Abstract: A secure and efficient key management system for utilizing a service key for retrieving service data transmitted to a terminal from a service center via a communication channel. A service key is inserted into a terminal and is used to enable the decryption of the received encrypted service data from the service center. The service center requests and obtains a coding key from a trust center when the service center receives a service key transmission request from the from the terminal. The service key transmission request includes a terminal identity number. The service center forwards the request to the trust center which returns the coding key associated with a decoding key corresponding to the specific terminal. The service center encrypts the service key with the coding key and transmits the service key to the terminal. The service key is decrypted in the terminal using the decoding key input to the terminal by the terminal manufacturer.

Abstract: A method for accessing at least a portion of the data on a microprocessor card, such as a Subscriber Identity Module (SIM) card having at least one freely accessible card number for use with mobile phones. A separate master card uses a self-contained key and encryption algorithm together with the accessible SIM card number to generate a first identification number that is communicated to and stored on the SIM card during initial programming of the SIM card. When access to data stored on the SIM card is thereafter required, a second identification number is calculated in the same manner, is communicated to the SIM card, and is compared on the SIM card with the stored first identification number. Access to the data stored on the SIM card is granted only when the first and second identification match.