A case for the accountable cloud

For many companies, clouds are becoming an interesting alternative to a dedicated IT infrastructure. However, cloud computing also carries certain risks for both the customer and the cloud provider. The customer places his computation and data on machines he cannot directly control; the provider agrees to run a service whose details he does not know. If something goes wrong - for example, data leaks to a competitor, or the computation returns incorrect results - it can be difficult for customer and provider to determinewhich of themhas caused the problem, and, in the absence of solid evidence, it is nearly impossible for them to hold each other responsible for the problem if a dispute arises. In this paper, we propose that the cloud should be made accountable to both the customer and the provider. Both parties should be able to check whether the cloud is running the service as agreed. If a problem appears, they should be able to determine which of them is responsible, and to prove the presence of the problem to a third party, such as an arbitrator or a judge. We outline the technical requirements for an accountable cloud, and we describe several challenges that are not yet met by current accountability techniques.