On the ITNewb.com website, there's this new tutorial looking at using the mcrypt libraries in PHP to help protect the data being passed around inside your application.

The ability to encrypt and safeguard data is an essential ability that every serious web developer should have in their arsenal. In this article we'll explore encrypting data with PHP and MCrypt (libmcrypt), storing it in a database, retrieving it from a database and decrypting it for use.

The tutorial walks you through a quick primer on what sort of cryptography the mcyrpt library offers and shows an example of a function (cryptastic!) that takes in the data and a key to return the encrypted value.

On the ITNewb.com site there's a recent tutorial that's been posted by Andrew Johnson about using the mcrypt library in your PHP apps for a simple level of data protection.

The ability to encrypt and safeguard data is an essential ability that every serious web developer should have in their arsenal. In this article we'll explore encrypting data with PHP and MCrypt (libmcrypt), storing it in a database, retrieving it from a database and decrypting it for use.

He works through what mcrypt is, where it can be downloaded from, a simple usage example and a more in-depth look at what its doing (making an IV, encrypting) and how to store the resulting encrypted information into a MySQL database table.