# phpman > perldoc > Crypt::OpenSSL::Random

## NAME
    [Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown) - OpenSSL/LibreSSL pseudo-random number generator access

## SYNOPSIS
      use [Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown);

      [Crypt::OpenSSL::Random::random_seed](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom%3A%3Arandomseed/markdown)($good_random_data);
      [Crypt::OpenSSL::Random::random_egd](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom%3A%3Arandomegd/markdown)("/tmp/entropy");
      [Crypt::OpenSSL::Random::random_status](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom%3A%3Arandomstatus/markdown)() or
        die "Unable to sufficiently seed the random number generator".

      my $ten_good_random_bytes = [Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown)::[random_bytes(10)](https://www.chedong.com/phpMan.php/man/randombytes/10/markdown);
      my $ten_ok_random_bytes = [Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown)::[random_pseudo_bytes(10)](https://www.chedong.com/phpMan.php/man/randompseudobytes/10/markdown);

## DESCRIPTION
    "[Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown)" provides the ability to seed and query the OpenSSL and LibreSSL
    library's pseudo-random number generators.

    Note: On LibreSSL "random_egd()" is not defined.

  EXPORT
    None by default.

## Static Methods
    random_bytes (IV num_bytes)
        This function, returns a specified number of cryptographically strong pseudo-random bytes
        from the PRNG. If the PRNG has not been seeded with enough randomness to ensure an
        unpredictable byte sequence, then a false value is returned.

    random_pseudo_bytes (IV num_bytes)
        This function, is similar to "random_bytes", but the resulting sequence of bytes 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.

    random_seed (PV random_bytes_string)
        This function seeds the PRNG with a supplied string of bytes. It returns true if the PRNG
        has sufficient seeding. Note: calling this function with non-random bytes is of limited
        value at best!

    random_egd (PV egd_string)
        This function seeds the PRNG with data from the specified entropy gathering daemon. Returns
        the number of bytes read from the daemon on success, or -1 if not enough bytes were read, or
        if the connection to the daemon failed.

        "libressl" considers this function insecure, so with libressl this function does not exist.

    random_status ()
        This function returns true if the PRNG has sufficient seeding.

## BUGS
    Because of the internal workings of OpenSSL's random library, the pseudo-random number generator
    (PRNG) accessed by [Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown) will be different than the one accessed by any other
    perl module. Hence, to use a module such as [Crypt::OpenSSL::Random](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AOpenSSL%3A%3ARandom/markdown), you will need to seed the
    PRNG used there from one used here. This class is still advantageous, however, as it centralizes
    other methods, such as "random_egd", in one place.

## AUTHOR
    Ian Robertson, "<iroberts@cpan.com>"

    Now maintained by Reini Urban, "<rurban@cpan.org>"

## LICENSE
    This module is available under the same licences as perl, the Artistic license and the GPL.

## SEE ALSO
### perl