Abstract

An apparatus for secure communications contains a controller for automatically selecting one of several data ciphering devices utilizing one of a plurality of ciphering algorithms common to transmitting and receiving terminals. A transmitter for transmitting encrypted data, and a receiver for receiving encrypted data are coupled to the plurality of ciphering devices. The controller automatically determines which of the ciphering devices to employ for any given secure communication. The method for establishing a secure communications link includes the steps of exchanging a first message for determining a common key generation and ciphering method and comparing a further shared message for validation of communications terminal security. Additionally, the steps of trading a still further message for providing data to form traffic keys to initialize key generators, interchanging an additional message for synchronizing and verifying synchronization of secure communications between secure communications terminals, and initiating secure communication are used.