Design And Implementation Of A Novel Graphical Password Strategy Based On Image-Redrawing

Alphanumeric passwords are popular in authentication, however, short and simple alphanumeric passwords are susceptible to attack, while long and complicated ones are hard to remember. Therefore, alphanumeric passwords can hardly meet the requirement of both memoribility and security. Graphical password schemes can solve the problem effectively as pictures always contain a large amount of information and people possess a remarkable better ability for recalling pictures than words. Draw-A-Secret (DAS) is a typical graphical password scheme based on user drawing, which records the coordinates of cells the stylus passes through and judges the user's legitimacy by matching user drawings. However, DAS has many drawbacks and provides low user experience, so it doesn't receive wide application actually.A novel graphical password strategy Yet Another Graphical Password (YAGP) inspired by DAS is proposed in this paper. YAGP adopts finer granularity, sets new coding rules, and brings up the idea of trend quadrants. YAGP can record the trends of user drawings, and divide the drawings according to their trends. The similarity of two user's drawings is estimated in YAGP in order to judge the user's legitimacy. Besides the principle, the design and implementation of YAGP are also introduced in this paper, and several experiments are made in order to determine some key parameters as well. The result of analysis and experiments illustrates that YAGP achieves better performance in usability, security and memorability.