Trust Management Systems in Cloud Services Environment: Taxonomy of Reputation Attacks and Defense Mechanisms

Using cloud data storage, large amounts of data can be stored by data owners in a flexible way and at low cost. Hence, there has been a major increase in online cloud service providers and their users. The privacy and security of data in the cloud computing environment is a major issue. Data privacy can be ensured by using a cryptographic access control method, so that data can only be accessed by authorized customers while keeping it inaccessible to unauthorized users. However, this type of cryptographic approach does not address the issue of trust. An integration between several trust models and cryptographic access control models has been presented in many research papers, the aim of which is to make data stored in cloud storage systems more secure. The objective of this study is to determine a solution that can suitably handle trust issues in access control models to decrease the risk as greater security to cloud storage systems, and the quality of decisions being made by data owners and cloud operators is improved. In this paper, we have presented a taxonomy for trust criteria and reputation attacks in cloud computing. Also, some of the fundamental concepts regarding trust management of services within cloud environments have been presented in this paper, along with the latest technologies. There are three layers in the model, and a series of dimensions are further determined for every layer (which are the assessment criteria), which serve as the benchmark to evaluate many research prototypes of trust models in a cloud computing environment by comparing these criteria when evaluating several trust models in a cloud computing environment. In this paper, a comparison of fifteen representative trust management research samples in cloud computing and the appropriate research domains were also carried out by employing this analytical model.