1PROVIDER-DIGEST(7ossl) OpenSSL PROVIDER-DIGEST(7ossl)
2
6 provider-digest - The digest library <-> provider functions
7
9 #include <openssl/core_dispatch.h>
10 #include <openssl/core_names.h>
11 /*
13 * Digests support the following function signatures in OSSL_DISPATCH arrays.
14 * (The function signatures are not actual functions).
15 */
16 /* Context management */
18 void *OSSL_FUNC_digest_newctx(void *provctx);
19 void OSSL_FUNC_digest_freectx(void *dctx);
20 void *OSSL_FUNC_digest_dupctx(void *dctx);
21 /* Digest generation */
23 int OSSL_FUNC_digest_init(void *dctx, const OSSL_PARAM params[]);
24 int OSSL_FUNC_digest_update(void *dctx, const unsigned char *in, size_t inl);
25 int OSSL_FUNC_digest_final(void *dctx, unsigned char *out, size_t *outl,
26 size_t outsz);
27 int OSSL_FUNC_digest_digest(void *provctx, const unsigned char *in, size_t inl,
28 unsigned char *out, size_t *outl, size_t outsz);
29 /* Digest parameter descriptors */
31 const OSSL_PARAM *OSSL_FUNC_digest_gettable_params(void *provctx);
32 /* Digest operation parameter descriptors */
34 const OSSL_PARAM *OSSL_FUNC_digest_gettable_ctx_params(void *dctx,
35 void *provctx);
36 const OSSL_PARAM *OSSL_FUNC_digest_settable_ctx_params(void *dctx,
37 void *provctx);
38 /* Digest parameters */
40 int OSSL_FUNC_digest_get_params(OSSL_PARAM params[]);
41 /* Digest operation parameters */
43 int OSSL_FUNC_digest_set_ctx_params(void *dctx, const OSSL_PARAM params[]);
44 int OSSL_FUNC_digest_get_ctx_params(void *dctx, OSSL_PARAM params[]);
45
47 This documentation is primarily aimed at provider authors. See
48 provider(7) for further information.
49 The DIGEST operation enables providers to implement digest algorithms
51 and make them available to applications via the API functions
52 EVP_DigestInit_ex(3), EVP_DigestUpdate(3) and EVP_DigestFinal(3) (and
53 other related functions).
54 All "functions" mentioned here are passed as function pointers between
56 libcrypto and the provider in OSSL_DISPATCH arrays via OSSL_ALGORITHM
57 arrays that are returned by the provider's provider_query_operation()
58 function (see "Provider Functions" in provider-base(7)).
59 All these "functions" have a corresponding function type definition
61 named OSSL_FUNC_{name}_fn, and a helper function to retrieve the
62 function pointer from an OSSL_DISPATCH element named OSSL_FUNC_{name}.
63 For example, the "function" OSSL_FUNC_digest_newctx() has these:
64 typedef void *(OSSL_FUNC_digest_newctx_fn)(void *provctx);
66 static ossl_inline OSSL_FUNC_digest_newctx_fn
67 OSSL_FUNC_digest_newctx(const OSSL_DISPATCH *opf);
68 OSSL_DISPATCH arrays are indexed by numbers that are provided as macros
70 in openssl-core_dispatch.h(7), as follows:
71 OSSL_FUNC_digest_newctx OSSL_FUNC_DIGEST_NEWCTX
73 OSSL_FUNC_digest_freectx OSSL_FUNC_DIGEST_FREECTX
74 OSSL_FUNC_digest_dupctx OSSL_FUNC_DIGEST_DUPCTX
75 OSSL_FUNC_digest_init OSSL_FUNC_DIGEST_INIT
77 OSSL_FUNC_digest_update OSSL_FUNC_DIGEST_UPDATE
78 OSSL_FUNC_digest_final OSSL_FUNC_DIGEST_FINAL
79 OSSL_FUNC_digest_digest OSSL_FUNC_DIGEST_DIGEST
80 OSSL_FUNC_digest_get_params OSSL_FUNC_DIGEST_GET_PARAMS
82 OSSL_FUNC_digest_get_ctx_params OSSL_FUNC_DIGEST_GET_CTX_PARAMS
83 OSSL_FUNC_digest_set_ctx_params OSSL_FUNC_DIGEST_SET_CTX_PARAMS
84 OSSL_FUNC_digest_gettable_params OSSL_FUNC_DIGEST_GETTABLE_PARAMS
86 OSSL_FUNC_digest_gettable_ctx_params OSSL_FUNC_DIGEST_GETTABLE_CTX_PARAMS
87 OSSL_FUNC_digest_settable_ctx_params OSSL_FUNC_DIGEST_SETTABLE_CTX_PARAMS
88 A digest algorithm implementation may not implement all of these
90 functions. In order to be usable all or none of
91 OSSL_FUNC_digest_newctx, OSSL_FUNC_digest_freectx,
92 OSSL_FUNC_digest_init, OSSL_FUNC_digest_update and
93 OSSL_FUNC_digest_final should be implemented. All other functions are
94 optional.
95 Context Management Functions
97 OSSL_FUNC_digest_newctx() should create and return a pointer to a
98 provider side structure for holding context information during a digest
99 operation. A pointer to this context will be passed back in a number
100 of the other digest operation function calls. The parameter provctx is
101 the provider context generated during provider initialisation (see
102 provider(7)).
103 OSSL_FUNC_digest_freectx() is passed a pointer to the provider side
105 digest context in the dctx parameter. This function should free any
106 resources associated with that context.
107 OSSL_FUNC_digest_dupctx() should duplicate the provider side digest
109 context in the dctx parameter and return the duplicate copy.
110 Digest Generation Functions
112 OSSL_FUNC_digest_init() initialises a digest operation given a newly
113 created provider side digest context in the dctx parameter. The
114 params, if not NULL, should be set on the context in a manner similar
115 to using OSSL_FUNC_digest_set_ctx_params().
116 OSSL_FUNC_digest_update() is called to supply data to be digested as
118 part of a previously initialised digest operation. The dctx parameter
119 contains a pointer to a previously initialised provider side context.
120 OSSL_FUNC_digest_update() should digest inl bytes of data at the
121 location pointed to by in. OSSL_FUNC_digest_update() may be called
122 multiple times for a single digest operation.
123 OSSL_FUNC_digest_final() generates a digest started through previous
125 OSSL_FUNC_digest_init() and OSSL_FUNC_digest_update() calls. The dctx
126 parameter contains a pointer to the provider side context. The digest
127 should be written to *out and the length of the digest to *outl. The
128 digest should not exceed outsz bytes.
129 OSSL_FUNC_digest_digest() is a "oneshot" digest function. No provider
131 side digest context is used. Instead the provider context that was
132 created during provider initialisation is passed in the provctx
133 parameter (see provider(7)). inl bytes at in should be digested and
134 the result should be stored at out. The length of the digest should be
135 stored in *outl which should not exceed outsz bytes.
136 Digest Parameters
138 See OSSL_PARAM(3) for further details on the parameters structure used
139 by these functions.
140 OSSL_FUNC_digest_get_params() gets details of the algorithm
142 implementation and stores them in params.
143 OSSL_FUNC_digest_set_ctx_params() sets digest operation parameters for
145 the provider side digest context dctx to params. Any parameter
146 settings are additional to any that were previously set. Passing NULL
147 for params should return true.
148 OSSL_FUNC_digest_get_ctx_params() gets digest operation details details
150 from the given provider side digest context dctx and stores them in
151 params. Passing NULL for params should return true.
152 OSSL_FUNC_digest_gettable_params() returns a constant OSSL_PARAM array
154 containing descriptors of the parameters that
155 OSSL_FUNC_digest_get_params() can handle.
156 OSSL_FUNC_digest_gettable_ctx_params() and
158 OSSL_FUNC_digest_settable_ctx_params() both return constant OSSL_PARAM
159 arrays as descriptors of the parameters that
160 OSSL_FUNC_digest_get_ctx_params() and OSSL_FUNC_digest_set_ctx_params()
161 can handle, respectively. The array is based on the current state of
162 the provider side context if dctx is not NULL and on the provider side
163 algorithm provctx otherwise.
164 Parameters currently recognised by built-in digests with this function
166 are as follows. Not all parameters are relevant to, or are understood
167 by all digests:
168 "blocksize" (OSSL_DIGEST_PARAM_BLOCK_SIZE) <unsigned integer>
170 The digest block size. The length of the "blocksize" parameter
171 should not exceed that of a size_t.
172 "size" (OSSL_DIGEST_PARAM_SIZE) <unsigned integer>
174 The digest output size. The length of the "size" parameter should
175 not exceed that of a size_t.
176 "flags" (OSSL_DIGEST_PARAM_FLAGS) <unsigned integer>
178 Diverse flags that describe exceptional behaviour for the digest:
179 EVP_MD_FLAG_ONESHOT
181 This digest method can only handle one block of input.
182 EVP_MD_FLAG_XOF
184 This digest method is an extensible-output function (XOF) and
185 supports setting the OSSL_DIGEST_PARAM_XOFLEN parameter.
186 EVP_MD_FLAG_DIGALGID_NULL
188 When setting up a DigestAlgorithmIdentifier, this flag will
189 have the parameter set to NULL by default. Use this for
190 PKCS#1. Note: if combined with EVP_MD_FLAG_DIGALGID_ABSENT,
191 the latter will override.
192 EVP_MD_FLAG_DIGALGID_ABSENT
194 When setting up a DigestAlgorithmIdentifier, this flag will
195 have the parameter be left absent by default. Note: if
196 combined with EVP_MD_FLAG_DIGALGID_NULL, the latter will be
197 overridden.
198 EVP_MD_FLAG_DIGALGID_CUSTOM
200 Custom DigestAlgorithmIdentifier handling via ctrl, with
201 EVP_MD_FLAG_DIGALGID_ABSENT as default. Note: if combined with
202 EVP_MD_FLAG_DIGALGID_NULL, the latter will be overridden.
203 Currently unused.
204 The length of the "flags" parameter should equal that of an
206 unsigned long int.
207 Digest Context Parameters
209 OSSL_FUNC_digest_set_ctx_params() sets digest parameters associated
210 with the given provider side digest context dctx to params. Any
211 parameter settings are additional to any that were previously set. See
212 OSSL_PARAM(3) for further details on the parameters structure.
213 OSSL_FUNC_digest_get_ctx_params() gets details of currently set
215 parameters values associated with the give provider side digest context
216 dctx and stores them in params. See OSSL_PARAM(3) for further details
217 on the parameters structure.
218
220 OSSL_FUNC_digest_newctx() and OSSL_FUNC_digest_dupctx() should return
221 the newly created provider side digest context, or NULL on failure.
222 OSSL_FUNC_digest_init(), OSSL_FUNC_digest_update(),
224 OSSL_FUNC_digest_final(), OSSL_FUNC_digest_digest(),
225 OSSL_FUNC_digest_set_params() and OSSL_FUNC_digest_get_params() should
226 return 1 for success or 0 on error.
227 OSSL_FUNC_digest_size() should return the digest size.
229 OSSL_FUNC_digest_block_size() should return the block size of the
231 underlying digest algorithm.
232
234 The EVP_Q_digest(), EVP_Digest() and EVP_DigestFinal_ex() API calls do
235 not expect the digest size to be larger than EVP_MAX_MD_SIZE. Any
236 algorithm which produces larger digests is unusable with those API
237 calls.
238
240 provider(7), OSSL_PROVIDER-FIPS(7), OSSL_PROVIDER-default(7),
241 OSSL_PROVIDER-legacy(7), EVP_MD-common(7), EVP_MD-BLAKE2(7),
242 EVP_MD-MD2(7), EVP_MD-MD4(7), EVP_MD-MD5(7), EVP_MD-MD5-SHA1(7),
243 EVP_MD-MDC2(7), EVP_MD-RIPEMD160(7), EVP_MD-SHA1(7), EVP_MD-SHA2(7),
244 EVP_MD-SHA3(7), EVP_MD-SHAKE(7), EVP_MD-SM3(7), EVP_MD-WHIRLPOOL(7),
245 life_cycle-digest(7), EVP_DigestInit(3)
246
248 The provider DIGEST interface was introduced in OpenSSL 3.0.
249
251 Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
252 Licensed under the Apache License 2.0 (the "License"). You may not use
254 this file except in compliance with the License. You can obtain a copy
255 in the file LICENSE in the source distribution or at
256 <https://www.openssl.org/source/license.html>.
2573.0.5 2022-11-01 PROVIDER-DIGEST(7ossl)