Public Proofs of Data Replication and Retrievability with User-friendly Replication

Proofs of Retrievability (PoRs) and Provable Data Possession (PDP) are efficient cryptographic solutions to monitoring the state of storage, enabling integrity verification without the necessity of retrieving data. However, such protocols fail to guarantee data availability, since it is too late for cloud clients to recover the corrupted data when notified. To remedy it, these protocols are extended to verify integrity of both the stored data and their redundant copies in the multi-replica environment. Most of the existing multi-replica PDP protocols not only consume considerable computation and bandwidth resources of clients to generate and upload replicas, but also lead economic losses to service providers due to abused replica discounts. Though the other few considered these problems and proposed some countermeasures, they imposed the linear cost of generating and uploading copy parameters on clients in replication algorithms and fail to realize public verifiability. In this paper, we propose a public proofs of data replication and retrievability protocol with user-friendly replication for the first time. One distinguishable property is the simultaneous achievement of user-friendly replication and public verifiability. Specifically, we design a novel replication algorithm, which imposes nearly no computation and a constant-size communication cost on clients. Subsequently, we employ non-interactive succinct proofs to make the verification public. Furthermore, we present a comprehensive analysis and extensive experiments to demonstrate the security and efficiency of the proposed protocol.