Merging CAPTCHA and Graphical Password on NP Hard Problems in AI: New Security Enhancing Technique

CAPTCHA (Completely Automated Public Turing Test to tell computers and human apart) is a test build by computer programs which human can pass but computer programs cannot pass. A new technology is built over the captcha called graphical captcha which is resilient to dictionary attacks and hence more secure. With the hybrid use of CAPTCHA and graphical password one can addresses a number of security problems such as relay attacks, online guessing attacks and also shoulder surfing attacks. CaRP (Captcha as a graphical password) is not act as a cure all technique but it stipulates security and usability to legitimate users in real time applications.