David Llewellyn-Jones

Lightweight Sybil Attack Detection in MANETs

Fully self-organized mobile ad hoc networks (MANETs) represent complex distributed systems that may also be part of a huge complex system, such as a complex system-of-systems used for crisis management operations. Due to the complex nature of MANETs and its resource constraint nodes, there has always been a need to develop lightweight security solutions. Since MANETs require a unique, distinct, and persistent identity per node in order for their security protocols to be viable, Sybil attacks pose a serious threat to such networks. A Sybil attacker can either create more than one identity on a single physical device in order to launch a coordinated attack on the network or can switch identities in order to weaken the detection process, thereby promoting lack of accountability in the network. In this research, we propose a lightweight scheme to detect the new identities of Sybil attackers without using centralized trusted third party or any extra hardware, such as directional antennae or a geographical positioning system. Through the help of extensive simulations and real-world testbed experiments, we are able to demonstrate that our proposed scheme detects Sybil identities with good accuracy even in the presence of mobility.

Monitoring connectivity in wireless sensor networks

It is important to have continuous connectivity in a wireless sensor network after it is deployed in a hostile environment. However, such networks are constrained by the low user-to-node ratio, limited energy and bandwidth resources, entities that are usually mobile, networks without fixed infrastructure and frequent failure due to problems of energy, vulnerability to attack, etc. To address these difficulties, there is a need for wireless sensor networks to be self-organizing and self-configuring so as to improve performance, increase energy efficiency, save resources and reduce data transmission. In this paper, we present a method for monitoring, maintaining and repairing the communication network of a dynamic mobile wireless sensor network, so that network connectivity is continuously available and provides fault tolerance. Specifically, we propose an algorithm for the detection and surveillance of articulation points in graph connectivity, including an algorithm for network auto-organization in the event that this occurs.

Analysis of Digital Image Watermark Attacks

Digital watermarking is one of the most widely used techniques for protection of ownership rights of digital audio, images and video. Its commercial applications range from copyright protection to digital rights management. The success of a digital watermarking technology depends heavily on its robustness to withstand attacks that are aimed at removing or destroying the watermark from its host data. This paper provides analysis of a number of digital image watermark attacks and attempts to classify them into categories. A set of experimental results are also provided to show the effect of these attacks on watermarks produced using different watermarking techniques.

Security in Wireless Sensor Networks

Humans are constantly inventing new technologies to fulfil their needs. Wireless sensor networks (WSNs) are a still developing technology consisting of multifunction sensor nodes that are small in size and communicate wirelessly over short distances. Sensor nodes incorporate properties for sensing the environment, data processing and communication with other sensors. The unique properties of WSNs increase flexibility and reduce user involvement in operational tasks such as in battlefields. Wireless sensor networks can perform an important role in many applications, such as patient health monitoring, environmental observation and building intrusion surveillance. In the future WSNs will become an integral part of our lives. However along with unique and different facilities, WSNs present unique and different challenges compared to traditional networks. In particular, wireless sensor nodes are battery operated, often having limited energy and bandwidth available for communications.

Designing for all in the house

The elderly population in the world is increasing rapidly and consequently so is demand for new technologies that allow them to live independently. Facilitating the control of household appliances and the home environment through various devices that encompass multimodal and ambient interfaces seems a way to achieve this. We tested three modalities of output - audio, visual and multimodal - using two different devices - palmtop and laptop - as realistic prototypes of household appliance controllers. Through experimental design the applicability of using icons and musical earcons as a medium to transmit information to the user and its suitability to the home was investigated. Results showed participants performed markedly better using the multimodal and visual interfaces than with the audio interface. In addition both groups performed better using the palmtop as compared to the laptop.

Applying Secure Data Aggregation techniques for a Structure and Density Independent Group Based Key Management Protocol

In many applications of Wireless Sensor Networks a Sink is interested in aggregated data instead of exact values from all sensors. To send aggregated data, it is also helpful to reduce the amount of data to be transmitted and thereby conserve energy. Indeed current in-network aggregation schemes are helpful to conserve energy but they are designed without considering possible security issues related to data privacy. Often we find wireless sensor networks designed with neighbouring nodes sharing keys or with decryption at aggregator nodes. In either situation the potential for aggregator nodes to be physically compromised means data privacy is at high risk. Therefore secure data aggregation is desirable where data can be aggregated without the need for decryption at aggregator nodes. Aggregation becomes especially challenging if end-to-end privacy between a source and a destination (sink or group leader) is required. In this paper we extend our Structure and Density Independent Group Based Key Management Protocol with the additional feature of secure data aggregation to provide better data privacy to every single node in a large scale Wireless Sensor Network.

Ambient interfaces for elderly people at home

The elderly population in the world is increasing rapidly and consequently so is demand for new technologies that allow them to live independently. Facilitating the control of household appliances and the home environment through various devices that encompass multimodal and ambient interfaces seems a way to achieve this. In this paper, we lay out the theoretical principles relating to the accommodation of technology for use in the home among older people, followed by a report supporting these principles based on experiments we have carried out. Three modalities of output – audio, visual and multimodal – were tested using two different devices – palmtop and laptop – as realistic prototypes of household appliance controllers. Through experimental design, the applicability of using icons and musical earcons as a medium to transmit information to the user and its suitability to the home was investigated. The use of musical earcons allowed the potential for an ambient interface to be compared with a traditional visual interface for older people. Results showed participants performed markedly better using the multimodal and visual interfaces than with the audio interface. In addition, both groups performed better using the palmtop as compared to the laptop.

The challenges of secure and trustworthy service composition in the Future Internet

The development of the Future Internet will see a move towards widespread use of services as a way of networked interaction. However, while the technologies for deploying services are well established, methods for ensuring trust and security are less well developed. In particular, current service security standards and technologies tend to be focussed on specific areas, such as security at the communication level. In order for users to be confident that their security requirements are being satisfied, a more holistic approach is required. For example, the security claims of a service should be known in advance, and a user should be able to make judgements about the trustworthiness of a service and its likelihood of fulfilling these claims. This should apply to services running in isolation, as well as those comprised of other services from different providers. We present a high level design of the Aniketos platform that aims to address some of these challenges, providing capabilities for managing trust, security and threats in relation to services in the Future Internet. While still at an early stage, this high level design provides an insight into how the platform is expected to develop in the future.

System-of-systems boundary check in a public event scenario

In any system-of-systems the potential exists for interactions between systems to occur that may affect the security of the overall system. We present a scenario that aims to highlight such problems, in particular that of security at a network boundary. This scenario considers cooperation and interactions between organisations and systems in the context of a major public event, such as a sporting or entertainment event. Based on this we present a modelling tool able to highlight potential access violations that might occur through transfer of data between multiple organisations and suggest ways to mitigate these vulnerabilities. The use of the modelling tool for network boundary checking is demonstrated, using the example scenario. Suggestions are made as to how security and effectiveness can be achieved by applying safeguards to vulnerable areas, while allowing the free flow of data between organisations where this is known to be safe.

Monitoring and measuring sedentary behaviour with the aid of human digital memories

There is growing global concern over the growing levels of obesity and the fact that people in general are not as active as they once were. Many believe that this is directly related to poor diet and our increasing reliance on technology, such as television, social networking, computer games, and voice activated home control systems. These kinds of activities increase sedentary behaviour across all age groups and is considered one of the main contributors to obesity and poor health. For this reason decreasing sedentary behaviour is considered a crucial theme within many research programs in health. Ironically, there is general agreement that the use of technology is likely to help researchers understand this type of behaviour. One interesting approach is based upon the use of human digital memories to provide visual lifelogs of a users activity and to identify the behaviour patterns of individuals. In this way visual lifelogs provide a way for users to evaluate their lifestyle choices. This paper discusses some of the key technologies used to achieve this and considers some of the challenges that still need to be addressed.