设计的软件安全模块是一个外置的硬件模块，提供版权保护、核心数据加密、稳定运行监控等功能。外置安全模块采用USB与PC主机连接，通过将安全模块内的微控制器虚拟为USB大容量存储设备，实现了免驱动的便携数据通道。设计了一种基于报文的分层通信协议栈作为安全模块与PC的通信规约，实现安全可靠的数据通信，并提供通用的调用接口。以电缆载流量分析软件为应用实例，说明安全模块的使用方法。

A software security module is designed,which is an external hardware module,and can provide such functions as copyright authentication,kernel data encryption,stable operation monitoring and so on.The external module uses USB to connect with host PC,and a free driver portable data channel is achieved by taking the microcontroller of security module as a virtual USB mass storage device.A communication protocol is designed for use between the security module and PC based on packets layered communication protocol stack,and thus to implement safe and reliable data communication.The usage of the security module is illustrated by taking the software for cable ampacity analysis as an application example.