Ask HN: PHP/MySQL Data Encryption

Forgive my ignorance, but I need to store some sensitive data in a MySQL database and this data will need to be retrieved and displayed to the user at a later time. I understand the various methods for encrypting/hashing and then comparing a password against the hash, but what I really need to do for this project is to be able to decrypt the data and display it as plain text.

Check out http://appwithphp.com/cryptography-and-php/ - it's a beginner/intermediate overview of how to implement one-way and two-way hashing/encryption in PHP. The concepts should be transferable to other languages though.