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_Digest, EVP_DigestInit_ex, EVP_DigestInit, EVP_DigestUpdate,
14 EVP_DigestFinal_ex, EVP_DigestFinalXOF, EVP_DigestFinal,
15 EVP_MD_is_a, EVP_MD_name, EVP_MD_provider,
16 EVP_MD_type, EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_flags,
18 EVP_MD_CTX_md, EVP_MD_CTX_type, EVP_MD_CTX_size, EVP_MD_CTX_block_size,
19 EVP_MD_CTX_md_data, EVP_MD_CTX_update_fn, EVP_MD_CTX_set_update_fn,
21 EVP_get_digestbyname, EVP_get_digestbynid, EVP_get_digestbyobj,
22 EVP_MD_CTX_pkey_ctx, EVP_MD_CTX_set_pkey_ctx,
23 EVP_MD_do_all_provided
28 #include <openssl/evp.h>
30 EVP_MD *EVP_MD_fetch(OPENSSL_CTX *ctx, const char *algorithm,
31 const char *properties);
32 int EVP_MD_up_ref(EVP_MD *md);
33 void EVP_MD_free(EVP_MD *md);
34 int EVP_MD_get_params(const EVP_MD *digest, OSSL_PARAM params[]);
35 const OSSL_PARAM *EVP_MD_gettable_params(const EVP_MD *digest);
36 EVP_MD_CTX *EVP_MD_CTX_new(void);
37 int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
38 void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
39 void EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void* p2);
40 int EVP_MD_CTX_get_params(EVP_MD_CTX *ctx, OSSL_PARAM params[]);
41 int EVP_MD_CTX_set_params(EVP_MD_CTX *ctx, const OSSL_PARAM params[]);
42 const OSSL_PARAM *EVP_MD_settable_ctx_params(const EVP_MD *md);
43 const OSSL_PARAM *EVP_MD_gettable_ctx_params(const EVP_MD *md);
44 const OSSL_PARAM *EVP_MD_CTX_settable_params(EVP_MD_CTX *ctx);
45 const OSSL_PARAM *EVP_MD_CTX_gettable_params(EVP_MD_CTX *ctx);
46 void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);
47 void EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags);
48 int EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags);
50 int EVP_Digest(const void *data, size_t count, unsigned char *md,
51 unsigned int *size, const EVP_MD *type, ENGINE *impl);
52 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
53 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
54 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
55 int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t len);
57 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
59 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
60 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
62 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
64 const char *EVP_MD_name(const EVP_MD *md);
65 int EVP_MD_is_a(const EVP_MD *md, const char *name);
66 const OSSL_PROVIDER *EVP_MD_provider(const EVP_MD *md);
67 int EVP_MD_type(const EVP_MD *md);
68 int EVP_MD_pkey_type(const EVP_MD *md);
69 int EVP_MD_size(const EVP_MD *md);
70 int EVP_MD_block_size(const EVP_MD *md);
71 unsigned long EVP_MD_flags(const EVP_MD *md);
73 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
74 const char *EVP_MD_CTX_name(const EVP_MD_CTX *ctx);
75 int EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
76 int EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
77 int EVP_MD_CTX_type(const EVP_MD_CTX *ctx);
78 void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);
79 int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
80 const void *data, size_t count);
81 void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
82 int (*update)(EVP_MD_CTX *ctx,
83 const void *data, size_t count));
85 const EVP_MD *EVP_md_null(void);
87 const EVP_MD *EVP_get_digestbyname(const char *name);
88 const EVP_MD *EVP_get_digestbynid(int type);
89 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
91 EVP_PKEY_CTX *EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx);
92 void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);
94 void EVP_MD_do_all_provided(OPENSSL_CTX *libctx,
95 void (*fn)(EVP_MD *mac, void *arg),
100 The EVP digest routines are a high level interface to message digests,
101 and should be used instead of the digest-specific functions.
103 The B<EVP_MD> type is a structure for digest method implementation.
109 Fetches the digest implementation for the given B<algorithm> from any
110 provider offering it, within the criteria given by the B<properties>.
111 See L<provider(7)/Fetching algorithms> for further information.
113 The returned value must eventually be freed with EVP_MD_free().
115 Fetched B<EVP_MD> structures are reference counted.
117 =item EVP_MD_up_ref()
119 Increments the reference count for an B<EVP_MD> structure.
123 Decrements the reference count for the fetched B<EVP_MD> structure.
124 If the reference count drops to 0 then the structure is freed.
126 =item EVP_MD_CTX_new()
128 Allocates and returns a digest context.
130 =item EVP_MD_CTX_reset()
132 Resets the digest context B<ctx>. This can be used to reuse an already
135 =item EVP_MD_CTX_free()
137 Cleans up digest context B<ctx> and frees up the space allocated to it.
139 =item EVP_MD_CTX_ctrl()
141 This is a legacy method. EVP_MD_CTX_set_params() and EVP_MD_CTX_get_params()
142 is the mechanism that should be used to set and get parameters that are used by
144 Performs digest-specific control actions on context B<ctx>. The control command
145 is indicated in B<cmd> and any additional arguments in B<p1> and B<p2>.
146 EVP_MD_CTX_ctrl() must be called after EVP_DigestInit_ex(). Other restrictions
147 may apply depending on the control type and digest implementation.
148 See L</CONTROLS> below for more information.
150 =item EVP_MD_get_params()
152 Retrieves the requested list of B<params> from a MD B<md>.
153 See L</PARAMETERS> below for more information.
155 =item EVP_MD_CTX_get_params()
157 Retrieves the requested list of B<params> from a MD context B<ctx>.
158 See L</PARAMETERS> below for more information.
160 =item EVP_MD_CTX_set_params()
162 Sets the list of B<params> into a MD context B<ctx>.
163 See L</PARAMETERS> below for more information.
165 =item EVP_MD_gettable_params(), EVP_MD_gettable_ctx_params(),
166 EVP_MD_settable_ctx_params(), EVP_MD_CTX_gettable_params(),
167 EVP_MD_CTX_settable_params()
169 Get a B<OSSL_PARAM> array that describes the retrievable and settable
170 parameters. EVP_MD_gettable_params() returns parameters that can be used with
171 EVP_MD_get_params(). EVP_MD_gettable_ctx_params() and
172 EVP_MD_CTX_gettable_params() return parameters that can be used with
173 EVP_MD_CTX_get_params(). EVP_MD_settable_ctx_params() and
174 EVP_MD_CTX_settable_params() return parameters that can be used with
175 EVP_MD_CTX_set_params().
176 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
178 =item EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), EVP_MD_CTX_test_flags()
180 Sets, clears and tests B<ctx> flags. See L</FLAGS> below for more information.
184 A wrapper around the Digest Init_ex, Update and Final_ex functions.
185 Hashes B<count> bytes of data at B<data> using a digest B<type> from ENGINE
186 B<impl>. The digest value is placed in B<md> and its length is written at B<size>
187 if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
188 If B<impl> is NULL the default implementation of digest B<type> is used.
190 =item EVP_DigestInit_ex()
192 Sets up digest context B<ctx> to use a digest B<type>.
193 B<type> is typically supplied by a function such as EVP_sha1(), or a
194 value explicitly fetched with EVP_MD_fetch().
196 If B<impl> is non-NULL, its implementation of the digest B<type> is used if
197 there is one, and if not, the default implementation is used.
199 =item EVP_DigestUpdate()
201 Hashes B<cnt> bytes of data at B<d> into the digest context B<ctx>. This
202 function can be called several times on the same B<ctx> to hash additional
205 =item EVP_DigestFinal_ex()
207 Retrieves the digest value from B<ctx> and places it in B<md>. If the B<s>
208 parameter is not NULL then the number of bytes of data written (i.e. the
209 length of the digest) will be written to the integer at B<s>, at most
210 B<EVP_MAX_MD_SIZE> bytes will be written. After calling EVP_DigestFinal_ex()
211 no additional calls to EVP_DigestUpdate() can be made, but
212 EVP_DigestInit_ex() can be called to initialize a new digest operation.
214 =item EVP_DigestFinalXOF()
216 Interfaces to extendable-output functions, XOFs, such as SHAKE128 and SHAKE256.
217 It retrieves the digest value from B<ctx> and places it in B<len>-sized <B>md.
218 After calling this function no additional calls to EVP_DigestUpdate() can be
219 made, but EVP_DigestInit_ex() can be called to initialize a new operation.
221 =item EVP_MD_CTX_copy_ex()
223 Can be used to copy the message digest state from B<in> to B<out>. This is
224 useful if large amounts of data are to be hashed which only differ in the last
227 =item EVP_DigestInit()
229 Behaves in the same way as EVP_DigestInit_ex() except it always uses the
230 default digest implementation and calls EVP_MD_CTX_reset().
232 =item EVP_DigestFinal()
234 Similar to EVP_DigestFinal_ex() except the digest context B<ctx> is
235 automatically cleaned up.
237 =item EVP_MD_CTX_copy()
239 Similar to EVP_MD_CTX_copy_ex() except the destination B<out> does not have to
244 Returns 1 if I<md> is an implementation of an algorithm that's
245 identifiable with I<name>, otherwise 0.
250 Return the name of the given message digest. For fetched message
251 digests with multiple names, only one of them is returned.
253 =item EVP_MD_provider()
255 Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
261 Return the size of the message digest when passed an B<EVP_MD> or an
262 B<EVP_MD_CTX> structure, i.e. the size of the hash.
264 =item EVP_MD_block_size(),
265 EVP_MD_CTX_block_size()
267 Return the block size of the message digest when passed an B<EVP_MD> or an
268 B<EVP_MD_CTX> structure.
273 Return the NID of the OBJECT IDENTIFIER representing the given message digest
274 when passed an B<EVP_MD> structure. For example, C<EVP_MD_type(EVP_sha1())>
275 returns B<NID_sha1>. This function is normally used when setting ASN1 OIDs.
277 =item EVP_MD_CTX_md_data()
279 Return the digest method private data for the passed B<EVP_MD_CTX>.
280 The space is allocated by OpenSSL and has the size originally set with
281 EVP_MD_meth_set_app_datasize().
283 =item EVP_MD_CTX_md()
285 Returns the B<EVP_MD> structure corresponding to the passed B<EVP_MD_CTX>. This
286 will be the same B<EVP_MD> object originally passed to EVP_DigestInit_ex() (or
287 other similar function) when the EVP_MD_CTX was first initialised. Note that
288 where explicit fetch is in use (see L<EVP_MD_fetch(3)>) the value returned from
289 this function will not have its reference count incremented and therefore it
290 should not be used after the EVP_MD_CTX is freed.
292 =item EVP_MD_CTX_set_update_fn()
294 Sets the update function for B<ctx> to B<update>.
295 This is the function that is called by EVP_DigestUpdate. If not set, the
296 update function from the B<EVP_MD> type specified at initialization is used.
298 =item EVP_MD_CTX_update_fn()
300 Returns the update function for B<ctx>.
304 Returns the B<md> flags. Note that these are different from the B<EVP_MD_CTX>
305 ones. See L<EVP_MD_meth_set_flags(3)> for more information.
307 =item EVP_MD_pkey_type()
309 Returns the NID of the public key signing algorithm associated with this
310 digest. For example EVP_sha1() is associated with RSA so this will return
311 B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms are no
312 longer linked this function is only retained for compatibility reasons.
316 A "null" message digest that does nothing: i.e. the hash it returns is of zero
319 =item EVP_get_digestbyname(),
320 EVP_get_digestbynid(),
321 EVP_get_digestbyobj()
323 Returns an B<EVP_MD> structure when passed a digest name, a digest B<NID> or an
324 B<ASN1_OBJECT> structure respectively.
326 =item EVP_MD_CTX_pkey_ctx()
328 Returns the B<EVP_PKEY_CTX> assigned to B<ctx>. The returned pointer should not
329 be freed by the caller.
331 =item EVP_MD_CTX_set_pkey_ctx()
333 Assigns an B<EVP_PKEY_CTX> to B<EVP_MD_CTX>. This is usually used to provide
334 a customized B<EVP_PKEY_CTX> to L<EVP_DigestSignInit(3)> or
335 L<EVP_DigestVerifyInit(3)>. The B<pctx> passed to this function should be freed
336 by the caller. A NULL B<pctx> pointer is also allowed to clear the B<EVP_PKEY_CTX>
337 assigned to B<ctx>. In such case, freeing the cleared B<EVP_PKEY_CTX> or not
338 depends on how the B<EVP_PKEY_CTX> is created.
340 =item EVP_MD_do_all_provided()
342 Traverses all messages digests implemented by all activated providers
343 in the given library context I<libctx>, and for each of the implementations,
344 calls the given function I<fn> with the implementation method and the given
351 See L<OSSL_PARAM(3)> for information about passing parameters.
353 EVP_MD_CTX_set_params() can be used with the following OSSL_PARAM keys:
357 =item "xoflen" (B<OSSL_PARAM_DIGEST_KEY_XOFLEN>) <unsigned integer>
359 Sets the digest length for extendable output functions.
360 It is used by the SHAKE algorithm and should not exceed what can be given
363 =item "pad_type" (B<OSSL_PARAM_DIGEST_KEY_PAD_TYPE>) <integer>
366 It is used by the MDC2 algorithm.
370 EVP_MD_CTX_get_params() can be used with the following OSSL_PARAM keys:
374 =item "micalg" (B<OSSL_PARAM_DIGEST_KEY_MICALG>) <UTF8 string>.
376 Gets the digest Message Integrity Check algorithm string. This is used when
377 creating S/MIME multipart/signed messages, as specified in RFC 3851.
378 It may be used by external engines or providers.
384 EVP_MD_CTX_ctrl() can be used to send the following standard controls:
388 =item EVP_MD_CTRL_MICALG
390 Gets the digest Message Integrity Check algorithm string. This is used when
391 creating S/MIME multipart/signed messages, as specified in RFC 3851.
392 The string value is written to B<p2>.
394 =item EVP_MD_CTRL_XOF_LEN
396 This control sets the digest length for extendable output functions to B<p1>.
397 Sending this control directly should not be necessary, the use of
398 C<EVP_DigestFinalXOF()> is preferred.
399 Currently used by SHAKE.
405 EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
406 can be used the manipulate and test these B<EVP_MD_CTX> flags:
410 =item EVP_MD_CTX_FLAG_ONESHOT
412 This flag instructs the digest to optimize for one update only, if possible.
414 =for comment EVP_MD_CTX_FLAG_CLEANED is internal, don't mention it
416 =for comment EVP_MD_CTX_FLAG_REUSE is internal, don't mention it
418 =for comment We currently avoid documenting flags that are only bit holder:
419 EVP_MD_CTX_FLAG_NON_FIPS_ALLOW, EVP_MD_CTX_FLAGS_PAD_*
421 =item EVP_MD_CTX_FLAG_NO_INIT
423 This flag instructs EVP_DigestInit() and similar not to initialise the
424 implementation specific data.
426 =item EVP_MD_CTX_FLAG_FINALISE
428 Some functions such as EVP_DigestSign only finalise copies of internal
429 contexts so additional data can be included after the finalisation call.
430 This is inefficient if this functionality is not required, and can be
431 disabled with this flag.
441 Returns a pointer to a B<EVP_MD> for success or NULL for failure.
443 =item EVP_MD_up_ref()
445 Returns 1 for success or 0 for failure.
447 =item EVP_DigestInit_ex(),
452 success and 0 for failure.
454 =item EVP_MD_CTX_ctrl()
456 Returns 1 if successful or 0 for failure.
458 =item EVP_MD_CTX_set_params(),
459 EVP_MD_CTX_get_params()
461 Returns 1 if successful or 0 for failure.
463 =item EVP_MD_CTX_settable_params(),
464 EVP_MD_CTX_gettable_params()
466 Return an array of constant B<OSSL_PARAM>s, or NULL if there is none
469 =item EVP_MD_CTX_copy_ex()
471 Returns 1 if successful or 0 for failure.
476 Returns the NID of the corresponding OBJECT IDENTIFIER or NID_undef if none
482 EVP_MD_CTX_block_size()
484 Returns the digest or block size in bytes.
488 Returns a pointer to the B<EVP_MD> structure of the "null" message digest.
490 =item EVP_get_digestbyname(),
491 EVP_get_digestbynid(),
492 EVP_get_digestbyobj()
494 Returns either an B<EVP_MD> structure or NULL if an error occurs.
496 =item EVP_MD_CTX_set_pkey_ctx()
498 This function has no return value.
504 The B<EVP> interface to message digests should almost always be used in
505 preference to the low level interfaces. This is because the code then becomes
506 transparent to the digest used and much more flexible.
508 New applications should use the SHA-2 (such as L<EVP_sha256(3)>) or the SHA-3
509 digest algorithms (such as L<EVP_sha3_512(3)>). The other digest algorithms
510 are still in common use.
512 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
513 set to NULL to use the default digest implementation.
515 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
516 obsolete but are retained to maintain compatibility with existing code. New
517 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
518 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
519 instead of initializing and cleaning it up on each call and allow non default
520 implementations of digests to be specified.
522 If digest contexts are not cleaned up after use,
523 memory leaks will occur.
525 EVP_MD_CTX_name(), EVP_MD_CTX_size(), EVP_MD_CTX_block_size(),
526 EVP_MD_CTX_type(), EVP_get_digestbynid() and EVP_get_digestbyobj() are defined
529 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
534 This example digests the data "Test Message\n" and "Hello World\n", using the
535 digest name passed on the command line.
539 #include <openssl/evp.h>
541 int main(int argc, char *argv[])
545 char mess1[] = "Test Message\n";
546 char mess2[] = "Hello World\n";
547 unsigned char md_value[EVP_MAX_MD_SIZE];
548 unsigned int md_len, i;
550 if (argv[1] == NULL) {
551 printf("Usage: mdtest digestname\n");
555 md = EVP_get_digestbyname(argv[1]);
557 printf("Unknown message digest %s\n", argv[1]);
561 mdctx = EVP_MD_CTX_new();
562 EVP_DigestInit_ex(mdctx, md, NULL);
563 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
564 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
565 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
566 EVP_MD_CTX_free(mdctx);
568 printf("Digest is: ");
569 for (i = 0; i < md_len; i++)
570 printf("%02x", md_value[i]);
578 L<EVP_MD_meth_new(3)>,
584 The full list of digest algorithms are provided below.
586 L<EVP_blake2b512(3)>,
597 L<provider(7)/Fetching algorithms>
601 The EVP_MD_CTX_create() and EVP_MD_CTX_destroy() functions were renamed to
602 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0, respectively.
604 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
605 later, so now EVP_sha1() can be used with RSA and DSA.
607 The EVP_dss1() function was removed in OpenSSL 1.1.0.
609 The EVP_MD_CTX_set_pkey_ctx() function was added in 1.1.1.
611 The EVP_MD_fetch(), EVP_MD_free(), EVP_MD_up_ref(), EVP_MD_CTX_set_params()
612 and EVP_MD_CTX_get_params() functions were added in 3.0.
616 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
618 Licensed under the Apache License 2.0 (the "License"). You may not use
619 this file except in compliance with the License. You can obtain a copy
620 in the file LICENSE in the source distribution or at
621 L<https://www.openssl.org/source/license.html>.