1 =pod 2 3 =head1 NAME 4 5 provider-rand - The random number generation library E<lt>-E<gt> provider 6 functions 7 8 =head1 SYNOPSIS 9 10 =for openssl multiple includes 11 12 #include <openssl/core_dispatch.h> 13 #include <openssl/core_names.h> 14 15 /* 16 * None of these are actual functions, but are displayed like this for 17 * the function signatures for functions that are offered as function 18 * pointers in OSSL_DISPATCH arrays. 19 */ 20 21 /* Context management */ 22 void *OSSL_FUNC_rand_newctx(void *provctx, void *parent, 23 const OSSL_DISPATCH *parent_calls); 24 void OSSL_FUNC_rand_freectx(void *ctx); 25 26 /* Random number generator functions: NIST */ 27 int OSSL_FUNC_rand_instantiate(void *ctx, unsigned int strength, 28 int prediction_resistance, 29 const unsigned char *pstr, size_t pstr_len, 30 const OSSL_PARAM params[]); 31 int OSSL_FUNC_rand_uninstantiate(void *ctx); 32 int OSSL_FUNC_rand_generate(void *ctx, unsigned char *out, size_t outlen, 33 unsigned int strength, int prediction_resistance, 34 const unsigned char *addin, size_t addin_len); 35 int OSSL_FUNC_rand_reseed(void *ctx, int prediction_resistance, 36 const unsigned char *ent, size_t ent_len, 37 const unsigned char *addin, size_t addin_len); 38 39 /* Random number generator functions: additional */ 40 size_t OSSL_FUNC_rand_nonce(void *ctx, unsigned char *out, size_t outlen, 41 int strength, size_t min_noncelen, 42 size_t max_noncelen); 43 size_t OSSL_FUNC_rand_get_seed(void *ctx, unsigned char **buffer, 44 int entropy, size_t min_len, size_t max_len, 45 int prediction_resistance, 46 const unsigned char *adin, size_t adin_len); 47 void OSSL_FUNC_rand_clear_seed(void *ctx, unsigned char *buffer, size_t b_len); 48 int OSSL_FUNC_rand_verify_zeroization(void *ctx); 49 50 /* Context Locking */ 51 int OSSL_FUNC_rand_enable_locking(void *ctx); 52 int OSSL_FUNC_rand_lock(void *ctx); 53 void OSSL_FUNC_rand_unlock(void *ctx); 54 55 /* RAND parameter descriptors */ 56 const OSSL_PARAM *OSSL_FUNC_rand_gettable_params(void *provctx); 57 const OSSL_PARAM *OSSL_FUNC_rand_gettable_ctx_params(void *ctx, void *provctx); 58 const OSSL_PARAM *OSSL_FUNC_rand_settable_ctx_params(void *ctx, void *provctx); 59 60 /* RAND parameters */ 61 int OSSL_FUNC_rand_get_params(OSSL_PARAM params[]); 62 int OSSL_FUNC_rand_get_ctx_params(void *ctx, OSSL_PARAM params[]); 63 int OSSL_FUNC_rand_set_ctx_params(void *ctx, const OSSL_PARAM params[]); 64 65 =head1 DESCRIPTION 66 67 This documentation is primarily aimed at provider authors. See L<provider(7)> 68 for further information. 69 70 The RAND operation enables providers to implement random number generation 71 algorithms and random number sources and make 72 them available to applications via the API function L<EVP_RAND(3)>. 73 74 =head2 Context Management Functions 75 76 OSSL_FUNC_rand_newctx() should create and return a pointer to a provider side 77 structure for holding context information during a rand operation. 78 A pointer to this context will be passed back in a number of the other rand 79 operation function calls. 80 The parameter I<provctx> is the provider context generated during provider 81 initialisation (see L<provider(7)>). 82 The parameter I<parent> specifies another rand instance to be used for 83 seeding purposes. If NULL and the specific instance supports it, the 84 operating system will be used for seeding. 85 The parameter I<parent_calls> points to the dispatch table for I<parent>. 86 Thus, the parent need not be from the same provider as the new instance. 87 88 OSSL_FUNC_rand_freectx() is passed a pointer to the provider side rand context in 89 the I<mctx> parameter. 90 If it receives NULL as I<ctx> value, it should not do anything other than 91 return. 92 This function should free any resources associated with that context. 93 94 =head2 Random Number Generator Functions: NIST 95 96 These functions correspond to those defined in NIST SP 800-90A and SP 800-90C. 97 98 OSSL_FUNC_rand_instantiate() is used to instantiate the DRBG I<ctx> at a requested 99 security I<strength>. In addition, I<prediction_resistance> can be requested. 100 Additional input I<addin> of length I<addin_len> bytes can optionally 101 be provided. The parameters specified in I<params> configure the DRBG and these 102 should be processed before instantiation. 103 104 OSSL_FUNC_rand_uninstantiate() is used to uninstantiate the DRBG I<ctx>. After being 105 uninstantiated, a DRBG is unable to produce output until it is instantiated 106 anew. 107 108 OSSL_FUNC_rand_generate() is used to generate random bytes from the DRBG I<ctx>. 109 It will generate I<outlen> bytes placing them into the buffer pointed to by 110 I<out>. The generated bytes will meet the specified security I<strength> and, 111 if I<prediction_resistance> is true, the bytes will be produced after reseeding 112 from a live entropy source. Additional input I<addin> of length I<addin_len> 113 bytes can optionally be provided. 114 115 =head2 Random Number Generator Functions: Additional 116 117 OSSL_FUNC_rand_nonce() is used to generate a nonce of the given I<strength> with a 118 length from I<min_noncelen> to I<max_noncelen>. If the output buffer I<out> is 119 NULL, the length of the nonce should be returned. 120 121 OSSL_FUNC_rand_get_seed() is used by deterministic generators to obtain their 122 seeding material from their parent. The seed bytes will meet the specified 123 security level of I<entropy> bits and there will be between I<min_len> 124 and I<max_len> inclusive bytes in total. If I<prediction_resistance> is 125 true, the bytes will be produced from a live entropy source. Additional 126 input I<addin> of length I<addin_len> bytes can optionally be provided. 127 A pointer to the seed material is returned in I<*buffer> and this must be 128 freed by a later call to OSSL_FUNC_rand_clear_seed(). 129 130 OSSL_FUNC_rand_clear_seed() frees a seed I<buffer> of length I<b_len> bytes 131 which was previously allocated by OSSL_FUNC_rand_get_seed(). 132 133 OSSL_FUNC_rand_verify_zeroization() is used to determine if the internal state of the 134 DRBG is zero. This capability is mandated by NIST as part of the self 135 tests, it is unlikely to be useful in other circumstances. 136 137 =head2 Context Locking 138 139 When DRBGs are used by multiple threads, there must be locking employed to 140 ensure their proper operation. Because locking introduces an overhead, it 141 is disabled by default. 142 143 OSSL_FUNC_rand_enable_locking() allows locking to be turned on for a DRBG and all of 144 its parent DRBGs. From this call onwards, the DRBG can be used in a thread 145 safe manner. 146 147 OSSL_FUNC_rand_lock() is used to lock a DRBG. Once locked, exclusive access 148 is guaranteed. 149 150 OSSL_FUNC_rand_unlock() is used to unlock a DRBG. 151 152 =head2 Rand Parameters 153 154 See L<OSSL_PARAM(3)> for further details on the parameters structure used by 155 these functions. 156 157 OSSL_FUNC_rand_get_params() gets details of parameter values associated with the 158 provider algorithm and stores them in I<params>. 159 160 OSSL_FUNC_rand_set_ctx_params() sets rand parameters associated with the given 161 provider side rand context I<ctx> to I<params>. 162 Any parameter settings are additional to any that were previously set. 163 Passing NULL for I<params> should return true. 164 165 OSSL_FUNC_rand_get_ctx_params() gets details of currently set parameter values 166 associated with the given provider side rand context I<ctx> and stores them 167 in I<params>. 168 Passing NULL for I<params> should return true. 169 170 OSSL_FUNC_rand_gettable_params(), OSSL_FUNC_rand_gettable_ctx_params(), 171 and OSSL_FUNC_rand_settable_ctx_params() all return constant L<OSSL_PARAM(3)> 172 arrays as descriptors of the parameters that OSSL_FUNC_rand_get_params(), 173 OSSL_FUNC_rand_get_ctx_params(), and OSSL_FUNC_rand_set_ctx_params() 174 can handle, respectively. OSSL_FUNC_rand_gettable_ctx_params() 175 and OSSL_FUNC_rand_settable_ctx_params() will return the parameters 176 associated with the provider side context I<ctx> in its current state 177 if it is not NULL. Otherwise, they return the parameters associated 178 with the provider side algorithm I<provctx>. 179 180 181 Parameters currently recognised by built-in rands are as follows. Not all 182 parameters are relevant to, or are understood by all rands: 183 184 =over 4 185 186 =item "state" (B<OSSL_RAND_PARAM_STATE>) <integer> 187 188 Returns the state of the random number generator. 189 190 =item "strength" (B<OSSL_RAND_PARAM_STRENGTH>) <unsigned integer> 191 192 Returns the bit strength of the random number generator. 193 194 =back 195 196 For rands that are also deterministic random bit generators (DRBGs), these 197 additional parameters are recognised. Not all 198 parameters are relevant to, or are understood by all DRBG rands: 199 200 =over 4 201 202 =item "reseed_requests" (B<OSSL_DRBG_PARAM_RESEED_REQUESTS>) <unsigned integer> 203 204 Reads or set the number of generate requests before reseeding the 205 associated RAND ctx. 206 207 =item "reseed_time_interval" (B<OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL>) <integer> 208 209 Reads or set the number of elapsed seconds before reseeding the 210 associated RAND ctx. 211 212 =item "max_request" (B<OSSL_DRBG_PARAM_RESEED_REQUESTS>) <unsigned integer> 213 214 Specifies the maximum number of bytes that can be generated in a single 215 call to OSSL_FUNC_rand_generate. 216 217 =item "min_entropylen" (B<OSSL_DRBG_PARAM_MIN_ENTROPYLEN>) <unsigned integer> 218 219 =item "max_entropylen" (B<OSSL_DRBG_PARAM_MAX_ENTROPYLEN>) <unsigned integer> 220 221 Specify the minimum and maximum number of bytes of random material that 222 can be used to seed the DRBG. 223 224 =item "min_noncelen" (B<OSSL_DRBG_PARAM_MIN_NONCELEN>) <unsigned integer> 225 226 =item "max_noncelen" (B<OSSL_DRBG_PARAM_MAX_NONCELEN>) <unsigned integer> 227 228 Specify the minimum and maximum number of bytes of nonce that can be used to 229 instantiate the DRBG. 230 231 =item "max_perslen" (B<OSSL_DRBG_PARAM_MAX_PERSLEN>) <unsigned integer> 232 233 =item "max_adinlen" (B<OSSL_DRBG_PARAM_MAX_ADINLEN>) <unsigned integer> 234 235 Specify the minimum and maximum number of bytes of personalisation string 236 that can be used with the DRBG. 237 238 =item "reseed_counter" (B<OSSL_DRBG_PARAM_RESEED_COUNTER>) <unsigned integer> 239 240 Specifies the number of times the DRBG has been seeded or reseeded. 241 242 =item "digest" (B<OSSL_DRBG_PARAM_DIGEST>) <UTF8 string> 243 244 =item "cipher" (B<OSSL_DRBG_PARAM_CIPHER>) <UTF8 string> 245 246 =item "mac" (B<OSSL_DRBG_PARAM_MAC>) <UTF8 string> 247 248 Sets the name of the underlying cipher, digest or MAC to be used. 249 It must name a suitable algorithm for the DRBG that's being used. 250 251 =item "properties" (B<OSSL_DRBG_PARAM_PROPERTIES>) <UTF8 string> 252 253 Sets the properties to be queried when trying to fetch an underlying algorithm. 254 This must be given together with the algorithm naming parameter to be 255 considered valid. 256 257 =back 258 259 =head1 RETURN VALUES 260 261 OSSL_FUNC_rand_newctx() should return the newly created 262 provider side rand context, or NULL on failure. 263 264 OSSL_FUNC_rand_gettable_params(), OSSL_FUNC_rand_gettable_ctx_params() and 265 OSSL_FUNC_rand_settable_ctx_params() should return a constant L<OSSL_PARAM(3)> 266 array, or NULL if none is offered. 267 268 OSSL_FUNC_rand_nonce() returns the size of the generated nonce, or 0 on error. 269 270 OSSL_FUNC_rand_get_seed() returns the size of the generated seed, or 0 on 271 error. 272 273 All of the remaining functions should return 1 for success or 0 on error. 274 275 =head1 NOTES 276 277 The RAND life-cycle is described in L<life_cycle-rand(7)>. Providers should 278 ensure that the various transitions listed there are supported. At some point 279 the EVP layer will begin enforcing the listed transitions. 280 281 =head1 SEE ALSO 282 283 L<provider(7)>, 284 L<RAND(7)>, 285 L<EVP_RAND(7)>, 286 L<life_cycle-rand(7)>, 287 L<EVP_RAND(3)> 288 289 =head1 HISTORY 290 291 The provider RAND interface was introduced in OpenSSL 3.0. 292 293 =head1 COPYRIGHT 294 295 Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved. 296 297 Licensed under the Apache License 2.0 (the "License"). You may not use 298 this file except in compliance with the License. You can obtain a copy 299 in the file LICENSE in the source distribution or at 300 L<https://www.openssl.org/source/license.html>. 301 302 =cut 303
Indexes created Sun Jul 05 00:25:41 UTC 2026