Theodoros Spyridopoulos

Dr. Theodoros Spyridopoulos


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2013 in Computers & Security
Verified
Journal Article
Closed access
TSTheodoros Spyridopoulos
Theodoros Spyridopoulos
GKG. Karanikas
G. Karanikas
TTTheo Tryfonas
Theo Tryfonas
GOGeorge Oikonomou
George Oikonomou

30 September 2022
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Book Chapter
Closed access
PDF file
OBOthmane Belarbi
Othmane Belarbi
AKAftab Aslam Parwaz Khan
Aftab Aslam Parwaz Khan
PCPietro Carnelli
Pietro Carnelli
TSTheodoros Spyridopoulos
Theodoros Spyridopoulos

1 January 2013
Verified
Conference Paper
Closed access
TSTheodoros Spyridopoulos
Theodoros Spyridopoulos
JMJ. May
J. May
TTTheo Tryfonas
Theo Tryfonas

3 December 2024 in Future Internet
Verified
Journal Article
Open access
PDF file
MAMuzun Saleh Althunayyan
Muzun Saleh Althunayyan
AJAmir Javed
Amir Javed
Omer RanaOmer Rana
Omer Rana
TSTheodoros Spyridopoulos
Theodoros Spyridopoulos
Intrusion detection systems (IDSs) are crucial for identifying cyberattacks on in-vehicle networks. To enhance IDS robustness and preserve user data privacy, researchers are increasingly adopting federated learning (FL). However, traditional FL-based IDSs depend on a single central aggregator, creating performance bottlenecks and introducing a single point of failure, thereby compromising robustness and scalability. To address these limitations, this paper proposes a Hierarchical Federated Learning (H-FL) framework to deploy and evaluate the performance of the IDS. The H-FL framework incorporates multiple edge aggregators alongside the central aggregator, mitigating single-point failure risks, improving scalability, and efficiently distributing computational load. We evaluate the proposed IDS using the H-FL framework on two car hacking datasets under realistic non-independent and identically distributed (non-IID) data scenarios. Experimental results demonstrate that deploying the IDS within an H-FL framework can enhance the F1-score by up to 10.63%, addressing the limitations of edge-FL in dataset diversity and attack coverage. Notably, H-FL improved the F1-score in 16 out of 24 evaluated scenarios. By enabling the IDS to learn from diverse data, driving conditions, and evolving threats, this approach substantially strengthens cybersecurity in modern vehicular systems.

6 June 2024 in IoT
Verified
Journal Article
Open access
PDF file
EAEirini Anthi
Eirini Anthi
LWLowri Williams
Lowri Williams
VIVasilis Ieropoulos
Vasilis Ieropoulos
TSTheodoros Spyridopoulos
Theodoros Spyridopoulos
With the increase in the adoption of Internet of Things (IoT) devices, the security threat they face has become more pervasive. Recent research has demonstrated that most IoT devices are insecure and vulnerable to a range of cyber attacks. The impact of such attacks can vary significantly, from affecting the service of the device itself to putting their owners and their personal information at risk. As a response to improving their security, the focus has been on attacks, specifically on the network layer. However, the importance and impact of other vulnerabilities, such as low-level Radio Frequency (RF) attacks, have been neglected. Such attacks are challenging to detect, and they can be deployed using non-expensive equipment and can cause significant damage. This paper explores security vulnerabilities that target RF communications on popular commercial IoT devices such as Wi-Fi, Zigbee, and 433 Mz. Using software-defined radio, a range of attacks were deployed against the devices, including jamming, replay attacks, packet manipulation, protocol reverse engineering, and harmonic frequency attacks. The results demonstrated that all devices used were susceptible to jamming attacks, and in some cases, they were rendered inoperable and required a hard reset to function correctly again. This finding highlights the lack of protection against both intentional and unintentional jamming. In addition, all devices demonstrated that they were susceptible to replay attacks, which highlights the need for more hardened security measures. Finally, this paper discusses proposals for defence mechanisms for enhancing the security of IoT devices against the aforementioned attacks.

1 July 2011 in International Journal of Digital Crime and Forensics
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Journal Article
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PDF file
TSTheodoros Spyridopoulos
Theodoros Spyridopoulos
Vasilios KatosVasilios Katos
Vasilios Katos
This paper examines the feasibility of developing a forensic acquisition tool in a distributed file system. Using GFS and KFS distributed file systems as vehicles and through representative scenarios and examples, the authors develop forensic acquisition processes and examine both the requirements of the tool and the distributed file system must meet in order to facilitate the acquisition. The authors conclude that cloud storage has features that can be leveraged to perform acquisition (such as redundancy and replication triggers) but also maintains a complexity, which is higher than traditional storage systems leading to a need for forensic-readiness-by-design.