1RAND_bytes(3)                       OpenSSL                      RAND_bytes(3)
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NAME

6       RAND_bytes, RAND_pseudo_bytes - generate random data
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SYNOPSIS

9        #include <openssl/rand.h>
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11        int RAND_bytes(unsigned char *buf, int num);
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13        int RAND_pseudo_bytes(unsigned char *buf, int num);
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DESCRIPTION

16       RAND_bytes() puts num cryptographically strong pseudo-random bytes into
17       buf. An error occurs if the PRNG has not been seeded with enough
18       randomness to ensure an unpredictable byte sequence.
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20       RAND_pseudo_bytes() puts num pseudo-random bytes into buf.  Pseudo-
21       random byte sequences generated by RAND_pseudo_bytes() will be unique
22       if they are of sufficient length, but are not necessarily
23       unpredictable. They can be used for non-cryptographic purposes and for
24       certain purposes in cryptographic protocols, but usually not for key
25       generation etc.
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27       The contents of buf is mixed into the entropy pool before retrieving
28       the new pseudo-random bytes unless disabled at compile time (see FAQ).
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RETURN VALUES

31       RAND_bytes() returns 1 on success, 0 otherwise. The error code can be
32       obtained by ERR_get_error(3). RAND_pseudo_bytes() returns 1 if the
33       bytes generated are cryptographically strong, 0 otherwise. Both
34       functions return -1 if they are not supported by the current RAND
35       method.
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SEE ALSO

38       rand(3), ERR_get_error(3), RAND_add(3)
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HISTORY

41       RAND_bytes() is available in all versions of SSLeay and OpenSSL.  It
42       has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added
43       in OpenSSL 0.9.5.
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471.0.2o                            2018-03-27                     RAND_bytes(3)