NAME
   Convert::Base32::Crockford - Encode/Decode Strings using Crockford
   Base32 Scheme

SYNOPSIS
       use Digest::SHA 'sha1';
       use Convert::Base32::Crockford;

       my $foo = "foo";
       my $digest = sha1($foo);
       my $base32 = encode_base32($digest);

       die unless $digest eq decode_base32($base32);

DESCRIPTION
   Base32 encoding is a human friendly way to encode binary strings. You
   see these encodings all the time in URLs.

   The "standard" encoding scheme is RFC 4648. Convert::Base32 is an
   excellent module for encoding/decoding this scheme.

   Douglas Crockford has proposed an alternate encoding scheme at
   <http://www.crockford.com/wrmg/base32.html>. It has many advantages,
   discussed below.

API
   This module is a wrapper of Convert::Base32, with the exact same API,
   but using the Crockford scheme.

   It exports these two subroutines:

   encode_base32
           my $crockford_base32_string = encode_base32($arbitrary_string);

   decode_base32
           my $arbitrary_string = decode_base32($crockford_base32_string);

ADVANTAGES
   From a computational perspective, the Crockford scheme offers no real
   advantages over RFC 4648. However, from the human/usability perspective
   I am convinced that the Crockford scheme is superior.

   Zero is Zero
       As with most numerical base encodings (like hex), Crockford counting
       starts at '0'. RFC 4648 counting starts at 'A', and '0' means 26. It
       would be very challenging for most humans to count using 4648.

   ASCII Sorting
       Crockford encoded strings of equal length, will sort in the same
       ASCII order as their numerical sort order.

   Lenient Decode
       The Crockford scheme allows extra characters like dash ('-') and
       common mistypes like 'O' for '0', when decoding. This accomodates
       some human error and also some human friendly formatting.

   More Digits
       This is a bit esoteric, but at the time of this writing, I am
       interested in encodings that contain at least one letter and and
       least one number. For a given length encoding, the Crockford scheme
       offers a bigger set of strings that meet this requirement than RFC
       4648.

NOTE
   There is a similarly named CPAN module called Encode::Base32::Crockford.
   It uses the Crockford encoding scheme but it only works on numbers (as
   of the time this module was written).

   Base32 and Base64 are almost always employed to encode *binary strings*
   into a human readable form. Encode::Base32::Crockford::base32_encode
   dies when you try to encode a string that is not string of ASCII digits.

CREDITS
   I met Douglas Crockford at the Taiwan OSDC conference in 2010. Smart
   guy. Thanks for this, Douglas.

   Thanks to miyagawa++ for his Convert::Base32 work.

AUTHOR
   Ingy döt Net <[email protected]>

COPYRIGHT
   Copyright 2011-2014. Ingy döt Net.

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

   See <http://www.perl.com/perl/misc/Artistic.html>

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