1PROVIDER-RAND(7ossl) OpenSSL PROVIDER-RAND(7ossl)
2
6 provider-rand - The random number generation library <-> provider
7 functions
8
10 #include <openssl/core_dispatch.h>
11 #include <openssl/core_names.h>
12 /*
14 * None of these are actual functions, but are displayed like this for
15 * the function signatures for functions that are offered as function
16 * pointers in OSSL_DISPATCH arrays.
17 */
18 /* Context management */
20 void *OSSL_FUNC_rand_newctx(void *provctx, void *parent,
21 const OSSL_DISPATCH *parent_calls);
22 void OSSL_FUNC_rand_freectx(void *ctx);
23 /* Random number generator functions: NIST */
25 int OSSL_FUNC_rand_instantiate(void *ctx, unsigned int strength,
26 int prediction_resistance,
27 const unsigned char *pstr, size_t pstr_len,
28 const OSSL_PARAM params[]);
29 int OSSL_FUNC_rand_uninstantiate(void *ctx);
30 int OSSL_FUNC_rand_generate(void *ctx, unsigned char *out, size_t outlen,
31 unsigned int strength, int prediction_resistance,
32 const unsigned char *addin, size_t addin_len);
33 int OSSL_FUNC_rand_reseed(void *ctx, int prediction_resistance,
34 const unsigned char *ent, size_t ent_len,
35 const unsigned char *addin, size_t addin_len);
36 /* Random number generator functions: additional */
38 size_t OSSL_FUNC_rand_nonce(void *ctx, unsigned char *out, size_t outlen,
39 int strength, size_t min_noncelen,
40 size_t max_noncelen);
41 size_t OSSL_FUNC_rand_get_seed(void *ctx, unsigned char **buffer,
42 int entropy, size_t min_len, size_t max_len,
43 int prediction_resistance,
44 const unsigned char *adin, size_t adin_len);
45 void OSSL_FUNC_rand_clear_seed(void *ctx, unsigned char *buffer, size_t b_len);
46 int OSSL_FUNC_rand_verify_zeroization(void *ctx);
47 /* Context Locking */
49 int OSSL_FUNC_rand_enable_locking(void *ctx);
50 int OSSL_FUNC_rand_lock(void *ctx);
51 void OSSL_FUNC_rand_unlock(void *ctx);
52 /* RAND parameter descriptors */
54 const OSSL_PARAM *OSSL_FUNC_rand_gettable_params(void *provctx);
55 const OSSL_PARAM *OSSL_FUNC_rand_gettable_ctx_params(void *ctx, void *provctx);
56 const OSSL_PARAM *OSSL_FUNC_rand_settable_ctx_params(void *ctx, void *provctx);
57 /* RAND parameters */
59 int OSSL_FUNC_rand_get_params(OSSL_PARAM params[]);
60 int OSSL_FUNC_rand_get_ctx_params(void *ctx, OSSL_PARAM params[]);
61 int OSSL_FUNC_rand_set_ctx_params(void *ctx, const OSSL_PARAM params[]);
62
64 This documentation is primarily aimed at provider authors. See
65 provider(7) for further information.
66 The RAND operation enables providers to implement random number
68 generation algorithms and random number sources and make them available
69 to applications via the API function EVP_RAND(3).
70 Context Management Functions
72 OSSL_FUNC_rand_newctx() should create and return a pointer to a
73 provider side structure for holding context information during a rand
74 operation. A pointer to this context will be passed back in a number
75 of the other rand operation function calls. The parameter provctx is
76 the provider context generated during provider initialisation (see
77 provider(7)). The parameter parent specifies another rand instance to
78 be used for seeding purposes. If NULL and the specific instance
79 supports it, the operating system will be used for seeding. The
80 parameter parent_calls points to the dispatch table for parent. Thus,
81 the parent need not be from the same provider as the new instance.
82 OSSL_FUNC_rand_freectx() is passed a pointer to the provider side rand
84 context in the mctx parameter. If it receives NULL as ctx value, it
85 should not do anything other than return. This function should free
86 any resources associated with that context.
87 Random Number Generator Functions: NIST
89 These functions correspond to those defined in NIST SP 800-90A and SP
90 800-90C.
91 OSSL_FUNC_rand_instantiate() is used to instantiate the DRBG ctx at a
93 requested security strength. In addition, prediction_resistance can be
94 requested. Additional input addin of length addin_len bytes can
95 optionally be provided. The parameters specified in params configure
96 the DRBG and these should be processed before instantiation.
97 OSSL_FUNC_rand_uninstantiate() is used to uninstantiate the DRBG ctx.
99 After being uninstantiated, a DRBG is unable to produce output until it
100 is instantiated anew.
101 OSSL_FUNC_rand_generate() is used to generate random bytes from the
103 DRBG ctx. It will generate outlen bytes placing them into the buffer
104 pointed to by out. The generated bytes will meet the specified
105 security strength and, if prediction_resistance is true, the bytes will
106 be produced after reseeding from a live entropy source. Additional
107 input addin of length addin_len bytes can optionally be provided.
108 Random Number Generator Functions: Additional
110 OSSL_FUNC_rand_nonce() is used to generate a nonce of the given
111 strength with a length from min_noncelen to max_noncelen. If the output
112 buffer out is NULL, the length of the nonce should be returned.
113 OSSL_FUNC_rand_get_seed() is used by deterministic generators to obtain
115 their seeding material from their parent. The seed bytes will meet the
116 specified security level of entropy bits and there will be between
117 min_len and max_len inclusive bytes in total. If prediction_resistance
118 is true, the bytes will be produced from a live entropy source.
119 Additional input addin of length addin_len bytes can optionally be
120 provided. A pointer to the seed material is returned in *buffer and
121 this must be freed by a later call to OSSL_FUNC_rand_clear_seed().
122 OSSL_FUNC_rand_clear_seed() frees a seed buffer of length b_len bytes
124 which was previously allocated by OSSL_FUNC_rand_get_seed().
125 OSSL_FUNC_rand_verify_zeroization() is used to determine if the
127 internal state of the DRBG is zero. This capability is mandated by
128 NIST as part of the self tests, it is unlikely to be useful in other
129 circumstances.
130 Context Locking
132 When DRBGs are used by multiple threads, there must be locking employed
133 to ensure their proper operation. Because locking introduces an
134 overhead, it is disabled by default.
135 OSSL_FUNC_rand_enable_locking() allows locking to be turned on for a
137 DRBG and all of its parent DRBGs. From this call onwards, the DRBG can
138 be used in a thread safe manner.
139 OSSL_FUNC_rand_lock() is used to lock a DRBG. Once locked, exclusive
141 access is guaranteed.
142 OSSL_FUNC_rand_unlock() is used to unlock a DRBG.
144 Rand Parameters
146 See OSSL_PARAM(3) for further details on the parameters structure used
147 by these functions.
148 OSSL_FUNC_rand_get_params() gets details of parameter values associated
150 with the provider algorithm and stores them in params.
151 OSSL_FUNC_rand_set_ctx_params() sets rand parameters associated with
153 the given provider side rand context ctx to params. Any parameter
154 settings are additional to any that were previously set. Passing NULL
155 for params should return true.
156 OSSL_FUNC_rand_get_ctx_params() gets details of currently set parameter
158 values associated with the given provider side rand context ctx and
159 stores them in params. Passing NULL for params should return true.
160 OSSL_FUNC_rand_gettable_params(), OSSL_FUNC_rand_gettable_ctx_params(),
162 and OSSL_FUNC_rand_settable_ctx_params() all return constant OSSL_PARAM
163 arrays as descriptors of the parameters that
164 OSSL_FUNC_rand_get_params(), OSSL_FUNC_rand_get_ctx_params(), and
165 OSSL_FUNC_rand_set_ctx_params() can handle, respectively.
166 OSSL_FUNC_rand_gettable_ctx_params() and
167 OSSL_FUNC_rand_settable_ctx_params() will return the parameters
168 associated with the provider side context ctx in its current state if
169 it is not NULL. Otherwise, they return the parameters associated with
170 the provider side algorithm provctx.
171 Parameters currently recognised by built-in rands are as follows. Not
173 all parameters are relevant to, or are understood by all rands:
174 "state" (OSSL_RAND_PARAM_STATE) <integer>
176 Returns the state of the random number generator.
177 "strength" (OSSL_RAND_PARAM_STRENGTH) <unsigned integer>
179 Returns the bit strength of the random number generator.
180 For rands that are also deterministic random bit generators (DRBGs),
182 these additional parameters are recognised. Not all parameters are
183 relevant to, or are understood by all DRBG rands:
184 "reseed_requests" (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
186 Reads or set the number of generate requests before reseeding the
187 associated RAND ctx.
188 "reseed_time_interval" (OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL) <integer>
190 Reads or set the number of elapsed seconds before reseeding the
191 associated RAND ctx.
192 "max_request" (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
194 Specifies the maximum number of bytes that can be generated in a
195 single call to OSSL_FUNC_rand_generate.
196 "min_entropylen" (OSSL_DRBG_PARAM_MIN_ENTROPYLEN) <unsigned integer>
198 "max_entropylen" (OSSL_DRBG_PARAM_MAX_ENTROPYLEN) <unsigned integer>
199 Specify the minimum and maximum number of bytes of random material
200 that can be used to seed the DRBG.
201 "min_noncelen" (OSSL_DRBG_PARAM_MIN_NONCELEN) <unsigned integer>
203 "max_noncelen" (OSSL_DRBG_PARAM_MAX_NONCELEN) <unsigned integer>
204 Specify the minimum and maximum number of bytes of nonce that can
205 be used to instantiate the DRBG.
206 "max_perslen" (OSSL_DRBG_PARAM_MAX_PERSLEN) <unsigned integer>
208 "max_adinlen" (OSSL_DRBG_PARAM_MAX_ADINLEN) <unsigned integer>
209 Specify the minimum and maximum number of bytes of personalisation
210 string that can be used with the DRBG.
211 "reseed_counter" (OSSL_DRBG_PARAM_RESEED_COUNTER) <unsigned integer>
213 Specifies the number of times the DRBG has been seeded or reseeded.
214 "digest" (OSSL_DRBG_PARAM_DIGEST) <UTF8 string>
216 "cipher" (OSSL_DRBG_PARAM_CIPHER) <UTF8 string>
217 "mac" (OSSL_DRBG_PARAM_MAC) <UTF8 string>
218 Sets the name of the underlying cipher, digest or MAC to be used.
219 It must name a suitable algorithm for the DRBG that's being used.
220 "properties" (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string>
222 Sets the properties to be queried when trying to fetch an
223 underlying algorithm. This must be given together with the
224 algorithm naming parameter to be considered valid.
225
227 OSSL_FUNC_rand_newctx() should return the newly created provider side
228 rand context, or NULL on failure.
229 OSSL_FUNC_rand_gettable_params(), OSSL_FUNC_rand_gettable_ctx_params()
231 and OSSL_FUNC_rand_settable_ctx_params() should return a constant
232 OSSL_PARAM array, or NULL if none is offered.
233 OSSL_FUNC_rand_nonce() returns the size of the generated nonce, or 0 on
235 error.
236 OSSL_FUNC_rand_get_seed() returns the size of the generated seed, or 0
238 on error.
239 All of the remaining functions should return 1 for success or 0 on
241 error.
242
244 The RAND life-cycle is described in life_cycle-rand(7). Providers
245 should ensure that the various transitions listed there are supported.
246 At some point the EVP layer will begin enforcing the listed
247 transitions.
248
250 provider(7), RAND(7), EVP_RAND(7), life_cycle-rand(7), EVP_RAND(3)
251
253 The provider RAND interface was introduced in OpenSSL 3.0.
254
256 Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
257 Licensed under the Apache License 2.0 (the "License"). You may not use
259 this file except in compliance with the License. You can obtain a copy
260 in the file LICENSE in the source distribution or at
261 <https://www.openssl.org/source/license.html>.
2623.0.5 2022-11-01 PROVIDER-RAND(7ossl)