A secure architecture for fieldbus/Internet gateways

Gateway interconnections between fieldbus systems and IP-based LANs are becoming increasingly popular, which raises security questions. We discuss methods to secure a gateway and present two different ways to apply appropriate authentication and encryption mechanisms. Furthermore, we propose an organizational concept that is suitable for the management of authorization keys. The favored means to store and distribute the keys is smart cards; however, a scheme based on user-names and passwords is also presented as a fall-back solution with restricted access rights. Performance measurements confirm that the smart card approach is more time-consuming, but acceptable for small data packets.