By now, I'm sure you've see the "turing test" images that sites have in an effort to bypass the usual form. They are the ones with the image beside them, forcing the user to actually be able to understand the letters in the image to make it past the form. Well, Colin Viebrock's weblog has a new posting that can help you create and use this powerful tool on your own site.

Here are some pieces of code to prevent access to parts of your site unless the user can pass a simple Turing test (also known as a CAPTCHA).

The code is pretty straightforward. You need two files: the image generating script and the protection script.

From there on, the actual code is pretty simple, forcing the users off to the turing.php for validation unless they already passed the test...