Restricted adaptive oblivious transfer

• Published in: Theoretical computer science Vol. 412; no. 46; pp. 6498 - 6506
• Main Author: Herranz, Javier
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 28.10.2011; Elsevier
• Subjects: Additives; Applied sciences; Computer science; control theory; systems; Constrictions; Construction; Cryptography; Data processing. List processing. Character string processing; Exact sciences and technology; Homomorphic encryption; Information systems. Data bases; Memory organisation. Data processing; Miscellaneous; Oblivious transfer; Policies; Protocol (computers); Secret sharing; Software; Theoretical computing; Oblivious transfer; Homomorphic encryption; Secret sharing; Primitive; Protocols; User; Computer theory; Sequential method; Database; Encryption
• ISSN: 0304-3975; 1879-2294
• DOI: 10.1016/j.tcs.2011.06.023

In this work we consider the following primitive, that we call restricted adaptive oblivious transfer. On the one hand, the owner of a database wants to restrict the access of users to this data according to some policy, in such a way that a user can only obtain information satisfying the restrictions imposed by the owner. On the other hand, a legitimate user wants to privately retrieve allowed parts of the data, in a sequential and adaptive way, without letting the owner know which part of the data is being obtained. After having formally described the components and required properties of a protocol for restricted adaptive oblivious transfer, we propose two generic ways to realize this primitive. The first one uses a cryptographic tool which has received a lot of attention from the literature in recent years: cryptosystems which are both multiplicatively and additively homomorphic. Our second generic construction is based on secret sharing schemes.