Network-aware Evaluation Environment for Reputation Systems

Parties of reputation systems rate each other and use ratings to compute reputation scores that drive their interactions. When deciding which reputation model to deploy in a network environment, it is important to find the most suitable model and to determine its right initial configuration. This calls for an engineering approach for describing, implementing and evaluating reputation systems while taking into account specific aspects of both the reputation systems and the networked environment where they will run. We present a software tool (NEVER) for network-aware evaluation of reputation systems and their rapid prototyping through experiments performed according to user-specified parameters. To demonstrate effectiveness of NEVER, we analyse reputation models based on the beta distribution and the maximum likelihood estimation

Trust Model for Optimized Cloud Services

Cloud computing with its inherent advantages draws attention for business critical applications, but concurrently expects high level of trust in cloud service providers. Reputation-based trust is emerging as a good choice to model trust of cloud service providers based on available evidence. Many existing reputation based systems either ignore or give less importance to uncertainty linked with the evidence. In this paper, we propose an uncertainty model and define our approach to compute opinion for cloud service providers. Using subjective logic operators along with the computed opinion values, we propose mechanisms to calculate the reputation of cloud service providers. We evaluate and compare our proposed model with existing reputation models

MARINE: Man-in-the-middle attack resistant trust model IN connEcted vehicles

Vehicular Ad-hoc NETwork (VANET), a novel technology holds a paramount importance within the transportation domain due to its abilities to increase traffic efficiency and safety. Connected vehicles propagate sensitive information which must be shared with the neighbors in a secure environment. However, VANET may also include dishonest nodes such as Man-in-the-Middle (MiTM) attackers aiming to distribute and share malicious content with the vehicles, thus polluting the network with compromised information. In this regard, establishing trust among connected vehicles can increase security as every participating vehicle will generate and propagate authentic, accurate and trusted content within the network. In this paper, we propose a novel trust model, namely, Man-in-the-middle Attack Resistance trust model IN connEcted vehicles (MARINE), which identifies dishonest nodes performing MiTM attacks in an efficient way as well as revokes their credentials. Every node running MARINE system first establishes trust for the sender by performing multi-dimensional plausibility checks. Once the receiver verifies the trustworthiness of the sender, the received data is then evaluated both directly and indirectly. Extensive simulations are carried out to evaluate the performance and accuracy of MARINE rigorously across three MiTM attacker models and the bench-marked trust model. Simulation results show that for a network containing 35% MiTM attackers, MARINE outperforms the state of the art trust model by 15%, 18%, and 17% improvements in precision, recall and F-score, respectively.N/A

Current capabilities, requirements and a proposed strategy for interdependency analysis in the UK

The UK government recently commissioned a research study to identify the state-of-the-art in Critical Infrastructure modelling and analysis, and the government/industry requirements for such tools and services. This study (Cetifs) concluded with a strategy aiming to bridge the gaps between the capabilities and requirements, which would establish interdependency analysis as a commercially viable service in the near future. This paper presents the findings of this study that was carried out by CSR, City University London, Adelard LLP, a safety/security consultancy and Cranfield University, defense academy of the UK

A synergistic reputation-policy based trust model for Grid resource selection

In the context of Grid computing, reputation-based trust management systems are playing an increasingly important role for supporting coordinated resource sharing and ensuring provision of quality of service. However, the existing Grid reputation-based trust management systems are considered limited as they are bounded to esoteric reputation-based trust models encompassing predefined metrics for calculating and selecting trusted computing resources and as a result, they prevent external involvement in the trust and reputation evaluation processes. This thesis suggests an alternative approach for reputation modelling founded on its core argument proclaiming that reputation is a subjective matter as well as context dependent. Consequently, it offers a synergistic reputation-policy based trust model for Grid resource selection. This exoteric trust model introduces a novel paradigm for evaluating Grid resources, in which Grid client applications (e.g. monitoring toolkits and resource brokers) are endeavoured to carry out an active participation in the trust and reputation evaluation processes. This is achieved by augmenting the standard reputation queries with a set of reputation-policy assertions constituting as complete trust metrics supplied into the reputation algorithm. Consecutively, the Grid Reputation-Policy Trust management system (GREPTrust) provides a concrete implementation for the trust model and it’s underlying artifacts whilst the GREPTrust testbed provides an adequate infrastructure for comparing the reputationpolicy trust model with a production available esoteric model (GridPP). Based on a computational finance case study, an internal workflow simulation utilises the GREPTrust testbed in order to empirically assess the criteria by which the synergistic reputation-policy based trust model outperforms esoteric trust models regarding resource selection and consequently provides substantive evidence that the reputation-policy paradigm is a welcome addition to the Grid computing community

Matrix powers algorithms for trust evaluation in PKI architectures

This paper deals with the evaluation of trust in public-key infrastructures. Different trust models have been proposed to interconnect the various PKI components in order to propagate the trust between them. In this paper we provide a new polynomial algorithm using linear algebra to assess trust relationships in a network using different trust evaluation schemes. The advantages are twofold: first the use of matrix computations instead of graph algorithms provides an optimized computational solution; second, our algorithm can be used for generic graphs, even in the presence of cycles. Our algorithm is designed to evaluate the trust using all existing (finite) trust paths between entities as a preliminary to any exchanges between PKIs. This can give a precise evaluation of trust, and accelerate for instance cross-certificate validation

Creating the strategic learning environment at City University London

Purpose: This paper describes the creation of a new approach to the implementation of educational technologies at a UK Higher Education Institution. Driven by changes in technology, an evaluation of the virtual learning environment (VLE) provided the opportunity to reassess the application of technology to the curriculum. However, such an evaluation and subsequent implementation is not about technology but a social process of negotiation and stakeholder engagement. The narrative of the evaluation is explored to offer lessons to other institutions. Design/methodology/approach: The paper takes a story telling approach as this enables greater emotional engagement with the reader as well as the description of the social and organisational aspects of such a VLE evaluation. This approach enables the difficulty of change in complex organisations, such as a University, to be addressed more fully. Findings: Key lessons from the evaluation of the VLE and resulting creation of the strategic learning environment (SLE) are drawn which can be of use to other institutions. The main finding is the fact that such evaluations and implementation of educational technologies are not about technical factors but about opportunities and threats presented by such technologies to the educational experience. These findings also inform future development of the SLE at the institution. Originality/value: This paper will be of interest to institutions that are undertaking evaluation exercises of their educational technology provision as well as those that are implementing new technologies or considering large scale organisational change

Accessing Patient Records in Virtual Healthcare Organisations

The ARTEMIS project is developing a semantic web service based P2P interoperability infrastructure for healthcare information systems that will allow healthcare providers to securely share patient records within virtual healthcare organisations. Authorisation decisions to access patient records across organisation boundaries can be very dynamic and must occur within a strict legislative framework. In ARTEMIS we are developing a dynamic authorisation mechanism called PBAC that provides a means of contextual and process oriented access control to enforce healthcare business processes. PBAC demonstrates how healthcare providers can dynamically share patient records for care pathways across organisation boundaries

The Role of Evidence in Establishing Trust in Repositories

This article arises from work by the Digital Curation Centre (DCC) Working Group examining mechanisms to roll out audit and certification services for digital repositories in the United Kingdom. Our attempt to develop a program for applying audit and certification processes and tools took as its starting point the RLG-NARA Audit Checklist for Certifying Digital Repositories. Our intention was to appraise critically the checklist and conceive a means of applying its mechanics within a diverse range of repository environments. We were struck by the realization that while a great deal of effort has been invested in determining the characteristics of a 'trusted digital repository', far less effort has concentrated on the ways in which the presence of the attributes can be demonstrated and their qualities measured. With this in mind we sought to explore the role of evidence within the certification process, and to identify examples of the types of evidence (e.g., documentary, observational, and testimonial) that might be desirable during the course of a repository audit.