RAND_SET_RAND_METHOD(3SSL)

✨ NAME ✨

ok bestie, so this page is all about RAND_set_rand_method, RAND_get_rand_method, and RAND_OpenSSL — they're the little trio that select the RAND method. it's the 3SSL girlies' page, and honestly? iconic but also kinda retired. more on that in a sec 🫶

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🌸 SYNOPSIS 🌸

first things first, you gotta pull in the header:

#include <openssl/rand.h>

now listen — these next functions have been deprecated since OpenSSL 3.0, and you can make them vanish entirely if you define OPENSSL_API_COMPAT with a version value that fits, peep 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 💅

ok so, real talk: every single function on this page is deprecated. no cap. if you're writing new code, you should be using RAND_set_DRBG_type(3), EVP_RAND(3), and EVP_RAND(7) instead. periodt.

so like, a RAND_METHOD is basically the little bundle of functions that OpenSSL uses for random number generation. it's the blueprint, the vibe, the whole recipe 🎀

• RAND_OpenSSL() — hands you back the default RAND_METHOD implementation by OpenSSL. and the way this one is so thoughtful?? it makes sure the PRNG state is unique for each thread. slay, literally.
• RAND_set_rand_method() — makes meth the method for PRNG use. simple as that bestie.
• RAND_get_rand_method() — returns a pointer to the current RAND_METHOD. peekaboo 👀

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🦋 THE RAND_METHOD STRUCTURE 🦋

here's what the struct is giving:

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;

so the fields point to functions that get used by, in order: RAND_seed(), RAND_bytes(), internal RAND cleanup, RAND_add(), RAND_pseudo_rand(), and RAND_status(). and if a function isn't implemented? each pointer can just be NULL. no pressure, no drama 💜

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🌈 RETURN VALUES 🌈

• RAND_set_rand_method() — returns 1 on success, 0 on failure. binary queen.
• RAND_get_rand_method() and RAND_OpenSSL() — both return pointers to their respective methods. 🫶

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👑 SEE ALSO 👑

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

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📜 HISTORY 📜

all of these functions were deprecated in OpenSSL 3.0. yeah. they're giving legacy, they're giving "we still love her but she's retired" 😭

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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 that's the whole page bestie, you ate it up fr fr 💖 this was the RAND_SET_RAND_METHOD(3SSL) page, from the 4.0.3 era, dated 2026-09-29. go forth and maybe use EVP_RAND instead, mwah 🎀✨