Cloud computing environments consisting of different modules that handle the security and trust issues of key components. One of the modules is responsible for authentication and identity management. This paper focuses on the issues related to the data security aspect of cloud computing. This paper surveys recent research related to single and multi-cloud security and addresses possible solutions. It is found that the research into the use of multi-cloud providers to maintain security has received less attention from the research community than has the use of single clouds. This paper aims to promote the use of multi-clouds due to its ability to reduce security risks that affect the cloud computing user.