Date of Award


Degree Name

Doctor of Philosophy


Computer Science

First Advisor

Dr. Leszek Lilien

Second Advisor

Dr. Ala Al-Fuqaha

Third Advisor

Dr. Ikhlas Abdel-Qader


The paradigm of Opportunistic Resource Utilization Networks (oppnets) advances technology in the field of ad hoc networks. The salient feature of oppnets is their use of “helpers” to expand opportunistically when the need for more resources or capabilities arises. Like any other pervasive computing systems, oppnets face numerous security and privacy challenges. These challenges are addressed by utilizing two major ideas: Pervasive Trust Foundation (PTF) and Active Data Bundles (ADBs). The PTF paradigm makes trust the basis for security and privacy in pervasive computing systems, including oppnets. The ADBs are self-protecting data constructs that encapsulate together—in an inseparable way—sensitive data, metadata (including privacy and other policies), and a virtual machine (including a policy enforcer).

We propose a Secure Privacy-Preserving Oppnet (SP2O) system, which integrates two smaller systems also proposed here: PTF-based Oppnets Architecture (POA) and ADB-based Oppnet Scheme (AOS). We present conceptual designs for the POA and AOS systems. POA ensures secure interactions among various oppnet entities in the face of its ad hoc growth. AOS protects sensitive data exchanged among all entities of an oppnet during its entire lifecycle. The proposed work is targeted at investigating the feasibility and effectiveness of the proposed SP2O system.

We evaluate SP2O using trust ratings for oppnet components within the SP2O framework, comparing SP2O to a baseline system – one not using trust ratings. Simulation experiments, implemented using C#, consider performance overhead introduced by SP2O. The experiments use two measures: success rates in completing a job and average times to complete a job. (The job involves using an oppnet in an emergency scenario in which a passerby needs the 9-1-1 service but is unable to call it herself.) The results show that SP2O introduces a 20% overhead (decrease) in success rates and a 23% overhead (increase) in average times to succeed. These overheads are the cost paid for improving security in terms of protecting SP2O from attacks by admitted helpers. Therefore, we have a tradeoff between a security gain and a system performance cost.

Access Setting

Dissertation-Campus Only

Restricted to Campus until