A Survey on Authorization in Distributed Systems: Information Storage, Data Retrieval and Trust Evaluation

In distributed environments, entities are distributed among different security domains and they do not have prior knowledge of one another. In this setting, distributed systems and their security components such as entities, certificates, credentials, policies and trust values are dynamic and constantly changing. Thus, access control models and trust approaches are necessary to support the dynamic and distributed features of such systems and their components. The objective of this paper is to present a comprehensive survey about the security research in distributed systems. We have reviewed the dynamic and distributed nature of the components and evaluation methods of major authorization systems and access control models in existing literature. Based on this overview, we present a survey of selected trust schemes. We provide a categorization for recommendation-based and reputation-based trust models based on trust evaluation. Additionally, we use credential or certificate storage and chain discovery methods for categorizing evidencebased and policy-based trust models. This work can be used as a reference guide to understand authorization and trust management and to further research fully decentralized and distributed authorization systems.