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RAND_get0_primary(3)                OpenSSL               RAND_get0_primary(3)



NAME
       RAND_get0_primary, RAND_get0_public, RAND_get0_private - get access to
       the global EVP_RAND_CTX instances

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/rand.h>

        EVP_RAND_CTX *RAND_get0_primary(OSSL_LIB_CTX *ctx);
        EVP_RAND_CTX *RAND_get0_public(OSSL_LIB_CTX *ctx);
        EVP_RAND_CTX *RAND_get0_private(OSSL_LIB_CTX *ctx);

DESCRIPTION
       The default RAND API implementation (RAND_OpenSSL()) utilizes three
       shared DRBG instances which are accessed via the RAND API:

       The public and private DRBG are thread-local instances, which are used
       by RAND_bytes() and RAND_priv_bytes(), respectively.  The primary DRBG
       is a global instance, which is not intended to be used directly, but is
       used internally to reseed the other two instances.

       These functions here provide access to the shared DRBG instances.

RETURN VALUES
       RAND_get0_primary() returns a pointer to the primary DRBG instance for
       the given OSSL_LIB_CTX ctx.

       RAND_get0_public() returns a pointer to the public DRBG instance for
       the given OSSL_LIB_CTX ctx.

       RAND_get0_private() returns a pointer to the private DRBG instance for
       the given OSSL_LIB_CTX ctx.

       In all the above cases the ctx parameter can be NULL in which case the
       default OSSL_LIB_CTX is used.

NOTES
       It is not thread-safe to access the primary DRBG instance.  The public
       and private DRBG instance can be accessed safely, because they are
       thread-local. Note however, that changes to these two instances apply
       only to the current thread.

       For that reason it is recommended not to change the settings of these
       three instances directly.  Instead, an application should change the
       default settings for new DRBG instances at initialization time, before
       creating additional threads.

       During initialization, it is possible to change the reseed interval and
       reseed time interval.  It is also possible to exchange the reseeding
       callbacks entirely.

       To set the type of DRBG that will be instantiated, use the
       RAND_set_DRBG_type(3) call before accessing the random number
       generation infrastructure.

SEE ALSO
       EVP_RAND(3), RAND_set_DRBG_type(3)

HISTORY
       These functions were added in OpenSSL 3.0.

COPYRIGHT
       Copyright 2020-2021 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>.



3.0.12                            2023-05-07              RAND_get0_primary(3)