Krista Bennett Christian Grothoff Tzvetan Horozov Ioana Patrascu Efficient Sharing of Encrypted Data. 107-120 2002 conf/acisp/2002 ACISP http://link.springer.de/link/service/series/0558/bibs/2384/23840107.htm db/conf/acisp/acisp2002.html#BennettGHP02