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Source Location Privacy for Wirless Sensor Networks

September 2014 – April 2018

Department of Computer Science, University of Warwick

Wireless sensor networks are useful for monitoring events over large areas for example, tracking the location of endangered species. However, by deploying this network to obtain data for conservation, it also reveals context information to an adversary about where the animals are. My PhD involved developing routing algorithms to delay an adversary in their attempt to locate the source of messages in such a network.

CAPRI

April 2018 – September 2018

WMG, University of Warwick

As connected and autonomous vehicles are expected to become commonplace on roads nationwide, new featured are being integrated into vehicles. This includes functionality such as vehicle-to-vehicle communication and machine learning models. It is important that we investigate and address security issues posed by the larger attack surface before a wide deployment. This project designed a reference architecture which facilitated attack surface analysis of connected autonomous vehicles.

IoT Transport and Mobility Demonstrator

August 2018 – May 2019

WMG, University of Warwick

With the vehicle-to-vehicle communications being used to facilitated new functionality, there is a need for new security mechanisms to protect this communication. Much work has already been undertaken to develop these mechanisms, but they are rarely tested in real-world environments. This project took existing security and privacy technqiues and performed a deployment at three sites in the UK to test their efficacy.

FAIR-SPACE

October 2018 – December 2019

WMG, University of Warwick

Access to space is becoming increasingly cheaper, meaning companies and organisations who were previously priced out of the market are now considering space-based deployments. These deployments may also include novel functionality such as debris collection. New entrants will lack the knowledge that well-established space organisations have about how to secure these systems and the new functionality will increase the ways in which these systems will be attacked. This project looked at ways in which these vulnerabilities could be identified and then formally proved to not be present.

PNT Cyber Resilience: a Lab2Live Observer Based Approach

January 2020 – March 2020

WMG, University of Warwick

Vehicular position, navigation, and timing (PNT) systems are of vital importance to current vehicles, future autonomous vehicles and infrastructure depending on time synchronisation. Existing GNSS infrastructure has limited mitigation to prevent a variety of attacks. This project performed a short feasibility study on practical attacks against a vehicle’s PNT system using a PNT attack emulator.

Evaluating Trustworthiness of Edge-Based Multi-Tenanted IoT Devices

March 2020 – March 2021

Department of Computer Science, University of Warwick

Resource-constrained IoT devices have typically been used to perform sensing and actuation, however, there is increasing interest in those devices performing decision making. However, if these tasks are computationally or memory intensive, then the IoT devices will not have insufficient resources to execute the tasks. One solution is to offload the tasks from resource-constrained IoT devices to resource-rich Edge nodes. For redundancy multiple Edge nodes should be provisioned, but this raises the question of which Edge node should be selected to perform a task. This project investigated building a middleware to perform task offloading based on a measure of behavioural trust with limited resources (e.g., 32 KiB of RAM).

publications

The Impact of Decreasing Transmit Power Levels on FlockLab To Achieve a Sparse Network

Summary

When developing techniques for IoT devices, it is preferable to perform testing on real devices in real situations such as on FlockLab 2, FIT IoT-LAB, and INDRIYA 2, as simulation will not perfectly reproduce these environments. However, IoT testbeds are not always deployed in the same scenarios for which techniques are developed for. It is often the case that testbeds are setup in existing facilities (such as inside office buildings) and devices are positioned close to each other. This means that there is currently a lack of testbeds supporting the testing of applications that will be deployed outside, on a large scale, with sparse connectivity. Commonly, the transmission power of device can be reduced in order to emulate a sparse network, this paper looked at the baseline effects of doing so.

Importance

Without understanding the baseline performance of a testbed, it becomes difficult to draw conclusions about the performance of the techniques that are being tested. This paper focused on understanding the noise floor and the impact that varying transmit power has on message transmit, message receive and current consumption performance. Due to the office environment there are certain characteristics that would be different in a large-scale outdoors environment. For example, the noise floor is affected by the provision of WiFi in the building. There is also a degree of link asymmetry that may be different in an outdoors environment.

Perspectives

Reducing the transmit power to obtain a spare network is a poor choice in order to obtain the desired network topology, but it may be the only option available given the currently available IoT testbeds. Future effort will be needed to set up testbeds in these different environments.

Privacy Challenges with Protecting Live Vehicular Location Context

Summary

Previous work on live location privacy protection for vehicle-to-vehicle (V2V) communication has rarely considered multiple sources of identity leakage. This is problematic as vehicles will exhibit multiple sources of identifying information. However, not all of this information will be available to all threat actors. Some identifying information will be easier and cheaper to obtain (e.g., via a sensor network listening for V2V communications) compared to other approaches (e.g., deploying a network of cameras). This paper identified the numerous sources of identity leakage from a vehicle and devices which may be present in it, the threat actors trying to violate the vehicle’s live location privacy, the techniques used to protect privacy, and ways in which identity sources and protection mechanisms can interact. Matrix of live location privacy threats and their relation to one another

Importance

There has been much focus on bringing autonomous vehicles to roads around the world and there has not always been as much emphasis on the new modes of connectivity future vehicles will have. The connectivity that new vehicles will be equipped with will allow tracking of vehicles with cheaper and less obvious equipment than before.

Perspectives

This research was performed to highlight the need for researchers to consider other identity sources and their interactions when developing techniques to protect the live location privacy of a vehicle. It is insufficient to focus on a single identity source. Depending on the type of identity source, multiple other technologies may need to be considered. For example, as ETSI V2X communication is based on IEEE 802.11p, devices that are eavesdropping those messages will also likely be able to eavesdrop messages from WiFi and Bluetooth devices. This means that privacy techniques for IEEE 802.11p also need to consider privacy techniques for these other technologies. An identity change can be linked if another devices does not synchronise the identity change

Trust Assessment in 32 KiB of RAM: Multi-application Trust-based Task Offloading for Resource-constrained IoT Nodes

Summary

There is increasing interest in using highly resource-constrained IoT devices to perform complex tasks. These resource might include limited processing power (e.g., 32MHz CPU), RAM (e.g., 32 KiB to 256 KiB), ROM (512 KiB), and potentially no stable storage. However, because of the limited resources an IoT device may need to offload expensive tasks to resource-rich devices. These might be a Cloud server or an Edge node if the latency of task responses is important. In order to address this issue, in this work we developed a middleware to facilitate task offloading using a measure of behavioural trust.

Importance

The key importance of this work is to understand exactly how much of the limited resources needs to be used to implement the middleware. This is because trust models that are used to assess which resource-rich device to offload a task to are typically very large. There is an assumption that “more information” = “better trust model”, but the limited resources mean that there is not much space available to store a behavioural trust model. Our implementation investigated the required design decisions to fit such a system on these IoT devices.

Perspectives

During this research we identified the challenges with using certain protocols. For example, MQTT uses TCP which requires a large amount of RAM in order to support the guarantees that TCP provides. MQTT-SN uses UDP, but was not implemented by the Contiki-NG IoT operating system we used. We also needed to understand the cost of securing the messages sent in this system. Due to issues identified in DTLS implementations we chose to investigate OSCORE to protect messages. This standard conveniently uses the hardware accelleration of the Zolertia RE-Mote devices we performed a deployment with. However, we had to minimise the use of Elliptic Curve operations due to the computational cost (even with hardware acceleration) that meant about 1 signature could be verified per second. Finally, future deployments of such a system will also need to design an appropriate trust model that fits within the limited memory remaining after implementing the task offloading middleware. Our use of the Beta Reputation System proved effective due to its small size.

talks

How To Stop Poachers Stealing Your Pandas

15 May 2018

Talk, Shop Front Theatre, Coventry, UK

Pint of Science is an annual event where researchers share their work in a informal context (the pub) with the general public. The aim of these events is to inform in a relaxed environment without. This talk presented on my researcher undertaken during my PhD and included a live demonstration of members of the public using a directional antenna to find the location of a small transmitter.

Warwick Postgraduate Colloquium in Computer Science

29 June 2018

Event, University of Warwick, Coventry, UK

The Warwick Postgraduate Colloquium in Computer Science (WPCCS) is a PhD student-run event which showcases the research performed by PhD students in the Department of Computer Science at the University of Warwick. I was chair of WPCCS 2016 and a member of the programme comittee for WPCCS 2017 and WPCCS 2018. Each year we received more presentations and posters submitted to the event as we tried to increase the event’s similarity to conferences PhD students would attend.

Competitive Advantage in the Digital Economy (CADE) Forum

20 May 2019

Event, University of Warwick in Venice, Venice, Italy

The Competitive Advantage in the Digital Economy (CADE) Forum aims to bring together academics and practitioners to discuss the challenges of the digital economy and present the latest cutting edge research. I was the Program Chair for the 2019 forum and that year the event focused on Smart Service Systems, Personal Data and Cyber Security. There were 28 speakers and 5 keynote speakers who gave presentations on a wide variety of topics. Funding to hold the event was obtained from a variety of sources, including winning funding from Warwick’s Institute of Advanced Study.

Orbit RRI Ethical Hackathon on Cyber Security

06 June 2019

Talk, Royal Holloway, University of London, Egham, UK

ORBIT’s aim is to promote Responsible Research and Innovation (RRI) to ensure the sustainability, acceptability and desirability of research. As part of this goal in June of 2019 they ran an Ethical Hackathon on Cyber Security of satellite systems. I was invited to give a guest talk on work applying formal verification to prove security properties of space systems being performed in the FAIR-SPACE hub. The summary of the event highlighted the depth understanding participants gained of RRI issues related to cyber security.

Towards Security Minded Verification: A Case Study of Cooperative Awareness Messages

06 November 2019

Talk, University of Coventry, Coventry, UK

I was invited to give a talk to Coventry University’s Institute for Future Transport and Cities on my work performed for FAIR-SPACE which investigated a formal verification of security properties of the generation of Cooperative Awareness Messages. One of the conclusions of this presentation was the difficulty of verifying non-functional security properties.

Trust Assessment in 32 KiB of RAM: Multi-application Trust-based Task Offloading for Resource-constrained IoT Nodes

22 March 2021

Conference Presentation, ACM Symposium of Applied Computing, Virtual Event, South Korea

There is an increasing demand for Internet of Things (IoT) systems comprised of resource-constrained sensor and actuator nodes executing increasingly complex applications, possibly simultaneously. IoT devices will not be able to execute computationally expensive tasks and will require more powerful computing nodes, called edge nodes, for such execution, in a process called computation offloading. When multiple powerful nodes are available, a selection problem arises: which edge node should a task be submitted to? This problem is even more acute when the system is subjected to attacks, such as DoS, or network perturbations such as system overload. In this presentation,a trust model-based system architecture for computation offloading is presented. The system architecture provides confidentiality, authentication and non-repudiation of messages in required scenarios and will operate within the resource constraints of embedded IoT nodes. The viability of the architecture is demonstrated with an example deployment of Beta Reputation System trust model on real hardware.

Trust Trackers for Computation Offloading in Edge Based IoT Networks

11 May 2021

Conference Presentation, IEEE INFOCOM, Virtual Event

Wireless Internet of Things (IoT) devices will be deployed to enable applications such as sensing and actuation. These devices are typically resource-constrained and are unable to perform resource-intensive computations. Therefore, these jobs need to be offloaded to resource-rich nodes at the edge of the IoT network for execution. However, the timeliness and correctness of edge nodes may not be trusted (such as during high network load or attack). In this presentation, we look at the applicability of trust for successful offloading. Traditionally, trust is computed at the application level, with suitable mechanisms to adjust for factors such as recency. However, these do not work well in IoT networks due to resource constraints. We propose a novel device called Trust Tracker (denoted by Σ) that provides higher-level applications with up-to-date trust information of the resource-rich nodes. We prove impossibility results regarding computation offloading and show that Σ is necessary and sufficient for correct offloading. We show that, Σ cannot be implemented even in a synchronous network and we compute the probability of offloading to a bad node, which we show to be negligible when a majority of nodes are correct. We perform a small-scale deployment to demonstrate our approach.