I am looking for a way to insert encrypted passwords into a database (MySQL) that I can decrypt later. I've done research and I've came to the conclusion that bcrypt would be the more secure way to store passwords, but then I can't get them back, and it's important that I know their passwords in case I need to login to their system (I don't want to rely on IP authentication).
http://php.net/manual/es/function.mcrypt-cbc.php has some good examples of using a library for encryption on both PHP and PERL, but PERL requires an additional library and PHP needs to be a certain version.
I am looking for a solution that has ability to run on PERL and PHP natively (no additional libraries) with versions that atleast a year old. No PHP 5.3 functions or anything of the like.
The system only has 100 or so users, so there isn't a huge risk of someone even getting access to the database, but just incase I want some kind of protection. If need be, I would be OK with having to add a library to PERL, but I can't really be picky with a PHP library or require PHP version higher than 5.0