| 摘要 |
In a mobile radio communications system comprising mobile radio units and a fixed infrastructure including a key management controller for managing the encryption keys used for secure communication, each mobile radio unit is provided with means which enable the user or the unit itself to initiate deletion of an encryption key, eg as a consequence of tamper detection or perceived threat to the user, and also with means which are capable of sending a key deletion report (which may be a deletion initiated, deletion successfully completed and/or deletion unsuccessful report) to the key management controller. On the basis of received report(s) from a unit, the system can determine whether an encryption key has been deleted successfully and only discard a key on the likelihood that it has been compromised. The key deletion reports can be pre-encrypted using the current encryption key in that unit and then sent on successful deletion of that key; acknowledgements back from the management controller can also be verified against pre-encrypted expected acknowledgements even after deletion of that key. Time lags in reporting deletions can also be used to assess likelihood of a key being compromised. |
