Patent ID: 7272226

Claim:
A method of a first entity generating a group short term public key for use in establishing a shared secret value with a second entity in a data communication system, said first entity having a plurality of members for participation in said communication system, each of said plurality of members having a long term private key and a corresponding long term public key, said method comprising said first entity: a) generating a short term private key and a corresponding short term public key for each of said plurality of members; b) exchanging short term public keys of said plurality of members within said one entity; c) for each of said plurality of members: i. computing an intra-entity shared key by mathematically combining said short term public keys of each of said plurality of members; and ii. computing a respective intra-entity public key by mathematically combining its short term private key, its long term private key and said intra-entity shared key; and d) combining said intra-entity public keys of said plurality of members to derive said group short term public key.