Communication method operable between two stations in communications network - transmitting messages between network access points by associated two interfaces, which have message encryption and decryption devices, respectively

摘要

When two stations (30,31), from among many, are authorised to communicate over the network (1) the message is encrypted before transmission, and decrypted by the receiving station. After encryption an unencrypted code word is added to the message. This is used by the receiving station to control the integrity of the message. Stations are connected to the network via access points (10, 19, 20, 29) and associated interfaces (8, 9). Each interface includes devices for encrypting and decrypting messages. ADVANTAGE - Avoids network difficulty in handling different protocols used by different types of station, by transferring any restrictions to level of stations themselves or their interfaces. Message reception independent of message frame content.