Affiliations: [a] Dipartimento di Informatica, Università degli Studi di Milano, 26013 Crema, Italy. E-mails: sabrina.decapitani@unimi.it, sara.foresti@unimi.it, pierangela.samarati@unimi.it | [b] Center for Secure Information Systems, George Mason University, 22030-4422 Fairfax, VA, USA. E-mail: jajodia@gmu.edu | [c] Dipartimento di Ingegneria Gestionale, dell’Informazione e della Produzione, Università degli Studi di Bergamo, 24044 Dalmine, Italy. E-mail: parabosc@unibg.it
Note: [1] A preliminary version of this paper appeared under the title “Optimizing integrity checks for join queries in the cloud,” in Proc. of the 28th Annual IFIP WG 11.3 Working Conference on Data and Applications Security and Privacy (DBSec 2014), Vienna, Austria, July 2014 [8].
Abstract: Cloud computing is receiving massive interest from users and companies for its convenient support of scalable access to data and services. The variety and diversification of offers by cloud providers allow users to selectively adopt storage and computational services as they best suit their needs, including cost saving considerations. In such an open context, security remains a major concern, as confidentiality and integrity of data and queries over them can be at risk. In this paper, we present efficient techniques to verify the integrity of join queries computed by potentially untrusted cloud providers, while also protecting data and computation confidentiality. Our techniques support joins among multiple data sources and introduce a limited overhead in query computation, enabling also economical savings, as the ability to assess integrity increases the spectrum of offers that can be considered for performing the computation. Formal analysis and experimental evaluations confirm the effectiveness and efficiency of our solutions.
