Daniele Micciancio Saurabh Panjwani Adaptive Security of Symbolic Encryption. 169-187 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3378&spage=169 2005 conf/tcc/2005 TCC db/conf/tcc/tcc2005.html#MicciancioP05