Research has shown that data security has always been an important aspect of quality of service for data service providers; but cloud computing poses new and challenging security threats. The most common security concerns for users of cloud storage are data confidentiality, integrity and availability. Microsoft has considered these concerns and responded with the Azure virtual private storage based on Searchable Encryption. Amazon has also responded to these security issues with its Amazon Web Services. In this paper, we investigate and compare in depth the features of Microsoft Azure and Amazon Web Services deemed to provide security with a particular focus on confidentiality, integrity and availability of data. © 2012 IEEE.