Patent ID: 8140844
Filing Date: 2012-03-20
Classification: H04L

Abstract:
1. A server apparatus for managing an encryption key used for multicast communication between a plurality of terminals, the server apparatus comprising: a first storage unit configured to store therein presence information including a communication state of the terminals; a second storage unit configured to store therein in associated manner a terminal identifier unique to each of the terminals and an encryption key to be used for multicast communication within a multicast group to which each of the terminals belongs; a receiving unit configured to receive a subscription request message from a first terminal from among the terminals, the subscription request message including a first terminal identifier unique to the first terminal and a request requesting subscription to presence information stored in the first storage unit; an acquiring unit configured to acquire a first encryption key to be used for multicast communication within a first multicast group to which the first terminal belongs from the second storage unit by using the first terminal identifier; and a transmitting unit configured to transmit an acquired first encryption key to the first terminal together with the presence information requested for subscription.