The security of authentication is based on password strength, and computer security depends on largely passwords to provide security. A secure password must be long and random, but it is difficult for users to remember passwords. Thus, users tend to choose short or simple passwords. Graphical password is a scheme consisting of clicking on image instead of typing password, it may help users to create easy, memorize easy and have a secure passwords. However, graphical password system is based on the images which can provide large password space; however, too many images will become a big problem to database storage. In this thesis, we improve a graphical system called ?PassPoints? and use the steganoaphy techniques to overcome the problem of database storage and provide more secure graphical password scheme than PassPoints. All the information hiding scheme can realize our scheme to build a secret key between users and server to solve the problem of database storage and propose a secure communication protocol to resist attacks on the internet.
