Taenam Cho Sang-Ho Lee A Key Recovery Mechanism for Reliable Group Key Management. 372-386 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2846&spage=372 2003 conf/acns/2003 ACNS db/conf/acns/acns2003.html#ChoL03