CAPCHA as Graphical Password

The most common computer authentication method is to use alphanumerical usernames and passwords. This method has been shown to have significant drawbacks. For example, user tends to pick a passwords that can be easily guessed. On the other hand, if a password is hard to guess, then it is often hard to remember. In this paper, we conduct a comprehensive survey of the existing graphical password techniques and captcha. Using hard AI problems for security is emerging as an exciting new paradigm, but has been underexplored. In this paper, we present a new security primitive based on hard AI problems, graphical password systems built on top of Captcha technology, which we call Captcha as graphical passwords (CaRP). CaRP is both a Captcha and a graphical password scheme .We discuss the strengths and limitations of each method and point out the future research directions in this area. And also major design and implementation issues are clearly explained. The main advantage of this method is it is difficult to hack. Keywords—Graphical password , password, CaRP, Captcha, dictionary attack, password guessing attack, security primitive.