the encrypt operation.
975 =item "tls1multi_encin" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_IN>) <octet string>
977 Supplies the data to encrypt for a TLS1 multiblock cipher operation.
979 =item "tls1multi_maxsndfrag" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_SEND_FRAGMENT>) <unsigned integer>
981 Sets the maximum send fragment size for a TLS1 multiblock cipher operation.
982 It must be set before using "tls1multi_maxbufsz".
983 The length of the "tls1multi_maxsndfrag" parameter should not exceed that of a B<size_t>.
985 =item "tls1multi_aad" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD>) <octet string>
987 Sets the authenticated additional data used by a TLS1 multiblock cipher operation.
988 The supplied data consists of 13 bytes of record data containing:
989 Bytes 0-7: The sequence number of the first record
990 Byte 8: The record type
991 Byte 9-10: The protocol version
992 Byte 11-12: Input length (Always 0)
994 "tls1multi_interleave" must also be set for this operation.
1000 The Mappings from EVP_CIPHER_CTX_ctrl() identifiers to PARAMETERS are listed
1001 in the following section. See the L</PARAMETERS> section for more details.
1003 EVP_CIPHER_CTX_ctrl() can be used to send the following standard controls:
1007 =item EVP_CTRL_AEAD_SET_IVLEN and EVP_CTRL_GET_IVLEN
1009 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1010 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1011 key "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN>).
1013 =item EVP_CTRL_AEAD_SET_IV_FIXED
1015 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1016 with an L<OSSL_PARAM(3)> item with the key "tlsivfixed"
1017 (B<OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED>).
1019 =item EVP_CTRL_AEAD_SET_MAC_KEY
1021 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1022 with an L<OSSL_PARAM(3)> item with the key "mackey"
1023 (B<OSSL_CIPHER_PARAM_AEAD_MAC_KEY>).
1025 =item EVP_CTRL_AEAD_SET_TAG and EVP_CTRL_AEAD_GET_TAG
1027 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1028 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1029 key "tag" (B<OSSL_CIPHER_PARAM_AEAD_TAG>).
1031 =item EVP_CTRL_CCM_SET_L
1033 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1034 with an L<OSSL_PARAM(3)> item with the key "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN>)
1035 with a value of (15 - L)
1039 There is no OSSL_PARAM mapping for this. Use EVP_CIPHER_CTX_copy() instead.
1041 =item EVP_CTRL_GCM_SET_IV_INV
1043 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1044 with an L<OSSL_PARAM(3)> item with the key "tlsivinv"
1045 (B<OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV>).
1047 =item EVP_CTRL_RAND_KEY
1049 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1050 with an L<OSSL_PARAM(3)> item with the key "randkey"
1051 (B<OSSL_CIPHER_PARAM_RANDOM_KEY>).
1053 =item EVP_CTRL_SET_KEY_LENGTH
1055 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1056 with an L<OSSL_PARAM(3)> item with the key "keylen" (B<OSSL_CIPHER_PARAM_KEYLEN>).
1058 =item EVP_CTRL_SET_RC2_KEY_BITS and EVP_CTRL_GET_RC2_KEY_BITS
1060 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1061 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1062 key "keybits" (B<OSSL_CIPHER_PARAM_RC2_KEYBITS>).
1064 =item EVP_CTRL_SET_RC5_ROUNDS and EVP_CTRL_GET_RC5_ROUNDS
1066 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1067 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1068 key "rounds" (B<OSSL_CIPHER_PARAM_ROUNDS>).
1070 =item EVP_CTRL_SET_SPEED
1072 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1073 with an L<OSSL_PARAM(3)> item with the key "speed" (B<OSSL_CIPHER_PARAM_SPEED>).
1075 =item EVP_CTRL_GCM_IV_GEN
1077 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_get_params() gets called
1078 with an L<OSSL_PARAM(3)> item with the key
1079 "tlsivgen" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN>).
1081 =item EVP_CTRL_AEAD_TLS1_AAD
1083 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() get called
1084 with an L<OSSL_PARAM(3)> item with the key
1085 "tlsaadpad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD>)
1086 followed by EVP_CIPHER_CTX_get_params() with a key of
1087 "tlsaadpad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD>).
1089 =item EVP_CTRL_TLS1_1_MULTIBLOCK_MAX_BUFSIZE
1091 When used with a fetched B<EVP_CIPHER>,
1092 EVP_CIPHER_CTX_set_params() gets called with an L<OSSL_PARAM(3)> item with the
1093 key OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_SEND_FRAGMENT
1094 followed by EVP_CIPHER_CTX_get_params() with a key of
1095 "tls1multi_maxbufsz" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_BUFSIZE>).
1097 =item EVP_CTRL_TLS1_1_MULTIBLOCK_AAD
1099 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1100 with L<OSSL_PARAM(3)> items with the keys
1101 "tls1multi_aad" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD>) and
1102 "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>)
1103 followed by EVP_CIPHER_CTX_get_params() with keys of
1104 "tls1multi_aadpacklen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD_PACKLEN>) and
1105 "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>).
1107 =item EVP_CTRL_TLS1_1_MULTIBLOCK_ENCRYPT
1109 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1110 with L<OSSL_PARAM(3)> items with the keys
1111 "tls1multi_enc" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC>),
1112 "tls1multi_encin" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_IN>) and
1113 "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>),
1114 followed by EVP_CIPHER_CTX_get_params() with a key of
1115 "tls1multi_enclen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_LEN>).
1121 EVP_CIPHER_CTX_set_flags(), EVP_CIPHER_CTX_clear_flags() and EVP_CIPHER_CTX_test_flags().
1122 can be used to manipulate and test these B<EVP_CIPHER_CTX> flags:
1126 =item EVP_CIPH_NO_PADDING
1128 Used by EVP_CIPHER_CTX_set_padding().
1130 See also L</Gettable and Settable EVP_CIPHER_CTX parameters> "padding"
1132 =item EVP_CIPH_FLAG_LENGTH_BITS
1134 See L</Settable EVP_CIPHER_CTX parameters> "use-bits".
1136 =item EVP_CIPHER_CTX_FLAG_WRAP_ALLOW
1138 Used for Legacy purposes only. This flag needed to be set to indicate the
1139 cipher handled wrapping.
1143 EVP_CIPHER_flags() uses the following flags that
1144 have mappings to L</Gettable EVP_CIPHER parameters>:
1148 =item EVP_CIPH_FLAG_AEAD_CIPHER
1150 See L</Gettable EVP_CIPHER parameters> "aead".
1152 =item EVP_CIPH_CUSTOM_IV
1154 See L</Gettable EVP_CIPHER parameters> "custom-iv".
1156 =item EVP_CIPH_FLAG_CTS
1158 See L</Gettable EVP_CIPHER parameters> "cts".
1160 =item EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK;
1162 See L</Gettable EVP_CIPHER parameters> "tls-multi".
1164 =item EVP_CIPH_RAND_KEY
1166 See L</Gettable EVP_CIPHER parameters> "has-randkey".
1170 EVP_CIPHER_flags() uses the following flags for legacy purposes only:
1174 =item EVP_CIPH_VARIABLE_LENGTH
1176 =item EVP_CIPH_FLAG_CUSTOM_CIPHER
1178 =item EVP_CIPH_ALWAYS_CALL_INIT
1180 =item EVP_CIPH_CTRL_INIT
1182 =item EVP_CIPH_CUSTOM_KEY_LENGTH
1184 =item EVP_CIPH_CUSTOM_COPY
1186 =item EVP_CIPH_FLAG_DEFAULT_ASN1
1188 See L<EVP_CIPHER_meth_set_flags(3)> for further information related to the above
1193 =head1 RETURN VALUES
1195 EVP_CIPHER_fetch() returns a pointer to a B<EVP_CIPHER> for success
1196 and B<NULL> for failure.
1198 EVP_CIPHER_up_ref() returns 1 for success or 0 otherwise.
1200 EVP_CIPHER_CTX_new() returns a pointer to a newly created
1201 B<EVP_CIPHER_CTX> for success and B<NULL> for failure.
1203 EVP_CIPHER_CTX_dup() returns a new EVP_MD_CTX if successful or NULL on failure.
1205 EVP_CIPHER_CTX_copy() returns 1 if successful or 0 for failure.
1207 EVP_EncryptInit_ex2(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex()
1208 return 1 for success and 0 for failure.
1210 EVP_DecryptInit_ex2() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
1211 EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success.
1213 EVP_CipherInit_ex2() and EVP_CipherUpdate() return 1 for success and 0 for failure.
1214 EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
1216 EVP_Cipher() returns the amount of encrypted / decrypted bytes, or -1
1217 on failure if the flag B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is set for the
1218 cipher. EVP_Cipher() returns 1 on success or 0 on failure, if the flag
1219 B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is not set for the cipher.
1221 EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure.
1223 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
1224 return an B<EVP_CIPHER> structure or NULL on error.
1226 EVP_CIPHER_get_nid() and EVP_CIPHER_CTX_get_nid() return a NID.
1228 EVP_CIPHER_get_block_size() and EVP_CIPHER_CTX_get_block_size() return the
1231 EVP_CIPHER_get_key_length() and EVP_CIPHER_CTX_get_key_length() return the key
1234 EVP_CIPHER_CTX_set_padding() always returns 1.
1236 EVP_CIPHER_get_iv_length() and EVP_CIPHER_CTX_get_iv_length() return the IV
1237 length or zero if the cipher does not use an IV.
1239 EVP_CIPHER_CTX_get_tag_length() return the tag length or zero if the cipher
1242 EVP_CIPHER_get_type() and EVP_CIPHER_CTX_get_type() return the NID of the
1243 cipher's OBJECT IDENTIFIER or NID_undef if it has no defined
1246 EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure.
1248 EVP_CIPHER_CTX_get_num() returns a nonnegative num value or
1249 B<EVP_CTRL_RET_UNSUPPORTED> if the implementation does not support the call
1250 or on any other error.
1252 EVP_CIPHER_CTX_set_num() returns 1 on success and 0 if the implementation
1253 does not support the call or on any other error.
1255 EVP_CIPHER_CTX_is_encrypting() returns 1 if the I<ctx> is set up for encryption
1258 EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater
1259 than zero for success and zero or a negative number on failure.
1261 EVP_CIPHER_CTX_rand_key() returns 1 for success.
1263 EVP_CIPHER_names_do_all() returns 1 if the callback was called for all names.
1264 A return value of 0 means that the callback was not called for any names.
1266 =head1 CIPHER LISTING
1268 All algorithms have a fixed key length unless otherwise stated.
1270 Refer to L</SEE ALSO> for the full list of ciphers available through the EVP
1275 =item EVP_enc_null()
1277 Null cipher: does nothing.
1281 =head1 AEAD INTERFACE
1283 The EVP interface for Authenticated Encryption with Associated Data (AEAD)
1284 modes are subtly altered and several additional I<ctrl> operations are supported
1285 depending on the mode specified.
1287 To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(),
1288 EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output
1289 parameter I<out> set to B<NULL>.
1291 When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal()
1292 indicates whether the operation was successful. If it does not indicate success,
1293 the authentication operation has failed and any output data B<MUST NOT> be used
1296 =head2 GCM and OCB Modes
1298 The following I<ctrl>s are supported in GCM and OCB modes.
1302 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
1304 Sets the IV length. This call can only be made before specifying an IV. If
1305 not called a default IV length is used.
1307 For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the
1310 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
1312 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
1313 This call can only be made when encrypting data and B<after> all data has been
1314 processed (e.g. after an EVP_EncryptFinal() call).
1316 For OCB, C<taglen> must either be 16 or the value previously set via
1317 B<EVP_CTRL_AEAD_SET_TAG>.
1319 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
1321 When decrypting, this call sets the expected tag to C<taglen> bytes from C<tag>.
1322 C<taglen> must be between 1 and 16 inclusive.
1323 The tag must be set prior to any call to EVP_DecryptFinal() or
1324 EVP_DecryptFinal_ex().
1326 For GCM, this call is only valid when decrypting data.
1328 For OCB, this call is valid when decrypting data to set the expected tag,
1329 and when encrypting to set the desired tag length.
1331 In OCB mode, calling this when encrypting with C<tag> set to C<NULL> sets the
1332 tag length. The tag length can only be set before specifying an IV. If this is
1333 not called prior to setting the IV during encryption, then a default tag length
1336 For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the
1337 maximum tag length for OCB.
1343 The EVP interface for CCM mode is similar to that of the GCM mode but with a
1344 few additional requirements and different I<ctrl> values.
1346 For CCM mode, the total plaintext or ciphertext length B<MUST> be passed to
1347 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output
1348 and input parameters (I<in> and I<out>) set to B<NULL> and the length passed in
1349 the I<inl> parameter.
1351 The following I<ctrl>s are supported in CCM mode.
1355 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
1357 This call is made to set the expected B<CCM> tag value when decrypting or
1358 the length of the tag (with the C<tag> parameter set to NULL) when encrypting.
1359 The tag length is often referred to as B<M>. If not set a default value is
1360 used (12 for AES). When decrypting, the tag needs to be set before passing
1361 in data to be decrypted, but as in GCM and OCB mode, it can be set after
1362 passing additional authenticated data (see L</AEAD INTERFACE>).
1364 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL)
1366 Sets the CCM B<L> value. If not set a default is used (8 for AES).
1368 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
1370 Sets the CCM nonce (IV) length. This call can only be made before specifying a
1371 nonce value. The nonce length is given by B<15 - L> so it is 7 by default for
1378 For SIV mode ciphers the behaviour of the EVP interface is subtly
1379 altered and several additional ctrl operations are supported.
1381 To specify any additional authenticated data (AAD) and/or a Nonce, a call to
1382 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made
1383 with the output parameter I<out> set to B<NULL>.
1385 RFC5297 states that the Nonce is the last piece of AAD before the actual
1386 encrypt/decrypt takes place. The API does not differentiate the Nonce from
1389 When decrypting the return value of EVP_DecryptFinal() or EVP_CipherFinal()
1390 indicates if the operation was successful. If it does not indicate success
1391 the authentication operation has failed and any output data B<MUST NOT>
1392 be used as it is corrupted.
1394 The API does not store the the SIV (Synthetic Initialization Vector) in
1395 the cipher text. Instead, it is stored as the tag within the EVP_CIPHER_CTX.
1396 The SIV must be retrieved from the context after encryption, and set into
1397 the context before decryption.
1399 This differs from RFC5297 in that the cipher output from encryption, and
1400 the cipher input to decryption, does not contain the SIV. This also means
1401 that the plain text and cipher text lengths are identical.
1403 The following ctrls are supported in SIV mode, and are used to get and set
1404 the Synthetic Initialization Vector:
1408 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag);
1410 Writes I<taglen> bytes of the tag value (the Synthetic Initialization Vector)
1411 to the buffer indicated by I<tag>. This call can only be made when encrypting
1412 data and B<after> all data has been processed (e.g. after an EVP_EncryptFinal()
1413 call). For SIV mode the taglen must be 16.
1415 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag);
1417 Sets the expected tag (the Synthetic Initialization Vector) to I<taglen>
1418 bytes from I<tag>. This call is only legal when decrypting data and must be
1419 made B<before> any data is processed (e.g. before any EVP_DecryptUpdate()
1420 calls). For SIV mode the taglen must be 16.
1424 SIV mode makes two passes over the input data, thus, only one call to
1425 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made
1426 with I<out> set to a non-B<NULL> value. A call to EVP_DecryptFinal() or
1427 EVP_CipherFinal() is not required, but will indicate if the update
1428 operation succeeded.
1430 =head2 ChaCha20-Poly1305
1432 The following I<ctrl>s are supported for the ChaCha20-Poly1305 AEAD algorithm.
1436 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
1438 Sets the nonce length. This call can only be made before specifying the nonce.
1439 If not called a default nonce length of 12 (i.e. 96 bits) is used. The maximum
1440 nonce length is 12 bytes (i.e. 96-bits). If a nonce of less than 12 bytes is set
1441 then the nonce is automatically padded with leading 0 bytes to make it 12 bytes
1444 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
1446 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
1447 This call can only be made when encrypting data and B<after> all data has been
1448 processed (e.g. after an EVP_EncryptFinal() call).
1450 C<taglen> specified here must be 16 (B<POLY1305_BLOCK_SIZE>, i.e. 128-bits) or
1453 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
1455 Sets the expected tag to C<taglen> bytes from C<tag>.
1456 The tag length can only be set before specifying an IV.
1457 C<taglen> must be between 1 and 16 (B<POLY1305_BLOCK_SIZE>) inclusive.
1458 This call is only valid when decrypting data.
1464 Where possible the B<EVP> interface to symmetric ciphers should be used in
1465 preference to the low-level interfaces. This is because the code then becomes
1466 transparent to the cipher used and much more flexible. Additionally, the
1467 B<EVP> interface will ensure the use of platform specific cryptographic
1468 acceleration such as AES-NI (the low-level interfaces do not provide the
1471 PKCS padding works by adding B<n> padding bytes of value B<n> to make the total
1472 length of the encrypted data a multiple of the block size. Padding is always
1473 added so if the data is already a multiple of the block size B<n> will equal
1474 the block size. For example if the block size is 8 and 11 bytes are to be
1475 encrypted then 5 padding bytes of value 5 will be added.
1477 When decrypting the final block is checked to see if it has the correct form.
1479 Although the decryption operation can produce an error if padding is enabled,
1480 it is not a strong test that the input data or key is correct. A random block
1481 has better than 1 in 256 chance of being of the correct format and problems with
1482 the input data earlier on will not produce a final decrypt error.
1484 If padding is disabled then the decryption operation will always succeed if
1485 the total amount of data decrypted is a multiple of the block size.
1487 The functions EVP_EncryptInit(), EVP_EncryptInit_ex(),
1488 EVP_EncryptFinal(), EVP_DecryptInit(), EVP_DecryptInit_ex(),
1489 EVP_CipherInit(), EVP_CipherInit_ex() and EVP_CipherFinal() are obsolete
1490 but are retained for compatibility with existing code. New code should
1491 use EVP_EncryptInit_ex2(), EVP_EncryptFinal_ex(), EVP_DecryptInit_ex2(),
1492 EVP_DecryptFinal_ex(), EVP_CipherInit_ex2() and EVP_CipherFinal_ex()
1493 because they can reuse an existing context without allocating and freeing
1496 There are some differences between functions EVP_CipherInit() and
1497 EVP_CipherInit_ex(), significant in some circumstances. EVP_CipherInit() fills
1498 the passed context object with zeros. As a consequence, EVP_CipherInit() does
1499 not allow step-by-step initialization of the ctx when the I<key> and I<iv> are
1500 passed in separate calls. It also means that the flags set for the CTX are
1501 removed, and it is especially important for the
1502 B<EVP_CIPHER_CTX_FLAG_WRAP_ALLOW> flag treated specially in
1503 EVP_CipherInit_ex().
1505 EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros.
1509 B<EVP_MAX_KEY_LENGTH> and B<EVP_MAX_IV_LENGTH> only refer to the internal
1510 ciphers with default key lengths. If custom ciphers exceed these values the
1511 results are unpredictable. This is because it has become standard practice to
1512 define a generic key as a fixed unsigned char array containing
1513 B<EVP_MAX_KEY_LENGTH> bytes.
1515 The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested
1516 for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode.
1520 Encrypt a string using IDEA:
1522 int do_crypt(char *outfile)
1524 unsigned char outbuf[1024];
1527 * Bogus key and IV: we'd normally set these from
1530 unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1531 unsigned char iv[] = {1,2,3,4,5,6,7,8};
1532 char intext[] = "Some Crypto Text";
1533 EVP_CIPHER_CTX *ctx;
1536 ctx = EVP_CIPHER_CTX_new();
1537 EVP_EncryptInit_ex2(ctx, EVP_idea_cbc(), key, iv, NULL);
1539 if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) {
1541 EVP_CIPHER_CTX_free(ctx);
1545 * Buffer passed to EVP_EncryptFinal() must be after data just
1546 * encrypted to avoid overwriting it.
1548 if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) {
1550 EVP_CIPHER_CTX_free(ctx);
1554 EVP_CIPHER_CTX_free(ctx);
1556 * Need binary mode for fopen because encrypted data is
1557 * binary data. Also cannot use strlen() on it because
1558 * it won't be NUL terminated and may contain embedded
1561 out = fopen(outfile, "wb");
1566 fwrite(outbuf, 1, outlen, out);
1571 The ciphertext from the above example can be decrypted using the B<openssl>
1572 utility with the command line (shown on two lines for clarity):
1575 -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename
1577 General encryption and decryption function example using FILE I/O and AES128
1580 int do_crypt(FILE *in, FILE *out, int do_encrypt)
1582 /* Allow enough space in output buffer for additional block */
1583 unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
1585 EVP_CIPHER_CTX *ctx;
1587 * Bogus key and IV: we'd normally set these from
1590 unsigned char key[] = "0123456789abcdeF";
1591 unsigned char iv[] = "1234567887654321";
1593 /* Don't set key or IV right away; we want to check lengths */
1594 ctx = EVP_CIPHER_CTX_new();
1595 EVP_CipherInit_ex2(ctx, EVP_aes_128_cbc(), NULL, NULL,
1597 OPENSSL_assert(EVP_CIPHER_CTX_get_key_length(ctx) == 16);
1598 OPENSSL_assert(EVP_CIPHER_CTX_get_iv_length(ctx) == 16);
1600 /* Now we can set key and IV */
1601 EVP_CipherInit_ex2(ctx, NULL, key, iv, do_encrypt, NULL);
1604 inlen = fread(inbuf, 1, 1024, in);
1607 if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) {
1609 EVP_CIPHER_CTX_free(ctx);
1612 fwrite(outbuf, 1, outlen, out);
1614 if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) {
1616 EVP_CIPHER_CTX_free(ctx);
1619 fwrite(outbuf, 1, outlen, out);
1621 EVP_CIPHER_CTX_free(ctx);
1625 Encryption using AES-CBC with a 256-bit key with "CS1" ciphertext stealing.
1627 int encrypt(const unsigned char *key, const unsigned char *iv,
1628 const unsigned char *msg, size_t msg_len, unsigned char *out)
1631 * This assumes that key size is 32 bytes and the iv is 16 bytes.
1632 * For ciphertext stealing mode the length of the ciphertext "out" will be
1633 * the same size as the plaintext size "msg_len".
1634 * The "msg_len" can be any size >= 16.
1636 int ret = 0, encrypt = 1, outlen, len;
1637 EVP_CIPHER_CTX *ctx = NULL;
1638 EVP_CIPHER *cipher = NULL;
1639 OSSL_PARAM params[2];
1641 ctx = EVP_CIPHER_CTX_new();
1642 cipher = EVP_CIPHER_fetch(NULL, "AES-256-CBC-CTS", NULL);
1643 if (ctx == NULL || cipher == NULL)
1647 * The default is "CS1" so this is not really needed,
1648 * but would be needed to set either "CS2" or "CS3".
1650 params[0] = OSSL_PARAM_construct_utf8_string(OSSL_CIPHER_PARAM_CTS_MODE,
1652 params[1] = OSSL_PARAM_construct_end();
1654 if (!EVP_CipherInit_ex2(ctx, cipher, key, iv, encrypt, params))
1657 /* NOTE: CTS mode does not support multiple calls to EVP_CipherUpdate() */
1658 if (!EVP_CipherUpdate(ctx, encrypted, &outlen, msg, msglen))
1660 if (!EVP_CipherFinal_ex(ctx, encrypted + outlen, &len))
1664 EVP_CIPHER_free(cipher);
1665 EVP_CIPHER_CTX_free(ctx);
1673 L<crypto(7)/ALGORITHM FETCHING>,
1674 L<provider-cipher(7)>,
1675 L<life_cycle-cipher(7)>
1677 Supported ciphers are listed in:
1679 L<EVP_aes_128_gcm(3)>,
1680 L<EVP_aria_128_gcm(3)>,
1682 L<EVP_camellia_128_ecb(3)>,
1683 L<EVP_cast5_cbc(3)>,
1690 L<EVP_rc5_32_12_16_cbc(3)>,
1696 Support for OCB mode was added in OpenSSL 1.1.0.
1698 B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result,
1699 EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup()
1700 disappeared. EVP_CIPHER_CTX_init() remains as an alias for
1701 EVP_CIPHER_CTX_reset().
1703 The EVP_CIPHER_CTX_cipher() function was deprecated in OpenSSL 3.0; use
1704 EVP_CIPHER_CTX_get0_cipher() instead.
1706 The EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2(), EVP_CipherInit_ex2(),
1707 EVP_CIPHER_fetch(), EVP_CIPHER_free(), EVP_CIPHER_up_ref(),
1708 EVP_CIPHER_CTX_get0_cipher(), EVP_CIPHER_CTX_get1_cipher(),
1709 EVP_CIPHER_get_params(), EVP_CIPHER_CTX_set_params(),
1710 EVP_CIPHER_CTX_get_params(), EVP_CIPHER_gettable_params(),
1711 EVP_CIPHER_settable_ctx_params(), EVP_CIPHER_gettable_ctx_params(),
1712 EVP_CIPHER_CTX_settable_params() and EVP_CIPHER_CTX_gettable_params()
1713 functions were added in 3.0.
1715 The EVP_CIPHER_nid(), EVP_CIPHER_name(), EVP_CIPHER_block_size(),
1716 EVP_CIPHER_key_length(), EVP_CIPHER_iv_length(), EVP_CIPHER_flags(),
1717 EVP_CIPHER_mode(), EVP_CIPHER_type(), EVP_CIPHER_CTX_nid(),
1718 EVP_CIPHER_CTX_block_size(), EVP_CIPHER_CTX_key_length(),
1719 EVP_CIPHER_CTX_iv_length(), EVP_CIPHER_CTX_tag_length(),
1720 EVP_CIPHER_CTX_num(), EVP_CIPHER_CTX_type(), and EVP_CIPHER_CTX_mode()
1721 functions were renamed to include C<get> or C<get0> in their names in
1722 OpenSSL 3.0, respectively. The old names are kept as non-deprecated
1725 The EVP_CIPHER_CTX_encrypting() function was renamed to
1726 EVP_CIPHER_CTX_is_encrypting() in OpenSSL 3.0. The old name is kept as
1727 non-deprecated alias macro.
1729 The EVP_CIPHER_CTX_flags() macro was deprecated in OpenSSL 1.1.0.
1731 EVP_CIPHER_CTX_dup() was added in OpenSSL 3.1.
1735 Copyright 2000-2022 The OpenSSL Project Authors. All Rights Reserved.
1737 Licensed under the Apache License 2.0 (the "License"). You may not use
1738 this file except in compliance with the License. You can obtain a copy
1739 in the file LICENSE in the source distribution or at
1740 L<https://www.openssl.org/source/license.html>.