Efficient and Secure Group based Collusion Resistant Public Auditing Scheme for Cloud Storage

Abstract

Tremendous changes have been seen in the arena of cloud computing from previous years. Many organizations share their data or files on cloud servers to avoid infrastructure and maintenance costs. Employees from different departments create their specific groups and share sensitive information among group members. Revoked users from the group may try to access this information by colluding with an untrusted cloud server. Many researchers have specified revocation procedures using re-signature, proxy-re-signature concept to deflect the collusion between the cloud server and a revoked user. But these techniques are costly in terms of communication overhead and verification cost if combined with auditing techniques to prove the integrity of outsourced data on the cloud server. To reduce this cost, a collusion resistant public auditing scheme with group member revocation is proposed in this paper. In this scheme, the data owner regularly updates the recent valid members list which is used by a third-party auditor to validate the signature so that collusion can be avoided. To verify the integrity of outsourced data, proposed scheme uses one of the modern cryptographic technique indistinguishability obfuscation combined with a one-way function which can reduce the verification time significantly. Experimental results show that the proposed scheme decreases the communication overhead and verification cost compared to existing schemes.