Crypt::OpenSSL::Random - phpMan

NAME
    Crypt::OpenSSL::Random - OpenSSL/LibreSSL pseudo-random number generator
    access

SYNOPSIS
      use Crypt::OpenSSL::Random;

      Crypt::OpenSSL::Random::random_seed($good_random_data);
      Crypt::OpenSSL::Random::random_egd("/tmp/entropy");
      Crypt::OpenSSL::Random::random_status() or
        die "Unable to sufficiently seed the random number generator".

      my $ten_good_random_bytes = Crypt::OpenSSL::Random::random_bytes(10);
      my $ten_ok_random_bytes = Crypt::OpenSSL::Random::random_pseudo_bytes(10);

DESCRIPTION
    "Crypt::OpenSSL::Random" 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
    will be different than the one accessed by any other perl module. Hence,
    to use a module such as Crypt::OpenSSL::Random, 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 AT cpan.com"

    Now maintained by Reini Urban, "rurban AT cpan.org"

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

SEE ALSO
    perl(1), rand(3), RAND_add(3), RAND_egd(3), RAND_bytes(3).