10.6. Acknowledgments

This material is based upon work supported by National Institute of Standards and Technology Computer Security Division; by Homeland Security Advanced Research Projects Agency under the contract FA8750-05-C-0212 administered by the Air Force Research Laboratory/Rome; by Air Force Research Laboratory/ Rome under the contract FA8750-06-C-0246; by Army Research Office under grant W911NF-05-1-0374; by Federal Aviation Administration under the contract DTFAWA-04-P-00278/0001; by National Science Foundation under grants CT-0627493, IIS-0242237, and IIS-0430402; and by Natural Sciences and Engineering Research Council of Canada under Discovery Grant N01035. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsoring organizations. The authors are grateful to the anonymous reviewers for their valuable comments.