Patents Represented by Attorney John R. Untermohle

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  • Secure communication system having long-term keying variable
    Patent number: 5428686
    Abstract: A secure communication apparatus incorporates a longterm, non-extractable master key variable which is held in common by all terminals. A pseudorandom bit sequence generator within the transmitter provides a binary bit stream which is transmitted unencrypted to the intended receiver. Both terminals simultaneously mix the master variable with the transmitted pseudorandom bit stream in an identical manner to create a common separate working variable which is subsequently used for data encryption and decryption.
    Type: Grant
    Filed: September 28, 1981
    Date of Patent: June 27, 1995
    Assignee: The United States of America as represented by the Direrctor of the National Security Agency
    Inventors: Carl D. Brown, Robert T. Kearns, Joseph A. Kersey