NAME

    Crypt::URandom - Provide non blocking randomness

VERSION

    This document describes Crypt::URandom version 0.40

SYNOPSIS

        use Crypt::URandom();
    
        my $random_string_50_bytes_long = Crypt::URandom::urandom(50);

    OR

        use Crypt::URandom qw( urandom );
    
        my $random_string_50_bytes_long = urandom(50);

DESCRIPTION

    This Module is intended to provide an interface to the strongest
    available source of non-blocking randomness on the current platform.
    Platforms currently supported are anything supporting /dev/urandom and
    versions of Windows greater than or equal to Windows 2000.

SUBROUTINES/METHODS

    urandom

      This function accepts an integer and returns a string of the same
      size filled with random data. The first call will initialize the
      native cryptographic libraries (if necessary) and load all the
      required Perl libraries. This call is a buffered read on non Win32
      platforms.

    urandom_ub

      This function accepts an integer and returns a string of the same
      size filled with random data. The first call will initialize the
      native cryptographic libraries (if necessary) and load all the
      required Perl libraries. This call is a unbuffered sysread on non
      Win32 platforms.

DIAGNOSTICS

    No secure alternative for random number generation for Win32 versions
    older than W2K

      The module cannot run on versions of Windows earlier than Windows
      2000 as there is no cryptographic functions provided by the operating
      system.

    Could not import CryptAcquireContext

      The module was unable to load the CryptAcquireContextA function from
      the advapi32 dynamic library. The advapi32 library cannot probably be
      loaded.

    CryptAcquireContext failed

      The module was unable to call the CryptAcquireContextA function from
      the advapi32 dynamic library.

    Could not import CryptGenRandom

      The module was unable to load the CryptGenRandom function from the
      advapi32 dynamic library.

    Could not import SystemFunction036

      The module was unable to load the SystemFunction036 function from the
      advapi32 dynamic library.

    The length argument must be supplied and must be an integer

      The get method must be called with an integer argument to describe
      how many random bytes are required.

    CryptGenRandom failed

      The Windows 2000 CryptGenRandom method call failed to generate the
      required amount of randomness

    RtlGenRand failed

      The post Windows 2000 RtlGenRand method call failed to generate the
      required amount of randomness

    Only read n bytes from path

      The /dev/urandom device did not return the desired amount of random
      bytes

    Failed to read from path

      The /dev/urandom device returned an error when being read from

    Failed to open path

      The /dev/urandom device returned an error when being opened

CONFIGURATION AND ENVIRONMENT

    Crypt::URandom requires no configuration files or environment
    variables.

DEPENDENCIES

      If the platform is Win32, the Win32::API module will be required.
      Otherwise no other modules other than those provided by perl will be
      required

INCOMPATIBILITIES

    None reported.

BUGS AND LIMITATIONS

    To report a bug, or view the current list of bugs, please visit
    https://github.com/david-dick/crypt-urandom/issues

AUTHOR

    David Dick <ddick@cpan.org>

ACKNOWLEDGEMENTS

    The Win32::API code for interacting with Microsoft's CryptoAPI was
    stolen with extreme gratitude from Crypt::Random::Source::Strong::Win32
    by Max Kanat-Alexander

LICENSE AND COPYRIGHT

    Copyright (c) 2023, David Dick <ddick@cpan.org>. All rights reserved.

    This module is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

DISCLAIMER OF WARRANTY

    BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
    FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT
    WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER
    PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND,
    EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
    ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
    YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
    NECESSARY SERVICING, REPAIR, OR CORRECTION.

    IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
    WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
    REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
    TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
    CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
    SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
    RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
    FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
    SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
    DAMAGES.