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- 1Attack resistance
- 1Human readability
- 1Optical character recognition
- 1Random field
- 1Security
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Fall 2014
Web security has become a critical issue due to the rising reliance of people on diverse types of online transactions. A CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a security mechanism that is widely used to maintain the security of web services by...
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Fall 2012
In this thesis, we develop a novel method of generating CAPTCHAs, which are used to protect online resources from abuse by computer agents. We view CAPTCHA generation as random field simulation and construct a CAPTCHA by evolving an initial state via resimulating pixels until the image becomes...