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_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,
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 const OSSL_PROVIDER *EVP_MD_provider(const EVP_MD *md);
66 int EVP_MD_type(const EVP_MD *md);
67 int EVP_MD_pkey_type(const EVP_MD *md);
68 int EVP_MD_size(const EVP_MD *md);
69 int EVP_MD_block_size(const EVP_MD *md);
70 unsigned long EVP_MD_flags(const EVP_MD *md);
72 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
73 const char *EVP_MD_CTX_name(const EVP_MD_CTX *ctx);
74 int EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
75 int EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
76 int EVP_MD_CTX_type(const EVP_MD_CTX *ctx);
77 void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);
78 int (*EVP_MD_CTX_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
79 const void *data, size_t count);
80 void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
81 int (*update)(EVP_MD_CTX *ctx,
82 const void *data, size_t count));
84 const EVP_MD *EVP_md_null(void);
86 const EVP_MD *EVP_get_digestbyname(const char *name);
87 const EVP_MD *EVP_get_digestbynid(int type);
88 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
90 EVP_PKEY_CTX *EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx);
91 void EVP_MD_CTX_set_pkey_ctx(EVP_MD_CTX *ctx, EVP_PKEY_CTX *pctx);
93 void EVP_MD_do_all_ex(OPENSSL_CTX *libctx,
94 void (*fn)(EVP_MD *mac, void *arg),
99 The EVP digest routines are a high level interface to message digests,
100 and should be used instead of the digest-specific functions.
102 The B<EVP_MD> type is a structure for digest method implementation.
108 Fetches the digest implementation for the given B<algorithm> from any
109 provider offering it, within the criteria given by the B<properties>.
110 See L<provider(7)/Fetching algorithms> for further information.
112 The returned value must eventually be freed with EVP_MD_free().
114 Fetched B<EVP_MD> structures are reference counted.
116 =item EVP_MD_up_ref()
118 Increments the reference count for an B<EVP_MD> structure.
122 Decrements the reference count for the fetched B<EVP_MD> structure.
123 If the reference count drops to 0 then the structure is freed.
125 =item EVP_MD_CTX_new()
127 Allocates and returns a digest context.
129 =item EVP_MD_CTX_reset()
131 Resets the digest context B<ctx>. This can be used to reuse an already
134 =item EVP_MD_CTX_free()
136 Cleans up digest context B<ctx> and frees up the space allocated to it.
138 =item EVP_MD_CTX_ctrl()
140 This is a legacy method. EVP_MD_CTX_set_params() and EVP_MD_CTX_get_params()
141 is the mechanism that should be used to set and get parameters that are used by
143 Performs digest-specific control actions on context B<ctx>. The control command
144 is indicated in B<cmd> and any additional arguments in B<p1> and B<p2>.
145 EVP_MD_CTX_ctrl() must be called after EVP_DigestInit_ex(). Other restrictions
146 may apply depending on the control type and digest implementation.
147 See L</CONTROLS> below for more information.
149 =item EVP_MD_get_params()
151 Retrieves the requested list of B<params> from a MD B<md>.
152 See L</PARAMETERS> below for more information.
154 =item EVP_MD_CTX_get_params()
156 Retrieves the requested list of B<params> from a MD context B<ctx>.
157 See L</PARAMETERS> below for more information.
159 =item EVP_MD_CTX_set_params()
161 Sets the list of B<params> into a MD context B<ctx>.
162 See L</PARAMETERS> below for more information.
164 =item EVP_MD_gettable_params(), EVP_MD_gettable_ctx_params(),
165 EVP_MD_settable_ctx_params(), EVP_MD_CTX_gettable_params(),
166 EVP_MD_CTX_settable_params()
168 Get a B<OSSL_PARAM> array that describes the retrievable and settable
169 parameters. EVP_MD_gettable_params() returns parameters that can be used with
170 EVP_MD_get_params(). EVP_MD_gettable_ctx_params() and
171 EVP_MD_CTX_gettable_params() return parameters that can be used with
172 EVP_MD_CTX_get_params(). EVP_MD_settable_ctx_params() and
173 EVP_MD_CTX_settable_params() return parameters that can be used with
174 EVP_MD_CTX_set_params().
175 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
177 =item EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags(), EVP_MD_CTX_test_flags()
179 Sets, clears and tests B<ctx> flags. See L</FLAGS> below for more information.
183 A wrapper around the Digest Init_ex, Update and Final_ex functions.
184 Hashes B<count> bytes of data at B<data> using a digest B<type> from ENGINE
185 B<impl>. The digest value is placed in B<md> and its length is written at B<size>
186 if the pointer is not NULL. At most B<EVP_MAX_MD_SIZE> bytes will be written.
187 If B<impl> is NULL the default implementation of digest B<type> is used.
189 =item EVP_DigestInit_ex()
191 Sets up digest context B<ctx> to use a digest B<type>.
192 B<type> is typically supplied by a function such as EVP_sha1(), or a
193 value explicitly fetched with EVP_MD_fetch().
195 If B<impl> is non-NULL, its implementation of the digest B<type> is used if
196 there is one, and if not, the default implementation is used.
198 =item EVP_DigestUpdate()
200 Hashes B<cnt> bytes of data at B<d> into the digest context B<ctx>. This
201 function can be called several times on the same B<ctx> to hash additional
204 =item EVP_DigestFinal_ex()
206 Retrieves the digest value from B<ctx> and places it in B<md>. If the B<s>
207 parameter is not NULL then the number of bytes of data written (i.e. the
208 length of the digest) will be written to the integer at B<s>, at most
209 B<EVP_MAX_MD_SIZE> bytes will be written. After calling EVP_DigestFinal_ex()
210 no additional calls to EVP_DigestUpdate() can be made, but
211 EVP_DigestInit_ex() can be called to initialize a new digest operation.
213 =item EVP_DigestFinalXOF()
215 Interfaces to extendable-output functions, XOFs, such as SHAKE128 and SHAKE256.
216 It retrieves the digest value from B<ctx> and places it in B<len>-sized <B>md.
217 After calling this function no additional calls to EVP_DigestUpdate() can be
218 made, but EVP_DigestInit_ex() can be called to initialize a new operation.
220 =item EVP_MD_CTX_copy_ex()
222 Can be used to copy the message digest state from B<in> to B<out>. This is
223 useful if large amounts of data are to be hashed which only differ in the last
226 =item EVP_DigestInit()
228 Behaves in the same way as EVP_DigestInit_ex() except it always uses the
229 default digest implementation.
231 =item EVP_DigestFinal()
233 Similar to EVP_DigestFinal_ex() except the digest context B<ctx> is
234 automatically cleaned up.
236 =item EVP_MD_CTX_copy()
238 Similar to EVP_MD_CTX_copy_ex() except the destination B<out> does not have to
244 Return the name of the given message digest.
246 =item EVP_MD_provider()
248 Returns an B<OSSL_PROVIDER> pointer to the provider that implements the given
254 Return the size of the message digest when passed an B<EVP_MD> or an
255 B<EVP_MD_CTX> structure, i.e. the size of the hash.
257 =item EVP_MD_block_size(),
258 EVP_MD_CTX_block_size()
260 Return the block size of the message digest when passed an B<EVP_MD> or an
261 B<EVP_MD_CTX> structure.
266 Return the NID of the OBJECT IDENTIFIER representing the given message digest
267 when passed an B<EVP_MD> structure. For example, C<EVP_MD_type(EVP_sha1())>
268 returns B<NID_sha1>. This function is normally used when setting ASN1 OIDs.
270 =item EVP_MD_CTX_md_data()
272 Return the digest method private data for the passed B<EVP_MD_CTX>.
273 The space is allocated by OpenSSL and has the size originally set with
274 EVP_MD_meth_set_app_datasize().
276 =item EVP_MD_CTX_md()
278 Returns the B<EVP_MD> structure corresponding to the passed B<EVP_MD_CTX>. This
279 will be the same B<EVP_MD> object originally passed to EVP_DigestInit_ex() (or
280 other similar function) when the EVP_MD_CTX was first initialised. Note that
281 where explicit fetch is in use (see L<EVP_MD_fetch(3)>) the value returned from
282 this function will not have its reference count incremented and therefore it
283 should not be used after the EVP_MD_CTX is freed.
285 =item EVP_MD_CTX_set_update_fn()
287 Sets the update function for B<ctx> to B<update>.
288 This is the function that is called by EVP_DigestUpdate. If not set, the
289 update function from the B<EVP_MD> type specified at initialization is used.
291 =item EVP_MD_CTX_update_fn()
293 Returns the update function for B<ctx>.
297 Returns the B<md> flags. Note that these are different from the B<EVP_MD_CTX>
298 ones. See L<EVP_MD_meth_set_flags(3)> for more information.
300 =item EVP_MD_pkey_type()
302 Returns the NID of the public key signing algorithm associated with this
303 digest. For example EVP_sha1() is associated with RSA so this will return
304 B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms are no
305 longer linked this function is only retained for compatibility reasons.
309 A "null" message digest that does nothing: i.e. the hash it returns is of zero
312 =item EVP_get_digestbyname(),
313 EVP_get_digestbynid(),
314 EVP_get_digestbyobj()
316 Returns an B<EVP_MD> structure when passed a digest name, a digest B<NID> or an
317 B<ASN1_OBJECT> structure respectively.
319 =item EVP_MD_CTX_pkey_ctx()
321 Returns the B<EVP_PKEY_CTX> assigned to B<ctx>. The returned pointer should not
322 be freed by the caller.
324 =item EVP_MD_CTX_set_pkey_ctx()
326 Assigns an B<EVP_PKEY_CTX> to B<EVP_MD_CTX>. This is usually used to provide
327 a customized B<EVP_PKEY_CTX> to L<EVP_DigestSignInit(3)> or
328 L<EVP_DigestVerifyInit(3)>. The B<pctx> passed to this function should be freed
329 by the caller. A NULL B<pctx> pointer is also allowed to clear the B<EVP_PKEY_CTX>
330 assigned to B<ctx>. In such case, freeing the cleared B<EVP_PKEY_CTX> or not
331 depends on how the B<EVP_PKEY_CTX> is created.
333 =item EVP_MD_do_all_ex()
335 Traverses all messages digests implemented by all activated providers
336 in the given library context I<libctx>, and for each of the implementations,
337 calls the given function I<fn> with the implementation method and the given
344 See L<OSSL_PARAM(3)> for information about passing parameters.
346 EVP_MD_CTX_set_params() can be used with the following OSSL_PARAM keys:
350 =item "xoflen" (B<OSSL_PARAM_DIGEST_KEY_XOFLEN>) <unsigned integer>
352 Sets the digest length for extendable output functions.
353 It is used by the SHAKE algorithm and should not exceed what can be given
356 =item "pad_type" (B<OSSL_PARAM_DIGEST_KEY_PAD_TYPE>) <integer>
359 It is used by the MDC2 algorithm.
363 EVP_MD_CTX_get_params() can be used with the following OSSL_PARAM keys:
367 =item "micalg" (B<OSSL_PARAM_DIGEST_KEY_MICALG>) <UTF8 string>.
369 Gets the digest Message Integrity Check algorithm string. This is used when
370 creating S/MIME multipart/signed messages, as specified in RFC 3851.
371 It may be used by external engines or providers.
377 EVP_MD_CTX_ctrl() can be used to send the following standard controls:
381 =item EVP_MD_CTRL_MICALG
383 Gets the digest Message Integrity Check algorithm string. This is used when
384 creating S/MIME multipart/signed messages, as specified in RFC 3851.
385 The string value is written to B<p2>.
387 =item EVP_MD_CTRL_XOF_LEN
389 This control sets the digest length for extendable output functions to B<p1>.
390 Sending this control directly should not be necessary, the use of
391 C<EVP_DigestFinalXOF()> is preferred.
392 Currently used by SHAKE.
398 EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
399 can be used the manipulate and test these B<EVP_MD_CTX> flags:
403 =item EVP_MD_CTX_FLAG_ONESHOT
405 This flag instructs the digest to optimize for one update only, if possible.
407 =for comment EVP_MD_CTX_FLAG_CLEANED is internal, don't mention it
409 =for comment EVP_MD_CTX_FLAG_REUSE is internal, don't mention it
411 =for comment We currently avoid documenting flags that are only bit holder:
412 EVP_MD_CTX_FLAG_NON_FIPS_ALLOW, EVP_MD_CTX_FLAGS_PAD_*
414 =item EVP_MD_CTX_FLAG_NO_INIT
416 This flag instructs EVP_DigestInit() and similar not to initialise the
417 implementation specific data.
419 =item EVP_MD_CTX_FLAG_FINALISE
421 Some functions such as EVP_DigestSign only finalise copies of internal
422 contexts so additional data can be included after the finalisation call.
423 This is inefficient if this functionality is not required, and can be
424 disabled with this flag.
434 Returns a pointer to a B<EVP_MD> for success or NULL for failure.
436 =item EVP_MD_up_ref()
438 Returns 1 for success or 0 for failure.
440 =item EVP_DigestInit_ex(),
445 success and 0 for failure.
447 =item EVP_MD_CTX_ctrl()
449 Returns 1 if successful or 0 for failure.
451 =item EVP_MD_CTX_set_params(),
452 EVP_MD_CTX_get_params()
454 Returns 1 if successful or 0 for failure.
456 =item EVP_MD_CTX_settable_params(),
457 EVP_MD_CTX_gettable_params()
459 Return an array of constant B<OSSL_PARAM>s, or NULL if there is none
462 =item EVP_MD_CTX_copy_ex()
464 Returns 1 if successful or 0 for failure.
469 Returns the NID of the corresponding OBJECT IDENTIFIER or NID_undef if none
475 EVP_MD_CTX_block_size()
477 Returns the digest or block size in bytes.
481 Returns a pointer to the B<EVP_MD> structure of the "null" message digest.
483 =item EVP_get_digestbyname(),
484 EVP_get_digestbynid(),
485 EVP_get_digestbyobj()
487 Returns either an B<EVP_MD> structure or NULL if an error occurs.
489 =item EVP_MD_CTX_set_pkey_ctx()
491 This function has no return value.
497 The B<EVP> interface to message digests should almost always be used in
498 preference to the low level interfaces. This is because the code then becomes
499 transparent to the digest used and much more flexible.
501 New applications should use the SHA-2 (such as L<EVP_sha256(3)>) or the SHA-3
502 digest algorithms (such as L<EVP_sha3_512(3)>). The other digest algorithms
503 are still in common use.
505 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
506 set to NULL to use the default digest implementation.
508 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
509 obsolete but are retained to maintain compatibility with existing code. New
510 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
511 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
512 instead of initializing and cleaning it up on each call and allow non default
513 implementations of digests to be specified.
515 If digest contexts are not cleaned up after use,
516 memory leaks will occur.
518 EVP_MD_CTX_name(), EVP_MD_CTX_size(), EVP_MD_CTX_block_size(),
519 EVP_MD_CTX_type(), EVP_get_digestbynid() and EVP_get_digestbyobj() are defined
522 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
527 This example digests the data "Test Message\n" and "Hello World\n", using the
528 digest name passed on the command line.
532 #include <openssl/evp.h>
534 int main(int argc, char *argv[])
538 char mess1[] = "Test Message\n";
539 char mess2[] = "Hello World\n";
540 unsigned char md_value[EVP_MAX_MD_SIZE];
541 unsigned int md_len, i;
543 if (argv[1] == NULL) {
544 printf("Usage: mdtest digestname\n");
548 md = EVP_get_digestbyname(argv[1]);
550 printf("Unknown message digest %s\n", argv[1]);
554 mdctx = EVP_MD_CTX_new();
555 EVP_DigestInit_ex(mdctx, md, NULL);
556 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
557 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
558 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
559 EVP_MD_CTX_free(mdctx);
561 printf("Digest is: ");
562 for (i = 0; i < md_len; i++)
563 printf("%02x", md_value[i]);
571 L<EVP_MD_meth_new(3)>,
577 The full list of digest algorithms are provided below.
579 L<EVP_blake2b512(3)>,
590 L<provider(7)/Fetching algorithms>
594 The EVP_MD_CTX_create() and EVP_MD_CTX_destroy() functions were renamed to
595 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0, respectively.
597 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
598 later, so now EVP_sha1() can be used with RSA and DSA.
600 The EVP_dss1() function was removed in OpenSSL 1.1.0.
602 The EVP_MD_CTX_set_pkey_ctx() function was added in 1.1.1.
604 The EVP_MD_fetch(), EVP_MD_free(), EVP_MD_up_ref(), EVP_MD_CTX_set_params()
605 and EVP_MD_CTX_get_params() functions were added in 3.0.
609 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
611 Licensed under the Apache License 2.0 (the "License"). You may not use
612 this file except in compliance with the License. You can obtain a copy
613 in the file LICENSE in the source distribution or at
614 L<https://www.openssl.org/source/license.html>.