A Comprehensive Survey on CAPTCHA and VRP

A Lot of security primitives are based on hard challenges that are solvable only by mathematical formulations. Use of Difficult AI problems for security has become an evolution for a new paradigm of security, but still left underexplored. In this paper, we will noticeably present a new security primitive based on hard AI problems, namely, a novel family of graphical password systems built on the basis of Captcha technology, which we call Captcha as graphical passwords (CaRP). CaRP is a complex combination of Captcha and a graphical password style. CaRP addresses a number of security problems altogether, such as online guessing attacks, relay attacks, and, if combined with dual-view technologies, shoulder-surfing attacks. CaRP alone becomes inefficient to prevent all security, hence this paper makes a survey of the various security measures for secure password schemes and gives a clear picture of the efficiencies of the different techniques. There is no panacea, but highly secure password offers reasonable security and usability and appears suit well with practical applications for improving online security.