Requirements for secure graphical password schemes

Visual or graphical passwords have been proposed as possible alternatives to alphanumeric passwords. People can remember these better and for longer periods than they can alphanumeric passwords. Visual passwords can, however, not yet be readily adopted for use due to the disadvantages associated with them. There has therefore been a move in literature to discussions on efficient implementation of visual password schemes. This paper analyses the current challenges in the design of visual password schemes as well as the factors affecting security and usability of such schemes. The paper further presents requirements of a visual password scheme providing ease of use, a large enough password space and secure password images.