Security Requirements and Protocols for a Broadcast Scenario

Previous work (e.g., [1], [2]) has characterized communication security requirements in connection-oriented (virtual circuit) environments supporting applications such as interactive communication and file transfer. This work has developed protocols to achieve these requirements using conventional ciphers (CC´s) such as the NBS data encryption standard (DES) [3]. More recently, several authors [4]-[6] have analyzed key distribution protocols for such environments based on CC´s and on public-key ciphers (PKC´s) such as the RSA algorithm [7], noting similarities in form, function, and vulnerability. Advances in satellite and packet radio technology [8], [9] and the development of high-speed, local area networks [10] have stimulated interest in broadcast protocols for various applications. This article examines security requirements for a simple broadcast scenario characteristic of some of these applications and develops protocols for achieving these requirements. Two sets of protocols, one based on CC´s and the other based on PKC´s, are developed and analyzed in terms of functionality and performance.