PALO ALTO--A team of Stanford University researchers has bad news to report about Captchas, those often unreadable, always annoying distorted letters that you're required to type in at many a Web site ...

A core security mechanism that keeps us all safe online is likely to fail within the next few years. This could cause a massive rekeying of websites and big shifts in how we approach online security.

One of the most annoying Internet experiences is having to deal with CAPTCHA and decode distorted text on a website to prove you are not a robot. But now, Google says it can tell you’re human just by ...