We consider a setting where records containing sensitive personal information are stored on a remote database managed by a storage provider. Each record in the database is co-owned by a fixed number of parties called data-subjects. The paper proposes a protocol that allows data-subjects to grant access to their records, to self-approved parties, without the DB manager being able to learn if and when their records are accessed. We provide constructions that allow a Receiver party to retrieve a DB record only if he has authorizations from all owners of the target record (respectively, from a subset of the owners of size greater than a threshold.) We also provide a construction where owners of the same record do not have equal ownership rights, and the record in question is retrieved using a set of authorizations consistent with a general access structure. The proposed constructions are efficient and use a pairing-based signature scheme. The presented protocol is proved secure under the Bilinear Diffie-Hellman assumption.
展开▼
