Access control and user authentication concerns in cloud computing environments

Cloud computing is a newfound service that has a rapid growth in IT industry during recent years. Despite the several advantages of this technology there are some issues such as security and privacy that affect the reliability of cloud computing models. Access control and user authentication are the most important security issues in cloud computing. Therefore, the research has been prepared to provide the overall information about this security concerns and specific details about the identified issues in access control and user authentication researches. Therefore, cloud computing benefits and disadvantages have been explained in the first part. The second part reviewed some of access control and user authentication algorithms and identifying benefits and weaknesses of each algorithm. The main aim of this survey is considering limitations and problems of previous research in the research area to find out the most challenging issue in access control and user authentication algorithms.