Xerox Corp has a new electronic encryption device designed to enable government computer users to send and receive classified and unclassified messages on the same local area network. Previously, messages of different classifications needed different, and sometimes isolated, networks. The device, called the Xerox Encryption Unit, has been submitted for endorsement under the US Government Commercial Comsec Endorsement Programme as meeting Type I standards for the protection of government information of the highest classification and sensitivity. The unit is activated by inserting a key-shaped electronic Crypto Ignition Key into a slot on the front of the unit, and deactivated when the key is removed. If an attempt is made to tamper with the unit, special circuitry detects the intrusion and immediately clears all cryptographic information, at the same time sounding an alarm within the unit and switching on a red light on the panel. Circuitry for the device, including the National Security Agency-endorsed encryption microchip, was developed by the Ultron Laboratories Corp unit of Tracor Inc and costs $5,000, with availability as soon as the National Security Agency endorses the thing, which Xerox expects next quarter.