ON THE DESIGN OF A SECURE ANONYMOUS CONFERENCE KEY DISTRIBUTION-SYSTEM

Consider a broadcasting network system. A secure anonymous conference has the property that, except for the chairperson, any member(even he is one of the legitimate members of the conference) has no knowledge a bout who are other legitimate or illegitimate members in the conferenc e. Extended from the Diffie-Hellman public key distribution system (PK DS), we propose a secure anonymous conference key distribution system (CKDS) by a geometric approach. Initially, each user in the system is assigned a secret key and a public key by the Diffie-Hellman PKDS. For originating a secure conference, the chairperson, ie. the originator, first randomly chooses a conference key CK and embeds the CK into two public interpolating polynomials. Only the legitimate conference memb ers can individually recover the CK by using their own secret keys alo ng with these two public interpolating polynomials. Afterwards, member s of the conference can communicate secretly by broadcasting messages encrypted by CK. The security of our CKDS is based on the Diffie-Hellm an PKDS. Further, the degree of each public interpolating polynomial i s about to the number of legitimate conference members. So that the tr ansmission cost for originating a secure anonymous conference is accep table. The replay and impersonating attacks on our CKDS are also dissc ussed.