5 RAND_bytes, RAND_priv_bytes, RAND_bytes_ex, RAND_priv_bytes_ex,
6 RAND_pseudo_bytes - generate random data
10 #include <openssl/rand.h>
12 int RAND_bytes(unsigned char *buf, int num);
13 int RAND_priv_bytes(unsigned char *buf, int num);
15 int RAND_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num);
16 int RAND_priv_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num);
18 Deprecated since OpenSSL 1.1.0, can be hidden entirely by defining
19 B<OPENSSL_API_COMPAT> with a suitable version value, see
20 L<openssl_user_macros(7)>:
22 int RAND_pseudo_bytes(unsigned char *buf, int num);
26 RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes
29 RAND_priv_bytes() has the same semantics as RAND_bytes(). It is intended to
30 be used for generating values that should remain private. If using the
31 default RAND_METHOD, this function uses a separate "private" PRNG
32 instance so that a compromise of the "public" PRNG instance will not
33 affect the secrecy of these private values, as described in L<RAND(7)>
36 RAND_bytes_ex() and RAND_priv_bytes_ex() are the same as RAND_bytes() and
37 RAND_priv_bytes() except that they both take an additional I<ctx> parameter.
38 The DRBG used for the operation is the public or private DRBG associated with
39 the specified I<ctx>. The parameter can be NULL, in which case
40 the default library context is used (see L<OPENSSL_CTX(3)>.
41 If the default RAND_METHOD has been changed then for compatibility reasons the
42 RAND_METHOD will be used in preference and the DRBG of the library context
47 Always check the error return value of RAND_bytes() and
48 RAND_priv_bytes() and do not take randomness for granted: an error occurs
49 if the CSPRNG has not been seeded with enough randomness to ensure an
50 unpredictable byte sequence.
54 RAND_bytes() and RAND_priv_bytes()
55 return 1 on success, -1 if not supported by the current
56 RAND method, or 0 on other failure. The error code can be
57 obtained by L<ERR_get_error(3)>.
63 L<RAND_priv_bytes(3)>,
74 RAND_pseudo_bytes() was deprecated in OpenSSL 1.1.0; use RAND_bytes() instead.
78 The RAND_priv_bytes() function was added in OpenSSL 1.1.1.
82 The RAND_bytes_ex() and RAND_priv_bytes_ex() functions were added in OpenSSL 3.0
88 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
90 Licensed under the Apache License 2.0 (the "License"). You may not use
91 this file except in compliance with the License. You can obtain a copy
92 in the file LICENSE in the source distribution or at
93 L<https://www.openssl.org/source/license.html>.