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 ...

If you’ve been online, you’ve at some point encountered some kind of Captcha, where you have to decode warped-looking letters and numbers. I don’t know about you, but these have been getting harder ...

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.