Michael Nitschinger has a new post to his blog today showing how you can secure the forms in Lithium using the handy CSRF token implemented directly in the framework.
CSRF (Cross-Site-Request-Forgery) attacks work by sending arbitary (form) requests from a victim. Normally, the receiving site (in our case the Controller who processes the form data) doesn't know where the data comes from. The CSRF protection in Lithium aims to solve this problem in an elegant and secure way. You can read more about those attacks here. Note that you'll need to clone the latest master branch of Lithium if you want to try it out now.
There's two parts to the protection, one on either side of things - a field in the form output and a check in the controller to see if the submitted value is correct. He includes code for a simple form (a title field and submit button) that lazy loads the Security helper and generates the token for you. He walks through the controller side of things a line at a time and includes a sample logging/forwarding bit in the second example to redirect users when the CSRF check doesn't pass.