Balancing confidentiality and efficiency in untrusted relational DBMSs

Ernesto Damiani, S. De Capitani Di Vimercati, Sushil Jajodia, Stefano Paraboschi, Pierangela Samarati

Research output: Contribution to journalConference articlepeer-review

271 Scopus citations


The scope and character of today's computing environments are progressively shifting from traditional, one-on-one client-server interaction to the new cooperative paradigm. It then becomes of primary importance to provide means of protecting the secrecy of the information, while guaranteeing its availability to legitimate clients. Operating on-line querying services securely on open networks is very difficult; therefore many enterprises outsource their data center operations to external application service providers. A promising direction towards prevention of unauthorized access to outsourced data is represented by encryption. However, data encryption is often supported for the sole purpose of protecting the data in storage and assumes trust in the server, that decrypts data for query execution. In this paper, we present a simple yet robust single-server solution for remote querying of encrypted databases on untrusted servers. Our approach is based on the use of indexing information attached to the encrypted database which can be used by the server to select the data to be returned in response to a query without the need of disclosing the database content. Our indexes balance the trade off between efficiency requirements in query execution and protection requirements due to possible inference attacks exploiting indexing information. We also investigate quantitative measures to model inference exposure and provide some related experimental results.

Original languageBritish English
Pages (from-to)93-102
Number of pages10
JournalProceedings of the ACM Conference on Computer and Communications Security
StatePublished - 2003
EventProceedings of the 10th ACM Conference on Computer and Communications Security, CCS 2003 - Washington, DC, United States
Duration: 27 Oct 200331 Oct 2003


  • Cryptography
  • Database service
  • Indexing


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