The recent technological progresses make sensor networks feasible to be widely used in both military and civilian applications. The nature of such networks makes energy consumption, communication delay and security the most essential issues for wireless sensor networks. However, these issues may be conflicting with each other. The existing works generally try to optimize one of these key issues without providing sufficient diversity and flexibility of various other requirements in protocol design. In this dissertation, we investigate the relationship and design trade-offs among these conflicting issues.To deal with the lifetime optimization and security issues, we propose a novel secure and efficient Cost-Aware SEcure Routing (CASER) protocol to address them through two adjustable parameters: energy balance control (EBC) and security level to enforce energy balance and increase lifetime and determine the probabilistic distribution of random walking that provides routing security. We derive a tight numerical formula to quantitatively estimate the routing efficiency through the number of routing hops for a given routing security level. We also prove that CASER scheme can provide provable security under the quantitative security measurement criteria. Simulation results also show that the proposed CASER scheme can provide an excellent balance between routing efficiency and security while extending the network lifetime.We then discover that the energy consumption is severely disproportional to the uniform energy deployment for the given network topology. To solve this problem, we propose an efficient non-uniform energy deployment strategy to optimize the network lifetime and increase the message delivery ratio under the same energy resource and security requirements. Our theoretical analysis and OPNET simulation results demonstrate that the updated CASER protocol can provide an excellent trade-off between routing efficiency and energy consumption, while significantly extending the lifetime of the sensor networks in all scenarios. For the non-uniform energy deployment, our analysis shows that we can increase the lifetime and the total number of messages that can be delivered by more than four times under the same energy deployment, while achieving a high message delivery ratio and preventing routing traceback attacks.In WSNs, congestion introduces not only buffer overflow, but also communication delay for forwarding messages from the source node to the sink. We propose a novel congestion-aware routing (CAR) scheme to reduce the end-to-end communication delay while increasing network throughput. CAR employs two routing strategies, shortest path routing strategy and congestion-aware strategy, to achieve a trade-off between energy efficiency and communication delay. The OPNET simulation results demonstrate that the proposed routing scheme can reduce the end-to-end communication delay by 50% while increasing the network throughput by more than two times in our settings.People-centric urban sensing is envisioned as a novel urban sensing paradigm. Security, communication delay and delivery ratio are essential design issues in people-centric urban sensing networks. To address these three issues concurrently, we propose a novel delay-aware privacy preserving (DAPP) transmission scheme based on a combination of two-phase forwarding and secret sharing. The two-phase forwarding method detaches connection between the application data server and the source nodes, which renders it infeasible for the application data server to estimate source node identities. The underlying secret sharing scheme and dynamic pseudonym ensure confidentiality of the collected data and anonymity of participating users. DAPP provides a framework to achieve a design trade-off among security, communication delay and delivery ratio. The security analysis demonstrates that DAPP can preserve location privacy while defending against side information attacks. Theoretical analysis and simulation results show that our proposed algorithms can provide a flexible and diverse security design option for routing and data forwarding algorithm design.
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