RAND_bytes(3)

     RAND_bytes(3)          0.9.6h (2002-09-25)          RAND_bytes(3)

     NAME
          RAND_bytes, RAND_pseudo_bytes - generate random data

     SYNOPSIS
           #include <openssl/rand.h>

           int RAND_bytes(unsigned char *buf, int num);

           int RAND_pseudo_bytes(unsigned char *buf, int num);

     DESCRIPTION
          RAND_bytes() puts num cryptographically strong pseudo-random
          bytes into buf. An error occurs if the PRNG has not been
          seeded with enough randomness to ensure an unpredictable
          byte sequence.

          RAND_pseudo_bytes() puts num pseudo-random bytes into buf.
          Pseudo-random byte sequences generated by
          RAND_pseudo_bytes() will be unique if they are of sufficient
          length, but are not necessarily unpredictable. They can be
          used for non-cryptographic purposes and for certain purposes
          in cryptographic protocols, but usually not for key
          generation etc.

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

     SEE ALSO
          rand(3), ERR_get_error(3), RAND_add(3)

     HISTORY
          RAND_bytes() is available in all versions of SSLeay and
          OpenSSL.  It has a return value since OpenSSL 0.9.5.
          RAND_pseudo_bytes() was added in OpenSSL 0.9.5.

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