摘要： IPSec是近年来被广泛采用的网络安全协议，它的应用之一VPN网关在需求的推动下支持越来越大的安全策略库（SPDB）。由于每一个进出的IP包都涉及对SPDB的查询，因此查询算法的效率至关重要。该文设计了一种基于键树思想的SPDB组织方式和相应的查找算法，使平均查找长度大为缩短。

关键词: IPSec, 安全策略数据库, 选择符, 键树, 平均查找长度

Abstract: IPSec is a kind of network security protocol, which is popularly used these years. One of its applications, VPN gateway, supports more security policy database (SPDB) by requirement. Since each in-out IP packet involves query to SPDB, efficiency of query algorithm is most important. The article designs a kind of SPDB organization based on key tree and corresponding query algorithm, which makes average query length shorten a lot.

中图分类号: 

• TP311.131