The Edge of the Cloud

T wo of the most important technological developments of the last few years are the emergence of mobile and cloud computing. By shifting the hardware and staffing costs of managing the computational infrastructure to third parties—such as Google, Microsoft, or Amazon—cloud computing has made it possible for small organizations and individuals to deploy world-scale services while paying only the marginal cost of actual resource usage. At the same time, the deployment of 3G and 4G networks and the rapid adoption of feature-rich smartphones have brought mobile computing into the mainstream. Here, we explore the intersection of pervasive and cloud computing. Mobile devices let users access cloud-based services and data anywhere and anytime, extending such devices’ reach into everyday life. Simultaneously, cloud computing platforms address the lack of local resources in mobile devices, thereby enabling resourceintensive next-generation applications. The articles in this issue consider how to secure data stored in the cloud and maintain access to cloud services despite disruptions in network communication.