Flexible identity-based remote data integrity checking for cloud storage with privacy preserving property

Provable data possession (PDP) protocol is a mechanism that guarantees the integrity of user’s cloud data, and many efficient protocols have been proposed. Many of them ignore data’s privacy against the third-party auditor (TPA) and also suffer from intricate management of certificates, which heavily relies on the public key infrastructure (PKI). In order to overcome the two shortcomings, Li et al. recently proposed an “identity-based” (IB) PDP protocol with the privacy-preserving property (IEEE Syst J, https://doi.org/10.1109/JSYST.2020.2978146 ). However, we find out that (1) their protocol has great communication overhead, (2) a PKI-based signature scheme is used as a building block, which results in their protocol is not completely identity-based. Hence, in this paper, we try to improve the performance of this protocol. Concretely, by adopting flexible data-splitting and tag-aggregating techniques, we can greatly reduce its communication overhead. A concrete example shows that the total communication overhead can be reduced over 99%. Moreover, by replacing with an identity-based signature, we can twist this protocol into a complete IB-PDP protocol.