SDL specification of a security architecture for WorldFIP

Fieldbuses are special purpose local area networks (LAN) used to connect all kinds of devices in a factory. The paper discusses security in fieldbuses, and presents a security architecture, such as WorldFIP (World Factory Instrumentation Protocol), for centralized fieldbuses. The discussion takes into account, on one hand, the security services defined by the OSI security architecture, and, on the other hand, the security mechanisms defined by WorldFIP. The discussion shows that there are two critical points for attacking this network: the bus arbitrator and the bus. The paper presents the specification, using the specification and description language (SDL), of a security architecture for WorldFIP based on the RC4 algorithm, which is a lightweight cryptographic stream cipher.