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 L<OSSL_PARAM(3)> array that describes the retrievable parameters
334 that can be used with EVP_CIPHER_get_params().
336 =item EVP_CIPHER_gettable_ctx_params() and EVP_CIPHER_CTX_gettable_params()
338 Get a constant L<OSSL_PARAM(3)> array that describes the retrievable parameters
339 that can be used with EVP_CIPHER_CTX_get_params().
340 EVP_CIPHER_gettable_ctx_params() returns the parameters that can be retrieved
341 from the algorithm, whereas EVP_CIPHER_CTX_gettable_params() returns the
342 parameters that can be retrieved in the context's current state.
344 =item EVP_CIPHER_settable_ctx_params() and EVP_CIPHER_CTX_settable_params()
346 Get a constant L<OSSL_PARAM(3)> array that describes the settable parameters
347 that can be used with EVP_CIPHER_CTX_set_params().
348 EVP_CIPHER_settable_ctx_params() returns the parameters that can be set from the
349 algorithm, whereas EVP_CIPHER_CTX_settable_params() returns the parameters that
350 can be set in the context's current state.
352 =item EVP_EncryptInit_ex2()
354 Sets up cipher context I<ctx> for encryption with cipher I<type>. I<type> is
355 typically supplied by calling EVP_CIPHER_fetch(). I<type> may also be set
356 using legacy functions such as EVP_aes_256_cbc(), but this is not recommended
357 for new applications. I<key> is the symmetric key to use and I<iv> is the IV to
358 use (if necessary), the actual number of bytes used for the key and IV depends
359 on the cipher. The parameters I<params> will be set on the context after
360 initialisation. It is possible to set all parameters to NULL except I<type> in
361 an initial call and supply the remaining parameters in subsequent calls, all of
362 which have I<type> set to NULL. This is done when the default cipher parameters
364 For B<EVP_CIPH_GCM_MODE> the IV will be generated internally if it is not
367 =item EVP_EncryptInit_ex()
369 This legacy function is similar to EVP_EncryptInit_ex2() when I<impl> is NULL.
370 The implementation of the I<type> from the I<impl> engine will be used if it
373 =item EVP_EncryptUpdate()
375 Encrypts I<inl> bytes from the buffer I<in> and writes the encrypted version to
376 I<out>. The pointers I<out> and I<in> may point to the same location, in which
377 case the encryption will be done in-place. If I<out> and I<in> point to different
378 locations, the two buffers must be disjoint, otherwise the operation might fail
379 or the outcome might be undefined.
381 This function can be called multiple times to encrypt successive blocks
382 of data. The amount of data written depends on the block alignment of the
384 For most ciphers and modes, the amount of data written can be anything
385 from zero bytes to (inl + cipher_block_size - 1) bytes.
386 For wrap cipher modes, the amount of data written can be anything
387 from zero bytes to (inl + cipher_block_size) bytes.
388 For stream ciphers, the amount of data written can be anything from zero
390 Thus, the buffer pointed to by I<out> must contain sufficient room for the
391 operation being performed.
392 The actual number of bytes written is placed in I<outl>.
394 If padding is enabled (the default) then EVP_EncryptFinal_ex() encrypts
395 the "final" data, that is any data that remains in a partial block.
396 It uses standard block padding (aka PKCS padding) as described in
397 the NOTES section, below. The encrypted
398 final data is written to I<out> which should have sufficient space for
399 one cipher block. The number of bytes written is placed in I<outl>. After
400 this function is called the encryption operation is finished and no further
401 calls to EVP_EncryptUpdate() should be made.
403 If padding is disabled then EVP_EncryptFinal_ex() will not encrypt any more
404 data and it will return an error if any data remains in a partial block:
405 that is if the total data length is not a multiple of the block size.
407 =item EVP_DecryptInit_ex2(), EVP_DecryptInit_ex(), EVP_DecryptUpdate()
408 and EVP_DecryptFinal_ex()
410 These functions are the corresponding decryption operations.
411 EVP_DecryptFinal() will return an error code if padding is enabled and the
412 final block is not correctly formatted. The parameters and restrictions are
413 identical to the encryption operations except that if padding is enabled the
414 decrypted data buffer I<out> passed to EVP_DecryptUpdate() should have
415 sufficient room for (I<inl> + cipher_block_size) bytes unless the cipher block
416 size is 1 in which case I<inl> bytes is sufficient.
418 =item EVP_CipherInit_ex2(), EVP_CipherInit_ex(), EVP_CipherUpdate() and
421 These functions can be used for decryption or encryption. The operation
422 performed depends on the value of the I<enc> parameter. It should be set to 1
423 for encryption, 0 for decryption and -1 to leave the value unchanged
424 (the actual value of 'enc' being supplied in a previous call).
426 =item EVP_CIPHER_CTX_reset()
428 Clears all information from a cipher context and free up any allocated memory
429 associated with it, except the I<ctx> itself. This function should be called
430 anytime I<ctx> is reused by another
431 EVP_CipherInit() / EVP_CipherUpdate() / EVP_CipherFinal() series of calls.
433 =item EVP_EncryptInit(), EVP_DecryptInit() and EVP_CipherInit()
435 Behave in a similar way to EVP_EncryptInit_ex(), EVP_DecryptInit_ex() and
436 EVP_CipherInit_ex() except if the I<type> is not a fetched cipher they use the
437 default implementation of the I<type>.
439 =item EVP_EncryptFinal(), EVP_DecryptFinal() and EVP_CipherFinal()
441 Identical to EVP_EncryptFinal_ex(), EVP_DecryptFinal_ex() and
442 EVP_CipherFinal_ex(). In previous releases they also cleaned up
443 the I<ctx>, but this is no longer done and EVP_CIPHER_CTX_cleanup()
444 must be called to free any context resources.
448 Encrypts or decrypts a maximum I<inl> amount of bytes from I<in> and leaves the
451 For legacy ciphers - If the cipher doesn't have the flag
452 B<EVP_CIPH_FLAG_CUSTOM_CIPHER> set, then I<inl> must be a multiple of
453 EVP_CIPHER_get_block_size(). If it isn't, the result is undefined. If the cipher
454 has that flag set, then I<inl> can be any size.
456 Due to the constraints of the API contract of this function it shouldn't be used
457 in applications, please consider using EVP_CipherUpdate() and
458 EVP_CipherFinal_ex() instead.
460 =item EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
462 Returns an B<EVP_CIPHER> structure when passed a cipher name, a cipher B<NID> or
463 an B<ASN1_OBJECT> structure respectively.
465 EVP_get_cipherbyname() will return NULL for algorithms such as "AES-128-SIV",
466 "AES-128-CBC-CTS" and "CAMELLIA-128-CBC-CTS" which were previously only
467 accessible via low level interfaces.
469 The EVP_get_cipherbyname() function is present for backwards compatibility with
470 OpenSSL prior to version 3 and is different to the EVP_CIPHER_fetch() function
471 since it does not attempt to "fetch" an implementation of the cipher.
472 Additionally, it only knows about ciphers that are built-in to OpenSSL and have
473 an associated NID. Similarly EVP_get_cipherbynid() and EVP_get_cipherbyobj()
474 also return objects without an associated implementation.
476 When the cipher objects returned by these functions are used (such as in a call
477 to EVP_EncryptInit_ex()) an implementation of the cipher will be implicitly
478 fetched from the loaded providers. This fetch could fail if no suitable
479 implementation is available. Use EVP_CIPHER_fetch() instead to explicitly fetch
480 the algorithm and an associated implementation from a provider.
482 See L<crypto(7)/ALGORITHM FETCHING> for more information about fetching.
484 The cipher objects returned from these functions do not need to be freed with
487 =item EVP_CIPHER_get_nid() and EVP_CIPHER_CTX_get_nid()
489 Return the NID of a cipher when passed an B<EVP_CIPHER> or B<EVP_CIPHER_CTX>
490 structure. The actual NID value is an internal value which may not have a
491 corresponding OBJECT IDENTIFIER.
493 =item EVP_CIPHER_CTX_set_flags(), EVP_CIPHER_CTX_clear_flags() and EVP_CIPHER_CTX_test_flags()
495 Sets, clears and tests I<ctx> flags. See L</FLAGS> below for more information.
497 For provided ciphers EVP_CIPHER_CTX_set_flags() should be called only after the
498 fetched cipher has been assigned to the I<ctx>. It is recommended to use
499 L</PARAMETERS> instead.
501 =item EVP_CIPHER_CTX_set_padding()
503 Enables or disables padding. This function should be called after the context
504 is set up for encryption or decryption with EVP_EncryptInit_ex2(),
505 EVP_DecryptInit_ex2() or EVP_CipherInit_ex2(). By default encryption operations
506 are padded using standard block padding and the padding is checked and removed
507 when decrypting. If the I<pad> parameter is zero then no padding is
508 performed, the total amount of data encrypted or decrypted must then
509 be a multiple of the block size or an error will occur.
511 =item EVP_CIPHER_get_key_length() and EVP_CIPHER_CTX_get_key_length()
513 Return the key length of a cipher when passed an B<EVP_CIPHER> or
514 B<EVP_CIPHER_CTX> structure. The constant B<EVP_MAX_KEY_LENGTH> is the maximum
515 key length for all ciphers. Note: although EVP_CIPHER_get_key_length() is fixed for
516 a given cipher, the value of EVP_CIPHER_CTX_get_key_length() may be different for
517 variable key length ciphers.
519 =item EVP_CIPHER_CTX_set_key_length()
521 Sets the key length of the cipher context.
522 If the cipher is a fixed length cipher then attempting to set the key
523 length to any value other than the fixed value is an error.
525 =item EVP_CIPHER_get_iv_length() and EVP_CIPHER_CTX_get_iv_length()
527 Return the IV length of a cipher when passed an B<EVP_CIPHER> or
528 B<EVP_CIPHER_CTX>. It will return zero if the cipher does not use an IV.
529 The constant B<EVP_MAX_IV_LENGTH> is the maximum IV length for all ciphers.
531 =item EVP_CIPHER_CTX_get_tag_length()
533 Returns the tag length of an AEAD cipher when passed a B<EVP_CIPHER_CTX>. It will
534 return zero if the cipher does not support a tag. It returns a default value if
535 the tag length has not been set.
537 =item EVP_CIPHER_get_block_size() and EVP_CIPHER_CTX_get_block_size()
539 Return the block size of a cipher when passed an B<EVP_CIPHER> or
540 B<EVP_CIPHER_CTX> structure. The constant B<EVP_MAX_BLOCK_LENGTH> is also the
541 maximum block length for all ciphers.
543 =item EVP_CIPHER_get_type() and EVP_CIPHER_CTX_get_type()
545 Return the type of the passed cipher or context. This "type" is the actual NID
546 of the cipher OBJECT IDENTIFIER and as such it ignores the cipher parameters
547 (40 bit RC2 and 128 bit RC2 have the same NID). If the cipher does not have an
548 object identifier or does not have ASN1 support this function will return
551 =item EVP_CIPHER_is_a()
553 Returns 1 if I<cipher> is an implementation of an algorithm that's identifiable
554 with I<name>, otherwise 0. If I<cipher> is a legacy cipher (it's the return
555 value from the likes of EVP_aes128() rather than the result of an
556 EVP_CIPHER_fetch()), only cipher names registered with the default library
557 context (see L<OSSL_LIB_CTX(3)>) will be considered.
559 =item EVP_CIPHER_get0_name() and EVP_CIPHER_CTX_get0_name()
561 Return the name of the passed cipher or context. For fetched ciphers with
562 multiple names, only one of them is returned. See also EVP_CIPHER_names_do_all().
564 =item EVP_CIPHER_names_do_all()
566 Traverses all names for the I<cipher>, and calls I<fn> with each name and
567 I<data>. This is only useful with fetched B<EVP_CIPHER>s.
569 =item EVP_CIPHER_get0_description()
571 Returns a description of the cipher, meant for display and human consumption.
572 The description is at the discretion of the cipher implementation.
574 =item EVP_CIPHER_get0_provider()
576 Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
579 =item EVP_CIPHER_CTX_get0_cipher()
581 Returns the B<EVP_CIPHER> structure when passed an B<EVP_CIPHER_CTX> structure.
582 EVP_CIPHER_CTX_get1_cipher() is the same except the ownership is passed to
585 =item EVP_CIPHER_get_mode() and EVP_CIPHER_CTX_get_mode()
587 Return the block cipher mode:
588 EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE,
589 EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE,
590 EVP_CIPH_WRAP_MODE, EVP_CIPH_OCB_MODE or EVP_CIPH_SIV_MODE.
591 If the cipher is a stream cipher then EVP_CIPH_STREAM_CIPHER is returned.
593 =item EVP_CIPHER_get_flags()
595 Returns any flags associated with the cipher. See L</FLAGS>
596 for a list of currently defined flags.
598 =item EVP_CIPHER_CTX_get_num() and EVP_CIPHER_CTX_set_num()
600 Gets or sets the cipher specific "num" parameter for the associated I<ctx>.
601 Built-in ciphers typically use this to track how much of the current underlying block
602 has been "used" already.
604 =item EVP_CIPHER_CTX_is_encrypting()
606 Reports whether the I<ctx> is being used for encryption or decryption.
608 =item EVP_CIPHER_CTX_flags()
610 A deprecated macro calling C<EVP_CIPHER_get_flags(EVP_CIPHER_CTX_get0_cipher(ctx))>.
613 =item EVP_CIPHER_param_to_asn1()
615 Sets the AlgorithmIdentifier "parameter" based on the passed cipher. This will
616 typically include any parameters and an IV. The cipher IV (if any) must be set
617 when this call is made. This call should be made before the cipher is actually
618 "used" (before any EVP_EncryptUpdate(), EVP_DecryptUpdate() calls for example).
619 This function may fail if the cipher does not have any ASN1 support.
621 =item EVP_CIPHER_asn1_to_param()
623 Sets the cipher parameters based on an ASN1 AlgorithmIdentifier "parameter".
624 The precise effect depends on the cipher. In the case of B<RC2>, for example,
625 it will set the IV and effective key length.
626 This function should be called after the base cipher type is set but before
627 the key is set. For example EVP_CipherInit() will be called with the IV and
628 key set to NULL, EVP_CIPHER_asn1_to_param() will be called and finally
629 EVP_CipherInit() again with all parameters except the key set to NULL. It is
630 possible for this function to fail if the cipher does not have any ASN1 support
631 or the parameters cannot be set (for example the RC2 effective key length
634 =item EVP_CIPHER_CTX_rand_key()
636 Generates a random key of the appropriate length based on the cipher context.
637 The B<EVP_CIPHER> can provide its own random key generation routine to support
638 keys of a specific form. I<key> must point to a buffer at least as big as the
639 value returned by EVP_CIPHER_CTX_get_key_length().
641 =item EVP_CIPHER_do_all_provided()
643 Traverses all ciphers implemented by all activated providers in the given
644 library context I<libctx>, and for each of the implementations, calls the given
645 function I<fn> with the implementation method and the given I<arg> as argument.
651 See L<OSSL_PARAM(3)> for information about passing parameters.
653 =head2 Gettable EVP_CIPHER parameters
655 When EVP_CIPHER_fetch() is called it internally calls EVP_CIPHER_get_params()
656 and caches the results.
658 EVP_CIPHER_get_params() can be used with the following L<OSSL_PARAM(3)> keys:
662 =item "mode" (B<OSSL_CIPHER_PARAM_MODE>) <unsigned integer>
664 Gets the mode for the associated cipher algorithm I<cipher>.
665 See L</EVP_CIPHER_get_mode() and EVP_CIPHER_CTX_get_mode()> for a list of valid modes.
666 Use EVP_CIPHER_get_mode() to retrieve the cached value.
668 =item "keylen" (B<OSSL_CIPHER_PARAM_KEYLEN>) <unsigned integer>
670 Gets the key length for the associated cipher algorithm I<cipher>.
671 Use EVP_CIPHER_get_key_length() to retrieve the cached value.
673 =item "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN>) <unsigned integer>
675 Gets the IV length for the associated cipher algorithm I<cipher>.
676 Use EVP_CIPHER_get_iv_length() to retrieve the cached value.
678 =item "blocksize" (B<OSSL_CIPHER_PARAM_BLOCK_SIZE>) <unsigned integer>
680 Gets the block size for the associated cipher algorithm I<cipher>.
681 The block size should be 1 for stream ciphers.
682 Note that the block size for a cipher may be different to the block size for
683 the underlying encryption/decryption primitive.
684 For example AES in CTR mode has a block size of 1 (because it operates like a
685 stream cipher), even though AES has a block size of 16.
686 Use EVP_CIPHER_get_block_size() to retrieve the cached value.
688 =item "aead" (B<OSSL_CIPHER_PARAM_AEAD>) <integer>
690 Gets 1 if this is an AEAD cipher algorithm, otherwise it gets 0.
691 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) to retrieve the
694 =item "custom-iv" (B<OSSL_CIPHER_PARAM_CUSTOM_IV>) <integer>
696 Gets 1 if the cipher algorithm I<cipher> has a custom IV, otherwise it gets 0.
697 Storing and initializing the IV is left entirely to the implementation, if a
699 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_CUSTOM_IV) to retrieve the
702 =item "cts" (B<OSSL_CIPHER_PARAM_CTS>) <integer>
704 Gets 1 if the cipher algorithm I<cipher> uses ciphertext stealing,
706 This is currently used to indicate that the cipher is a one shot that only
707 allows a single call to EVP_CipherUpdate().
708 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_CTS) to retrieve the
711 =item "tls-multi" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK>) <integer>
713 Gets 1 if the cipher algorithm I<cipher> supports interleaving of crypto blocks,
714 otherwise it gets 0. The interleaving is an optimization only applicable to certain
716 Use (EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK) to retrieve the
719 =item "has-randkey" (B<OSSL_CIPHER_PARAM_HAS_RANDKEY>) <integer>
721 Gets 1 if the cipher algorithm I<cipher> supports the gettable EVP_CIPHER_CTX
722 parameter B<OSSL_CIPHER_PARAM_RANDOM_KEY>. Only DES and 3DES set this to 1,
723 all other OpenSSL ciphers return 0.
727 =head2 Gettable and Settable EVP_CIPHER_CTX parameters
729 The following L<OSSL_PARAM(3)> keys can be used with both EVP_CIPHER_CTX_get_params()
730 and EVP_CIPHER_CTX_set_params().
734 =item "padding" (B<OSSL_CIPHER_PARAM_PADDING>) <unsigned integer>
736 Gets or sets the padding mode for the cipher context I<ctx>.
737 Padding is enabled if the value is 1, and disabled if the value is 0.
738 See also EVP_CIPHER_CTX_set_padding().
740 =item "num" (B<OSSL_CIPHER_PARAM_NUM>) <unsigned integer>
742 Gets or sets the cipher specific "num" parameter for the cipher context I<ctx>.
743 Built-in ciphers typically use this to track how much of the current underlying
744 block has been "used" already.
745 See also EVP_CIPHER_CTX_get_num() and EVP_CIPHER_CTX_set_num().
747 =item "keylen" (B<OSSL_CIPHER_PARAM_KEYLEN>) <unsigned integer>
749 Gets or sets the key length for the cipher context I<ctx>.
750 The length of the "keylen" parameter should not exceed that of a B<size_t>.
751 See also EVP_CIPHER_CTX_get_key_length() and EVP_CIPHER_CTX_set_key_length().
753 =item "tag" (B<OSSL_CIPHER_PARAM_AEAD_TAG>) <octet string>
755 Gets or sets the AEAD tag for the associated cipher context I<ctx>.
756 See L<EVP_EncryptInit(3)/AEAD Interface>.
758 =item "keybits" (B<OSSL_CIPHER_PARAM_RC2_KEYBITS>) <unsigned integer>
760 Gets or sets the effective keybits used for a RC2 cipher.
761 The length of the "keybits" parameter should not exceed that of a B<size_t>.
763 =item "rounds" (B<OSSL_CIPHER_PARAM_ROUNDS>) <unsigned integer>
765 Gets or sets the number of rounds to be used for a cipher.
766 This is used by the RC5 cipher.
768 =item "alg_id_param" (B<OSSL_CIPHER_PARAM_ALGORITHM_ID_PARAMS>) <octet string>
770 Used to pass the DER encoded AlgorithmIdentifier parameter to or from
771 the cipher implementation. Functions like L<EVP_CIPHER_param_to_asn1(3)>
772 and L<EVP_CIPHER_asn1_to_param(3)> use this parameter for any implementation
773 that has the flag B<EVP_CIPH_FLAG_CUSTOM_ASN1> set.
775 =item "cts_mode" (B<OSSL_CIPHER_PARAM_CTS_MODE>) <UTF8 string>
777 Gets or sets the cipher text stealing mode. For all modes the output size is the
778 same as the input size. The input length must be greater than or equal to the
779 block size. (The block size for AES and CAMELLIA is 16 bytes).
781 Valid values for the mode are:
787 The NIST variant of cipher text stealing.
788 For input lengths that are multiples of the block size it is equivalent to
789 using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher otherwise the second last
790 cipher text block is a partial block.
794 For input lengths that are multiples of the block size it is equivalent to
795 using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher, otherwise it is the same as
800 The Kerberos5 variant of cipher text stealing which always swaps the last
801 cipher text block with the previous block (which may be a partial or full block
802 depending on the input length). If the input length is exactly one full block
803 then this is equivalent to using a "AES-XXX-CBC" or "CAMELLIA-XXX-CBC" cipher.
807 The default is "CS1".
808 This is only supported for "AES-128-CBC-CTS", "AES-192-CBC-CTS", "AES-256-CBC-CTS",
809 "CAMELLIA-128-CBC-CTS", "CAMELLIA-192-CBC-CTS" and "CAMELLIA-256-CBC-CTS".
811 =item "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>) <unsigned integer>
813 Sets or gets the number of records being sent in one go for a tls1 multiblock
814 cipher operation (either 4 or 8 records).
818 =head2 Gettable EVP_CIPHER_CTX parameters
820 The following L<OSSL_PARAM(3)> keys can be used with EVP_CIPHER_CTX_get_params():
824 =item "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN> and <B<OSSL_CIPHER_PARAM_AEAD_IVLEN>) <unsigned integer>
826 Gets the IV length for the cipher context I<ctx>.
827 The length of the "ivlen" parameter should not exceed that of a B<size_t>.
828 See also EVP_CIPHER_CTX_get_iv_length().
830 =item "iv" (B<OSSL_CIPHER_PARAM_IV>) <octet string OR octet ptr>
832 Gets the IV used to initialize the associated cipher context I<ctx>.
833 See also EVP_CIPHER_CTX_get_original_iv().
835 =item "updated-iv" (B<OSSL_CIPHER_PARAM_UPDATED_IV>) <octet string OR octet ptr>
837 Gets the updated pseudo-IV state for the associated cipher context, e.g.,
838 the previous ciphertext block for CBC mode or the iteratively encrypted IV
839 value for OFB mode. Note that octet pointer access is deprecated and is
840 provided only for backwards compatibility with historical libcrypto APIs.
841 See also EVP_CIPHER_CTX_get_updated_iv().
843 =item "randkey" (B<OSSL_CIPHER_PARAM_RANDOM_KEY>) <octet string>
845 Gets an implementation specific randomly generated key for the associated
846 cipher context I<ctx>. This is currently only supported by DES and 3DES (which set
847 the key to odd parity).
849 =item "taglen" (B<OSSL_CIPHER_PARAM_AEAD_TAGLEN>) <unsigned integer>
851 Gets the tag length to be used for an AEAD cipher for the associated cipher
852 context I<ctx>. It gets a default value if it has not been set.
853 The length of the "taglen" parameter should not exceed that of a B<size_t>.
854 See also EVP_CIPHER_CTX_get_tag_length().
856 =item "tlsaadpad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD>) <unsigned integer>
858 Gets the length of the tag that will be added to a TLS record for the AEAD
859 tag for the associated cipher context I<ctx>.
860 The length of the "tlsaadpad" parameter should not exceed that of a B<size_t>.
862 =item "tlsivgen" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN>) <octet string>
864 Gets the invocation field generated for encryption.
865 Can only be called after "tlsivfixed" is set.
866 This is only used for GCM mode.
868 =item "tls1multi_enclen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_LEN>) <unsigned integer>
870 Get the total length of the record returned from the "tls1multi_enc" operation.
872 =item "tls1multi_maxbufsz" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_BUFSIZE>) <unsigned integer>
874 Gets the maximum record length for a TLS1 multiblock cipher operation.
875 The length of the "tls1multi_maxbufsz" parameter should not exceed that of a B<size_t>.
877 =item "tls1multi_aadpacklen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD_PACKLEN>) <unsigned integer>
879 Gets the result of running the "tls1multi_aad" operation.
881 =item "tls-mac" (B<OSSL_CIPHER_PARAM_TLS_MAC>) <octet ptr>
883 Used to pass the TLS MAC data.
887 =head2 Settable EVP_CIPHER_CTX parameters
889 The following L<OSSL_PARAM(3)> keys can be used with EVP_CIPHER_CTX_set_params():
893 =item "mackey" (B<OSSL_CIPHER_PARAM_AEAD_MAC_KEY>) <octet string>
895 Sets the MAC key used by composite AEAD ciphers such as AES-CBC-HMAC-SHA256.
897 =item "speed" (B<OSSL_CIPHER_PARAM_SPEED>) <unsigned integer>
899 Sets the speed option for the associated cipher context. This is only supported
900 by AES SIV ciphers which disallow multiple operations by default.
901 Setting "speed" to 1 allows another encrypt or decrypt operation to be
902 performed. This is used for performance testing.
904 =item "use-bits" (B<OSSL_CIPHER_PARAM_USE_BITS>) <unsigned integer>
906 Determines if the input length I<inl> passed to EVP_EncryptUpdate(),
907 EVP_DecryptUpdate() and EVP_CipherUpdate() is the number of bits or number of bytes.
908 Setting "use-bits" to 1 uses bits. The default is in bytes.
909 This is only used for B<CFB1> ciphers.
911 This can be set using EVP_CIPHER_CTX_set_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS).
913 =item "tls-version" (B<OSSL_CIPHER_PARAM_TLS_VERSION>) <integer>
915 Sets the TLS version.
917 =item "tls-mac-size" (B<OSSL_CIPHER_PARAM_TLS_MAC_SIZE>) <unsigned integer>
919 Set the TLS MAC size.
921 =item "tlsaad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD>) <octet string>
923 Sets TLSv1.2 AAD information for the associated cipher context I<ctx>.
924 TLSv1.2 AAD information is always 13 bytes in length and is as defined for the
925 "additional_data" field described in section 6.2.3.3 of RFC5246.
927 =item "tlsivfixed" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED>) <octet string>
929 Sets the fixed portion of an IV for an AEAD cipher used in a TLS record
930 encryption/ decryption for the associated cipher context.
931 TLS record encryption/decryption always occurs "in place" so that the input and
932 output buffers are always the same memory location.
933 AEAD IVs in TLSv1.2 consist of an implicit "fixed" part and an explicit part
934 that varies with every record.
935 Setting a TLS fixed IV changes a cipher to encrypt/decrypt TLS records.
936 TLS records are encrypted/decrypted using a single OSSL_FUNC_cipher_cipher call per
938 For a record decryption the first bytes of the input buffer will be the explicit
939 part of the IV and the final bytes of the input buffer will be the AEAD tag.
940 The length of the explicit part of the IV and the tag length will depend on the
941 cipher in use and will be defined in the RFC for the relevant ciphersuite.
942 In order to allow for "in place" decryption the plaintext output should be
943 written to the same location in the output buffer that the ciphertext payload
944 was read from, i.e. immediately after the explicit IV.
946 When encrypting a record the first bytes of the input buffer should be empty to
947 allow space for the explicit IV, as will the final bytes where the tag will
949 The length of the input buffer will include the length of the explicit IV, the
950 payload, and the tag bytes.
951 The cipher implementation should generate the explicit IV and write it to the
952 beginning of the output buffer, do "in place" encryption of the payload and
953 write that to the output buffer, and finally add the tag onto the end of the
956 Whether encrypting or decrypting the value written to I<*outl> in the
957 OSSL_FUNC_cipher_cipher call should be the length of the payload excluding the explicit
958 IV length and the tag length.
960 =item "tlsivinv" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV>) <octet string>
962 Sets the invocation field used for decryption.
963 Can only be called after "tlsivfixed" is set.
964 This is only used for GCM mode.
966 =item "tls1multi_enc" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC>) <octet string>
968 Triggers a multiblock TLS1 encrypt operation for a TLS1 aware cipher that
969 supports sending 4 or 8 records in one go.
970 The cipher performs both the MAC and encrypt stages and constructs the record
972 "tls1multi_enc" supplies the output buffer for the encrypt operation,
973 "tls1multi_encin" & "tls1multi_interleave" must also be set in order to supply
974 values to the encrypt operation.
976 =item "tls1multi_encin" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_IN>) <octet string>
978 Supplies the data to encrypt for a TLS1 multiblock cipher operation.
980 =item "tls1multi_maxsndfrag" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_SEND_FRAGMENT>) <unsigned integer>
982 Sets the maximum send fragment size for a TLS1 multiblock cipher operation.
983 It must be set before using "tls1multi_maxbufsz".
984 The length of the "tls1multi_maxsndfrag" parameter should not exceed that of a B<size_t>.
986 =item "tls1multi_aad" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD>) <octet string>
988 Sets the authenticated additional data used by a TLS1 multiblock cipher operation.
989 The supplied data consists of 13 bytes of record data containing:
990 Bytes 0-7: The sequence number of the first record
991 Byte 8: The record type
992 Byte 9-10: The protocol version
993 Byte 11-12: Input length (Always 0)
995 "tls1multi_interleave" must also be set for this operation.
997 =item "xts_standard" (B<OSSL_CIPHER_PARAM_XTS_STANDARD>) <UTF8 string>
999 Sets the XTS standard to use with SM4-XTS algorithm. XTS mode has two
1000 implementations, one is standardized in IEEE Std. 1619-2007 and has
1001 been widely used (e.g., XTS AES), the other is proposed recently
1002 (GB/T 17964-2021 implemented in May 2022) and is currently only used
1005 The main difference between them is the multiplication by the
1006 primitive element E<alpha> to calculate the tweak values. The IEEE
1007 Std 1619-2007 noted that the multiplication "is a left shift of each
1008 byte by one bit with carry propagating from one byte to the next
1009 one", which means that in each byte, the leftmost bit is the most
1010 significant bit. But in GB/T 17964-2021, the rightmost bit is the
1011 most significant bit, thus the multiplication becomes a right shift
1012 of each byte by one bit with carry propagating from one byte to the
1015 Valid values for the mode are:
1021 The GB/T 17964-2021 variant of SM4-XTS algorithm.
1025 The IEEE Std. 1619-2007 variant of SM4-XTS algorithm.
1029 The default value is "GB".
1035 The Mappings from EVP_CIPHER_CTX_ctrl() identifiers to PARAMETERS are listed
1036 in the following section. See the L</PARAMETERS> section for more details.
1038 EVP_CIPHER_CTX_ctrl() can be used to send the following standard controls:
1042 =item EVP_CTRL_AEAD_SET_IVLEN and EVP_CTRL_GET_IVLEN
1044 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1045 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1046 key "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN>).
1048 =item EVP_CTRL_AEAD_SET_IV_FIXED
1050 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1051 with an L<OSSL_PARAM(3)> item with the key "tlsivfixed"
1052 (B<OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED>).
1054 =item EVP_CTRL_AEAD_SET_MAC_KEY
1056 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1057 with an L<OSSL_PARAM(3)> item with the key "mackey"
1058 (B<OSSL_CIPHER_PARAM_AEAD_MAC_KEY>).
1060 =item EVP_CTRL_AEAD_SET_TAG and EVP_CTRL_AEAD_GET_TAG
1062 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1063 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1064 key "tag" (B<OSSL_CIPHER_PARAM_AEAD_TAG>).
1066 =item EVP_CTRL_CCM_SET_L
1068 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1069 with an L<OSSL_PARAM(3)> item with the key "ivlen" (B<OSSL_CIPHER_PARAM_IVLEN>)
1070 with a value of (15 - L)
1074 There is no OSSL_PARAM mapping for this. Use EVP_CIPHER_CTX_copy() instead.
1076 =item EVP_CTRL_GCM_SET_IV_INV
1078 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1079 with an L<OSSL_PARAM(3)> item with the key "tlsivinv"
1080 (B<OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV>).
1082 =item EVP_CTRL_RAND_KEY
1084 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1085 with an L<OSSL_PARAM(3)> item with the key "randkey"
1086 (B<OSSL_CIPHER_PARAM_RANDOM_KEY>).
1088 =item EVP_CTRL_SET_KEY_LENGTH
1090 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1091 with an L<OSSL_PARAM(3)> item with the key "keylen" (B<OSSL_CIPHER_PARAM_KEYLEN>).
1093 =item EVP_CTRL_SET_RC2_KEY_BITS and EVP_CTRL_GET_RC2_KEY_BITS
1095 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1096 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1097 key "keybits" (B<OSSL_CIPHER_PARAM_RC2_KEYBITS>).
1099 =item EVP_CTRL_SET_RC5_ROUNDS and EVP_CTRL_GET_RC5_ROUNDS
1101 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() and
1102 EVP_CIPHER_CTX_get_params() get called with an L<OSSL_PARAM(3)> item with the
1103 key "rounds" (B<OSSL_CIPHER_PARAM_ROUNDS>).
1105 =item EVP_CTRL_SET_SPEED
1107 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1108 with an L<OSSL_PARAM(3)> item with the key "speed" (B<OSSL_CIPHER_PARAM_SPEED>).
1110 =item EVP_CTRL_GCM_IV_GEN
1112 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_get_params() gets called
1113 with an L<OSSL_PARAM(3)> item with the key
1114 "tlsivgen" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN>).
1116 =item EVP_CTRL_AEAD_TLS1_AAD
1118 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() get called
1119 with an L<OSSL_PARAM(3)> item with the key
1120 "tlsaad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD>)
1121 followed by EVP_CIPHER_CTX_get_params() with a key of
1122 "tlsaadpad" (B<OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD>).
1124 =item EVP_CTRL_TLS1_1_MULTIBLOCK_MAX_BUFSIZE
1126 When used with a fetched B<EVP_CIPHER>,
1127 EVP_CIPHER_CTX_set_params() gets called with an L<OSSL_PARAM(3)> item with the
1128 key OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_SEND_FRAGMENT
1129 followed by EVP_CIPHER_CTX_get_params() with a key of
1130 "tls1multi_maxbufsz" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_MAX_BUFSIZE>).
1132 =item EVP_CTRL_TLS1_1_MULTIBLOCK_AAD
1134 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1135 with L<OSSL_PARAM(3)> items with the keys
1136 "tls1multi_aad" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD>) and
1137 "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>)
1138 followed by EVP_CIPHER_CTX_get_params() with keys of
1139 "tls1multi_aadpacklen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_AAD_PACKLEN>) and
1140 "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>).
1142 =item EVP_CTRL_TLS1_1_MULTIBLOCK_ENCRYPT
1144 When used with a fetched B<EVP_CIPHER>, EVP_CIPHER_CTX_set_params() gets called
1145 with L<OSSL_PARAM(3)> items with the keys
1146 "tls1multi_enc" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC>),
1147 "tls1multi_encin" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_IN>) and
1148 "tls1multi_interleave" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_INTERLEAVE>),
1149 followed by EVP_CIPHER_CTX_get_params() with a key of
1150 "tls1multi_enclen" (B<OSSL_CIPHER_PARAM_TLS1_MULTIBLOCK_ENC_LEN>).
1156 EVP_CIPHER_CTX_set_flags(), EVP_CIPHER_CTX_clear_flags() and EVP_CIPHER_CTX_test_flags().
1157 can be used to manipulate and test these B<EVP_CIPHER_CTX> flags:
1161 =item EVP_CIPH_NO_PADDING
1163 Used by EVP_CIPHER_CTX_set_padding().
1165 See also L</Gettable and Settable EVP_CIPHER_CTX parameters> "padding"
1167 =item EVP_CIPH_FLAG_LENGTH_BITS
1169 See L</Settable EVP_CIPHER_CTX parameters> "use-bits".
1171 =item EVP_CIPHER_CTX_FLAG_WRAP_ALLOW
1173 Used for Legacy purposes only. This flag needed to be set to indicate the
1174 cipher handled wrapping.
1178 EVP_CIPHER_flags() uses the following flags that
1179 have mappings to L</Gettable EVP_CIPHER parameters>:
1183 =item EVP_CIPH_FLAG_AEAD_CIPHER
1185 See L</Gettable EVP_CIPHER parameters> "aead".
1187 =item EVP_CIPH_CUSTOM_IV
1189 See L</Gettable EVP_CIPHER parameters> "custom-iv".
1191 =item EVP_CIPH_FLAG_CTS
1193 See L</Gettable EVP_CIPHER parameters> "cts".
1195 =item EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK;
1197 See L</Gettable EVP_CIPHER parameters> "tls-multi".
1199 =item EVP_CIPH_RAND_KEY
1201 See L</Gettable EVP_CIPHER parameters> "has-randkey".
1205 EVP_CIPHER_flags() uses the following flags for legacy purposes only:
1209 =item EVP_CIPH_VARIABLE_LENGTH
1211 =item EVP_CIPH_FLAG_CUSTOM_CIPHER
1213 =item EVP_CIPH_ALWAYS_CALL_INIT
1215 =item EVP_CIPH_CTRL_INIT
1217 =item EVP_CIPH_CUSTOM_KEY_LENGTH
1219 =item EVP_CIPH_CUSTOM_COPY
1221 =item EVP_CIPH_FLAG_DEFAULT_ASN1
1223 See L<EVP_CIPHER_meth_set_flags(3)> for further information related to the above
1228 =head1 RETURN VALUES
1230 EVP_CIPHER_fetch() returns a pointer to a B<EVP_CIPHER> for success
1231 and B<NULL> for failure.
1233 EVP_CIPHER_up_ref() returns 1 for success or 0 otherwise.
1235 EVP_CIPHER_CTX_new() returns a pointer to a newly created
1236 B<EVP_CIPHER_CTX> for success and B<NULL> for failure.
1238 EVP_CIPHER_CTX_dup() returns a new EVP_MD_CTX if successful or NULL on failure.
1240 EVP_CIPHER_CTX_copy() returns 1 if successful or 0 for failure.
1242 EVP_EncryptInit_ex2(), EVP_EncryptUpdate() and EVP_EncryptFinal_ex()
1243 return 1 for success and 0 for failure.
1245 EVP_DecryptInit_ex2() and EVP_DecryptUpdate() return 1 for success and 0 for failure.
1246 EVP_DecryptFinal_ex() returns 0 if the decrypt failed or 1 for success.
1248 EVP_CipherInit_ex2() and EVP_CipherUpdate() return 1 for success and 0 for failure.
1249 EVP_CipherFinal_ex() returns 0 for a decryption failure or 1 for success.
1251 EVP_Cipher() returns 1 on success or 0 on failure, if the flag
1252 B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is not set for the cipher.
1253 EVP_Cipher() returns the number of bytes written to I<out> for encryption / decryption, or
1254 the number of bytes authenticated in a call specifying AAD for an AEAD cipher, if the flag
1255 B<EVP_CIPH_FLAG_CUSTOM_CIPHER> is set for the cipher.
1257 EVP_CIPHER_CTX_reset() returns 1 for success and 0 for failure.
1259 EVP_get_cipherbyname(), EVP_get_cipherbynid() and EVP_get_cipherbyobj()
1260 return an B<EVP_CIPHER> structure or NULL on error.
1262 EVP_CIPHER_get_nid() and EVP_CIPHER_CTX_get_nid() return a NID.
1264 EVP_CIPHER_get_block_size() and EVP_CIPHER_CTX_get_block_size() return the
1267 EVP_CIPHER_get_key_length() and EVP_CIPHER_CTX_get_key_length() return the key
1270 EVP_CIPHER_CTX_set_padding() always returns 1.
1272 EVP_CIPHER_get_iv_length() and EVP_CIPHER_CTX_get_iv_length() return the IV
1273 length, zero if the cipher does not use an IV and a negative value on error.
1275 EVP_CIPHER_CTX_get_tag_length() return the tag length or zero if the cipher
1278 EVP_CIPHER_get_type() and EVP_CIPHER_CTX_get_type() return the NID of the
1279 cipher's OBJECT IDENTIFIER or NID_undef if it has no defined
1282 EVP_CIPHER_CTX_cipher() returns an B<EVP_CIPHER> structure.
1284 EVP_CIPHER_CTX_get_num() returns a nonnegative num value or
1285 B<EVP_CTRL_RET_UNSUPPORTED> if the implementation does not support the call
1286 or on any other error.
1288 EVP_CIPHER_CTX_set_num() returns 1 on success and 0 if the implementation
1289 does not support the call or on any other error.
1291 EVP_CIPHER_CTX_is_encrypting() returns 1 if the I<ctx> is set up for encryption
1294 EVP_CIPHER_param_to_asn1() and EVP_CIPHER_asn1_to_param() return greater
1295 than zero for success and zero or a negative number on failure.
1297 EVP_CIPHER_CTX_rand_key() returns 1 for success and zero or a negative number
1300 EVP_CIPHER_names_do_all() returns 1 if the callback was called for all names.
1301 A return value of 0 means that the callback was not called for any names.
1303 =head1 CIPHER LISTING
1305 All algorithms have a fixed key length unless otherwise stated.
1307 Refer to L</SEE ALSO> for the full list of ciphers available through the EVP
1312 =item EVP_enc_null()
1314 Null cipher: does nothing.
1318 =head1 AEAD INTERFACE
1320 The EVP interface for Authenticated Encryption with Associated Data (AEAD)
1321 modes are subtly altered and several additional I<ctrl> operations are supported
1322 depending on the mode specified.
1324 To specify additional authenticated data (AAD), a call to EVP_CipherUpdate(),
1325 EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made with the output
1326 parameter I<out> set to B<NULL>. In this case, on success, the parameter
1327 I<outl> is set to the number of bytes authenticated.
1329 When decrypting, the return value of EVP_DecryptFinal() or EVP_CipherFinal()
1330 indicates whether the operation was successful. If it does not indicate success,
1331 the authentication operation has failed and any output data B<MUST NOT> be used
1334 =head2 GCM and OCB Modes
1336 The following I<ctrl>s are supported in GCM and OCB modes.
1340 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
1342 Sets the IV length. This call can only be made before specifying an IV. If
1343 not called a default IV length is used.
1345 For GCM AES and OCB AES the default is 12 (i.e. 96 bits). For OCB mode the
1348 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
1350 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
1351 This call can only be made when encrypting data and B<after> all data has been
1352 processed (e.g. after an EVP_EncryptFinal() call).
1354 For OCB, C<taglen> must either be 16 or the value previously set via
1355 B<EVP_CTRL_AEAD_SET_TAG>.
1357 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
1359 When decrypting, this call sets the expected tag to C<taglen> bytes from C<tag>.
1360 C<taglen> must be between 1 and 16 inclusive.
1361 The tag must be set prior to any call to EVP_DecryptFinal() or
1362 EVP_DecryptFinal_ex().
1364 For GCM, this call is only valid when decrypting data.
1366 For OCB, this call is valid when decrypting data to set the expected tag,
1367 and when encrypting to set the desired tag length.
1369 In OCB mode, calling this when encrypting with C<tag> set to C<NULL> sets the
1370 tag length. The tag length can only be set before specifying an IV. If this is
1371 not called prior to setting the IV during encryption, then a default tag length
1374 For OCB AES, the default tag length is 16 (i.e. 128 bits). It is also the
1375 maximum tag length for OCB.
1381 The EVP interface for CCM mode is similar to that of the GCM mode but with a
1382 few additional requirements and different I<ctrl> values.
1384 For CCM mode, the total plaintext or ciphertext length B<MUST> be passed to
1385 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() with the output
1386 and input parameters (I<in> and I<out>) set to B<NULL> and the length passed in
1387 the I<inl> parameter.
1389 The following I<ctrl>s are supported in CCM mode.
1393 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
1395 This call is made to set the expected B<CCM> tag value when decrypting or
1396 the length of the tag (with the C<tag> parameter set to NULL) when encrypting.
1397 The tag length is often referred to as B<M>. If not set a default value is
1398 used (12 for AES). When decrypting, the tag needs to be set before passing
1399 in data to be decrypted, but as in GCM and OCB mode, it can be set after
1400 passing additional authenticated data (see L</AEAD INTERFACE>).
1402 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_CCM_SET_L, ivlen, NULL)
1404 Sets the CCM B<L> value. If not set a default is used (8 for AES).
1406 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
1408 Sets the CCM nonce (IV) length. This call can only be made before specifying a
1409 nonce value. The nonce length is given by B<15 - L> so it is 7 by default for
1416 Both the AES-SIV and AES-GCM-SIV ciphers fall under this mode.
1418 For SIV mode ciphers the behaviour of the EVP interface is subtly
1419 altered and several additional ctrl operations are supported.
1421 To specify any additional authenticated data (AAD) and/or a Nonce, a call to
1422 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made
1423 with the output parameter I<out> set to B<NULL>.
1425 RFC5297 states that the Nonce is the last piece of AAD before the actual
1426 encrypt/decrypt takes place. The API does not differentiate the Nonce from
1429 When decrypting the return value of EVP_DecryptFinal() or EVP_CipherFinal()
1430 indicates if the operation was successful. If it does not indicate success
1431 the authentication operation has failed and any output data B<MUST NOT>
1432 be used as it is corrupted.
1434 The API does not store the the SIV (Synthetic Initialization Vector) in
1435 the cipher text. Instead, it is stored as the tag within the EVP_CIPHER_CTX.
1436 The SIV must be retrieved from the context after encryption, and set into
1437 the context before decryption.
1439 This differs from RFC5297 in that the cipher output from encryption, and
1440 the cipher input to decryption, does not contain the SIV. This also means
1441 that the plain text and cipher text lengths are identical.
1443 The following ctrls are supported in SIV mode, and are used to get and set
1444 the Synthetic Initialization Vector:
1448 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag);
1450 Writes I<taglen> bytes of the tag value (the Synthetic Initialization Vector)
1451 to the buffer indicated by I<tag>. This call can only be made when encrypting
1452 data and B<after> all data has been processed (e.g. after an EVP_EncryptFinal()
1453 call). For SIV mode the taglen must be 16.
1455 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag);
1457 Sets the expected tag (the Synthetic Initialization Vector) to I<taglen>
1458 bytes from I<tag>. This call is only legal when decrypting data and must be
1459 made B<before> any data is processed (e.g. before any EVP_DecryptUpdate()
1460 calls). For SIV mode the taglen must be 16.
1464 SIV mode makes two passes over the input data, thus, only one call to
1465 EVP_CipherUpdate(), EVP_EncryptUpdate() or EVP_DecryptUpdate() should be made
1466 with I<out> set to a non-B<NULL> value. A call to EVP_DecryptFinal() or
1467 EVP_CipherFinal() is not required, but will indicate if the update
1468 operation succeeded.
1470 =head2 ChaCha20-Poly1305
1472 The following I<ctrl>s are supported for the ChaCha20-Poly1305 AEAD algorithm.
1476 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
1478 Sets the nonce length. This call is now redundant since the only valid value
1479 is the default length of 12 (i.e. 96 bits).
1480 Prior to OpenSSL 3.0 a nonce of less than 12 bytes could be used to automatically
1481 pad the iv with leading 0 bytes to make it 12 bytes in length.
1483 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen, tag)
1485 Writes C<taglen> bytes of the tag value to the buffer indicated by C<tag>.
1486 This call can only be made when encrypting data and B<after> all data has been
1487 processed (e.g. after an EVP_EncryptFinal() call).
1489 C<taglen> specified here must be 16 (B<POLY1305_BLOCK_SIZE>, i.e. 128-bits) or
1492 =item EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen, tag)
1494 Sets the expected tag to C<taglen> bytes from C<tag>.
1495 The tag length can only be set before specifying an IV.
1496 C<taglen> must be between 1 and 16 (B<POLY1305_BLOCK_SIZE>) inclusive.
1497 This call is only valid when decrypting data.
1503 Where possible the B<EVP> interface to symmetric ciphers should be used in
1504 preference to the low-level interfaces. This is because the code then becomes
1505 transparent to the cipher used and much more flexible. Additionally, the
1506 B<EVP> interface will ensure the use of platform specific cryptographic
1507 acceleration such as AES-NI (the low-level interfaces do not provide the
1510 PKCS padding works by adding B<n> padding bytes of value B<n> to make the total
1511 length of the encrypted data a multiple of the block size. Padding is always
1512 added so if the data is already a multiple of the block size B<n> will equal
1513 the block size. For example if the block size is 8 and 11 bytes are to be
1514 encrypted then 5 padding bytes of value 5 will be added.
1516 When decrypting the final block is checked to see if it has the correct form.
1518 Although the decryption operation can produce an error if padding is enabled,
1519 it is not a strong test that the input data or key is correct. A random block
1520 has better than 1 in 256 chance of being of the correct format and problems with
1521 the input data earlier on will not produce a final decrypt error.
1523 If padding is disabled then the decryption operation will always succeed if
1524 the total amount of data decrypted is a multiple of the block size.
1526 The functions EVP_EncryptInit(), EVP_EncryptInit_ex(),
1527 EVP_EncryptFinal(), EVP_DecryptInit(), EVP_DecryptInit_ex(),
1528 EVP_CipherInit(), EVP_CipherInit_ex() and EVP_CipherFinal() are obsolete
1529 but are retained for compatibility with existing code. New code should
1530 use EVP_EncryptInit_ex2(), EVP_EncryptFinal_ex(), EVP_DecryptInit_ex2(),
1531 EVP_DecryptFinal_ex(), EVP_CipherInit_ex2() and EVP_CipherFinal_ex()
1532 because they can reuse an existing context without allocating and freeing
1535 There are some differences between functions EVP_CipherInit() and
1536 EVP_CipherInit_ex(), significant in some circumstances. EVP_CipherInit() fills
1537 the passed context object with zeros. As a consequence, EVP_CipherInit() does
1538 not allow step-by-step initialization of the ctx when the I<key> and I<iv> are
1539 passed in separate calls. It also means that the flags set for the CTX are
1540 removed, and it is especially important for the
1541 B<EVP_CIPHER_CTX_FLAG_WRAP_ALLOW> flag treated specially in
1542 EVP_CipherInit_ex().
1544 Ignoring failure returns of the B<EVP_CIPHER_CTX> initialization functions can
1545 lead to subsequent undefined behavior when calling the functions that update or
1546 finalize the context. The only valid calls on the B<EVP_CIPHER_CTX> when
1547 initialization fails are calls that attempt another initialization of the
1548 context or release the context.
1550 EVP_get_cipherbynid(), and EVP_get_cipherbyobj() are implemented as macros.
1554 B<EVP_MAX_KEY_LENGTH> and B<EVP_MAX_IV_LENGTH> only refer to the internal
1555 ciphers with default key lengths. If custom ciphers exceed these values the
1556 results are unpredictable. This is because it has become standard practice to
1557 define a generic key as a fixed unsigned char array containing
1558 B<EVP_MAX_KEY_LENGTH> bytes.
1560 The ASN1 code is incomplete (and sometimes inaccurate) it has only been tested
1561 for certain common S/MIME ciphers (RC2, DES, triple DES) in CBC mode.
1565 Encrypt a string using IDEA:
1567 int do_crypt(char *outfile)
1569 unsigned char outbuf[1024];
1572 * Bogus key and IV: we'd normally set these from
1575 unsigned char key[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1576 unsigned char iv[] = {1,2,3,4,5,6,7,8};
1577 char intext[] = "Some Crypto Text";
1578 EVP_CIPHER_CTX *ctx;
1581 ctx = EVP_CIPHER_CTX_new();
1582 if (!EVP_EncryptInit_ex2(ctx, EVP_idea_cbc(), key, iv, NULL)) {
1584 EVP_CIPHER_CTX_free(ctx);
1588 if (!EVP_EncryptUpdate(ctx, outbuf, &outlen, intext, strlen(intext))) {
1590 EVP_CIPHER_CTX_free(ctx);
1594 * Buffer passed to EVP_EncryptFinal() must be after data just
1595 * encrypted to avoid overwriting it.
1597 if (!EVP_EncryptFinal_ex(ctx, outbuf + outlen, &tmplen)) {
1599 EVP_CIPHER_CTX_free(ctx);
1603 EVP_CIPHER_CTX_free(ctx);
1605 * Need binary mode for fopen because encrypted data is
1606 * binary data. Also cannot use strlen() on it because
1607 * it won't be NUL terminated and may contain embedded
1610 out = fopen(outfile, "wb");
1615 fwrite(outbuf, 1, outlen, out);
1620 The ciphertext from the above example can be decrypted using the B<openssl>
1621 utility with the command line (shown on two lines for clarity):
1624 -K 000102030405060708090A0B0C0D0E0F -iv 0102030405060708 <filename
1626 General encryption and decryption function example using FILE I/O and AES128
1629 int do_crypt(FILE *in, FILE *out, int do_encrypt)
1631 /* Allow enough space in output buffer for additional block */
1632 unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
1634 EVP_CIPHER_CTX *ctx;
1636 * Bogus key and IV: we'd normally set these from
1639 unsigned char key[] = "0123456789abcdeF";
1640 unsigned char iv[] = "1234567887654321";
1642 /* Don't set key or IV right away; we want to check lengths */
1643 ctx = EVP_CIPHER_CTX_new();
1644 if (!EVP_CipherInit_ex2(ctx, EVP_aes_128_cbc(), NULL, NULL,
1645 do_encrypt, NULL)) {
1647 EVP_CIPHER_CTX_free(ctx);
1650 OPENSSL_assert(EVP_CIPHER_CTX_get_key_length(ctx) == 16);
1651 OPENSSL_assert(EVP_CIPHER_CTX_get_iv_length(ctx) == 16);
1653 /* Now we can set key and IV */
1654 if (!EVP_CipherInit_ex2(ctx, NULL, key, iv, do_encrypt, NULL)) {
1656 EVP_CIPHER_CTX_free(ctx);
1661 inlen = fread(inbuf, 1, 1024, in);
1664 if (!EVP_CipherUpdate(ctx, outbuf, &outlen, inbuf, inlen)) {
1666 EVP_CIPHER_CTX_free(ctx);
1669 fwrite(outbuf, 1, outlen, out);
1671 if (!EVP_CipherFinal_ex(ctx, outbuf, &outlen)) {
1673 EVP_CIPHER_CTX_free(ctx);
1676 fwrite(outbuf, 1, outlen, out);
1678 EVP_CIPHER_CTX_free(ctx);
1682 Encryption using AES-CBC with a 256-bit key with "CS1" ciphertext stealing.
1684 int encrypt(const unsigned char *key, const unsigned char *iv,
1685 const unsigned char *msg, size_t msg_len, unsigned char *out)
1688 * This assumes that key size is 32 bytes and the iv is 16 bytes.
1689 * For ciphertext stealing mode the length of the ciphertext "out" will be
1690 * the same size as the plaintext size "msg_len".
1691 * The "msg_len" can be any size >= 16.
1693 int ret = 0, encrypt = 1, outlen, len;
1694 EVP_CIPHER_CTX *ctx = NULL;
1695 EVP_CIPHER *cipher = NULL;
1696 OSSL_PARAM params[2];
1698 ctx = EVP_CIPHER_CTX_new();
1699 cipher = EVP_CIPHER_fetch(NULL, "AES-256-CBC-CTS", NULL);
1700 if (ctx == NULL || cipher == NULL)
1704 * The default is "CS1" so this is not really needed,
1705 * but would be needed to set either "CS2" or "CS3".
1707 params[0] = OSSL_PARAM_construct_utf8_string(OSSL_CIPHER_PARAM_CTS_MODE,
1709 params[1] = OSSL_PARAM_construct_end();
1711 if (!EVP_CipherInit_ex2(ctx, cipher, key, iv, encrypt, params))
1714 /* NOTE: CTS mode does not support multiple calls to EVP_CipherUpdate() */
1715 if (!EVP_CipherUpdate(ctx, out, &outlen, msg, msg_len))
1717 if (!EVP_CipherFinal_ex(ctx, out + outlen, &len))
1721 EVP_CIPHER_free(cipher);
1722 EVP_CIPHER_CTX_free(ctx);
1730 L<crypto(7)/ALGORITHM FETCHING>,
1731 L<provider-cipher(7)>,
1732 L<life_cycle-cipher(7)>
1734 Supported ciphers are listed in:
1736 L<EVP_aes_128_gcm(3)>,
1737 L<EVP_aria_128_gcm(3)>,
1739 L<EVP_camellia_128_ecb(3)>,
1740 L<EVP_cast5_cbc(3)>,
1747 L<EVP_rc5_32_12_16_cbc(3)>,
1753 Support for OCB mode was added in OpenSSL 1.1.0.
1755 B<EVP_CIPHER_CTX> was made opaque in OpenSSL 1.1.0. As a result,
1756 EVP_CIPHER_CTX_reset() appeared and EVP_CIPHER_CTX_cleanup()
1757 disappeared. EVP_CIPHER_CTX_init() remains as an alias for
1758 EVP_CIPHER_CTX_reset().
1760 The EVP_CIPHER_CTX_cipher() function was deprecated in OpenSSL 3.0; use
1761 EVP_CIPHER_CTX_get0_cipher() instead.
1763 The EVP_EncryptInit_ex2(), EVP_DecryptInit_ex2(), EVP_CipherInit_ex2(),
1764 EVP_CIPHER_fetch(), EVP_CIPHER_free(), EVP_CIPHER_up_ref(),
1765 EVP_CIPHER_CTX_get0_cipher(), EVP_CIPHER_CTX_get1_cipher(),
1766 EVP_CIPHER_get_params(), EVP_CIPHER_CTX_set_params(),
1767 EVP_CIPHER_CTX_get_params(), EVP_CIPHER_gettable_params(),
1768 EVP_CIPHER_settable_ctx_params(), EVP_CIPHER_gettable_ctx_params(),
1769 EVP_CIPHER_CTX_settable_params() and EVP_CIPHER_CTX_gettable_params()
1770 functions were added in 3.0.
1772 The EVP_CIPHER_nid(), EVP_CIPHER_name(), EVP_CIPHER_block_size(),
1773 EVP_CIPHER_key_length(), EVP_CIPHER_iv_length(), EVP_CIPHER_flags(),
1774 EVP_CIPHER_mode(), EVP_CIPHER_type(), EVP_CIPHER_CTX_nid(),
1775 EVP_CIPHER_CTX_block_size(), EVP_CIPHER_CTX_key_length(),
1776 EVP_CIPHER_CTX_iv_length(), EVP_CIPHER_CTX_tag_length(),
1777 EVP_CIPHER_CTX_num(), EVP_CIPHER_CTX_type(), and EVP_CIPHER_CTX_mode()
1778 functions were renamed to include C<get> or C<get0> in their names in
1779 OpenSSL 3.0, respectively. The old names are kept as non-deprecated
1782 The EVP_CIPHER_CTX_encrypting() function was renamed to
1783 EVP_CIPHER_CTX_is_encrypting() in OpenSSL 3.0. The old name is kept as
1784 non-deprecated alias macro.
1786 The EVP_CIPHER_CTX_flags() macro was deprecated in OpenSSL 1.1.0.
1788 EVP_CIPHER_CTX_dup() was added in OpenSSL 3.2.
1792 Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.
1794 Licensed under the Apache License 2.0 (the "License"). You may not use
1795 this file except in compliance with the License. You can obtain a copy
1796 in the file LICENSE in the source distribution or at
1797 L<https://www.openssl.org/source/license.html>.