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.

Abstract: A mobile harvester unit provided with a row crop attachment having a plurality of laterally spaced generally fore-and-aft dividers defining one or more elongated passageways for accommodating rows of crop material. Crop severing means are disposed along each passageway for cutting crop being guided rearwardly during operation. Feeder assemblies, disposed in longitudinal alignment with the dividers, comprise gathering fingers extending from at least three rigid bars adjacent the passageways. The bars, mounted at equal intervals on rigid rotatable elements, are rotatably driven to impart intermittent rearward motion of the fingers in the passageway to urge crop toward the harvesting unit.