Oblivious Outsourced Storage With Delegation

In the past few years, outsourcing private data to untrusted servers has become an important challenge. This raises severe questions concerning the security and privacy of the data on the external storage. In this paper, the authors consider a scenario where multiple clients want to share data on a server, while hiding all access patterns. They propose here a first solution to this problem based on Oblivious RAM (ORAM) techniques. Data owners can delegate rights to external new clients enabling them to privately access portions of the outsourced data served by a curious server.