分析链路通信协议和网络驱动程序接口规范(NDIS)结构,提出一种基于加密以太网卡的链路通信系统方案,讨论该方案在NDIS中的设计及实现原理,给出通信协议在微端口驱动程序中的实现方法,并对通信密钥的保护和使用方式进行分析和设计。该链路通信系统加/解密透明、安全性高、运行效率高,适用于构建安全局域网。 This paper analyzes link communication protocol and network driver interface specification (NDIS) structure, proposes a link communication system scheme based on encrypted Ethernet card, discusses the design and implementation principle of this scheme in NDIS, Procedures to achieve the method, and the communication key protection and use of the way to analyze and design. The link communication system encryption / decryption transparent, high security, high efficiency, suitable for building a secure local area network.