Patent ID: 8781132

Claim:
A method of group rekeying radios for link layer encryption (LLE) in a radio network comprising a plurality of network locations, the method comprising, at a radio network communications device: broadcasting a first key announcement broadcast (KAB) outgoing signalling packet indicating (i) a first group key link layer encryption key (GKEK) used for LLE encrypting and decrypting updated future LLE keys (LEKs), the updated future LEKs to be used for LLE encrypting and decrypting inbound and outbound group communications between a base station and mobile stations operating within a corresponding coverage area of the base station, and (ii) at least a second GKEK; receiving, via respective authentication response inbound signalling packets from each of the mobile stations, an indication of which GKEKs each mobile station has in its possession, and storing the indications; determining, as a function of the indications of which GKEKs each mobile station has in its possession, which one of the first GKEK and the second GKEK to use in encrypting a first updated future LEK; and causing the first updated future LEK to be encrypted via the determined one of the first GKEK and the second GKEK, and to be broadcast to the mobile stations.