inserts the device, it will receive a new sequence and the old copied one will be useless thereafter. If the thief has gotten to his machine during the night, he may be able to act into the net; but when the user attempts to start up in the morning the thief's device will no longer work, thus flagging the fact that penetration has occurred. This concept appears particularly attractive in office environments where physical structures and guarding arrangements will not be sufficiently rigorous to assure that crypto-equipments cannot be accessed by unauthorized people. References External links Article on STU-III and CIK by Jerry Proc KSD-64 at Crypto Museum Encryption device accessories Key management National Security Agency encryption devices