Do Background Images Improve “Draw a Secret” Graphical Passwords?

Dunphy, P. and Yan, J. 2007. Do background images improve "draw a secret" graphical passwords?. In Proceedings of the 14th ACM Conference on Computer and Communications Security (Alexandria, Virginia, USA, October 28 - 31, 2007). CCS '07. ACM, New York, NY, 36-47.

Summary

The authors use DAS passwords in conjunction with background images in order to improve the complexity of the passwords without harming user recall. A user would typically choose a small portion of an image to draw on, which could increase the complexity of the password if the image itself was complex.

The paper contains great user studies focusing on the recall of passwords, the complexity of images, what images users chose to draw on, and what recall errors occurred.


Discussion

This is another DAS paper, and, like the previously blogged one, shows how much room the graphical password field has to grow. The studies in this paper were phenomenally thorough, and if we ever start a sketching passwords project this is the paper we should all read.

Graphical Passwords & Qualitative Spatial Relations

Lin, D., Dunphy, P., Olivier, P., and Yan, J. 2007. Graphical passwords & qualitative spatial relations. In Proceedings of the 3rd Symposium on Usable Privacy and Security (Pittsburgh, Pennsylvania, July 18 - 20, 2007). SOUPS '07, vol. 229. ACM, New York, NY, 161-162.

Summary

The authors modify the Draw-a-Secret (DAS) scheme where users draw a graphical password in a grid so that the "looking over the shoulder" phenomenon could be reduced. A DAS password is a simple encoding of a drawn stroke using a grid and directions, such as up, right, up.

The extended abstract presents a Qualitative Draw-a-Secret (QDAS) scheme that changes DAS by first assigning a number to each grid. Then, the grid itself varies based on the direction changes of the stroke. The grid changes based on cell height and width.

Discussion

Although this extended abstract wasn't too informative, it did give me some thoughts about how we could use sketch recognition techniques to improve upon drawn passwords.