Date of Award

Fall 11-15-2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Computational Analysis and Modeling

First Advisor

Manki Min

Abstract

The rapid expansion of low-resource devices, coupled with advances in telecommunications, has significantly increased the number of connected devices and enabled the development of affordable, energy-efficient, portable, and high-performance sensors for diverse applications. However, this convenience comes with security and privacy concerns related to the reliability of hardware, software, and communication infrastructure. The extensive interconnectivity of limited-resource devices and the transmission of large data volumes pose significant security challenges in wireless networks. The future wireless technologies, such as 5G, will enable the transfer of critical data, including personal, financial, military, and industrial information, necessitating secure communication in wireless networks. Generally, security can be achieved through classical cryptography or physical layer security. Classical cryptography techniques and their associated protocols are commonly used to secure data transfers and distribute encryption keys. Nevertheless, in highly constrained environments, these algorithms are costly and inefficient to implement, thus unsuitable for providing cryptographic solutions. They introduce many challenges, including resource consumption and the management and distribution of keys to diverse resource-constrained devices. On the other hand, recent research has focused on leveraging the reciprocity and unpredictability of wireless fading channels for physical-layer security, enabling the generation of symmetric cryptographic keys that safeguard transmissions between two entities. However, current techniques are plagued by high bit-disagreement rates and poor randomness in the generated bits. In addition, cryptographic hash algorithms ensure the preservation of data integrity, even as attackers’ computational capabilities continue to advance. Lightweight cryptographic hash functions, a less complex variant of existing techniques, effectively address the challenges of securing communication in constrained devices, such as RFIDs and sensors, as well as in devices with abundant resources that interact with them, including machine-to-machine, machine-to-device, and device-to-device communication. Their applicability extends to other domains with similar characteristics. Therefore, this work introduces an improved quantization algorithm and a lightweight hash function for the physical-layer security protocols. The proposed key generation scheme was benchmarked using the NIST randomness test suite and compared against existing approaches. Additionally, the hash function was evaluated to assess its implementation cost, efficiency, and security properties. The analysis results demonstrate that the proposed hash function achieves excellent performance across multiple metrics.

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