Abstract
In recent years, cloud computing has become a popular option for a number of different businesses sectors. It is a paradigm employed to deliver a range of computing services, such as sharing resources via the Internet. Security issues in cloud computing necessitates the need for a mechanism to keep the system safe and reliable. An access control mechanism is one that permits or denies access to cloud services. This paper presents a survey of access control models in Cloud Computing. Several existing surveys on access control mechanisms in cloud computing mainly focused on traditional access control models and encryption-based access control models while the others focused on applying blockchain technology in cloud access control. However, access models possess different characteristics, such as the system's reliance on a centralized cloud trusted system administrator to manage the access policy or adopting decentralized approach. This paper reviews and analyses existing access control mechanisms in cloud computing, based on centralized and decentralized access control models, provides detailed comparisons on each model's advantages and limitations, and discusses the challenges of, and future research direction for access control.