Minimum-cost Network Hardening, Steven E. Noel, Sushil Jajodia, Brian C. O'Berry, Michael A. Jacobs, US 7,555,778, June 30.2009

Fingerprinting and Recognition of Data, Neil Johnson, Zoran Duric, and Sushil Jajodia, US 7,127,106 B1, October 24, 2006