A method and apparatus for providing cryptographic protection of a data stream are described in accordance with the Open Systems Interconnection (OSI) model for a communication system. This cryptographic protection is accomplished on the transmitting side by assigning a packet sequence number to a packet...http://www.google.com/patents/US5319712?utm_source=gb-gplus-sharePatent US5319712 - Method and apparatus for providing cryptographic protection of a data stream in a communication system
