Patent ID: 7548622

Claim:
A method for concealing a parameter transferred between a first and second device, comprising: generating, by the first device, a control signal and a parameter signal; encrypting or hashing by the first device a portion of the control signal with the parameter signal to generate an encrypted or hashed parameter signal and control signal; transmitting by the first device to the second device the control signal and the encrypted or hashed parameter signal and control signal; receiving by the second device from the first device the control signal and the encrypted or hashed parameter signal and control signal; using by the second device the control signal to decrypt or inversely transform the encrypted or hashed parameter signal and control signal; generating by the second device a destination parameter signal depending upon a comparison of the control signal and the decrypted or inversely transformed control signal; generating by the first device a key index signal; generating by the first device a key variable signal; transmitting by the first device to the second device the key index signal and the key variable signal; receiving by the second device from the first device the key index signal and the key variable signal; generating by the second device an intermediate key signal using the key index signal and a key table; and generating by the second device the second key signal using the intermediate key signal and the key variable signal.