Candidate: Radi Abubaker
Title: Novel Physical-Layer Protocols for detecting Relay Attacks using the Channel State
Date: December 10, 2024
Time: 12:30 PM
Place: EIT 3151-53
Supervisor(s): Gong, Guang
Abstract:
A relay attack is a set of simple, but powerful attacks that can be used to circumvent entity authentication protocols. Through the forwarding of legitimate and real-time messages, relay attacks can cause unexpected authentications to occur, despite the use of modern cryptographic methods, such as digital signatures and message authentication codes. Relay attacks are primarily used by attackers to fraudulently authenticate cyber-physical systems, leading to undesirable responses in the real-world. For example, the relay attack can be used to start vehicles, activate payment systems, and illegally access secured areas. Current solutions are not widely tested and come with trade-offs, which motivates the use of the wireless channel of the physical-layer of communications in wireless systems as a novel prospect for detecting relay attacks.
This thesis details the theory, motivation, design, and implementation of four physical-layer protocols that can individually detect either a decode-and-forward or an amplify-and-forward relay attack, occurring in a wireless challenge-response entity authentication protocol. Each protocol utilizes different aspects of the wireless channel to perform the detection. The first proposed protocol leverages channel reciprocity to detect a decode-and-forward relay attack. The second proposed protocol generalizes detection to non-reciprocal channels to detect decode-and-forward relay attacks under more adversarial conditions.
The third proposed protocol utilizes the change in distribution of a relayed channel as a feature to detect amplify-and-forward relay attacks. The fourth proposed protocol utilizes a deep neural network to generalize feature selection to detect an amplify-and-forward relay attack. Each protocol builds on work from prior physical-layer research, but introduces novel ideas to handle attacks that have not been well explored.
To evaluate the performance of these protocols, this thesis performs Monte-Carlo simulations, hardware implementations on software defined radios, and theoretical performance evaluations. These results show practically that physical-layer based relay attack detection using the wireless channel is capable of robustly detecting relay attacks, while simultaneously providing ubiquitous high-throughput data communications, which other potential solutions lack.
The thesis is organized into nine chapters. The first three chapters details the background and motivations of the relay attack. The next five chapters focuses on the protocol designs and their theoretical performance evaluation. The last chapter details the hardware implementation on embedded software-defined radios and the novel processes required to implement the protocols.