Bruce Kirchoff David Remington Lixin Fu Fereidoon Sadri A New Type of Image-Based Key. 825-829 2008 BMEI (1) http://doi.ieeecomputersociety.org/10.1109/BMEI.2008.301 conf/bmei/2008-1 db/conf/bmei/bmei2008-1.html#KirchoffRFS08