A communications system and method is provided to reliably protect communication systems, such as mobile phone systems, from unauthorized use, as well as to make the interception of wireless communication more difficult. Specifically, the static wireless phone number or other similar identifiers are not used for identification and authorization during communication between the mobile unit and a base station. Instead, a set of private identifiers is determined and is known only to the phone company and the base stations controlling the mobile phone calls. These private identifiers allow dynamic and continual updating of the mobile phone and base station directories with current valid identifiers that are used for communication between the devices.