PHP Captcha without session

Question

Ok, here is an issue: in the project i\'m working on, we can\'t rely on server-side sessions for any functionality.

The problem is that common captcha solutions fro

Answer 1

Make your hidden input field just a random sequence. Store this random data in the database along with the captcha information, so you can look up the correct captcha with it.

You will also need to set a short-ish time to live for each captcha generated. Finally, you can store and track in the database the number of attempts on each captcha and impose a hard limit on it (3 guesses and it is a permanent fail).