Crypt::OpenSSL::Random - phpMan

Random(3pm)                    User Contributed Perl Documentation                    Random(3pm)

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).

perl v5.34.0                                2022-02-06                                Random(3pm)

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