RAND_set_DRBG_type, RAND_set_seed_source_type - specify the global random number generator types

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       Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance
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3.5.0                                              2025-06-04                           RAND_SET_DRBG_TYPE(3SSL)

RAND_set_DRBG_type() specifies the random bit generator that will be used within the library context ctx.
       A generator of name drbg with properties propq will be fetched.  It will be instantiated with either
       cipher or digest as its underlying cryptographic algorithm.  This specifies the type that will be used
       for the primary, public and private random instances.

       RAND_set_seed_source_type() specifies the seed source that will be used within the library context ctx.
       The seed source of name seed with properties propq will be fetched and used to seed the primary random
       bit generator.

        unsigned char bytes[100];
        RAND_set_seed_source_type(NULL, "JITTER", NULL);
        RAND_bytes(bytes, 100);

       These functions were added in OpenSSL 3.0.

       RAND_set_DRBG_type, RAND_set_seed_source_type - specify the global random number generator types

       These functions must be called before the random bit generators are first created in the library context.
       They will return an error if the call is made too late.

       The default DRBG is "CTR-DRBG" using the "AES-256-CTR" cipher.

       The default seed source can be configured when OpenSSL is compiled by setting
       -DOPENSSL_DEFAULT_SEED_SRC=SEED-SRC. If not set then "SEED-SRC" is used.

       These function return 1 on success and 0 on failure.

EVP_RAND(3), RAND_get0_primary(3)

        #include <openssl/rand.h>

        int RAND_set_DRBG_type(OSSL_LIB_CTX *ctx, const char *drbg, const char *propq,
                               const char *cipher, const char *digest);
        int RAND_set_seed_source_type(OSSL_LIB_CTX *ctx, const char *seed,
                                      const char *propq);