| 摘要 |
A distributed firewall is utilized in conjunction with a memory-mapped serial communications interface such as that defined by the IEEE 1394 specification to permit secure data transmission between selected nodes over the interface. The distributed firewall incorporates security managers in the selected nodes that are respectively configured to control access to their associated nodes, thereby restricting access to such nodes to only authorized entities. The security manager in at least one of the nodes is implemented in the physical (PHY) layer for the communications interface. The security manager controls access to its associated node by selectively modifying data packets received from unauthorized entities in such a manner that acceptance of the modified data packets by the link layer is inhibited, e.g., by modifying the checksum in a data packet so that, upon receipt by the link layer of the associated node, the data packet is determined to be invalid by the link layer. As a result, the link layer may disregard the data packet so that effectively the unauthorized attempt to access the node is ignored.
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