Graphical password system using scalable multi-grid method

Abstract

Textual password has been the basis of most authentication systems. In fact, overcoming the vulnerabilities of textual password have always been contentions. However, it has been the major attraction for crackers and attackers. On the other hand, users has always been facing difficulty for remembering a complex password which is considered as secure, thus most of the users are likely to create password which is simple, short and easy to remember. Therefore, graphical password system was invented as an alternative password scheme in order to solve this problem. In the current graphical password systems, there are several problems raised due to i) limited password spaces among existing schemes and ii) common problem of shoulder surfing attack. Thus, an improved scheme named Multi-Grid Background Pass-Go (MGBPG) has been proposed and implemented to alleviate the aforementioned problem. Before proposing the scheme, a classification of graphical password system is presented, analysed and synthesised along with some of related works in terms of its algorithm used, and their advantages and disadvantages. Subsequently, the proposed scheme is analysed and evaluated for its password space, shoulder surfing and dictionary attacks attenuation. From the analysis result, it has been proven that the proposed scheme is able to offer more password spaces (up to 676 selectable spots) as compared to other existing schemes. Moreover, it has been proven that the proposed scheme is able to resist shoulder surfing and dictionary attacks. In a nutshell, the comparative results of this research show that the proposed scheme has achieved the objectives of the study and defeated other existing schemes. As an additional advantage, the proposed scheme also offers better improvement by increasing user memorability by using the grid line scaling function in comparison to other existing schemes.