Proof of Storage (POR or PDP) is a cryptographic tool, which enables information proprietor or third-party auditor to audit integrity of information stored remotely in a cloud storage server, without keeping a local copy of information or downloading information back during auditing. We observe that all existing publically verifiable POS plans to experience the ill effects of a serious drawback: It is slow to authentication tags for all information blocks, due to many expensive group exponentiation operations. Surprisingly, it is even much slower than regular organize transferring speed and turns into the bottleneck of the setup period of the POS conspire. We propose another variant formulation called “Delegatable proof of Storage”.
In this new relaxed formulation, we can develop a POS plot, which on one side is as proficient as private key POS plans, what’s more, on the opposite side can bolster the third party auditor and can switch auditors whenever near the functionalities of publically verifiable POS plans. Compared with traditional publicly obvious POS plans, we speed up the tag generation process by at least several hundred times, without sacrificing efficiency in some other aspect. In the same way as other existing plans, we can likewise speed up our tag generation process by N times utilizing N CPU cores in parallel. We demonstrate that our plan is sound under Bilinear Strong Diffie-Hellman assumption, and it is privacy preserving against auditor under the Discrete Log assumption. The two verifications are given in the standard model.
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