I'm currently looking around for a php based alternative to CAPTCHA style turing tests for web forms.

For various reasons standard CAPTCHA style is unsuitable for my current project, and I've been looking around - a variant of the KittenAuth or Human Auth looks promising, particularly the scope for branding this style up with your own image sets but before I make a decision are there any others I should look at?

I just had a google for "KittenAuth" neat idea, takes up alot of webpage space compared to captcha

I think a random logic question is also a good way. and also it means that it should keep some of the complete morons out your site too

I would do some mathematic script...

It would generate a random set of numbers, figure out the answer, then check to make sure that the answer that you provided it correct. It doesn't sound that hard to make.

The best thing to do:

Put a blank field, and hide it with CSS. If it's filled in a bot is using the form.

Time stamps work well also, to make a timestamp get the time (using time() function), md5 it. Put it in a session, then post the timestamp. On the process page check if there the same, if they are all's good, otherwise die() the script.

http://www.webmaster-talk.com/php-fo...-top-tips.html - More information