Patent ID: 7864961

Claim:
A method of managing a mobile multicast key using a foreign key, comprising: a first step of allowing a first secure relay server to search a list of secure relay servers which are connected to the access point controlling a region where microwaves to a mobile terminal overlap, to find a second secure relay server, the mobile terminal currently subscribing to the first secure relay server; a second step of allowing the first secure relay server to request the second secure relay server to delegated authenticate the mobile terminal on behalf of the mobile terminal and allowing the first secure relay server to join a multicast group of the second secure relay server; a third step of allowing the second secure relay server to transmit a foreign group key and multicast address information to the first secure relay server, after the second secure relay server accepts to delegated authenticate the mobile terminal; and a fourth step of allowing the second secure relay server to transmit multimedia stream to the mobile terminal using the foreign group key and allowing the mobile terminal to remote-subscribe to the second secure relay server.