SESIV: Secure and efficient smart contract based integrity verification of outsourced data

Securing remote data storage is a serious concern in cloud computing. Though it provides cost-saving benefits for data owners, it poses security risks due to losing physical control over data. As a result, ensuring data integrity through auditing services becomes essential while preserving privacy. Therefore, researchers propose many public data auditing schemes using third-party auditors to alleviate computational burdens on the user side. However, a concern in the public auditing approach is the susceptibility to malicious behaviour of third-party auditors, which might compromise the accuracy and timeliness of auditing results. Existing solutions built upon RSA signatures and bilinear pairings often incur substantial computation and communication costs, rendering their integrity verification models inefficient and impractical. Recent proposals have used blockchain technology for public auditing schemes to address these challenges. This work presents a secure and efficient privacy-preserving data integrity verification model using smart contract, for outsourced data. Further, we extend the proposed scheme to support multiple owners, batch integrity verification, and dynamic auditing. The proposed scheme leverages digital signatures and public-key cryptography to ensure data integrity and secure authentication. The key aspect of the proposed scheme is to validate data integrity with minimal computational overhead for the auditor with a verification time of 0.143 ms (independent of the number of shard messages $n$ and number of challenge blocks $c$), which is 33.33% lower than that of WWH scheme. The security analysis and implementation result show that the proposed scheme is secure and efficient.