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PROVIDER-RAND(7ossl)                OpenSSL               PROVIDER-RAND(7ossl)



NAME

       provider-rand - The random number generation library <-> provider
       functions


SYNOPSIS

        #include <openssl/core_dispatch.h>
        #include <openssl/core_names.h>

        /*
         * None of these are actual functions, but are displayed like this for
         * the function signatures for functions that are offered as function
         * pointers in OSSL_DISPATCH arrays.
         */

        /* Context management */
        void *OSSL_FUNC_rand_newctx(void *provctx, void *parent,
                                    const OSSL_DISPATCH *parent_calls);
        void OSSL_FUNC_rand_freectx(void *ctx);

        /* Random number generator functions: NIST */
        int OSSL_FUNC_rand_instantiate(void *ctx, unsigned int strength,
                                       int prediction_resistance,
                                       const unsigned char *pstr, size_t pstr_len,
                                       const OSSL_PARAM params[]);
        int OSSL_FUNC_rand_uninstantiate(void *ctx);
        int OSSL_FUNC_rand_generate(void *ctx, unsigned char *out, size_t outlen,
                                    unsigned int strength, int prediction_resistance,
                                    const unsigned char *addin, size_t addin_len);
        int OSSL_FUNC_rand_reseed(void *ctx, int prediction_resistance,
                                  const unsigned char *ent, size_t ent_len,
                                  const unsigned char *addin, size_t addin_len);

        /* Random number generator functions: additional */
        size_t OSSL_FUNC_rand_nonce(void *ctx, unsigned char *out, size_t outlen,
                                    int strength, size_t min_noncelen,
                                    size_t max_noncelen);
        size_t OSSL_FUNC_rand_get_seed(void *ctx, unsigned char **buffer,
                                       int entropy, size_t min_len, size_t max_len,
                                       int prediction_resistance,
                                       const unsigned char *adin, size_t adin_len);
        void OSSL_FUNC_rand_clear_seed(void *ctx, unsigned char *buffer, size_t b_len);
        int OSSL_FUNC_rand_verify_zeroization(void *ctx);

        /* Context Locking */
        int OSSL_FUNC_rand_enable_locking(void *ctx);
        int OSSL_FUNC_rand_lock(void *ctx);
        void OSSL_FUNC_rand_unlock(void *ctx);

        /* RAND parameter descriptors */
        const OSSL_PARAM *OSSL_FUNC_rand_gettable_params(void *provctx);
        const OSSL_PARAM *OSSL_FUNC_rand_gettable_ctx_params(void *ctx, void *provctx);
        const OSSL_PARAM *OSSL_FUNC_rand_settable_ctx_params(void *ctx, void *provctx);

        /* RAND parameters */
        int OSSL_FUNC_rand_get_params(OSSL_PARAM params[]);
        int OSSL_FUNC_rand_get_ctx_params(void *ctx, OSSL_PARAM params[]);
        int OSSL_FUNC_rand_set_ctx_params(void *ctx, const OSSL_PARAM params[]);


DESCRIPTION

       This documentation is primarily aimed at provider authors. See
       provider(7) for further information.

       The RAND operation enables providers to implement random number
       generation algorithms and random number sources and make them available
       to applications via the API function EVP_RAND(3).

   Context Management Functions
       OSSL_FUNC_rand_newctx() should create and return a pointer to a
       provider side structure for holding context information during a rand
       operation.  A pointer to this context will be passed back in a number
       of the other rand operation function calls.  The parameter provctx is
       the provider context generated during provider initialisation (see
       provider(7)).  The parameter parent specifies another rand instance to
       be used for seeding purposes.  If NULL and the specific instance
       supports it, the operating system will be used for seeding.  The
       parameter parent_calls points to the dispatch table for parent.  Thus,
       the parent need not be from the same provider as the new instance.

       OSSL_FUNC_rand_freectx() is passed a pointer to the provider side rand
       context in the mctx parameter.  If it receives NULL as ctx value, it
       should not do anything other than return.  This function should free
       any resources associated with that context.

   Random Number Generator Functions: NIST
       These functions correspond to those defined in NIST SP 800-90A and SP
       800-90C.

       OSSL_FUNC_rand_instantiate() is used to instantiate the DRBG ctx at a
       requested security strength.  In addition, prediction_resistance can be
       requested.  Additional input addin of length addin_len bytes can
       optionally be provided.  The parameters specified in params configure
       the DRBG and these should be processed before instantiation.

       OSSL_FUNC_rand_uninstantiate() is used to uninstantiate the DRBG ctx.
       After being uninstantiated, a DRBG is unable to produce output until it
       is instantiated anew.

       OSSL_FUNC_rand_generate() is used to generate random bytes from the
       DRBG ctx.  It will generate outlen bytes placing them into the buffer
       pointed to by out.  The generated bytes will meet the specified
       security strength and, if prediction_resistance is true, the bytes will
       be produced after reseeding from a live entropy source.  Additional
       input addin of length addin_len bytes can optionally be provided.

   Random Number Generator Functions: Additional
       OSSL_FUNC_rand_nonce() is used to generate a nonce of the given
       strength with a length from min_noncelen to max_noncelen. If the output
       buffer out is NULL, the length of the nonce should be returned.

       OSSL_FUNC_rand_get_seed() is used by deterministic generators to obtain
       their seeding material from their parent.  The seed bytes will meet the
       specified security level of entropy bits and there will be between
       min_len and max_len inclusive bytes in total.  If prediction_resistance
       is true, the bytes will be produced from a live entropy source.
       Additional input addin of length addin_len bytes can optionally be
       provided.  A pointer to the seed material is returned in *buffer and
       this must be freed by a later call to OSSL_FUNC_rand_clear_seed().

       OSSL_FUNC_rand_clear_seed() frees a seed buffer of length b_len bytes
       which was previously allocated by OSSL_FUNC_rand_get_seed().

       OSSL_FUNC_rand_verify_zeroization() is used to determine if the
       internal state of the DRBG is zero.  This capability is mandated by
       NIST as part of the self tests, it is unlikely to be useful in other
       circumstances.

   Context Locking
       When DRBGs are used by multiple threads, there must be locking employed
       to ensure their proper operation.  Because locking introduces an
       overhead, it is disabled by default.

       OSSL_FUNC_rand_enable_locking() allows locking to be turned on for a
       DRBG and all of its parent DRBGs.  From this call onwards, the DRBG can
       be used in a thread safe manner.

       OSSL_FUNC_rand_lock() is used to lock a DRBG.  Once locked, exclusive
       access is guaranteed.

       OSSL_FUNC_rand_unlock() is used to unlock a DRBG.

   Rand Parameters
       See OSSL_PARAM(3) for further details on the parameters structure used
       by these functions.

       OSSL_FUNC_rand_get_params() gets details of parameter values associated
       with the provider algorithm and stores them in params.

       OSSL_FUNC_rand_set_ctx_params() sets rand parameters associated with
       the given provider side rand context ctx to params.  Any parameter
       settings are additional to any that were previously set.  Passing NULL
       for params should return true.

       OSSL_FUNC_rand_get_ctx_params() gets details of currently set parameter
       values associated with the given provider side rand context ctx and
       stores them in params.  Passing NULL for params should return true.

       OSSL_FUNC_rand_gettable_params(), OSSL_FUNC_rand_gettable_ctx_params(),
       and OSSL_FUNC_rand_settable_ctx_params() all return constant
       OSSL_PARAM(3) arrays as descriptors of the parameters that
       OSSL_FUNC_rand_get_params(), OSSL_FUNC_rand_get_ctx_params(), and
       OSSL_FUNC_rand_set_ctx_params() can handle, respectively.
       OSSL_FUNC_rand_gettable_ctx_params() and
       OSSL_FUNC_rand_settable_ctx_params() will return the parameters
       associated with the provider side context ctx in its current state if
       it is not NULL.  Otherwise, they return the parameters associated with
       the provider side algorithm provctx.

       Parameters currently recognised by built-in rands are as follows. Not
       all parameters are relevant to, or are understood by all rands:

       "state" (OSSL_RAND_PARAM_STATE) <integer>
           Returns the state of the random number generator.

       "strength" (OSSL_RAND_PARAM_STRENGTH) <unsigned integer>
           Returns the bit strength of the random number generator.

       "fips-indicator" (OSSL_RAND_PARAM_FIPS_APPROVED_INDICATOR) <integer>
           A getter that returns 1 if the operation is FIPS approved, or 0
           otherwise.  This option is used by the OpenSSL FIPS provider and is
           not supported by all EVP_RAND sources.

       For rands that are also deterministic random bit generators (DRBGs),
       these additional parameters are recognised. Not all parameters are
       relevant to, or are understood by all DRBG rands:

       "reseed_requests" (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
           Reads or set the number of generate requests before reseeding the
           associated RAND ctx.

       "reseed_time_interval" (OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL) <integer>
           Reads or set the number of elapsed seconds before reseeding the
           associated RAND ctx.

       "max_request" (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
           Specifies the maximum number of bytes that can be generated in a
           single call to OSSL_FUNC_rand_generate.

       "min_entropylen" (OSSL_DRBG_PARAM_MIN_ENTROPYLEN) <unsigned integer>
       "max_entropylen" (OSSL_DRBG_PARAM_MAX_ENTROPYLEN) <unsigned integer>
           Specify the minimum and maximum number of bytes of random material
           that can be used to seed the DRBG.

       "min_noncelen" (OSSL_DRBG_PARAM_MIN_NONCELEN) <unsigned integer>
       "max_noncelen" (OSSL_DRBG_PARAM_MAX_NONCELEN) <unsigned integer>
           Specify the minimum and maximum number of bytes of nonce that can
           be used to instantiate the DRBG.

       "max_perslen" (OSSL_DRBG_PARAM_MAX_PERSLEN) <unsigned integer>
       "max_adinlen" (OSSL_DRBG_PARAM_MAX_ADINLEN) <unsigned integer>
           Specify the minimum and maximum number of bytes of personalisation
           string that can be used with the DRBG.

       "reseed_counter" (OSSL_DRBG_PARAM_RESEED_COUNTER) <unsigned integer>
           Specifies the number of times the DRBG has been seeded or reseeded.

       "digest" (OSSL_DRBG_PARAM_DIGEST) <UTF8 string>
       "cipher" (OSSL_DRBG_PARAM_CIPHER) <UTF8 string>
       "mac" (OSSL_DRBG_PARAM_MAC) <UTF8 string>
           Sets the name of the underlying cipher, digest or MAC to be used.
           It must name a suitable algorithm for the DRBG that's being used.

       "properties" (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string>
           Sets the properties to be queried when trying to fetch an
           underlying algorithm.  This must be given together with the
           algorithm naming parameter to be considered valid.

       The OpenSSL FIPS provider also supports the following parameters:

       "fips-indicator" (OSSL_DRBG_PARAM_FIPS_APPROVED_INDICATOR) <integer>
           A getter that returns 1 if the operation is FIPS approved, or 0
           otherwise.  This may be used after calling
           OSSL_FUNC_rand_generate(). It may return 0 if the "digest-check" is
           set to 0.

       "digest-check" (OSSL_DRBG_PARAM_FIPS_DIGEST_CHECK) <integer>
           If required this parameter should be set before the digest is set.
           The default value of 1 causes an error when the digest is set if
           the digest is not FIPS approved (e.g. truncated digests). Setting
           this to 0 will ignore the error and set the approved "fips-
           indicator" to 0.  This option breaks FIPS compliance if it causes
           the approved "fips-indicator" to return 0.


RETURN VALUES

       OSSL_FUNC_rand_newctx() should return the newly created provider side
       rand context, or NULL on failure.

       OSSL_FUNC_rand_gettable_params(), OSSL_FUNC_rand_gettable_ctx_params()
       and OSSL_FUNC_rand_settable_ctx_params() should return a constant
       OSSL_PARAM(3) array, or NULL if none is offered.

       OSSL_FUNC_rand_nonce() returns the size of the generated nonce, or 0 on
       error.

       OSSL_FUNC_rand_get_seed() returns the size of the generated seed, or 0
       on error.

       All of the remaining functions should return 1 for success or 0 on
       error.


NOTES

       The RAND life-cycle is described in life_cycle-rand(7).  Providers
       should ensure that the various transitions listed there are supported.
       At some point the EVP layer will begin enforcing the listed
       transitions.


SEE ALSO

       provider(7), RAND(7), EVP_RAND(7), life_cycle-rand(7), EVP_RAND(3)


HISTORY

       The provider RAND interface was introduced in OpenSSL 3.0.  The Rand
       Parameters "fips-indicator" and "digest-check" were added in OpenSSL
       3.4.


COPYRIGHT

       Copyright 2020-2024 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.

3.4.0                             2024-10-29              PROVIDER-RAND(7ossl)

openssl 3.4.0 - Generated Sat Nov 23 14:55:03 CST 2024
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