Analysis and Enhancement of a Lattice-Based Data Outsourcing Scheme With Public Integrity Verification

Recently, Zhang et al. proposed a lattice-based data outsourcing scheme with public integrity verification (DOPIV), which enables an original data owner to delegate a proxy to generate the signatures of data and outsource them to the cloud server. They employed a third party auditor (TPA) to check the integrity of the outsourced data and any TPA can verify the data integrity efficiently. DOPIV is claimed to achieve proxy-oriented secure data outsourcing as well as storage correctness guarantee. Unfortunately, we find that there exist vulnerabilities in DOPIV which allow the cloud server to simply delete the received data without being noticed by the TPA. Fortunately, we come up with a simple and efficient solution to thwart the proposed attack. Our improved scheme maintains all the features claimed in DOPIV.