Man, captchas suck.
I think we all agree that captchas are fairly useless and more often than not cause more annoyance than good.
Most captchas are easily broken if someone sets their mind to it. Especially the one that came with this blog script! And even if they do stop bots they also stop blind or visually impaired people from using your system too.
But they are an unfortunate necessity, especially on the high traffic parts of my site like the mini polls where there's currently a captcha I hand coded especially for the mini polls. And so far I'm shocked to say I've not had any spam on there except the usual human spam.
However, today I have constructed an uber-captcha, which I quite like. It is slightly hard to read though.
This new one uses just PHP, no separate app (not possible on this server) or anything like that, and it generates an animated GIF file where every frame is totally unreadable, but when animated together it becomes readable to the human eye.
That's the idea anyway. I might have gone a bit overboard with methods to try and stop people using image filters on layers to get readable text again and it's now fairly hard to read: (hit esc in Firefox to stop it looping and see how messed up a single frame is)
Anyway, feedback would be great on this. Any ideas on what I could do to make it more readable, yet still being awkward to crack.
Also, anyone who cracks it with their own code (no script kiddies) wins a free sandwich
Fancy code or code in an esoteric language gets you a coke to go with your sandwich!
To play around with it and see what percentage of them you get right go to http://sandbox.palmnet.me.uk/gifcaptcha/, let me know what scores you get in the comments.