Patent attributes
A network usage control method comprises receiving (S2, S5) a handset identifier (e.g. an IMEI number) of a requesting terminal device (2) seeking to use a mobile network (4); retrieving verification information (S7) for verifying an identity of an authorised terminal device associated with the handset identifier; verifying (S9), based on the verification information, whether the requesting terminal device (2) is the authorised terminal device; and controlling (S10, S11) usage of the mobile network by the requesting terminal ON device in dependence on whether the requesting terminal device is verified as the authorised terminal device. Cryptographic keys can be used to bind the handset identifier to a particular handset and verify that a device presenting a given handset identifier is actually the authorised handset for that handset identifier. This prevents thieves being able to circumvent blacklisted handset identifier of a stolen handset by cloning a valid handset identifier from another device.
