Service-oriented trust and reputation management system for multi-tier cloud

Cloud based applications demand a higher level of security, privacy, and reliability toward a more cost effective solution. One of the challenges for the users of cloud-based services and applications is finding the most trusted provider for the minimum cost. The trusted providers from each customer can have different interpretation, or with different priority of the meaning. Furthermore, a tier-1 cloud service provider that delivers a service can receive the service, partially or fully, from tier-2 cloud service providers. In this paper, we propose a system to evaluate the trust, per delivered service by each provider and per each subject of the trust. Then, we propose an application of our trust system in choosing the best provider by a customer through minimizing the cost and maximizing the service-oriented trust. Our analysis shows the security, efficiency and applicability of our system in a multi-tier cloud environment.