5 EVP_MD_fetch, EVP_MD_up_ref, EVP_MD_free,
6 EVP_MD_get_params, EVP_MD_gettable_params,
7 EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy,
8 EVP_MD_CTX_copy_ex, EVP_MD_CTX_ctrl,
9 EVP_MD_CTX_set_params, EVP_MD_CTX_get_params,
10 EVP_MD_settable_ctx_params, EVP_MD_gettable_ctx_params,
11 EVP_MD_CTX_settable_params, EVP_MD_CTX_gettable_params,
12 EVP_MD_CTX_set_flags, EVP_MD_CTX_clear_flags, EVP_MD_CTX_test_flags,
13 EVP_Q_digest, EVP_Digest, EVP_DigestInit_ex2, EVP_DigestInit_ex, EVP_DigestInit,
14 EVP_DigestUpdate, EVP_DigestFinal_ex, EVP_DigestFinalXOF, EVP_DigestFinal,
15 EVP_MD_is_a, EVP_MD_get0_name, EVP_MD_get0_description,
16 EVP_MD_names_do_all, EVP_MD_get0_provider, EVP_MD_get_type,
17 EVP_MD_get_pkey_type, EVP_MD_get_size, EVP_MD_get_block_size, EVP_MD_get_flags,
18 EVP_MD_CTX_get0_name, EVP_MD_CTX_md, EVP_MD_CTX_get0_md, EVP_MD_CTX_get1_md,
19 EVP_MD_CTX_get_type, EVP_MD_CTX_get_size, EVP_MD_CTX_get_block_size,
20 EVP_MD_CTX_get0_md_data, EVP_MD_CTX_update_fn, EVP_MD_CTX_set_update_fn,
22 EVP_get_digestbyname, EVP_get_digestbynid, EVP_get_digestbyobj,
23 EVP_MD_CTX_get_pkey_ctx, EVP_MD_CTX_set_pkey_ctx,
24 EVP_MD_do_all_provided,
25 EVP_MD_type, EVP_MD_nid, EVP_MD_name, EVP_MD_pkey_type, EVP_MD_size,
26 EVP_MD_block_size, EVP_MD_flags, EVP_MD_CTX_size, EVP_MD_CTX_block_size,
27 EVP_MD_CTX_type, EVP_MD_CTX_pkey_ctx, EVP_MD_CTX_md_data
32 #include <openssl/evp.h>
34 EVP_MD *EVP_MD_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
35 const char *properties);
36 int EVP_MD_up_ref(EVP_MD *md);
37 void EVP_MD_free(EVP_MD *md);
38 int EVP_MD_get_params(const EVP_MD *digest, OSSL_PARAM params[]);
39 const OSSL_PARAM *EVP_MD_gettable_params(const EVP_MD *digest);
40 EVP_MD_CTX *EVP_MD_CTX_new(void);
41 int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
42 void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
43 void EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void* p2);
44 int EVP_MD_CTX_get_params(EVP_MD_CTX *ctx, OSSL_PARAM params[]);
45 int EVP_MD_CTX_set_params(EVP_MD_CTX *ctx, const OSSL_PARAM params[]);
46 const OSSL_PARAM *EVP_MD_settable_ctx_params(const EVP_MD *md);
47 const OSSL_PARAM *EVP_MD_gettable_ctx_params(const EVP_MD *md);
48 const OSSL_PARAM *EVP_MD_CTX_settable_params(EVP_MD_CTX *ctx);
49 const OSSL_PARAM *EVP_MD_CTX_gettable_params(EVP_MD_CTX *ctx);
50 void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);
51 void EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags);
52 int EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags);
54 int EVP_Q_digest(OSSL_LIB_CTX *libctx, const char *name, const char *propq,
55 const void *data, size_t datalen,
56 unsigned char *md, size_t *mdlen);
57 int EVP_Digest(const void *data, size_t count, unsigned char *md,
58 unsigned int *size, const EVP_MD *type, ENGINE *impl);
59 int EVP_DigestInit_ex2(EVP_MD_CTX *ctx, const EVP_MD *type,
60 const OSSL_PARAM params[]);
61 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
62 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
63 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
64 int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t len);
66 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
68 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
69 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
71 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
73 const char *EVP_MD_get0_name(const EVP_MD *md);
74 const char *EVP_MD_get0_description(const EVP_MD *md);
75 int EVP_MD_is_a(const EVP_MD *md, const char *name);
76 int EVP_MD_names_do_all(const EVP_MD *md,
77 void (*fn)(const char *name, void *data),
79 const OSSL_PROVIDER *EVP_MD_get0_provider(const EVP_MD *md);
80 int EVP_MD_get_type(const EVP_MD *md);
81 int EVP_MD_get_pkey_type(const EVP_MD *md);
82 int EVP_MD_get_size(const EVP_MD *md);
83 int EVP_MD_get_block_size(const EVP_MD *md);
84 unsigned long EVP_MD_get_flags(const EVP_MD *md);
86 const EVP_MD *EVP_MD_CTX_get0_md(const EVP_MD_CTX *ctx);
87 EVP_MD *EVP_MD_CTX_get1_md(EVP_MD_CTX *ctx);
88 const char *EVP_MD_CTX_get0_name(const EVP_MD_CTX *ctx);
89 int EVP_MD_CTX_get_size(const EVP_MD_CTX *ctx);
90 int EVP_MD_CTX_get_block_size(const EVP_MD_CTX *ctx);
91 int EVP_MD_CTX_get_type(const EVP_MD_CTX *ctx);
92 void *EVP_MD_CTX_get0_md_data(const EVP_MD_CTX *ctx);
94 const EVP_MD *EVP_md_null(void);
96 const EVP_MD *EVP_get_digestbyname(const char *name);
97 const EVP_MD *EVP_get_digestbynid(int type);
98 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
100 EVP_PKEY_CTX *EVP_MD_CTX_get_pkey_ctx(const EVP_MD_CTX *ctx);
101 void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);
103 void EVP_MD_do_all_provided(OSSL_LIB_CTX *libctx,
104 void (*fn)(EVP_MD *mac, void *arg),
107 #define EVP_MD_type EVP_MD_get_type
108 #define EVP_MD_nid EVP_MD_get_type
109 #define EVP_MD_name EVP_MD_get0_name
110 #define EVP_MD_pkey_type EVP_MD_get_pkey_type
111 #define EVP_MD_size EVP_MD_get_size
112 #define EVP_MD_block_size EVP_MD_get_block_size
113 #define EVP_MD_flags EVP_MD_get_flags
114 #define EVP_MD_CTX_size EVP_MD_CTX_get_size
115 #define EVP_MD_CTX_block_size EVP_MD_CTX_get_block_size
116 #define EVP_MD_CTX_type EVP_MD_CTX_get_type
117 #define EVP_MD_CTX_pkey_ctx EVP_MD_CTX_get_pkey_ctx
118 #define EVP_MD_CTX_md_data EVP_MD_CTX_get0_md_data
120 Deprecated since OpenSSL 3.0, can be hidden entirely by defining
121 B<OPENSSL_API_COMPAT> with a suitable version value, see
122 L<openssl_user_macros(7)>:
124 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
126 int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
127 const void *data, size_t count);
129 void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
130 int (*update)(EVP_MD_CTX *ctx,
131 const void *data, size_t count));
135 The EVP digest routines are a high-level interface to message digests,
136 and should be used instead of the digest-specific functions.
138 The B<EVP_MD> type is a structure for digest method implementation.
144 Fetches the digest implementation for the given I<algorithm> from any
145 provider offering it, within the criteria given by the I<properties>.
146 See L<crypto(7)/ALGORITHM FETCHING> for further information.
148 The returned value must eventually be freed with EVP_MD_free().
150 Fetched B<EVP_MD> structures are reference counted.
152 =item EVP_MD_up_ref()
154 Increments the reference count for an B<EVP_MD> structure.
158 Decrements the reference count for the fetched B<EVP_MD> structure.
159 If the reference count drops to 0 then the structure is freed.
161 =item EVP_MD_CTX_new()
163 Allocates and returns a digest context.
165 =item EVP_MD_CTX_reset()
167 Resets the digest context I<ctx>. This can be used to reuse an already
170 =item EVP_MD_CTX_free()
172 Cleans up digest context I<ctx> and frees up the space allocated to it.
174 =item EVP_MD_CTX_ctrl()
176 I<This is a legacy method. EVP_MD_CTX_set_params() and EVP_MD_CTX_get_params()
177 is the mechanism that should be used to set and get parameters that are used by
180 Performs digest-specific control actions on context I<ctx>. The control command
181 is indicated in I<cmd> and any additional arguments in I<p1> and I<p2>.
182 EVP_MD_CTX_ctrl() must be called after EVP_DigestInit_ex2(). Other restrictions
183 may apply depending on the control type and digest implementation.
185 If this function happens to be used with a fetched B<EVP_MD>, it will
186 translate the controls that are known to OpenSSL into L<OSSL_PARAM(3)>
187 parameters with keys defined by OpenSSL and call EVP_MD_CTX_get_params() or
188 EVP_MD_CTX_set_params() as is appropriate for each control command.
190 See L</CONTROLS> below for more information, including what translations are
193 =item EVP_MD_get_params()
195 Retrieves the requested list of I<params> from a MD I<md>.
196 See L</PARAMETERS> below for more information.
198 =item EVP_MD_CTX_get_params()
200 Retrieves the requested list of I<params> from a MD context I<ctx>.
201 See L</PARAMETERS> below for more information.
203 =item EVP_MD_CTX_set_params()
205 Sets the list of I<params> into a MD context I<ctx>.
206 See L</PARAMETERS> below for more information.
208 =item EVP_MD_gettable_params()
210 Get a constant B<OSSL_PARAM> array that describes the retrievable parameters
211 that can be used with EVP_MD_get_params(). See L<OSSL_PARAM(3)> for the
212 use of B<OSSL_PARAM> as a parameter descriptor.
214 =item EVP_MD_gettable_ctx_params(), EVP_MD_CTX_gettable_params()
216 Get a constant B<OSSL_PARAM> array that describes the retrievable parameters
217 that can be used with EVP_MD_CTX_get_params(). EVP_MD_gettable_ctx_params()
218 returns the parameters that can be retrieved from the algorithm, whereas
219 EVP_MD_CTX_gettable_params() returns the parameters that can be retrieved
220 in the context's current state. See L<OSSL_PARAM(3)> for the use of
221 B<OSSL_PARAM> as a parameter descriptor.
223 =item EVP_MD_settable_ctx_params(), EVP_MD_CTX_settable_params()
225 Get a constant B<OSSL_PARAM> array that describes the settable parameters
226 that can be used with EVP_MD_CTX_set_params(). EVP_MD_settable_ctx_params()
227 returns the parameters that can be set from the algorithm, whereas
228 EVP_MD_CTX_settable_params() returns the parameters that can be set in the
229 context's current state. See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM>
230 as a parameter descriptor.
232 =item EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), EVP_MD_CTX_test_flags()
234 Sets, clears and tests I<ctx> flags. See L</FLAGS> below for more information.
236 =item EVP_Q_digest() is a quick one-shot digest function.
238 It hashes I<datalen> bytes of data at I<data> using the digest algorithm
239 I<name>, which is fetched using the optional I<libctx> and I<propq> parameters.
240 The digest value is placed in I<md> and its length is written at I<mdlen>
241 if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
245 A wrapper around the Digest Init_ex, Update and Final_ex functions.
246 Hashes I<count> bytes of data at I<data> using a digest I<type> from ENGINE
247 I<impl>. The digest value is placed in I<md> and its length is written at I<size>
248 if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
249 If I<impl> is NULL the default implementation of digest I<type> is used.
251 =item EVP_DigestInit_ex2()
253 Sets up digest context I<ctx> to use a digest I<type>.
254 I<type> is typically supplied by a function such as EVP_sha1(), or a
255 value explicitly fetched with EVP_MD_fetch().
257 The parameters B<params> are set on the context after initialisation.
259 The I<type> parameter can be NULL if I<ctx> has been already initialized
260 with another EVP_DigestInit_ex() call and has not been reset with
263 =item EVP_DigestInit_ex()
265 Sets up digest context I<ctx> to use a digest I<type>.
266 I<type> is typically supplied by a function such as EVP_sha1(), or a
267 value explicitly fetched with EVP_MD_fetch().
269 If I<impl> is non-NULL, its implementation of the digest I<type> is used if
270 there is one, and if not, the default implementation is used.
272 The I<type> parameter can be NULL if I<ctx> has been already initialized
273 with another EVP_DigestInit_ex() call and has not been reset with
276 =item EVP_DigestUpdate()
278 Hashes I<cnt> bytes of data at I<d> into the digest context I<ctx>. This
279 function can be called several times on the same I<ctx> to hash additional
282 =item EVP_DigestFinal_ex()
284 Retrieves the digest value from I<ctx> and places it in I<md>. If the I<s>
285 parameter is not NULL then the number of bytes of data written (i.e. the
286 length of the digest) will be written to the integer at I<s>, at most
287 B<EVP_MAX_MD_SIZE> bytes will be written. After calling EVP_DigestFinal_ex()
288 no additional calls to EVP_DigestUpdate() can be made, but
289 EVP_DigestInit_ex2() can be called to initialize a new digest operation.
291 =item EVP_DigestFinalXOF()
293 Interfaces to extendable-output functions, XOFs, such as SHAKE128 and SHAKE256.
294 It retrieves the digest value from I<ctx> and places it in I<len>-sized I<md>.
295 After calling this function no additional calls to EVP_DigestUpdate() can be
296 made, but EVP_DigestInit_ex2() can be called to initialize a new operation.
298 =item EVP_MD_CTX_copy_ex()
300 Can be used to copy the message digest state from I<in> to I<out>. This is
301 useful if large amounts of data are to be hashed which only differ in the last
304 =item EVP_DigestInit()
306 Behaves in the same way as EVP_DigestInit_ex2() except it doesn't set any
307 parameters and calls EVP_MD_CTX_reset() so it cannot be used with an I<type>
310 =item EVP_DigestFinal()
312 Similar to EVP_DigestFinal_ex() except after computing the digest
313 the digest context I<ctx> is automatically cleaned up with EVP_MD_CTX_reset().
315 =item EVP_MD_CTX_copy()
317 Similar to EVP_MD_CTX_copy_ex() except the destination I<out> does not have to
322 Returns 1 if I<md> is an implementation of an algorithm that's
323 identifiable with I<name>, otherwise 0.
325 If I<md> is a legacy digest (it's the return value from the likes of
326 EVP_sha256() rather than the result of an EVP_MD_fetch()), only cipher
327 names registered with the default library context (see
328 L<OSSL_LIB_CTX(3)>) will be considered.
330 =item EVP_MD_get0_name(),
331 EVP_MD_CTX_get0_name()
333 Return the name of the given message digest. For fetched message
334 digests with multiple names, only one of them is returned; it's
335 recommended to use EVP_MD_names_do_all() instead.
337 =item EVP_MD_names_do_all()
339 Traverses all names for the I<md>, and calls I<fn> with each name and
340 I<data>. This is only useful with fetched B<EVP_MD>s.
342 =item EVP_MD_get0_description()
344 Returns a description of the digest, meant for display and human consumption.
345 The description is at the discretion of the digest implementation.
347 =item EVP_MD_get0_provider()
349 Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
352 =item EVP_MD_get_size(),
353 EVP_MD_CTX_get_size()
355 Return the size of the message digest when passed an B<EVP_MD> or an
356 B<EVP_MD_CTX> structure, i.e. the size of the hash.
358 =item EVP_MD_get_block_size(),
359 EVP_MD_CTX_get_block_size()
361 Return the block size of the message digest when passed an B<EVP_MD> or an
362 B<EVP_MD_CTX> structure.
364 =item EVP_MD_get_type(),
365 EVP_MD_CTX_get_type()
367 Return the NID of the OBJECT IDENTIFIER representing the given message digest
368 when passed an B<EVP_MD> structure. For example, C<EVP_MD_get_type(EVP_sha1())>
369 returns B<NID_sha1>. This function is normally used when setting ASN1 OIDs.
371 =item EVP_MD_CTX_get0_md_data()
373 Return the digest method private data for the passed B<EVP_MD_CTX>.
374 The space is allocated by OpenSSL and has the size originally set with
375 EVP_MD_meth_set_app_datasize().
377 =item EVP_MD_CTX_get0_md(), EVP_MD_CTX_get1_md()
379 EVP_MD_CTX_get0_md() returns
380 the B<EVP_MD> structure corresponding to the passed B<EVP_MD_CTX>. This
381 will be the same B<EVP_MD> object originally passed to EVP_DigestInit_ex2() (or
382 other similar function) when the EVP_MD_CTX was first initialised. Note that
383 where explicit fetch is in use (see L<EVP_MD_fetch(3)>) the value returned from
384 this function will not have its reference count incremented and therefore it
385 should not be used after the EVP_MD_CTX is freed.
386 EVP_MD_CTX_get1_md() is the same except the ownership is passed to the
387 caller and is from the passed B<EVP_MD_CTX>.
389 =item EVP_MD_CTX_set_update_fn()
391 Sets the update function for I<ctx> to I<update>.
392 This is the function that is called by EVP_DigestUpdate(). If not set, the
393 update function from the B<EVP_MD> type specified at initialization is used.
395 =item EVP_MD_CTX_update_fn()
397 Returns the update function for I<ctx>.
399 =item EVP_MD_get_flags()
401 Returns the I<md> flags. Note that these are different from the B<EVP_MD_CTX>
402 ones. See L<EVP_MD_meth_set_flags(3)> for more information.
404 =item EVP_MD_get_pkey_type()
406 Returns the NID of the public key signing algorithm associated with this
407 digest. For example EVP_sha1() is associated with RSA so this will return
408 B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms are no
409 longer linked this function is only retained for compatibility reasons.
413 A "null" message digest that does nothing: i.e. the hash it returns is of zero
416 =item EVP_get_digestbyname(),
417 EVP_get_digestbynid(),
418 EVP_get_digestbyobj()
420 Returns an B<EVP_MD> structure when passed a digest name, a digest B<NID> or an
421 B<ASN1_OBJECT> structure respectively.
423 The EVP_get_digestbyname() function is present for backwards compatibility with
424 OpenSSL prior to version 3 and is different to the EVP_MD_fetch() function
425 since it does not attempt to "fetch" an implementation of the cipher.
426 Additionally, it only knows about digests that are built-in to OpenSSL and have
427 an associated NID. Similarly EVP_get_digestbynid() and EVP_get_digestbyobj()
428 also return objects without an associated implementation.
430 When the digest objects returned by these functions are used (such as in a call
431 to EVP_DigestInit_ex()) an implementation of the digest will be implicitly
432 fetched from the loaded providers. This fetch could fail if no suitable
433 implementation is available. Use EVP_MD_fetch() instead to explicitly fetch
434 the algorithm and an associated implementation from a provider.
436 See L<crypto(7)/ALGORITHM FETCHING> for more information about fetching.
438 The digest objects returned from these functions do not need to be freed with
441 =item EVP_MD_CTX_get_pkey_ctx()
443 Returns the B<EVP_PKEY_CTX> assigned to I<ctx>. The returned pointer should not
444 be freed by the caller.
446 =item EVP_MD_CTX_set_pkey_ctx()
448 Assigns an B<EVP_PKEY_CTX> to B<EVP_MD_CTX>. This is usually used to provide
449 a customized B<EVP_PKEY_CTX> to L<EVP_DigestSignInit(3)> or
450 L<EVP_DigestVerifyInit(3)>. The I<pctx> passed to this function should be freed
451 by the caller. A NULL I<pctx> pointer is also allowed to clear the B<EVP_PKEY_CTX>
452 assigned to I<ctx>. In such case, freeing the cleared B<EVP_PKEY_CTX> or not
453 depends on how the B<EVP_PKEY_CTX> is created.
455 =item EVP_MD_do_all_provided()
457 Traverses all messages digests implemented by all activated providers
458 in the given library context I<libctx>, and for each of the implementations,
459 calls the given function I<fn> with the implementation method and the given
466 See L<OSSL_PARAM(3)> for information about passing parameters.
468 EVP_MD_CTX_set_params() can be used with the following OSSL_PARAM keys:
472 =item "xoflen" (B<OSSL_DIGEST_PARAM_XOFLEN>) <unsigned integer>
474 Sets the digest length for extendable output functions.
475 It is used by the SHAKE algorithm and should not exceed what can be given
478 =item "pad-type" (B<OSSL_DIGEST_PARAM_PAD_TYPE>) <unsigned integer>
480 Sets the padding type.
481 It is used by the MDC2 algorithm.
485 EVP_MD_CTX_get_params() can be used with the following OSSL_PARAM keys:
489 =item "micalg" (B<OSSL_PARAM_DIGEST_KEY_MICALG>) <UTF8 string>.
491 Gets the digest Message Integrity Check algorithm string. This is used when
492 creating S/MIME multipart/signed messages, as specified in RFC 3851.
493 It may be used by external engines or providers.
499 EVP_MD_CTX_ctrl() can be used to send the following standard controls:
503 =item EVP_MD_CTRL_MICALG
505 Gets the digest Message Integrity Check algorithm string. This is used when
506 creating S/MIME multipart/signed messages, as specified in RFC 3851.
507 The string value is written to I<p2>.
509 When used with a fetched B<EVP_MD>, EVP_MD_CTX_get_params() gets called with
510 an L<OSSL_PARAM(3)> item with the key "micalg" (B<OSSL_DIGEST_PARAM_MICALG>).
512 =item EVP_MD_CTRL_XOF_LEN
514 This control sets the digest length for extendable output functions to I<p1>.
515 Sending this control directly should not be necessary, the use of
516 EVP_DigestFinalXOF() is preferred.
517 Currently used by SHAKE.
519 When used with a fetched B<EVP_MD>, EVP_MD_CTX_get_params() gets called with
520 an L<OSSL_PARAM(3)> item with the key "xoflen" (B<OSSL_DIGEST_PARAM_XOFLEN>).
526 EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
527 can be used the manipulate and test these B<EVP_MD_CTX> flags:
531 =item EVP_MD_CTX_FLAG_ONESHOT
533 This flag instructs the digest to optimize for one update only, if possible.
535 =for comment EVP_MD_CTX_FLAG_CLEANED is internal, don't mention it
537 =for comment EVP_MD_CTX_FLAG_REUSE is internal, don't mention it
539 =for comment We currently avoid documenting flags that are only bit holder:
540 EVP_MD_CTX_FLAG_NON_FIPS_ALLOW, EVP_MD_CTX_FLAGS_PAD_*
542 =item EVP_MD_CTX_FLAG_NO_INIT
544 This flag instructs EVP_DigestInit() and similar not to initialise the
545 implementation specific data.
547 =item EVP_MD_CTX_FLAG_FINALISE
549 Some functions such as EVP_DigestSign only finalise copies of internal
550 contexts so additional data can be included after the finalisation call.
551 This is inefficient if this functionality is not required, and can be
552 disabled with this flag.
562 Returns a pointer to a B<EVP_MD> for success or NULL for failure.
564 =item EVP_MD_up_ref()
566 Returns 1 for success or 0 for failure.
568 =item EVP_Q_digest(),
570 EVP_DigestInit_ex2(),
573 EVP_DigestFinal_ex(),
574 EVP_DigestFinalXOF(), and
578 success and 0 for failure.
580 =item EVP_MD_CTX_ctrl()
582 Returns 1 if successful or 0 for failure.
584 =item EVP_MD_CTX_set_params(),
585 EVP_MD_CTX_get_params()
587 Returns 1 if successful or 0 for failure.
589 =item EVP_MD_CTX_settable_params(),
590 EVP_MD_CTX_gettable_params()
592 Return an array of constant B<OSSL_PARAM>s, or NULL if there is none
595 =item EVP_MD_CTX_copy_ex()
597 Returns 1 if successful or 0 for failure.
599 =item EVP_MD_get_type(),
600 EVP_MD_get_pkey_type()
602 Returns the NID of the corresponding OBJECT IDENTIFIER or NID_undef if none
605 =item EVP_MD_get_size(),
606 EVP_MD_get_block_size(),
607 EVP_MD_CTX_get_size(),
608 EVP_MD_CTX_get_block_size()
610 Returns the digest or block size in bytes.
614 Returns a pointer to the B<EVP_MD> structure of the "null" message digest.
616 =item EVP_get_digestbyname(),
617 EVP_get_digestbynid(),
618 EVP_get_digestbyobj()
620 Returns either an B<EVP_MD> structure or NULL if an error occurs.
622 =item EVP_MD_CTX_set_pkey_ctx()
624 This function has no return value.
626 =item EVP_MD_names_do_all()
628 Returns 1 if the callback was called for all names. A return value of 0 means
629 that the callback was not called for any names.
635 The B<EVP> interface to message digests should almost always be used in
636 preference to the low-level interfaces. This is because the code then becomes
637 transparent to the digest used and much more flexible.
639 New applications should use the SHA-2 (such as L<EVP_sha256(3)>) or the SHA-3
640 digest algorithms (such as L<EVP_sha3_512(3)>). The other digest algorithms
641 are still in common use.
643 For most applications the I<impl> parameter to EVP_DigestInit_ex() will be
644 set to NULL to use the default digest implementation.
646 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
647 obsolete but are retained to maintain compatibility with existing code. New
648 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
649 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
650 instead of initializing and cleaning it up on each call and allow non default
651 implementations of digests to be specified.
653 If digest contexts are not cleaned up after use,
654 memory leaks will occur.
656 EVP_MD_CTX_get0_name(), EVP_MD_CTX_get_size(), EVP_MD_CTX_get_block_size(),
657 EVP_MD_CTX_get_type(), EVP_get_digestbynid() and EVP_get_digestbyobj() are
660 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
665 This example digests the data "Test Message\n" and "Hello World\n", using the
666 digest name passed on the command line.
670 #include <openssl/evp.h>
672 int main(int argc, char *argv[])
676 char mess1[] = "Test Message\n";
677 char mess2[] = "Hello World\n";
678 unsigned char md_value[EVP_MAX_MD_SIZE];
679 unsigned int md_len, i;
681 if (argv[1] == NULL) {
682 printf("Usage: mdtest digestname\n");
686 md = EVP_get_digestbyname(argv[1]);
688 printf("Unknown message digest %s\n", argv[1]);
692 mdctx = EVP_MD_CTX_new();
693 EVP_DigestInit_ex2(mdctx, md, NULL);
694 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
695 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
696 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
697 EVP_MD_CTX_free(mdctx);
699 printf("Digest is: ");
700 for (i = 0; i < md_len; i++)
701 printf("%02x", md_value[i]);
709 L<EVP_MD_meth_new(3)>,
715 L<crypto(7)/ALGORITHM FETCHING>,
716 L<provider-digest(7)>,
717 L<life_cycle-digest(7)>
719 The full list of digest algorithms are provided below.
721 L<EVP_blake2b512(3)>,
735 The EVP_MD_CTX_create() and EVP_MD_CTX_destroy() functions were renamed to
736 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0, respectively.
738 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
739 later, so now EVP_sha1() can be used with RSA and DSA.
741 The EVP_dss1() function was removed in OpenSSL 1.1.0.
743 The EVP_MD_CTX_set_pkey_ctx() function was added in OpenSSL 1.1.1.
745 The EVP_Q_digest(), EVP_DigestInit_ex2(),
746 EVP_MD_fetch(), EVP_MD_free(), EVP_MD_up_ref(),
747 EVP_MD_get_params(), EVP_MD_CTX_set_params(), EVP_MD_CTX_get_params(),
748 EVP_MD_gettable_params(), EVP_MD_gettable_ctx_params(),
749 EVP_MD_settable_ctx_params(), EVP_MD_CTX_settable_params() and
750 EVP_MD_CTX_gettable_params() functions were added in OpenSSL 3.0.
752 The EVP_MD_type(), EVP_MD_nid(), EVP_MD_name(), EVP_MD_pkey_type(),
753 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_flags(), EVP_MD_CTX_size(),
754 EVP_MD_CTX_block_size(), EVP_MD_CTX_type(), and EVP_MD_CTX_md_data()
755 functions were renamed to include C<get> or C<get0> in their names in
756 OpenSSL 3.0, respectively. The old names are kept as non-deprecated
759 The EVP_MD_CTX_md() function was deprecated in OpenSSL 3.0; use
760 EVP_MD_CTX_get0_md() instead.
761 EVP_MD_CTX_update_fn() and EVP_MD_CTX_set_update_fn() were deprecated
766 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
768 Licensed under the Apache License 2.0 (the "License"). You may not use
769 this file except in compliance with the License. You can obtain a copy
770 in the file LICENSE in the source distribution or at
771 L<https://www.openssl.org/source/license.html>.