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Title "RAND_SET_RAND_METHOD 3ossl"
RAND_SET_RAND_METHOD 3ossl "2023-09-19" "3.0.11" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
RAND_set_rand_method, RAND_get_rand_method, RAND_OpenSSL - select RAND method
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/rand.h> .Ve

The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining \s-1OPENSSL_API_COMPAT\s0 with a suitable version value, see openssl_user_macros\|(7):

.Vb 1 RAND_METHOD *RAND_OpenSSL(void); \& int RAND_set_rand_method(const RAND_METHOD *meth); \& const RAND_METHOD *RAND_get_rand_method(void); .Ve

"DESCRIPTION"
Header "DESCRIPTION" All of the functions described on this page are deprecated. Applications should instead use RAND_set_DRBG_type\|(3), \s-1EVP_RAND\s0\|(3) and \s-1EVP_RAND\s0\|(7).

A \s-1RAND_METHOD\s0 specifies the functions that OpenSSL uses for random number generation.

\fBRAND_OpenSSL() returns the default \s-1RAND_METHOD\s0 implementation by OpenSSL. This implementation ensures that the \s-1PRNG\s0 state is unique for each thread.

If an \s-1ENGINE\s0 is loaded that provides the \s-1RAND API,\s0 however, it will be used instead of the method returned by RAND_OpenSSL(). This is deprecated in OpenSSL 3.0.

\fBRAND_set_rand_method() makes meth the method for \s-1PRNG\s0 use. If an \s-1ENGINE\s0 was providing the method, it will be released first.

\fBRAND_get_rand_method() returns a pointer to the current \s-1RAND_METHOD\s0.

"THE RAND_METHOD STRUCTURE"
Header "THE RAND_METHOD STRUCTURE" .Vb 8 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; .Ve

The fields point to functions that are used by, in order, \fBRAND_seed(), RAND_bytes(), internal \s-1RAND\s0 cleanup, RAND_add(), RAND_pseudo_rand() and RAND_status(). Each pointer may be \s-1NULL\s0 if the function is not implemented.

"RETURN VALUES"
Header "RETURN VALUES" \fBRAND_set_rand_method() returns 1 on success and 0 on failure. \fBRAND_get_rand_method() and RAND_OpenSSL() return pointers to the respective methods.
"SEE ALSO"
Header "SEE ALSO" \s-1EVP_RAND\s0\|(3), \fBRAND_set_DRBG_type\|(3), \fBRAND_bytes\|(3), \fBENGINE_by_id\|(3), \s-1EVP_RAND\s0\|(7), \s-1RAND\s0\|(7)
"HISTORY"
Header "HISTORY" All of these functions were deprecated in OpenSSL 3.0.
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.