This paper presents a comprehensive study on the
challenges and issues of security in cloud computing. We first
look into the impacts of the distinctive characteristics of cloud
computing, namely, multi-tenancy, elasticity and third party
control, upon the security requirements. Then, we analyze the
cloud security requirements in terms of the fundamental issues,
i.e., confidentiality, integrity, availability, trust, and audit and
compliance. Furthermore, we discuss the taxonomy for security
issues in cloud computing. Finally, we summarize the security
issues in cloud computing by a cloud security architecture.