Enhanced Reputation Scoring for Online Auctions

To handle the uncertainty inherent in eCommerce transactions, reputation systems have emerged as a way to represent reliability and develop trust between transaction participants. Despite the value added by reputation systems, limitations of existent systems remain (Malaga 2001). We empirically test Porter et al.’s (2004) reputation scoring procedure, which was designed to address the shortcomings of current systems. This study uses computer simulation to replicate the auction process between buyers and sellers with reputation scores calculated using both the Porter et al. model and the eBay auction model. Results from the two models are then analyzed to show that the Porter et al. model more accurately estimates reputation scores

Research on Enterprises Reputation Evaluation Based on B2B Transaction Platform

Based on traders’ goods, service,the way of transaction and transaction time, the paper establishes the B2B traders’ reputation evaluation index system, and applies the Analytic Hierarchy Process to give weight. Using the reputation evaluation model, the paper takes into account evaluators’ own reputation, transaction amount, transaction time and other factors, dynamically adjusting reputation value and generating the reputation value of traders which is as the basis for the traders to choose the trading partners, and to promote the development of B2B e-commerce.Key words: B2B; Traders; Enterprises reputation; Evaluatio

Decentralized reputation-based trust for assessing agent reliability under aggregate feedback

Reputation mechanisms allow agents to establish trust in other agents' intentions and capabilities in the absence of direct interactions. In this paper, we are concerned with establishing trust on the basis of reputation information in open, decentralized systems of interdependent autonomous agents. We present a completely decentralized reputation mechanism to increase the accuracy of agents' assessments of other agents' capabilities and allow them to develop appropriate levels of trust in each other as providers of reliable information. Computer simulations show the reputation system's ability to track an agent's actual capabilitie

Dynamical trust and reputation computation model for B2C E-Commerce

Trust is one of the most important factors that influence the successful application of network service environments, such as e-commerce, wireless sensor networks, and online social networks. Computation models associated with trust and reputation have been paid special attention in both computer societies and service science in recent years. In this paper, a dynamical computation model of reputation for B2C e-commerce is proposed. Firstly, conceptions associated with trust and reputation are introduced, and the mathematical formula of trust for B2C e-commerce is given. Then a dynamical computation model of reputation is further proposed based on the conception of trust and the relationship between trust and reputation. In the proposed model, classical varying processes of reputation of B2C e-commerce are discussed. Furthermore, the iterative trust and reputation computation models are formulated via a set of difference equations based on the closed-loop feedback mechanism. Finally, a group of numerical simulation experiments are performed to illustrate the proposed model of trust and reputation. Experimental results show that the proposed model is effective in simulating the dynamical processes of trust and reputation for B2C e-commerce

A stochastic Reputation System Architecture to support the Partner Selection in Virtual Organisations

In recent business environments, collaborations among organisations raise an increased demand for swift establishment. Such collaborations are increasingly formed without prior experience of the other partner\u27s previous performance. The STochastic REputation system (STORE) is designed to provide swift, automated decision support for selecting partner organisations. STORE is based on a stochastic trust model and evaluated by means of multi agent simulations in Virtual Organisation scenarios

Preference Uncertainty and Trust in Decision Making

A fuzzy approach for handling uncertain preferences is developed within the paradigm of the Graph Model for Conflict Resolution and new advances in trust modeling and assessment are put forward for permitting decision makers (DMs) to decide with whom to cooperate and trust in order to move from a potential resolution to a more preferred one that is not attainable on an individual basis. The applicability and the usefulness of the fuzzy preference and trust research for giving an enhanced strategic understanding about a dispute and its possible resolution are demonstrated by employing a realworld environmental conflict as well as two generic games that represent a wide range of real life encounters dealing with trust and cooperation dilemmas. The introduction of the uncertain preference representation extends the applicability of the Graph Model for Conflict Resolution to handle conflicts with missing or incomplete preference information. Assessing the presence of trust will help to compensate for the missing information and bridge the gap between a desired outcome and a feared betrayal. These advances in the areas of uncertain preferences and trust have potential applications in engineering decision making, electronic commerce, multiagent systems, international trade and many other areas where conflict is present. In order to model a conflict, it is assumed that the decision makers, options, and the preferences of the decision makers over possible states are known. However, it is often the case that the preferences are not known for certain. This could be due to lack of information, impreciseness, or misinformation intentionally supplied by a competitor. Fuzzy logic is applied to handle this type of information. In particular, it allows a decision maker to express preferences using linguistic terms rather than exact values. It also makes use of data intervals rather than crisp values which could accommodate minor shifts in values without drastically changing the overall results. The four solution concepts of Nash, general metarationality, symmetric metarationality, and sequential stability for determining stability and potential resolutions to a conflict, are extended to accommodate the new fuzzy preference representation. The newly proposed solution concepts are designed to work for two and more than two decision maker cases. Hypothetical and real life conflicts are used to demonstrate the applicability of this newly proposed procedure. Upon reaching a conflict resolution, it might be in the best interests of some of the decision makers to cooperate and form a coalition to move from the current resolution to a better one that is not achievable on an individual basis. This may require moving to an intermediate state or states which may be less preferred by some of the coalition members while being more preferred by others compared to the original or the final state. When the move is irreversible, which is the case in most real life situations, this requires the existence of a minimum level of trust to remove any fears of betrayal. The development of trust modeling and assessment techniques, allows decision makers to decide with whom to cooperate and trust. Illustrative examples are developed to show how this modeling works in practice. The new theoretical developments presented in this research enhance the applicability of the Graph Model for Conflict Resolution. The proposed trust modeling allows a reasonable way of analyzing and predicting the formation of coalitions in conflict analysis and cooperative game theory. It also opens doors for further research and developments in trust modeling in areas such as electronic commerce and multiagent systems

Trust Establishment Mechanisms for Distributed Service Environments

The aim and motivation of this dissertation can be best described in one of the most important application fields, the cloud computing. It has changed entire business model of service-oriented computing environments in the last decade. Cloud computing enables information technology related services in a more dynamic and scalable way than before – more cost-effective than before due to the economy of scale and of sharing resources. These opportunities are too attractive for consumers to ignore in today’s highly competitive service environments. The way to realise these opportunities, however, is not free of obstacles. Services offered in cloud computing environments are often composed of multiple service components, which are hosted in distributed systems across the globe and managed by multiple parties. Potential consumers often feel that they lose the control over their data, due to the lack of transparent service specification and unclear security assurances in such environments. These issues encountered by the consumers boiled down to an unwillingness to depend on the service providers regarding the services they offer in the marketplaces. Therefore, consumers have to be put in a position where they can reliably assess the dependability of a service provider. At the same time, service providers have to be able to truthfully present the service-specific security capabilities. If both of these objectives can be achieved, consumers have a basis to make well-founded decisions about whether or not to depend on a particular service provider out of many alternatives. In this thesis, computational trust mechanisms are leveraged to assess the capabilities and evaluate the dependability of service providers. These mechanisms, in the end, potentially support consumers to establish trust on service providers in distributed service environments, e.g., cloud computing. In such environments, acceptable quality of the services can be maintained if the providers possess required capabilities regarding different service-specific attributes, e.g., security, performance, compliance. As services in these environments are often composed of multiple services, subsystems and components, evaluating trustworthiness of the service providers based on the service-specific attributes is non-trivial. In this vein, novel mechanisms are proposed for assessing and evaluating the trustworthiness of service providers considering the trustworthiness of composite services. The scientific contributions towards those novel mechanisms are summarised as follows: • Firstly, we introduce a list of service-specific attributes, QoS+ [HRM10, HHRM12], based on a systematic and comprehensive analysis of existing literatures in the field of cloud computing security and trust. • Secondly, a formal framework [SVRH11, RHMV11a, RHMV11b] is proposed to analyse the composite services along with their required service-specific attributes considering consumer requirements and represent them in simplified meaningful terms, i.e., Propositional Logic Terms (PLTs). • Thirdly, a novel trust evaluation framework CertainLogic [RHMV11a, RHMV11b, HRHM12a, HRHM12b] is proposed to evaluate the PLTs, i.e., capabilities of service providers. The framework provides computational operators to evaluate the PLTs, considering that uncertain and conflicting information are associated with each of the PLTs and those information can be derived from multiple sources. • Finally, harnessing these technical building blocks we present a novel trust management architecture [HRM11] for cloud computing marketplaces. The architecture is designed to support consumers in assessing and evaluating the trustworthiness of service providers based on the published information about their services. The novel contributions of this thesis are evaluated using proof-of-concept-system, prototype implementations and formal proofs. The proof-of-concept-system [HRMV13, HVM13a, HVM13b] is a realisation of the proposed architecture for trust management in cloud marketplaces. The realisation of the system is implemented based on a self-assessment framework, proposed by the Cloud Security Alliance, where the formal framework and computational operators of CertainLogic are applied. The realisation of the system enables consumers to evaluate the trustworthiness of service providers based on their published datasets in the CSA STAR. A number of experiments are conducted in different cloud computing scenarios leveraging the datasets in order to demonstrate the technical feasibility of the contributions made in this thesis. Additionally, the prototype implementations of CertainLogic framework provide means to demonstrate the characteristics of the computational operators by means of various examples. The formal framework as well as computational operators of CertainLogic are validated against desirable mathematical properties, which are supported by formal algebraic proofs

Synthesising end-to-end security schemes through endorsement intermediaries

Composing secure interaction protocols dynamically for e-commerce continue to pose a number of challenges, such as lack of standard notations for expressing requirements and the difficulty involved in enforcing them. Furthermore, interaction with unknown entities may require finding common trusted intermediaries. Securing messages sent through such intermediaries require schemes that provide end-to-end security guarantees. In the past, e-commerce protocols such as SET were created to provide such end-to-end guarantees. However, such complex hand crafted protocols proved difficult to model check. This thesis addresses the end-to-end problems in an open dynamic setting where trust relationships evolve, and requirements of interacting entities change over time. Before interaction protocols can be synthesised, a number of research questions must be addressed. Firstly, to meet end-to-end security requirements, the security level along the message path must be made to reflect the requirements. Secondly, the type of endorsement intermediaries must reflect the message category. Thirdly, intermediaries must be made liable for their endorsements. This thesis proposes a number of solutions to address the research problems. End-to-end security requirements were arrived by aggregating security requirements of all interacting parties. These requirements were enforced by interleaving and composing basic schemes derived from challenge-response mechanisms. The institutional trust promoting mechanism devised allowed all vital data to be endorsed by authorised category specific intermediaries. Intermediaries were made accountable for their endorsements by being required to discharge or transfer proof obligations placed on them. The techniques devised for aggregating and enforcing security requirements allow dynamic creation of end-to-end security schemes. The novel interleaving technique devised allows creation of provably secure multiparty schemes for any number of recipients. The structured technique combining compositional approach with appropriate invariants and preconditions makes model checking of synthesised schemes unnecessary. The proposed framework combining endorsement trust with schemes making intermediaries accountable provides a way to alleviate distrust between previously unknown e-commerce entities

A framework for decentralised trust reasoning.

Recent developments in the pervasiveness and mobility of computer systems in open computer networks have invalidated traditional assumptions about trust in computer communications security. In a fundamentally decentralised and open network such as the Internet, the responsibility for answering the question of whether one can trust another entity on the network now lies with the individual agent, and not a priori a decision to be governed by a central authority. Online agents represent users' digital identities. Thus, we believe that it is reasonable to explore social models of trust for secure agent communication. The thesis of this work is that it is feasible to design and formalise a dynamic model of trust for secure communications based on the properties of social trust. In showing this, we divide this work into two phases. The aim of the first is to understand the properties and dynamics of social trust and its role in computer systems. To this end, a thorough review of trust, and its supporting concept, reputation, in the social sciences was carried out. We followed this by a rigorous analysis of current trust models, comparing their properties with those of social trust. We found that current models were designed in an ad-hoc basis, with regards to trust properties. The aim of the second phase is to build a framework for trust reasoning in distributed systems. Knowledge from the previous phase is used to design and formally specify, in Z, a computational trust model. A simple model for the communication of recommendations, the recommendation protocol, is also outlined to complement the model. Finally an analysis of possible threats to the model is carried out. Elements of this work have been incorporated into Sun's JXTA framework and Ericsson Research's prototype trust model