New method to avoid hacking of "captcha" security codes

Washington, Dec 30 (ANI): Researchers at Tel Aviv University have found 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 and newsletter sign-up forms to prevent computer robots from hacking into servers and databases.

While these codes are becoming increasingly complicated for an average person to use, they are not immune to security holes.

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.

Cohen-Or said that 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.

He said that 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," as defined by the researchers, is a unique human ability to collect fragments of seemingly useless information, then synthesize and perceive it as an identifiable whole. So far, computers don't have this skill.

"Computer vision algorithms are completely incapable of effectively processing emergence images," said Cohen-Or's faculty colleague 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.

"We're not claiming in our research paper that we've developed a whole new captcha technology. But we are taking a step towards that - something that could lead to a much better captcha, to highlight the big difference between men and bots. If it were to be turned into a solution, however, we wouldn't be able to give humans a multiple choice answer or common word answer for what they see, so we'll need to develop a way to use it. We have a few ideas in the works," said Cohen-Or.

The study was presented at a recent SIGGRAPH conference. (ANI)