Here is a list of PHP scripts built for data encryption.
Link Guard is a PHP Script that allows you to hide actual location of your download files by converting it into an encrypted url based on user’s IP address.
Crypty is a lightweight PHP script, allowing you to create a fully functional website dedicated to hashing strings.
This package provides a subscripting mechanism to use in you application.
UCM Plugin: Data Encryption
This plugin lets you encrypt sensitive data in UCM so it is safe from prying eyes.