Patent ID: 8275130

Claim:
A secret key registration system which registers a secret key in each of a remote communication terminal and a communication peer, which performs wireless communication with the remote communication terminal, the secret key registration system comprising: a remote communication terminal which generates a wireless signal encrypted by the secret key and transmits the encrypted wireless signal through wireless communication; a communication peer which receives the encrypted wireless signal from the remote communication terminal through the wireless communication and decrypts the encrypted wireless signal with the secret key; a writer which generates a registration code that is varied whenever registering the registration code and writes the registration code to the remote communication terminal; a first transformation equation and a second transformation equation for generating the secret key, in which the registration code is transformed with the first transformation equation to generate intermediate data, and the generated intermediate data is transformed with the second transformation equation to generate the secret key, the first transformation equation being stored in each of the writer and the communication peer, and the second transformation equation being stored in each of the remote communication terminal and the communication peer; wherein the writer is configured to transmit the registration code to the remote communication terminal, apply the registration code to the first transformation equation stored in the writer to generate the intermediate data, and transmit the intermediate data to the remote communication terminal, wherein the remote communication terminal is configured to apply the intermediate data to the second transformation equation stored in the remote communication terminal to generate the secret key, register the generated secret key in the remote communication terminal, and transmit the registration code stored in the remote communication terminal to the communication peer through wireless communication, and wherein the communication peer is configured to apply the registration code received from the remote communication terminal to the first transformation equation stored in the communication peer to generate the intermediate data, apply the generated intermediate data to the second transformation equation stored in the communication peer to generate the secret key, and register the generated secret key in the communication peer, wherein the remote communication terminal, which is separated from the writer, stores the second transformation equation but does not store the first transformation equation, and wherein the writer, which is separated from the remote communication terminal, stores the first transformation equation but does not store the second transformation equation.