Abstract
Access control is one of the imperative defense frontlines for digital computing environments especially for pervasive computing environments such as cloud computing and the internet of things (IoT) characterized by heterogeneous and distributed services and resources. Although, numerous access control models (ACM) have been implemented and used to prevent unauthorized access to cloud services and resources, these models may not prove efficacious to prevent overexposure and underexposure of data. More granular access control models or fine-grained access control therefore are developed to enable more itemized authorization policies. This paper presents a comparative analysis of different ACM used in the cloud with a focus on fine-grained access control models. First, we discuss the existing ACMs then and present the state-of-the-art research efforts carried out in the domain. Finally, we provide our analysis of the existing cloud-based access control methods and identify the gaps in the field for future work. This survey aims to improve the understanding and application of ACMs in the cloud and pave the road for future works in this area.