ACCESS CONTROL OVER MULTICAST

PROBLEM TO BE SOLVED: To securely communicate published information over a multicast communication channel without the need to generate a random key for each published information, regarding the published information of a hierarchical information aggregate. SOLUTION: A multicast host is provided for distributing information published about a plurality of topics to each of which a topic encryption key is related, to subscriber devices of these topics. The multicast host includes: a means for receiving information relating to a topic; means for accessing subscriber data 104 representing one or more users subscribing the topic; a means for retrieving a topic encryption key associated with the topic; means 150 for encrypting the information with the retrieved topic encryption key; and a means 152 for distributing the information to the one or more users. The topic encryption key is encrypted by using a logical key hierarchical structure, in which a logical key corresponds to the users, and distributed to the subscriber devices. COPYRIGHT: (C)2011,JPO&INPIT