SDL Technical Report SRI-SDL-04-02 April 6, 2004 Lightweight Key Management in Wireless Sensor Networks by Leveraging Initial Trust Bruno Dutertre Steven Cheung Joshua Levy This research is sponsored by DARPA under contract number F30602-02-C-0212. The views herein are those of the authors and do not necessarily reflect the views of the supporting agency. System Design Laboratory 333 Ravenswood Ave. Menlo Park, CA 94025 (650) 326-6200 Facsimile: (650) 859-2844