1. Concordia Institute for Information Systems Engineering, Concordia University, Quebec, Canada. E-mails: n_alheb@ciise.concordia.ca, wang@ciise.concordia.ca
2. Faculty of Computing and Information Technology, King Abdulaziz University, Jeddag, KSA
3. Center for Secure Information Systems, George Mason University, VA, USA. E-mail: jajodia@gmu.edu
4. Computer Security Division, National Institute of Standards and Technology, MD, USA. E-mail: anoop.singhal@nist.gov