Date Added: Apr 2012
With cloud computing and storage services, data is not only stored in the cloud, but routinely shared among a large number of users in a group. It remains elusive, however, to design an efficient mechanism to audit the integrity of such shared data, while still preserving identity privacy. In this paper, the authors propose Knox, a privacy-preserving auditing mechanism for data stored in the cloud and shared among a large number of users in a group. In particular, they utilize group signatures to construct homomorphic authenticators, so that a Third Party Auditor (TPA) is able to verify the integrity of shared data for users without retrieving the entire data.