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_dup,
8 EVP_MD_CTX_copy, 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 EVP_MD_CTX *EVP_MD_CTX_dup(const EVP_MD_CTX *in);
67 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
69 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
70 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
72 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
74 const char *EVP_MD_get0_name(const EVP_MD *md);
75 const char *EVP_MD_get0_description(const EVP_MD *md);
76 int EVP_MD_is_a(const EVP_MD *md, const char *name);
77 int EVP_MD_names_do_all(const EVP_MD *md,
78 void (*fn)(const char *name, void *data),
80 const OSSL_PROVIDER *EVP_MD_get0_provider(const EVP_MD *md);
81 int EVP_MD_get_type(const EVP_MD *md);
82 int EVP_MD_get_pkey_type(const EVP_MD *md);
83 int EVP_MD_get_size(const EVP_MD *md);
84 int EVP_MD_get_block_size(const EVP_MD *md);
85 unsigned long EVP_MD_get_flags(const EVP_MD *md);
87 const EVP_MD *EVP_MD_CTX_get0_md(const EVP_MD_CTX *ctx);
88 EVP_MD *EVP_MD_CTX_get1_md(EVP_MD_CTX *ctx);
89 const char *EVP_MD_CTX_get0_name(const EVP_MD_CTX *ctx);
90 int EVP_MD_CTX_get_size(const EVP_MD_CTX *ctx);
91 int EVP_MD_CTX_get_block_size(const EVP_MD_CTX *ctx);
92 int EVP_MD_CTX_get_type(const EVP_MD_CTX *ctx);
93 void *EVP_MD_CTX_get0_md_data(const EVP_MD_CTX *ctx);
95 const EVP_MD *EVP_md_null(void);
97 const EVP_MD *EVP_get_digestbyname(const char *name);
98 const EVP_MD *EVP_get_digestbynid(int type);
99 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
101 EVP_PKEY_CTX *EVP_MD_CTX_get_pkey_ctx(const EVP_MD_CTX *ctx);
102 void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);
104 void EVP_MD_do_all_provided(OSSL_LIB_CTX *libctx,
105 void (*fn)(EVP_MD *mac, void *arg),
108 #define EVP_MD_type EVP_MD_get_type
109 #define EVP_MD_nid EVP_MD_get_type
110 #define EVP_MD_name EVP_MD_get0_name
111 #define EVP_MD_pkey_type EVP_MD_get_pkey_type
112 #define EVP_MD_size EVP_MD_get_size
113 #define EVP_MD_block_size EVP_MD_get_block_size
114 #define EVP_MD_flags EVP_MD_get_flags
115 #define EVP_MD_CTX_size EVP_MD_CTX_get_size
116 #define EVP_MD_CTX_block_size EVP_MD_CTX_get_block_size
117 #define EVP_MD_CTX_type EVP_MD_CTX_get_type
118 #define EVP_MD_CTX_pkey_ctx EVP_MD_CTX_get_pkey_ctx
119 #define EVP_MD_CTX_md_data EVP_MD_CTX_get0_md_data
121 The following functions have been deprecated since OpenSSL 3.0, and can be
122 hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
123 see L<openssl_user_macros(7)>:
125 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
127 int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
128 const void *data, size_t count);
130 void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
131 int (*update)(EVP_MD_CTX *ctx,
132 const void *data, size_t count));
136 The EVP digest routines are a high-level interface to message digests,
137 and should be used instead of the digest-specific functions.
139 The B<EVP_MD> type is a structure for digest method implementation.
145 Fetches the digest implementation for the given I<algorithm> from any
146 provider offering it, within the criteria given by the I<properties>.
147 See L<crypto(7)/ALGORITHM FETCHING> for further information.
149 The returned value must eventually be freed with EVP_MD_free().
151 Fetched B<EVP_MD> structures are reference counted.
153 =item EVP_MD_up_ref()
155 Increments the reference count for an B<EVP_MD> structure.
159 Decrements the reference count for the fetched B<EVP_MD> structure.
160 If the reference count drops to 0 then the structure is freed.
162 =item EVP_MD_CTX_new()
164 Allocates and returns a digest context.
166 =item EVP_MD_CTX_reset()
168 Resets the digest context I<ctx>. This can be used to reuse an already
171 =item EVP_MD_CTX_free()
173 Cleans up digest context I<ctx> and frees up the space allocated to it.
175 =item EVP_MD_CTX_ctrl()
177 I<This is a legacy method. EVP_MD_CTX_set_params() and EVP_MD_CTX_get_params()
178 is the mechanism that should be used to set and get parameters that are used by
181 Performs digest-specific control actions on context I<ctx>. The control command
182 is indicated in I<cmd> and any additional arguments in I<p1> and I<p2>.
183 EVP_MD_CTX_ctrl() must be called after EVP_DigestInit_ex2(). Other restrictions
184 may apply depending on the control type and digest implementation.
186 If this function happens to be used with a fetched B<EVP_MD>, it will
187 translate the controls that are known to OpenSSL into L<OSSL_PARAM(3)>
188 parameters with keys defined by OpenSSL and call EVP_MD_CTX_get_params() or
189 EVP_MD_CTX_set_params() as is appropriate for each control command.
191 See L</CONTROLS> below for more information, including what translations are
194 =item EVP_MD_get_params()
196 Retrieves the requested list of I<params> from a MD I<md>.
197 See L</PARAMETERS> below for more information.
199 =item EVP_MD_CTX_get_params()
201 Retrieves the requested list of I<params> from a MD context I<ctx>.
202 See L</PARAMETERS> below for more information.
204 =item EVP_MD_CTX_set_params()
206 Sets the list of I<params> into a MD context I<ctx>.
207 See L</PARAMETERS> below for more information.
209 =item EVP_MD_gettable_params()
211 Get a constant B<OSSL_PARAM> array that describes the retrievable parameters
212 that can be used with EVP_MD_get_params(). See L<OSSL_PARAM(3)> for the
213 use of B<OSSL_PARAM> as a parameter descriptor.
215 =item EVP_MD_gettable_ctx_params(), EVP_MD_CTX_gettable_params()
217 Get a constant B<OSSL_PARAM> array that describes the retrievable parameters
218 that can be used with EVP_MD_CTX_get_params(). EVP_MD_gettable_ctx_params()
219 returns the parameters that can be retrieved from the algorithm, whereas
220 EVP_MD_CTX_gettable_params() returns the parameters that can be retrieved
221 in the context's current state. See L<OSSL_PARAM(3)> for the use of
222 B<OSSL_PARAM> as a parameter descriptor.
224 =item EVP_MD_settable_ctx_params(), EVP_MD_CTX_settable_params()
226 Get a constant B<OSSL_PARAM> array that describes the settable parameters
227 that can be used with EVP_MD_CTX_set_params(). EVP_MD_settable_ctx_params()
228 returns the parameters that can be set from the algorithm, whereas
229 EVP_MD_CTX_settable_params() returns the parameters that can be set in the
230 context's current state. See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM>
231 as a parameter descriptor.
233 =item EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), EVP_MD_CTX_test_flags()
235 Sets, clears and tests I<ctx> flags. See L</FLAGS> below for more information.
237 =item EVP_Q_digest() is a quick one-shot digest function.
239 It hashes I<datalen> bytes of data at I<data> using the digest algorithm
240 I<name>, which is fetched using the optional I<libctx> and I<propq> parameters.
241 The digest value is placed in I<md> and its length is written at I<mdlen>
242 if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
246 A wrapper around the Digest Init_ex, Update and Final_ex functions.
247 Hashes I<count> bytes of data at I<data> using a digest I<type> from ENGINE
248 I<impl>. The digest value is placed in I<md> and its length is written at I<size>
249 if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
250 If I<impl> is NULL the default implementation of digest I<type> is used.
252 =item EVP_DigestInit_ex2()
254 Sets up digest context I<ctx> to use a digest I<type>.
255 I<type> is typically supplied by a function such as EVP_sha1(), or a
256 value explicitly fetched with EVP_MD_fetch().
258 The parameters B<params> are set on the context after initialisation.
260 The I<type> parameter can be NULL if I<ctx> has been already initialized
261 with another EVP_DigestInit_ex() call and has not been reset with
264 =item EVP_DigestInit_ex()
266 Sets up digest context I<ctx> to use a digest I<type>.
267 I<type> is typically supplied by a function such as EVP_sha1(), or a
268 value explicitly fetched with EVP_MD_fetch().
270 If I<impl> is non-NULL, its implementation of the digest I<type> is used if
271 there is one, and if not, the default implementation is used.
273 The I<type> parameter can be NULL if I<ctx> has been already initialized
274 with another EVP_DigestInit_ex() call and has not been reset with
277 =item EVP_DigestUpdate()
279 Hashes I<cnt> bytes of data at I<d> into the digest context I<ctx>. This
280 function can be called several times on the same I<ctx> to hash additional
283 =item EVP_DigestFinal_ex()
285 Retrieves the digest value from I<ctx> and places it in I<md>. If the I<s>
286 parameter is not NULL then the number of bytes of data written (i.e. the
287 length of the digest) will be written to the integer at I<s>, at most
288 B<EVP_MAX_MD_SIZE> bytes will be written. After calling EVP_DigestFinal_ex()
289 no additional calls to EVP_DigestUpdate() can be made, but
290 EVP_DigestInit_ex2() can be called to initialize a new digest operation.
292 =item EVP_DigestFinalXOF()
294 Interfaces to extendable-output functions, XOFs, such as SHAKE128 and SHAKE256.
295 It retrieves the digest value from I<ctx> and places it in I<len>-sized I<md>.
296 After calling this function no additional calls to EVP_DigestUpdate() can be
297 made, but EVP_DigestInit_ex2() can be called to initialize a new operation.
299 =item EVP_MD_CTX_dup()
301 Can be used to duplicate the message digest state from I<in>. This is useful
302 to avoid multiple EVP_MD_fetch() calls or if large amounts of data are to be
303 hashed which only differ in the last few bytes.
305 =item EVP_MD_CTX_copy_ex()
307 Can be used to copy the message digest state from I<in> to I<out>. This is
308 useful if large amounts of data are to be hashed which only differ in the last
311 =item EVP_DigestInit()
313 Behaves in the same way as EVP_DigestInit_ex2() except it doesn't set any
314 parameters and calls EVP_MD_CTX_reset() so it cannot be used with an I<type>
317 =item EVP_DigestFinal()
319 Similar to EVP_DigestFinal_ex() except after computing the digest
320 the digest context I<ctx> is automatically cleaned up with EVP_MD_CTX_reset().
322 =item EVP_MD_CTX_copy()
324 Similar to EVP_MD_CTX_copy_ex() except the destination I<out> does not have to
329 Returns 1 if I<md> is an implementation of an algorithm that's
330 identifiable with I<name>, otherwise 0.
332 If I<md> is a legacy digest (it's the return value from the likes of
333 EVP_sha256() rather than the result of an EVP_MD_fetch()), only cipher
334 names registered with the default library context (see
335 L<OSSL_LIB_CTX(3)>) will be considered.
337 =item EVP_MD_get0_name(),
338 EVP_MD_CTX_get0_name()
340 Return the name of the given message digest. For fetched message
341 digests with multiple names, only one of them is returned; it's
342 recommended to use EVP_MD_names_do_all() instead.
344 =item EVP_MD_names_do_all()
346 Traverses all names for the I<md>, and calls I<fn> with each name and
347 I<data>. This is only useful with fetched B<EVP_MD>s.
349 =item EVP_MD_get0_description()
351 Returns a description of the digest, meant for display and human consumption.
352 The description is at the discretion of the digest implementation.
354 =item EVP_MD_get0_provider()
356 Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
359 =item EVP_MD_get_size(),
360 EVP_MD_CTX_get_size()
362 Return the size of the message digest when passed an B<EVP_MD> or an
363 B<EVP_MD_CTX> structure, i.e. the size of the hash.
365 =item EVP_MD_get_block_size(),
366 EVP_MD_CTX_get_block_size()
368 Return the block size of the message digest when passed an B<EVP_MD> or an
369 B<EVP_MD_CTX> structure.
371 =item EVP_MD_get_type(),
372 EVP_MD_CTX_get_type()
374 Return the NID of the OBJECT IDENTIFIER representing the given message digest
375 when passed an B<EVP_MD> structure. For example, C<EVP_MD_get_type(EVP_sha1())>
376 returns B<NID_sha1>. This function is normally used when setting ASN1 OIDs.
378 =item EVP_MD_CTX_get0_md_data()
380 Return the digest method private data for the passed B<EVP_MD_CTX>.
381 The space is allocated by OpenSSL and has the size originally set with
382 EVP_MD_meth_set_app_datasize().
384 =item EVP_MD_CTX_get0_md(), EVP_MD_CTX_get1_md()
386 EVP_MD_CTX_get0_md() returns
387 the B<EVP_MD> structure corresponding to the passed B<EVP_MD_CTX>. This
388 will be the same B<EVP_MD> object originally passed to EVP_DigestInit_ex2() (or
389 other similar function) when the EVP_MD_CTX was first initialised. Note that
390 where explicit fetch is in use (see L<EVP_MD_fetch(3)>) the value returned from
391 this function will not have its reference count incremented and therefore it
392 should not be used after the EVP_MD_CTX is freed.
393 EVP_MD_CTX_get1_md() is the same except the ownership is passed to the
394 caller and is from the passed B<EVP_MD_CTX>.
396 =item EVP_MD_CTX_set_update_fn()
398 Sets the update function for I<ctx> to I<update>.
399 This is the function that is called by EVP_DigestUpdate(). If not set, the
400 update function from the B<EVP_MD> type specified at initialization is used.
402 =item EVP_MD_CTX_update_fn()
404 Returns the update function for I<ctx>.
406 =item EVP_MD_get_flags()
408 Returns the I<md> flags. Note that these are different from the B<EVP_MD_CTX>
409 ones. See L<EVP_MD_meth_set_flags(3)> for more information.
411 =item EVP_MD_get_pkey_type()
413 Returns the NID of the public key signing algorithm associated with this
414 digest. For example EVP_sha1() is associated with RSA so this will return
415 B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms are no
416 longer linked this function is only retained for compatibility reasons.
420 A "null" message digest that does nothing: i.e. the hash it returns is of zero
423 =item EVP_get_digestbyname(),
424 EVP_get_digestbynid(),
425 EVP_get_digestbyobj()
427 Returns an B<EVP_MD> structure when passed a digest name, a digest B<NID> or an
428 B<ASN1_OBJECT> structure respectively.
430 The EVP_get_digestbyname() function is present for backwards compatibility with
431 OpenSSL prior to version 3 and is different to the EVP_MD_fetch() function
432 since it does not attempt to "fetch" an implementation of the cipher.
433 Additionally, it only knows about digests that are built-in to OpenSSL and have
434 an associated NID. Similarly EVP_get_digestbynid() and EVP_get_digestbyobj()
435 also return objects without an associated implementation.
437 When the digest objects returned by these functions are used (such as in a call
438 to EVP_DigestInit_ex()) an implementation of the digest will be implicitly
439 fetched from the loaded providers. This fetch could fail if no suitable
440 implementation is available. Use EVP_MD_fetch() instead to explicitly fetch
441 the algorithm and an associated implementation from a provider.
443 See L<crypto(7)/ALGORITHM FETCHING> for more information about fetching.
445 The digest objects returned from these functions do not need to be freed with
448 =item EVP_MD_CTX_get_pkey_ctx()
450 Returns the B<EVP_PKEY_CTX> assigned to I<ctx>. The returned pointer should not
451 be freed by the caller.
453 =item EVP_MD_CTX_set_pkey_ctx()
455 Assigns an B<EVP_PKEY_CTX> to B<EVP_MD_CTX>. This is usually used to provide
456 a customized B<EVP_PKEY_CTX> to L<EVP_DigestSignInit(3)> or
457 L<EVP_DigestVerifyInit(3)>. The I<pctx> passed to this function should be freed
458 by the caller. A NULL I<pctx> pointer is also allowed to clear the B<EVP_PKEY_CTX>
459 assigned to I<ctx>. In such case, freeing the cleared B<EVP_PKEY_CTX> or not
460 depends on how the B<EVP_PKEY_CTX> is created.
462 =item EVP_MD_do_all_provided()
464 Traverses all messages digests implemented by all activated providers
465 in the given library context I<libctx>, and for each of the implementations,
466 calls the given function I<fn> with the implementation method and the given
473 See L<OSSL_PARAM(3)> for information about passing parameters.
475 EVP_MD_CTX_set_params() can be used with the following OSSL_PARAM keys:
479 =item "xoflen" (B<OSSL_DIGEST_PARAM_XOFLEN>) <unsigned integer>
481 Sets the digest length for extendable output functions.
482 It is used by the SHAKE algorithm and should not exceed what can be given
485 =item "pad-type" (B<OSSL_DIGEST_PARAM_PAD_TYPE>) <unsigned integer>
487 Sets the padding type.
488 It is used by the MDC2 algorithm.
492 EVP_MD_CTX_get_params() can be used with the following OSSL_PARAM keys:
496 =item "micalg" (B<OSSL_PARAM_DIGEST_KEY_MICALG>) <UTF8 string>.
498 Gets the digest Message Integrity Check algorithm string. This is used when
499 creating S/MIME multipart/signed messages, as specified in RFC 3851.
500 It may be used by external engines or providers.
506 EVP_MD_CTX_ctrl() can be used to send the following standard controls:
510 =item EVP_MD_CTRL_MICALG
512 Gets the digest Message Integrity Check algorithm string. This is used when
513 creating S/MIME multipart/signed messages, as specified in RFC 3851.
514 The string value is written to I<p2>.
516 When used with a fetched B<EVP_MD>, EVP_MD_CTX_get_params() gets called with
517 an L<OSSL_PARAM(3)> item with the key "micalg" (B<OSSL_DIGEST_PARAM_MICALG>).
519 =item EVP_MD_CTRL_XOF_LEN
521 This control sets the digest length for extendable output functions to I<p1>.
522 Sending this control directly should not be necessary, the use of
523 EVP_DigestFinalXOF() is preferred.
524 Currently used by SHAKE.
526 When used with a fetched B<EVP_MD>, EVP_MD_CTX_get_params() gets called with
527 an L<OSSL_PARAM(3)> item with the key "xoflen" (B<OSSL_DIGEST_PARAM_XOFLEN>).
533 EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
534 can be used the manipulate and test these B<EVP_MD_CTX> flags:
538 =item EVP_MD_CTX_FLAG_ONESHOT
540 This flag instructs the digest to optimize for one update only, if possible.
542 =for comment EVP_MD_CTX_FLAG_CLEANED is internal, don't mention it
544 =for comment EVP_MD_CTX_FLAG_REUSE is internal, don't mention it
546 =for comment We currently avoid documenting flags that are only bit holder:
547 EVP_MD_CTX_FLAG_NON_FIPS_ALLOW, EVP_MD_CTX_FLAGS_PAD_*
549 =item EVP_MD_CTX_FLAG_NO_INIT
551 This flag instructs EVP_DigestInit() and similar not to initialise the
552 implementation specific data.
554 =item EVP_MD_CTX_FLAG_FINALISE
556 Some functions such as EVP_DigestSign only finalise copies of internal
557 contexts so additional data can be included after the finalisation call.
558 This is inefficient if this functionality is not required, and can be
559 disabled with this flag.
569 Returns a pointer to a B<EVP_MD> for success or NULL for failure.
571 =item EVP_MD_up_ref()
573 Returns 1 for success or 0 for failure.
575 =item EVP_Q_digest(),
577 EVP_DigestInit_ex2(),
580 EVP_DigestFinal_ex(),
581 EVP_DigestFinalXOF(), and
585 success and 0 for failure.
587 =item EVP_MD_CTX_ctrl()
589 Returns 1 if successful or 0 for failure.
591 =item EVP_MD_CTX_set_params(),
592 EVP_MD_CTX_get_params()
594 Returns 1 if successful or 0 for failure.
596 =item EVP_MD_CTX_settable_params(),
597 EVP_MD_CTX_gettable_params()
599 Return an array of constant B<OSSL_PARAM>s, or NULL if there is none
602 =item EVP_MD_CTX_dup()
604 Returns a new EVP_MD_CTX if successful or NULL on failure.
606 =item EVP_MD_CTX_copy_ex()
608 Returns 1 if successful or 0 for failure.
610 =item EVP_MD_get_type(),
611 EVP_MD_get_pkey_type()
613 Returns the NID of the corresponding OBJECT IDENTIFIER or NID_undef if none
616 =item EVP_MD_get_size(),
617 EVP_MD_get_block_size(),
618 EVP_MD_CTX_get_size(),
619 EVP_MD_CTX_get_block_size()
621 Returns the digest or block size in bytes.
625 Returns a pointer to the B<EVP_MD> structure of the "null" message digest.
627 =item EVP_get_digestbyname(),
628 EVP_get_digestbynid(),
629 EVP_get_digestbyobj()
631 Returns either an B<EVP_MD> structure or NULL if an error occurs.
633 =item EVP_MD_CTX_set_pkey_ctx()
635 This function has no return value.
637 =item EVP_MD_names_do_all()
639 Returns 1 if the callback was called for all names. A return value of 0 means
640 that the callback was not called for any names.
646 The B<EVP> interface to message digests should almost always be used in
647 preference to the low-level interfaces. This is because the code then becomes
648 transparent to the digest used and much more flexible.
650 New applications should use the SHA-2 (such as L<EVP_sha256(3)>) or the SHA-3
651 digest algorithms (such as L<EVP_sha3_512(3)>). The other digest algorithms
652 are still in common use.
654 For most applications the I<impl> parameter to EVP_DigestInit_ex() will be
655 set to NULL to use the default digest implementation.
657 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
658 obsolete but are retained to maintain compatibility with existing code. New
659 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
660 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
661 instead of initializing and cleaning it up on each call and allow non default
662 implementations of digests to be specified.
664 If digest contexts are not cleaned up after use,
665 memory leaks will occur.
667 EVP_MD_CTX_get0_name(), EVP_MD_CTX_get_size(), EVP_MD_CTX_get_block_size(),
668 EVP_MD_CTX_get_type(), EVP_get_digestbynid() and EVP_get_digestbyobj() are
671 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
676 This example digests the data "Test Message\n" and "Hello World\n", using the
677 digest name passed on the command line.
681 #include <openssl/evp.h>
683 int main(int argc, char *argv[])
687 char mess1[] = "Test Message\n";
688 char mess2[] = "Hello World\n";
689 unsigned char md_value[EVP_MAX_MD_SIZE];
690 unsigned int md_len, i;
692 if (argv[1] == NULL) {
693 printf("Usage: mdtest digestname\n");
697 md = EVP_get_digestbyname(argv[1]);
699 printf("Unknown message digest %s\n", argv[1]);
703 mdctx = EVP_MD_CTX_new();
704 EVP_DigestInit_ex2(mdctx, md, NULL);
705 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
706 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
707 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
708 EVP_MD_CTX_free(mdctx);
710 printf("Digest is: ");
711 for (i = 0; i < md_len; i++)
712 printf("%02x", md_value[i]);
720 L<EVP_MD_meth_new(3)>,
726 L<crypto(7)/ALGORITHM FETCHING>,
727 L<provider-digest(7)>,
728 L<life_cycle-digest(7)>
730 The full list of digest algorithms are provided below.
732 L<EVP_blake2b512(3)>,
746 The EVP_MD_CTX_create() and EVP_MD_CTX_destroy() functions were renamed to
747 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0, respectively.
749 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
750 later, so now EVP_sha1() can be used with RSA and DSA.
752 The EVP_dss1() function was removed in OpenSSL 1.1.0.
754 The EVP_MD_CTX_set_pkey_ctx() function was added in OpenSSL 1.1.1.
756 The EVP_Q_digest(), EVP_DigestInit_ex2(),
757 EVP_MD_fetch(), EVP_MD_free(), EVP_MD_up_ref(),
758 EVP_MD_get_params(), EVP_MD_CTX_set_params(), EVP_MD_CTX_get_params(),
759 EVP_MD_gettable_params(), EVP_MD_gettable_ctx_params(),
760 EVP_MD_settable_ctx_params(), EVP_MD_CTX_settable_params() and
761 EVP_MD_CTX_gettable_params() functions were added in OpenSSL 3.0.
763 The EVP_MD_type(), EVP_MD_nid(), EVP_MD_name(), EVP_MD_pkey_type(),
764 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_flags(), EVP_MD_CTX_size(),
765 EVP_MD_CTX_block_size(), EVP_MD_CTX_type(), and EVP_MD_CTX_md_data()
766 functions were renamed to include C<get> or C<get0> in their names in
767 OpenSSL 3.0, respectively. The old names are kept as non-deprecated
770 The EVP_MD_CTX_md() function was deprecated in OpenSSL 3.0; use
771 EVP_MD_CTX_get0_md() instead.
772 EVP_MD_CTX_update_fn() and EVP_MD_CTX_set_update_fn() were deprecated
775 EVP_MD_CTX_dup() was added in OpenSSL 3.2.
779 Copyright 2000-2022 The OpenSSL Project Authors. All Rights Reserved.
781 Licensed under the Apache License 2.0 (the "License"). You may not use
782 this file except in compliance with the License. You can obtain a copy
783 in the file LICENSE in the source distribution or at
784 L<https://www.openssl.org/source/license.html>.