#!/usr/bin/perl
use strict;
use warnings;

use Crypt::CBC;
use MIME::Base64::URLSafe qw( urlsafe_b64encode urlsafe_b64decode );

my $key = 'secret';

sub url_encode {
    my ( $string, $iv ) = @_;
    return urlsafe_b64encode( $iv . Crypt::CBC->new(
        '-key'    => $key,
        '-header' => 'none',
        '-iv'     => $iv,
        '-cypher' => 'Blowfish',
    )->encrypt($string) );
}

sub url_decode {
    my $b64 = urlsafe_b64decode( $_[0] );

    return Crypt::CBC->new(
        '-key'    => $key,
        '-header' => 'none',
        '-iv'     => substr( $b64, 0, 8 ),
        '-cypher' => 'Blowfish',
    )->decrypt( substr( $b64, 8 ) );
}

foreach ( 1 .. 5 ) {
    my $iv = join( '', map { [ 'a' .. 'z' ]->[ rand(26) ] } ( 1 .. 8 ) );

    my $en_string = url_encode( 'http://perlmonks.org', $iv );
    my $de_string = url_decode($en_string);

    print $iv, ' : ', $en_string, ' => ', $de_string, "\n";
}