Patent ID: 6941457

Claim:
A method for providing shared secret keys for communicating through a secure channel between members of a dynamically changing multicast group connected over an insecure network, the method comprising the computer-implemented steps of: computing a first shared secret key for establishing a first multicast group that includes a set of one or more first members; generating a first multicast group exchange key based on the first shared secret key; receiving a first user exchange key from a first user requesting entry into the first multicast group; computing a second secret key k 1 based on the first user exchange key and the first shared secret key according to the relation k 1 =(Y′ k mod (n)), wherein Y′ represents the first user exchange key, k represents the first shared secret key, and n is a prime number selected by themembers of the multicast group and previously used to generate the first shared secret key k; sending the first multicast group exchange key to the first user, wherein the first multicast group exchange key allows the first user to generate the second shared secret key; and establishing a second multicast group whose members include the first user and the set of one or more first members of the first multicast group, wherein the second shared secret key provides a first secure channel for communicating between members of the second multicast group over the insecure network.