RAND_SET_RAND_METHOD(3ossl)

✨ RAND_SET_RAND_METHOD(3ossl) ✨

okay bestie, so this is a page from the OpenSSL manual (section 3ossl, if you're keeping track 🎀) and honestly? it's giving "we don't do this anymore" energy. but you still gotta know it, so let's go 💅

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🌸 NAME 🌸

RAND_set_rand_method, RAND_get_rand_method, RAND_OpenSSL — the trio for picking your RAND method. 🎀

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🦋 SYNOPSIS 🦋

#include <openssl/rand.h>

okay so heads up before the code: the following functions have been deprecated since OpenSSL 3.0, and you can hide them entirely by defining OPENSSL_API_COMPAT with a suitable version value — see openssl_user_macros(7) for the deets. 🙈

RAND_METHOD *RAND_OpenSSL(void);

int RAND_set_rand_method(const RAND_METHOD *meth);

const RAND_METHOD *RAND_get_rand_method(void);

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💖 DESCRIPTION 💖

so like, all of the functions on this page are deprecated. fr fr. applications should instead use RAND_set_DRBG_type(3), EVP_RAND(3) and EVP_RAND(7). that's the vibe now. 💅

a RAND_METHOD specifies the functions that OpenSSL uses for random number generation. iconic little struct of function pointers, honestly.

RAND_OpenSSL() returns the default RAND_METHOD implementation by OpenSSL. the way this implementation ensures that the PRNG state is unique for each thread? obsessed. 🧵✨

if an ENGINE is loaded that provides the RAND API, however, it will be used instead of the method returned by RAND_OpenSSL(). but bestie, that's deprecated in OpenSSL 3.0, so. yeah. 💀

RAND_set_rand_method() makes meth the method for PRNG use. and if an ENGINE was providing the method, it will be released first. polite of it honestly. 🫶

RAND_get_rand_method() returns a pointer to the current RAND_METHOD. simple as. 🍓

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👑 THE RAND_METHOD STRUCTURE 👑

typedef struct rand_meth_st {
    int (*seed)(const void *buf, int num);
    int (*bytes)(unsigned char *buf, int num);
    void (*cleanup)(void);
    int (*add)(const void *buf, int num, double entropy);
    int (*pseudorand)(unsigned char *buf, int num);
    int (*status)(void);
} RAND_METHOD;

the fields point to functions that are used by, in order, RAND_seed(), RAND_bytes(), internal RAND cleanup, RAND_add(), RAND_pseudo_rand() and RAND_status(). ✨

and each pointer may be NULL if the function is not implemented — no cap, that's allowed. 🌈

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⭐ RETURN VALUES ⭐

• RAND_set_rand_method() returns 1 on success and 0 on failure. main character returns energy tbh 🔥
• RAND_get_rand_method() and RAND_OpenSSL() return pointers to the respective methods. 🎀

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🫶 SEE ALSO 🫶

EVP_RAND(3), RAND_set_DRBG_type(3), RAND_bytes(3), ENGINE_by_id(3), EVP_RAND(7), RAND(7)

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🌸 HISTORY 🌸

all of these functions were deprecated in OpenSSL 3.0. that's the whole history section, bestie, short and sweet 😭

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💜 COPYRIGHT 💜

Copyright 2000-2021 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>.

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ok so real talk: everything here is deprecated, don't be out here using it in new code, use RAND_set_DRBG_type(3) and EVP_RAND(3) instead. iykyk 💅

and that's the page!! this lil rewrite came from OpenSSL 3.5.6, dated 2026-04-07 — catch you never, bestie, RAND_SET_RAND_METHOD(3ossl) out 🦋💖