Design And Implementation Of A Novel Recognition-Based Graphical Password Scheme

Alphanumeric passwords are the most popular authentication methods, but they can hardly meet the requirements of both high security and memorability at the same time. Compared with the traditional alphanumeric passwords, the newly emerging graphical passwords take full advantage of the large amount of information and better memorability of pictures, and achieve better performance in usability, memorability and security. Of the existing graphical passwords types, recognition-based graphical passwords can provide the simplest authentication process and the most precise authentication result, and the only thing that users need to do is to choose pass-images from graphics set. What is more, people's ability of graphics recognition is not restricted to factors like educational background and intellectual level. Therefore, recognition-based graphical passwords can be widely used. There have already been several recognition-based graphical password schemes available nowadays, however, various defects can be found in these schemes such as low security which restricts the advantages of graphical passwords a lot.A novel graphical password scheme ColorLogin is proposed in this paper. ColorLogin introduces the background colors of images into the authentication process for the first time, which contributes to the user's selection of pass-images and the reduction of authentication time. To satisfy different requirements of system security, ColorLogin offers different security levels. In addition, there are different image libraries corresponding to different passwords security levels which can prevent ColorLogin from being attacked by intersection analysis. Besides the principles mentioned above, winlogon of Windows XP is analyzed and ColorLoginGina is implemented to instead the standard GINA. At last, a series of experiments are conducted, and the experiment results as well as the analysis illustrate that ColorLogin can achieve better performance in usability, security and memorability.