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New Puzzles That Tell Humans From Machines
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To stay one jump ahead of fraudsters and their automated rogue programs, researchers are devising more versions of CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) puzzles to help Web sites block abuse that includes spam e-mail, illegal postings and skewed online voting. Researchers at Google are testing a new CAPTCHA that requires people to turn upright randomly rotated images, like that of a parrot perched temporarily upside-down on a branch. The task is a breeze for people — using a cellphone touchscreen, for example, to flip the image — but hard for machines.
From The New York Times
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