Towards practical privacy-preserving digital rights management for cloud computing

We propose a privacy-preserving digital rights management scheme for (future) cloud computing. Users buy software from software providers and execute it at computing centers. Our solution allows software providers to provide different license models, like execute at most n-times models. Users´ anonymity and unlinkability of actions are preserved and thus, profile building is not even possible under (a) pseudonym. Privacy protection in the honest-but-curious model is achieved by combining ring signatures with an anonymous recipient scheme. We employ secret sharing in a unique manner that allows the software provider to expose the user´s identity if the user commits fraud, e.g. by exceeding the execution limit n.