A universal method for realizing non-repudiable provable data possession in cloud storage

Provable data possession (PDP) and proofs of retrievability (POR) are techniques for a client to verify the integrity of outsourced data on an untrusted server, and numerous PDP/POR schemes with public or private verification have been proposed so far. However, existing schemes cannot handle the following issue satisfactorily: Driven by profits, a malicious client may accuse an honest server and repudiate the correct proof of data possession. Based on the commitment function, we present a universal method that can reform any private verification PDP/POR scheme into a non-repudiable PDP (NRPDP)/POR scheme. As a case study, we propose a concrete NRPDP scheme with private verification, which allows both the client and the server to prove their innocence and verify whether the other side is honest. Moreover, we prove the security of both the method and NRPDP in the random oracle model and implement a prototype based on the NRPDP scheme in a realistic cloud platform. Experimental results on large dataset (10GB) show that the NRPDP can be executed efficiently as private verification schemes and outperforms the public schemes more than 60% in terms of verification time. Foremost, non-repudiation can be guaranteed efficaciously in NRPDP.