Readings:
The first PHP reading for this week is chapter 9 in Progamming PHP. Then read an online tutorial for creating a CAPTCHA, such as this one. Finally read chapter 4 in Essential PHP Security to understand the risks involved in using sessions.

Key Concepts:
-Creating images in PHP
-Embedding your image
-How to create a CAPTCHA
-Sessions
-Different methods on how hackers exploit sessions
-How to protect against those methods

Exercises:
Create a few images using PHP. Then implement a CAPTCHA that allows the user to view your images if they are able to correctly bypass the CAPTCHA by not being a robot. Include the header and modified footer file. And remember to explore anything else you find that is interesting!