Today at SXSW, Ian Muir led a brief discussion on how to prevent captcha cracking. One of the problems with any technical solution is that any human can still “crack captchas” for the wrong reasons: either because they are paid to by spammers, or tricked into cracking the captcha by the spammers (in exchange for free porn in some cases!)
The only way we’ll ever be able to prevent the abuse of other humans to aid the spammers is to de-incentivize the spammers & the humans they use for their nefarious goals.
In the cracking-captchas-to-access-porn case, here’s my solution:
Randomly add the following text to different areas of the captcha:
“You can find high quality free porn at http://someurl.com”
Why crack captchas for porn when you know where to get it for free?
Next up, we need to prevent the abuse of poor foreigners to crack captchas. To solve this, add the following text to the captcha:
“You can be paid more to work at Amazon’s mechanical turk at thisurl.com”
I think this would be a great win for our side in the captcha/spam arms race.