Group key hierarchical management method and system for broadband cluster system, and terminal

The invention provides a group key hierarchical management method for a broadband cluster system. The method comprises: a system side generating a group root key for a group, and issuing the group root key to a terminal in the group; when a group call is established, the system side generating a group call security parameter, based on the group root key and the group call security parameter, generating a non-access stratum key and an access stratum key, and issuing the group call security parameter to a listening user terminal in the group; and the system side, based on the non-access stratum key and the access stratum key, protecting the group call shared channel of the group call. The invention also provides a group key hierarchical management system for a broadband cluster system, and a terminal. According to the invention, the system side issues the group root key such that the flexibility of the group root key is improved. Besides, during the group call, a corresponding security parameter is utilized, such that the system security degree is further improved.