Master of Science in Computer Science (MSCS)


Computer Science

Document Type



The proliferation of a range of wireless devices, from the cheap low power resource starved sensor nodes to the ubiquitous cell phones and PDA's has resulted in their use in many applications. Due to their inherent broadcast nature Security and Privacy in wireless networks is harder than the wired networks. Along with the traditional security requirements like confidentiality, integrity and non-repudiation new requirements like privacy and anonymity are important in wireless networks. These factors combined with the fact that nodes in a wireless network may have different resource availabilities and trust levels makes security in wireless networks extremely challenging. The functional lifetime of sensor networks in general is longer than the operational lifetime of a single node, due to limited battery power. Therefore to keep the network working multiple deployments of sensor nodes are needed. In this thesis, we analyze the vulnerability of the existing key predistribution schemes arising out of the repeated use of fixed key information through multiple deployments. We also develop SCON, an approach for key management that provides a significant improvement in security using multiple key pools. SCON performs better in a heterogeneous environment. We present a key distribution scheme that allows mobile sensor nodes to connect with stationary nodes of several networks. We develop a key distribution scheme for a semi ad-hoc network of cell phones. This scheme ensures that cell phones are able to communicate securely with each other when the phones are unable to connect to the base station. It is different from the traditional ad hoc networks because the phones were part of a centralized network before the base station ceased to work. This allows efficient distribution of key material making the existing schemes for ad hoc networks ineffective. In this thesis we present a mechanism for implementing authenticated broadcasts which ensure non-repudiation using identity based cryptography. We also develop a reputation based mechanism for the distributed detection and revocation of malicious cell phones. Schemes which use the cell phone for secure spatial authentication have also been presented.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Arjan Durresi