Data Confidentiality: to which extent cryptography and secured hardware can help

Data confidentiality has become a major concern for individuals as well as for companies and administrations. In a classical client-server setting, the access control management is performed on the server, relying on the assumption that the server is a trusted party. However, this assumption no longer holds given the increasing vulnerability of database servers facing a growing number of external and even internal attacks. This paper studies different alternatives exploiting cryptographic techniques and/or tamper-resistant hardware to fight against these attacks. The pros and cons of each alternative are analyzed in terms of security, access control granularity and preserved database features (performance, query processing, volume of data). Finally, this paper sketches a hybrid approach mixing data encryption, integrity control and secured hardware that could pave the way for future highly secured DBMS.