VPND源程序分析

Analysis for VPND program

通过对 ＶＰＮＤ（ｖｉｒｔｕａｌ Ｐｒｉｖａｔｅ ｎｅｔｗｏｒｋ ｄａｅｍｏｎ）源程序的分析，介绍了虚拟专用网络实现过程中使用到的密钥交换技术和加密机制．同时，对程序结构、流程和加密算法作了较详细的分析．该方法可用Ｉｎｔｅｒｎｅｔ代替租赁专线实现不同地点网络的安全互联．对于在世界各地拥有许多分支机构的企业来说，它是一种较为简易、实用的解决方案．

The article focuses on VPND program code. The key exchange techniques and encrypted (decrypted) method with Blowfish encryption algorithm in virtual private network implement are introduced. The architecture, flowchart and algorithm are discussed in detail. This solutions can securely interconnect networks at different places with internet instead of leased lines, which is a good solution to enterprises distributed around the world.