Oblivious Access Control Policies for Cloud Based Data Sharing Systems

Conventional procedures to ensure authorized data access by using access control policies are not suitable for cloud storage systems as these procedures can reveal valid access parameters to a cloud service provider. In this paper, we have proposed oblivious access control policy evaluation (O-ACE); a data sharing system, which obliviously evaluates access control policy on a cloud server and provisions access to the outsourced data. O-ACE reveals no useful information about the access control policy neither to the cloud service provider nor to the unauthorized users. Through the security analysis of O-ACE it has been observed that computational complexity to compromise privacy of the outsourced data is same as reverting asymmetric encryption without valid key pair. We have realized O-ACE for Google Cloud. Our evaluation results show the fact that O-ACE CPU utilization cost is 0.01–0.30 dollar per 1,000 requests.