| 摘要 |
A method of encrypting information to be transmitted in a wireless communication system employing an encryption protocol that uses an encryption key, the method characterised by the steps of:<BR> ```combining an individual identifier (e.g. a layer-2 MAC identity) related to a transmission sender with a shared key related to a type of transmission to form a transmission encryption key; and<BR> ```encrypting a transmission using said transmission encryption key. The invention could be applied in an internet protocol (IP) data network, where the layer-3 source ID of a packet could be used as a key modifier in a transmission where the contents of the packet are encrypted. Furthermore, the shared key may relate to any type of transmission, such as an emergency group call, pre-emptive priority call, an encrypted broadcast call or any other mobile radio communication where encryption is used. The system is operable in a direct mode of operation (DMO) and the manner of combining the individual identifier with a shared key can be changed, the change being notified to other users of the shared key. |
