Multicast communications are expanded to include the concept of private multicasts. An address space dedicated to multicast is partitioned into a subspace for public multicasts and a subspace for private multicasts. A public key/private key encryption pair is used for private multicasts and installed...http://www.google.com.tw/patents/US6816966?utm_source=gb-gplus-share專利 US6816966 - Techniques for securing data flow in internet multicasting
