Toru Nakanishi Masayuki Tao Yuji Sugiyama A Group Signature Scheme Committing the Group. 73-84 2002 conf/icics/2002 ICICS http://link.springer.de/link/service/series/0558/bibs/2513/25130073.htm db/conf/icics/icics2002.html#NakanishiTS02