System and method for transmitting and receiving secret information, and wireless local communication device using the same

A method for transmitting and receiving secret information between a device and a wireless local communication device over a location-limited channel, the method comprising:

• transmitting public key information from the wireless local communication device to the device;
• generating, at the device, a ciphertext using the public key information and transmitting the generated ciphertext to the wireless local communication device;
• and
• decrypting the received ciphertext at the wireless local communication device.

A control data transmission method, comprising:

• sending a public key over a location-limited channel by a control device;
• generating a cipher text by a controlled device using the public key;
• sending the cipher text over the channel;
• encrypting of the control data by the control device using the cipher text;
• sending the encrypted control data over the channel;
• and
• decrypting the control data by the controlled device using the cipher text.

A control data transmission system, comprising:

• a location-limited channel;
• a control device sending a public key over the channel;
• and
• a controlled device receiving the public key over the channel, generating a cipher text using the public key and sending the cipher text over the channel, and wherein the control device encrypting of the control data using the cipher text and sending the encrypted control data over the channel, and the controlled device decrypting the control data using the cipher text.