Scribble-a-Secret: Similarity-Based Password Authentication Using Sketches

Authors:
Mizuki Oka, Kazuhiko Kato, University of Tsukuba
Yingqing Xu, Lin Liang, Fang Wen, Microsoft Research Asia

Summary:
A graphical password scheme which allows user to sketch a password( sequence of strokes does not matter).
Edge Orientation Pattern feature: This feature is known for its robustness in recognition. It accommodates change in direction and spatial orientation. The image captured from user input is characterized by R orientations and then reduced to N orientations. Larger R results in less robustness. So it is reduced to N which is trade off between variation capturing and robustness.

Template creation: The templates are matched to user data using correlation factor. Given a set of edge orientation pattern, the correlation factor with the template is calculated.
The evaluation was done using 87 users. The effectiveness of edge orientation and blurring were studied. The false +ve and -ve rates were studied.

Disccusion:
The scheme looks similar to the Brendon's idea of searching photos with Annotation. Why not show the user an image he knows and ask him to draw a sketch . Can this be used as the password?
About this idea, there are a lot of things that needs to be measured. How many passwords can a user remember at a time? Average(time) retaining power of the user, time to set up a password, variations in password set by single user,...