Abstract: A deciphering unit having input and output matrices connected to a master ift register to permit flexible access to its stages. The output matrix allows selection of four register positions in the master shift register from which data is fed to a correspondence generator where it is partially descrambled. Subsequently, the input matrix allows selection of four input register positions for the partially descrambled data, and one input register position for serial key shift register data. A comparison matrix selects eight bit positions to allow comparison of the descrambled master shift register data with a predetermined eight bit word. Upon favorable comparison a four bit word is transmitted to a base interrogating station for identification. Also, the same apparatus can be used for enciphering by shifting the data in the master shift register in a reverse manner.

Abstract: A system for secure communications between first and second locations where he first location measures the location of the second location. The first location then codes that measured location along with a random reply channel code for communications from the second location to the first location. The first location then transmits the two codes to the second location which decodes the two signals. The second location then measures it's own location and compares it with the received location. The newly measured location is coded and transmitted to the first station on the randomly selected reply channel.

Abstract: The device is an IFF Authentication System for sending and receiving of coded intelligence. So as to reduce an alien's chances of using the intelligence transmitted, the system uses a clock to provide signals for additional encipherment or scrambling of the coded intelligence. The clock is easily synchronized and provides continuously changing code encipherment for maximum protection and is connected into the system at a variety of predetermined places depending on the componential design of the particular system being used.