CAPTCHAs are those now ubiquitous challenges you encounter to prove that you’re a human and not a bot when you go to log in to many websites. As a computer scientist, I see CAPTCHAs as an effective ...

You have probably seen Captchas - puzzles that ask you to pick out all the bicycles in an image or to decipher letters that are written in squiggly lines. These riddles are designed to let you buy ...

From Rorschach tests to trigonometry, this 48-level gauntlet is the most infuriating test of your humanity yet. Can you ...

Are you a human? It’s an age-old question made more pressing by the ability for millions of computers to shut down websites or snipe auctions out from under regular, non-robotic buyers. What’s more, ...

Researchers have found that bots are shockingly good at completing CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart), which are those small, annoying puzzles ...

A captcha is a security test that verifies a user's identity as human. CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart." Be aware that some captchas may ...

The Carnegie-Mellon University team behind the reCAPTCHA service is continuing to expand its effort to mix basic security and useful work. CAPTCHAs are the distorted text that helps various online ...

There was a good post on ZDNet recently talking about how a market has developed for the bulk-purchasing of Gmail, Hotmail and Yahoo email accounts (amongst others). The market rate seems to be around ...

[Image: Stanford University] You know those annoying boxes of jumbled, multicolored, slanted, crossed-out, or reversed text that are practically indecipherable to prove to a Website that you are human ...

Captchas are well known for keeping automated spammers out and letting humans in. However, ReCaptcha is a rather clever service using them to help digitize books scanned into the Internet Archive as ...