Multi-stage Packet Filtering in Network Smart Cards

Network smart cards are smart cards with networking capabilities. They have opened new opportunities for the use of smart cards in Internet applications. At the same time, network smart cards are exposed to network security threats just as other computers on the Internet. Unfortunately, existing designs of network security mechanisms, such as packet filtering, may not be best suited for smart cards because the computing resources of the cards are too limited. This paper presents a new packet filtering approach that overcomes this difficulty. The packet filtering is performed in multiple stages. It drops unwanted packets as early as possible, starting at the I/O interrupt level. This builds a network firewall inside smart cards and reduces resource usage for packet processing. It can be used with different hardware and software configurations and with various filter rules. Advantages of this approach include better security, reduced memory usage, and enhanced performance.