Controlling Data-Flow in the Cloud

A big obstacle for using cloud services is that users have no control over the locations where their data are stored or processed, respectively. This paper presents a program analysis approach that enables clients to negotiate services with undesired locations. Clients may only use services that guarantee not to use (directly or indirectly) services on undesired locations for processing or storing the clients' data. In order to increase trust in the answers given by services during the negotiation process, a cryptographic approach similar to Web page certification is proposed. We show that a static data-flow analysis combined with a cryptographic approach ensures that clients' data do not reach undesired locations in the cloud.