I've added another free article to my growing collection:
This article creates the necessary functions in steps, so that you hopefully better understand the final product and can make your own modifications to better suit your needs. If you're just interested in the code, you can look in the code repository for Essential PHP Security:
You might also be interested in Trick-Out Your Session Handler, an article by John Herren on Zend Developer Zone.
Note: Over the next few weeks, I hope to catch up on posting past articles as well as resuming my regular writing of both Security Corner and Guru Speak. Until then, there are 17 free articles available for you to read. Enjoy!