Graphical passwords have been proposed as an alternative to textual passwords, due to its complexity that users are having in remembering their password combination. Graphical password was introduced by Blonder in 1996, which was easier to remember because of its graphical content.
Therefore usability and memo ability are improved. In this paper, we propose and develop a new graphical password called GPBSDI (Graphical Password Based on Sub and Decoy Images) for user authentication.