A NEW AUTHENTICATION SCHEME FOR SECURITY USING CAPTCHA PASSWORD

Many security primitives are based on hard mathematical problems. Using hard AI problems for security is emerging as an exciting new paradigm, but has been under - explored. In this paper, we present a new security primitive based on hard AI problems, namely, a novel family of graphical password systems built on top of Captcha technology, which we call Captcha as graphical passwords (CaGP). CaGP is both a Captcha and a graphical password scheme . CaGP addresses a number of security problems altogether, such as online guessing attacks, relay attacks, and, if combined with dual - view technologies, shoulder - surfing attacks. Notably, a CaGP password can be found only probabilistically by automatic onl ine guessing attacks even if the password is in the search set. CaGP also offers a novel approach to address the well - known image hotspot problem in popular graphical password systems, such as PassPoints, that often leads to weak password choices. CaGP is not a panacea, but it offers reasonable security and usability and appears to fit well with some practical applications for improving online security.