A graphical password is an authentication system that works by having the user select from images, in a specific order, presented in a graphical user interface (GUI). For this reason, the graphical-password approach is called graphical user authentication (GUA). The most common computer authentication method is to use alphanumerical usernames and passwords. This method has been shown to have significant disadvantages. For e.g, users tend to choose passwords that can be easily guessed. On the other hand, if a password is difficult to guess, then it is often difficult to remember. To overcome this problem of low security, Authentication methods are developed by researchers that use images as password. In this research paper, we conduct a comprehensive survey of the existing graphical password techniques and provide a possible theory of our own. Graphical password schemes have been proposed as a possible alternative to text-based schemes, by the fact that humans can remember pictures better than text; Pictures are generally easier to be remembered or recognized than text.

Keywords: Password, Graphical, Authentication.