Cryptographic initialisation wherein RNC server instructs one communication partner to add an encryption flag to and begin encrypting its communications

摘要

A RNC server (103) operating in a C-plane (control plane) issues an encryption-start instruction (53-1) to a media gateway (MG) (104) or a terminal (200) operating in the U plane (user plane). Whichever of the MG and terminal, receives the instruction, encrypts U-Plane information using a predetermined secret key, and adds a predetermined encryption-start bit to the encrypted U-Plane information (53-2) for transmission to the other (53-3) (its communication partner). The communication partner, upon detection of the encryption-start information, decrypts the received U-Plane information using the predetermined secret key. The system may be used with IMT-2000 system configurations and should result in faster set up than the conventional system of specifying a frame number for encryption to commence.