Hiding behind the clouds: Efficient, privacy-preserving queries via cloud proxies

This paper proposes PriView, a privacy-preserving technique for querying third-party services from mobile devices. Classical private information retrieval (PIR) schemes are difficult to deploy and use, since they require the target service to be replicated and modified. To avoid this problem, PriView utilizes a novel, proxy-mediated form of PIR, in which the client device fetches XORs of dummy query responses from each of two proxies and combines them to produce the required result. Unlike conventional PIR, PriView does not require the third-party service to be replicated or modified in any way. We evaluated a PriView implementation for the Google Static Maps service utilizing an Android OS front-end and Amazon EC2 proxies. PriView is able to provide tunable confidentiality with low overhead, allowing bandwidth usage, power consumption, and end-to-end latency to scale sublinearly with the provided degree of confidentiality.