This document discusses privacy and security issues related to cloud computing. It begins with an abstract that notes cloud computing presents a double-edged sword from privacy and security standpoints, as storing sensitive data in the cloud increases risks, but cloud providers may offer low-cost security. The document then provides more details on the technological and institutional challenges to privacy and security in cloud computing, such as new vulnerabilities discovered, the virtual and dynamic nature of cloud architectures reducing user control, and the lag of institutional responses compared to the fast pace of technological changes. Finally, it presents a model showing how characteristics of the cloud affect perceptions of its security and privacy, while formal and informal institutions affect perceptions of its legitimacy, and how these together influence adoption decisions