Efficient Group Proof of Storage with Malicious-Member Distinction and Revocation

Proof of Storage (POS) is a system utilized by a client to verify whether the original data is intact while being possessed by an untrusted server. In a grouping application, multiple members share and verify the same file, and the group manager is responsible for determining if the data has been manipulated based on the responses from group members. However, a malicious member may repudiate a correct proof; therefore, it is important to distinguish the honest members from malicious ones. To the best of our knowledge, none of the existing group-oriented schemes have solved this challenge efficiently and up to the desired satisfaction. In this paper, based on matrix calculation, pseudo-random functions, and commitment functions, we propose a new Group Proof of Storage with Malicious-Member Distinction and Revocation scheme (DR-GPOS). Specifically, in terms of functionality, DR-GPOS can distinguish and revoke the malicious members, as well as, guarantee the integrity and deduplication of the outsourced data. From a security perspective, DR-GPOS can also resist against selective attacks and the collusion attacks from the revoked members (e.g. forging proofs by colluding with the server). The security properties of the proposed schemes have also been formally proven in a standard model. We have further implemented it in a real-world (Baidu) cloud server, to evaluate the performance with large scale data (> 10 G).