New method to avoid hacking of 'captcha' security codes
By siliconindia   |   Thursday, 31 December 2009, 21:53 IST   |    2 Comments
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New method to avoid hacking of 'captcha' security codes
Washington: A new way to fix the security holes linked with the popular 'captcha' security mechanism - wavy letters websites ask us to type into a box - used by web pages to prevent computer robots from hacking into servers - has been found by researchers at the Tel Aviv University. While these codes are becoming increasingly complicated for use, they are not immune to security holes, reports ANI. A research project led by Prof. Danny Cohen-Or of Tel Aviv University's Blavatnik School of Computer Sciences demonstrates how a new kind of video captcha code may be harder to outsmart. According to Cohen-Or, the foundation of the work is really pure research, but it opens the door so security researchers can think a little differently. "Humans have a very special skill that computer bots have not yet been able to master. We can see what's called an 'emergence image' - an object on a computer screen that becomes recognizable only when it's moving - and identify this image in a matter of seconds. While a person can't 'see' the image as a stationary object on a mottled background, it becomes part of our gestalt as it moves, allowing us to recognize and process it," said Cohen-Or. In the new study, co-authored with colleagues in Taiwan, Saudi Arabia and India, Cohen-Or has described a synthesis technique that generates pictures of 3-D objects, like a running man or a flying airplane. The technique will allow security developers to generate an infinite number of moving 'emergence' images that will be virtually impossible for any computer algorithm to decode. Emergence is a unique human ability to collect fragments of seemingly useless information, then synthesize and perceive it as an identifiable whole. At present, computers don't have this skill. "Computer vision algorithms are completely incapable of effectively processing emergence images," said Dr. Lior Wolf, a Co-author of the study. The scientists have warned that it will take some time before this research can be applied in the real world, but they are currently defining parameters that identify the 'perception difficulty level' of various images that might be used in future security technologies.

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