A limited tracking system and associated method that enable the use of personal encoded identification media to limit access to tracking information. The tracking system provides concurrent time-limited access to a large number of people, objects, information, services, and other resources, and has particular applicability to credit cards, dining cards, telephone calling cards, health cards, driver's licenses, video store cards, car access cards, building access cards, computer access cards, and like identification badges or cards. The tracking system includes a transmitter module incorporated in a badge, and a receiver module incorporated in a secure server. The transmitter module contains an encryptor and a watch crystal that keeps track of time, such that the encryptor encrypts the current time with the user's private key, and periodically transmits the encrypted current time to the receiver module, as a code list. The server stores the private keys of all the users, and, in turn, encrypts the current times of all the badges with the corresponding private keys of the users, to generate an authentication table. An authenticator compares the received code list to the authentication table, seeking matches that are indicative of the validity of the transmitting badges.