Secure and Reliable Code Dissemination for Wireless Sensor Networks.

摘要

Wireless sensor networks are considered ideal candidates for a wide range of applications, such as industry monitoring, data acquisition in hazardous environments, and military operations. It is desirable and sometimes necessary to reprogram sensor nodes through wireless links after they are deployed, due to, for example, the need of removing bugs and adding new functionalities. The process of propagating a new code image to the nodes in a wireless sensor network is commonly referred to as code dissemination. Code dissemination requires reliable delivery of code images through lossy wireless channels, typical in wireless sensor networks. In addition, code dissemination must be protected from various malicious attacks to ensure both integrity and availability of the remote programming service. This thesis includes three studies for efficient, secure, and reliable code dissemination in wireless sensor networks.;First, we present the design, development, and evaluation of a secure and DoS-resistant code dissemination system named Seluge for wireless sensor networks. Seluge is a secure extension to Deluge , a de facto code dissemination system for wireless sensor networks. It provides security protections for code dissemination, including the integrity protection of code images and resistance to various DoS attacks that exploit code dissemination protocols. Seluge is superior to all previous attempts for secure code dissemination, and is the only solution that seamlessly integrates the security mechanisms and the Deluge efficient propagation strategies. Besides the theoretical analysis that demonstrates the security and performance of Seluge, we also reports the experimental evaluation of Seluge in a network of MicaZ motes, which shows the efficiency of Seluge in practice.;Second, we present a channel migration scheme, which can be used to mitigate wireless jamming attacks against code dissemination in wireless sensor networks. By exploiting the multiple wireless channels typically available on the existing wireless sensor platforms, our scheme uses a flexible and resilient approach to switch communication channels, which enables sensor nodes to continue the normal code dissemination operations in the presence of jamming attacks. A nice property of the proposed scheme is that it does not depend on any single, fixed channel and executes in a decentralized and independent way on each sensor node. To enhance the jamming resilience of Seluge and investigate the effectiveness of the proposed channel migration scheme, we apply the channel migration scheme to Seluge, and evaluate the resulting protocol through both theoretical analysis and experimental evaluation in a testbed of MicaZ motes. Both results indicate that our channel migration scheme can effectively and efficiently mitigate jamming attacks.;Third, we present the design, implementation, and evaluation of an efficient, reliable, and secure code dissemination scheme called FEC-Seluge, which integrates forward error correction (FEC) into Seluge to improve the efficiency while preserving the same level of security protection as in Seluge. At the heart of FEC-Seluge is a novel proactive transmission mechanism, which achieves both efficiency and loss-tolerance in code dissemination. To balance the efficiency and loss-tolerance capabilities, we develop a technique to estimate the optimal amount of redundancy in proactive transmission for a given network condition. We evaluate FEC-Seluge through experiments in a testbed environment. The experimental results show that FEC-Seluge achieves much better performance than both Seluge and LR-Seluge, an existing FEC extension to Seluge.