An efficient framework for verifiable access control based dynamic data updates in public cloud

Abstract

Attribute-based encryption enables the users to get the data only if attributes of the users are satisfied with the access policy embedded in the ciphertext. Whenever it is used in a collaborative environment, user’s claim policy has to be verified before permitting them to update the data. In the existing system, it is verified by the computationally expensive attribute-based signature. We are proposing an efficient method to compute the signature of the encrypted message and claim policy, which enables claim policy verification and thereby allow the users to modify the data. In this system, public cloud server (PCS) permits the users to modify the outsourced data in the cloud after verifying the user’s claim policy signature. It does not disclose the claim policy to the cloud service provider, PCS, and unauthorized users. Data owner is able to verify the integrity of the outsourced data set to ensure that the data is always intact with him. He can also validate the updated data by incorporating the signature. The proposed scheme is privacy preserving and avoids insider attack.