A Privacy-Preserving Access Control Protocol for Database as a Service

Database as a Service (DaaS) is a common service mode in Cloud Computing. Based on Feldman (t,n) VSS protocol and ElGamal homomorphism property, we proposed a privacy-preserving access control protocol for DaaS. Using Secret Sharing, we can protect the security of data owner´s dataset, based on ElGamal homomorphism property, the data requester´s query combining with the proxy servers´ access control strategy, the data requesters can obtain the query results when they have enough permission. Theoretical analysis shows that without the Trust Third Party, the protocol can hide the proxy servers´ access control information, while protecting both the data owner´s and the data requesters´ privacy.