A method of identifying an external device that sent a message and then determining whether to process the message based in part on the identity of the external device that sent the message. The implanted device receives a message from the external device and identifies an external device ID in the received message. The external device ID identifies the external device that sent the message. The implanted device then compares the external device ID from the message to a stored list of approved external device IDs. The implanted device processes the message when the external device ID matches one or the approved external device IDs in the stored list of approved external device IDs. However, the message is disregarded when the external device ID does not match any of the approved external device IDs in the stored list of approved external device IDs.