How to create a nice captcha
Oktober 22nd, 2008 • flash, idea
Surfing through the internet you propably often see captchas. Most captchas look like this or even uglier:
So what’s that capture thing about? These things shall protect the website from spam by bots. Bots are scanning the sourcecode of the page or using website snapshot techniques to automaticly fill out forms. So the text needs to be ugly otherwise the bot might “guess” the text rendered in the captcha image.
But:
I think there’s a better more pretty solution for that problem. Use Flash! The Idea: A swf gets the captcha via php and displays it. So sourcecode analysing wouldn’t help the bot. And the screenshot trick will not work too: Most screenshot scripts can’t see flash.
But if you want to be really save you just have to create a captcha swf that’s shown on click or fades in or similar animation techniques. With swfobject you can also provide a fallback method for non flash users.
So a captcha in my page (I’m not using any) could look like this:
So finally the web might become beautifull again. Ok well that’s way too optimistic, but the how to is now here. I’never tested this on a real project so I can just guess that it will work.