Kyu Young Choi Jung Yeon Hwang Dong Hoon Lee Efficient ID-based Group Key Agreement with Bilinear Maps. 130-144 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2947&spage=130 2004 conf/pkc/2004 Public Key Cryptography db/conf/pkc/pkc2004.html#ChoiHL04