Alexandra Boldyreva Nut Taesombut Online Encryption Schemes: New Security Notions and Constructions. 1-14 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2964&spage=1 2004 conf/ctrsa/2004 CT-RSA db/conf/ctrsa/ctrsa2004.html#BoldyrevaT04