Captcha PHP 2.0

Captcha PHP is a PHP class library that works without cookies. It is extremely easy to integrate into existing sites and your < form > processing logic. And it requires no database.
It strives to be more user-friendly. It gives visual feedback while you enter a solution (AJAX). And it accepts a few misguessed letters. Additionally it has an accessible riddle built in, optional modules and many configuration settings.
Integration:
On a page that contains a form (maybe even just a login or registration mask), you simply call the ::form() function to get a CAPTCHA image and input box generated, after you did include() the "captcha.php" file:

< /form >
Per default this just outputs the CAPTCHA < img > and an additional solution < input > box - wrapped in a few < div >s.
In the receiving PHP script or part, you then simply invoke the ::solved() function, which will return a boolean value of true, if the user correctly specified the displayed letters and numbers.
...
if ($_POST && captcha::solved()) {
// ok, proceed
}
else {
// error, or redisplay the CAPTCHA
}
The static captcha:: class functions do not print an error message themselves. But you have to integrate the ::solved() function into your form processing logic anyhow.
You can of course also instantiate the real "easy_captcha" class yourself, but typically the static "captcha" API is all you need.
Instead of embedding the CAPTCHA with an existing form, you could of course create a pre-check page - in multi form wizards. It was then for example up to you to transfer the solved-state, and prevent repeated loops or circumvention methods.
Enhancements:
- This version is almost completely rewritten, but retains the simple API.
- A new default drawing mode was added.
- It allows fuzzy solutions and gives feedback via "AJAX".
- The textual riddle was changed into a math question.
- It now manages temporary files to track CAPTCHA solving extensively, but retains support for optional time-tagged pass cookies.
- Logging and URL-triggered activation was added.