Nowadays, user authentication is one of the important topics in information security. Authentication is necessary in multi-user systems. User name and password are used to authenticate a user. Text-based strong password scheme can provide security to a certain degree. Users tend to pick short passwords or passwords that are easy to remember, which makes the passwords vulnerable for attackers to break. Furthermore, textual password is vulnerable to shoulder-surfing, hidden camera and spy-ware attacks. Graphical authentication has been proposed as a possible alternative solution to text-based authentication, motivated particularly by the fact that humans can remember images better than text. However, they are mostly vulnerable to shoulder surfing. In this paper, we propose a Multi-level Scalable Textual-Graphical Password Authentication Scheme for web based applications. This scheme integrates both graphical and textual password schemes, and provides multi-level authentication scheme as compared to previously proposed single level scheme. In this scheme multi-level authentication is obtained by making use of SMS service, hence provides more secure service. This scheme shows significant potential bridging the gap between conventional textual password and graphical password. Further enhancements of this scheme are proposed and briefly discussed.
A Pattern-Based Password Authentication Scheme for Minimizing Shoulder Surfing Attack
