Efficient and Verifiable Proof of Replication with Fast Fault Localization

Proof of replication technique has been widely used to verify whether the cloud service providers (CSPs) store multiple replications of a file with dedicated and unique storage space, which effectively prevents CSPs from colluding and storing only one copy of the file. In this field, many representative schemes have been proposed and applied to various scenarios. However, most of the existing schemes are based on the timing assumption (i.e., the verifier rejects the proof of replication if the prover’s response is timeout) and do not explicitly consider the problem of batch verification and fault localization. This will bring unnecessary computational overhead to the verifier and reduce the efficiency of batch auditing. To address the above problems, we propose a verifiable proof of replication scheme with fast fault localization and high efficiency. By integrating incompressible encoding and homomorphic linear authenticator, our scheme can effectively audit the integrity of file replications without timing assumptions. To support batch verification and fault localization, we propose a reversed signature aggregation tree (Rev-tree) by integrating the quick binary search and exponent testing. Compared with the traditional binary tree, Rev-tree can further reduce the overhead of batch verification and effectively locate a single fault replication. Moreover, benefit from the property of Rev-tree taking the existing error probability as an estimate of the rest of the tree, our scheme can adjust the verification strategy dynamically to meet with different situations. Finally, security analysis and experimental results show that our scheme is secure and efficient in proof of replication and fast fault localization.