Ernesto Damiani Sabrina De Capitani di Vimercati Sara Foresti Sushil Jajodia Stefano Paraboschi Pierangela Samarati An Experimental Evaluation of Multi-Key Strategies for Data Outsourcing. 385-396 2007 SEC http://dx.doi.org/10.1007/978-0-387-72367-9_33 conf/sec/2007 db/conf/sec/sec2007.html#DamianiVFJPS07