A multi-dimensional trust and reputation calculation model for cloud computing environments

Today cloud computing is prone to security and privacy threats. Decrement in security within clouds contributes to a loss of clients-confidence, lack of control and loss of trustworthiness in cloud service providers. Loss of control occurs when clients lose their control over their own resources in the hand of service provider. As lack of authentication and access control placed by providers, loss of control contributes to greater security concern. In this research, a novel trust framework is proposed which focus on tackling the loss of central concern by granting back control to the cloud clients in ensuring their service provider environments fully secure and trustworthy. Secondly, the trust model also functions in ensuring that both client and service providers transaction follows set of security mechanism in place. The results proved that both trust need to be enforced is any cloud. Thus the proposed trust model contributes as a mean to solve the security challenges known as loss of control.KeywordsCloud computingTrustLoss of ControlAuthenticationAccess control

The interest in cloud computing and its techniques are gaining exponentially in IT industries because of its cost-effective architecture and services. However, these flexible services of cloud bring many security and privacy challenges due to loss of control over the data. This paper focuses on an analysis of various computational trust models in cloud security environment. The computational trust models that are used to build secure cloud architectures are not available in a blended fashion to overcome security and privacy challenges. The paper aims to contribute to the literature review to assist researchers who are striving to contribute in this area. The main objective of this review is to identify and analyse the recently published research topics related to trust models and trust mechanisms for cloud with regard to research activity and proposed approaches. The future work is to design a trust mechanism for cloud security models to achieve the higher level of security.

Utility based cloud services can efficiently provide various supportive services to different service providers. Trust negotiations with federated identity management are vital for preserving privacy in open systems such as distributed collaborative systems. However, due to the large amounts of server based communications involved in trust negotiations scalability issues prove to be less cumbersome when offloaded on to the cloud as a utility service. In this view, we propose trust based federated identity management as a cloud based utility service. The main component of this model is the trust establishment between the cloud service provider and the identity providers. We propose novel trust metrics based on the potential vulnerability to be attacked, the available security enforcements and a novel cost metric based on policy dependencies to rank the cooperativeness of identity providers. Practical use of these trust metrics is demonstrated by analyses using simulated data sets, attack history data: published by MIT Lincoln laboratory, real-life attacks and vulnerabilities extracted from Common Vulnerabilities and Exposures (CVE) repository and fuzzy rule based evaluations. The results of the evaluations imply the significance of the proposed trust model to support cloud based utility services to ensure reliable trust negotiations using federated identity management.

During the past decade, online trust and reputation systems have provided cogent answers to emerging challenges in the global computing infrastructures relating to computer and network security, electronic commerce, virtual enterprises, social networks and cloud computing. The goal of these systems in such global computing infrastructures is to allow entities to reason about the trustworthiness of other entities and to make autonomous decisions on the basis of trust. This requires the development of computational trust models that enable entities to reason about trust and to verify the properties of a particular interaction. The robustness of these mechanisms is one of the critical factors required for the success of this technology. In this paper, we briefly present characteristics of existing online trust and reputation models and systems through a multidimensional framework that can serve as a basis to understand the current state of the art in the area. The critical open challenges that limit the effectiveness of today's trust and reputation systems are discussed by providing a comprehensive literature review. Furthermore, we present a set of our contributions as a way to address some of these challenges.

Cloud computing has emerged as a new computing paradigm, with provisioning model generally consisting of cloud service providers (CSPs), network service providers (NSPs), and end users. The associated economics has opened up a new research area; and with the expansion of the cloud computing market, the relationship between CSPs and NSPs, is changing profoundly. In addition to providing the default network services, traditional NSPs, in attempt to compete with CSPs, have started offering cloud services to end users. Though much progress has been made toward addressing competitions among CSPs themselves or among NSPs themselves, few studies have focused on the competition between CSPs and NSPs. In this paper, we investigate the problem of insufficient studies on the competition between CSPs and NSPs by presenting a new economic model to characterize the competition between CSPs and NSPs, and by conducting thorough theoretical analysis as well as numeric experiments to validate the proposed model. We believe, based on results, that the proposed economic model is general and feasible, and thus is applicable to modeling the competition among service providers in cloud computing market.

The main objective of this research work is to design and develop a Fuzzy Logic based trust and reputation model for secure resource allocation in cloud computing. The cloud computing is one of the major topics discussed among the IT professionals in recent days. In this paper trust manager and reputation manager based approach is used to update the security. Initially, the user access a resource block through the scheduling manager and a form will send to the user after accessing the resource block to fill the attribute values of trust factor and reputation factor. The trust factor and reputation value is then calculated for the resource center and it is given to the Fuzzy Logic system to get the security score of a resource center. The benefit of our proposed technique is to provide the security controls in accessing the cloud resources from cloud computing due to various security issues happened in networks, databases, resource scheduling, transaction management and load balancing.

Cloud computing is currently the most hyped and popular paradigm in the domain of distributed computing. Multiple vendors are providing infrastructure, platform, and software-related cloud products or solutions, and the number of such vendors is growing rapidly. But the reality is that there is very little in the form of standards in general and interoperability standards in particular. This leads to a challenging situation for cloud service consumers as they need to use solutions provided by multiple cloud vendors in order to fulfill their business requirements, and the lack of standardization leads to lack of interoperability among the solutions provided by varied vendors. Service brokers act as intermediaries between the cloud service providers and consumers. The role of service brokers becomes critical in situations that need integration among multiple systems as they bridge the interoperability gaps among multiple cloud solutions and thus compensate for the lack of standards. They do so by acting as agents adding value on behalf of the service consumers. The usage of such cloud brokers also helps to future-proof the solution as service brokers add a layer of indirection, thus enabling loose coupling among the cloud service consumers and providers. The aim of this chapter is to review the role of cloud service brokers in cloud computing. The review includes consolidation of the definitions and characteristics of cloud service brokers, review of the current brokerage solutions, and interfacing requirements. Also presented are a high-level cloud service broker functional architecture, criteria for selection of a cloud service broker, future trends and review of benefits, and challenges of using cloud service brokers.

Online service is used to be as Pay-Per-Use in Cloud computing. Service user need not be in a long time contract with cloud service providers. Service level agreements (SLAs) are understandings marked between a cloud service providers and others, for example, a service user, intermediary operator, or observing operators. Since cloud computing is an ongoing technology giving numerous services to basic business applications and adaptable systems to manage online agreements are significant. SLA maintains the quality-of-service to the cloud user. If service provider fails to maintain the required service SLA is considered to be SLA violated. The main aim is to minimize the SLA violations for maintain the QoS of their cloud users. In this research article, a toolbox is proposed to help the procedure of exchanging of a SLA with the service providers that will enable the cloud client in indicating service quality demands and an algorithm as well as Negotiation model is also proposed to negotiate the request with the service providers to produce a better agreement between service provider and cloud service consumer. Subsequently, the discussed framework can reduce SLA violations as well as negotiation disappointments and have expanded cost-adequacy. Moreover, the suggested SLA toolkit is additionally productive to clients so clients can secure a sensible value repayment for diminished QoS or conceding time. This research shows the assurance level in the cloud service providers can be kept up by as yet conveying the services with no interruption from the client's perspective

Trust and reputation systems represent a significant trend in decision support including selection of best match cloud providers to process Big Data. Reputation is often considered as a collective measure of trustworthiness based on the referrals or ratings from members in a community. Reputation systems have been applied in various applications such as online service provision. However, reputation models do not reflect user's quality of service (QoS) preferences and thus they might not be satisfied with the recommendations from others. In this paper, we propose a de-centralized reputation-based trust model that incorporates the user QoS preferences to select the best match Cloud Service Provider to process Big Data. Our trust model relies on three multi-attribute decision-making (MADM) methods including Simple Additive Weighting (SAW), Weighted Product Method (WPM), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). We conducted several experiments using simulated cloud environment to validate our trust model and assess the three MADM methods. The results show that the proposed model is pliable to users' requirements and efficiently evaluate trust of cloud providers.

Cloud computing is the next generation computer system which extends network architecture into dynamic and large scale capacity by using visualization techniques. Transparent and secure data provenance will enhance the level of trust in the Cloud. Recent literature on securing data provenance focuses only on providing partial part of security elements in their mechanisms, thus they could not provide full protection to the data provenance as a whole. This paper presents the provenance description and challenges in providing security assurances in the Cloud. The paper also proposes a novel trust model for data provenance in cloud computing. The model will be used for securing the transaction process of storing and accessing the data provenance. The paper describes in detail the flow process of the model to achieve a high level of trust in cloud services. The significance of this research is to enhance the level of trust in the cloud services via comprehensive trust model which consists all aspects of security elements in the model.

Cloud computing has been rapidly evolving and various organizations are updating their infrastructure and services to the cloud computing system. However, being a relatively new technology, users of cloud computing are facing various issues that need to be addressed. Identifying the risks associated and establishing trust in that is one such major issue that needs to be addressed. This article has focused on the various concepts related to trust in the cloud environment, technicalities of trust being used and evaluated, the trust models with an objective of identifying the inclusion of psychological dimensions and attributes in the assessment, evaluation, and management process. The results from the review have indicated that as such there are no models found which contribute to incorporating the psychological attributes. As an extension of the assessment, an integration of two important aspects are recommended in the existing trust model. The inclusion of psychological attributes that consist of motivation, perception, learning, and personality attributes; and an initial stage of assessment model in a top-down approach scheme for identifying the effectiveness of cloud service providers based on the collaborative trust information-sharing mechanism and by using techniques such as rankings and ratings.

A trust model was proposed for the open grid market. Our trust model emphasizes the importance of both direct trust and indirect trust/reputation when evaluating the trustworthiness of a grid service provider. Since many factors contribute to the direct and indirect trusts, a new method based on Multiple Attribute Decision Making (MADM) theory was proposed to determine the objective weights of both direct and indirect trusts. The simulation results demonstrate that our trust model reflects the trustworthiness of a service provider more accurately than the weighted feedback model and eBay trust model and thus improves users' satisfaction in the open grid environment.

Public fog nodes extend cloud services for the Internet of Things (IoT) clients and smart devices to provide additional computation capabilities, storage space, and reduce latency and response time. The openness and pervasiveness of public fog nodes leads to the requirement of using trust models to ensure reliability, security, privacy, and meet the service-level agreements (SLAs). Conventional trust models for public fog nodes are centrally configured, deployed, and maintained considering security, privacy, and SLA requirements. However, these trust models enforce centralized governance policies across the system which leads towards the single-point-of-failure and single-point-of-compromise over IoT devices' and users' personal data. This paper proposes a decentralized trust model in order to maintain the reputation of publicly available fog nodes. The reputation is maintained considering users' opinions about their past interactions with the public fog nodes. The proposed trust model is designed using public Ethereum blockchain and smart contract technologies in order to enable decentralized trustworthy service provisioning between IoT devices and public fog nodes. The proposed approach is tested and evaluated in terms of security, performance, and cost. The results show that using blockchain for decentralized reputation management could become more advantageous when compared to the existing centralized trust models.

Trust plays important roles in diverse decentralized environments, including our society at large. Computational trust models help to, for instance, guide users' judgements in online auction sites about other users; or determine quality of contributions in web 2.0 sites. Most of the existing trust models, however, require historical information about past behavior of a specific agent being evaluated - information that is not always available. In contrast, in real life interactions among users, in order to make the first guess about the trustworthiness of a stranger, we commonly use our instinct - essentially stereotypes developed from our past interactions with similar people. We propose StereoTrust, a computational trust model inspired by real life stereotypes. A user forms stereotypes using her previous transactions with other agents. A stereotype contains certain features of agents and an expected outcome of the transaction. These features can be taken from agents' profile information, or agents' observed behavior in the system. When facing a stranger, the stereotypes matching stranger's profile are aggregated to derive his expected trust. Additionally, when some information about stranger's previous transactions is available, StereoTrust uses it to refine the stereotype matching. According to our experiments, StereoTrust compares favorably with existing trust models that use different kind of information and more complete historical information. Moreover, because evaluation is done according to user's personal stereotypes, the system is completely distributed and the result obtained is personalized. StereoTrust can be used as a complimentary mechanism to provide the initial trust value for a stranger, especially when there is no trusted, common third parties.

The operation of bring-your-own-device (BYOD) in the cloud has not only opened cloud servers to more threats but inflicted additional costs on cloud security as it would have to monitor employee devices and their operations. Many organizations therefore have adopted zero trust scheme for BYOD access control management in cloud environment. However, zero trust model introduces extra cost and hostility against internal employees, who have a certain level of trust, as against outsiders. This paper posits that trust quantification for BYOD access control management should be determined by cloud service providers and employers in a dynamic and continuous manner based on session and information values. The paper therefore presents a collaborative-based dynamic trust model that fuses the perspectives of BYOD employer and cloud service provider agents (trustees) for BYOD Nodes (trustors) access control management. The trustees provide prior evidences about the BYOD requests from which plausible inferences are drawn. Three framing of trusts including employee, device and program trusts are formulated based on reliable trust metrics. Dempster-Shafer Belief Function is used to evaluate the belief scores of the trustors’ requests from the probabilities assigned by the trustees. The model is applied to two BYOD nodes, with varying session and information values. The outcomes reveal that the collaborative-based dynamic trust model ensures reduced cost and improved usability compared to zero trust model.