New on WebReference.com there's a follow up article that talks about using encryption built into PHP to handle login information and authentication.

Following up on "Implementing One-way Encryption in PHP," my previous tutorial about using one-way encryption to build a secure online diary application, this article explores using PHP encryption for login authentication. It presents the two scripts that make up the diary application: the login and diary scripts, as well as the necessary database server connection script.

His script example shows how to use the md5 hashing function to compare passwords with the ones in the database as well as a modification that uses the mcrypt libraries to encrypt some sample text.