摘要隐蔽信道的概念最初是由Lampson在1973年提出，其给出的隐蔽信道的定义为：不是被设计或本意不是用来传输信息的通信信道。随着计算机网络的发展，网络数据流中利用隐蔽信道来进行非法通信已逐渐成为威胁网络信息安全的一种重要手段。许多研究者对传输层和网络层进行研究，构造了大量网络隐蔽信道。但是，随着防火墙和NAT设备的广泛使用，单纯利用这两层构造隐蔽通道变得困难。更多的研究者把目光投向对HTTP等应用层协议的网络隐蔽信道进行研究。本文讨论了网络中基于应用层HTTP协议构造隐蔽信道的方法，提出了一种利用HTTP首部字母的大小写变换构造隐蔽信道的实现方法和性能分析。完成的主要工作如下：61643

    （1）对网络隐蔽信道的相关技术进行总结和归纳。

（2）需求调研和分析。

（3）分析利用HTTP首部字母大小写变换构造网络隐蔽通道的可行性方案。

（4）在Windows平台下，编程实现各功能模块。

毕业论文关键字  隐蔽信道  HTTP协议  网络信息隐蔽

Title   Design and Implementation the covert channel based on The HTTP header case transforms                                                   

Abstract Covert channel concept was originally proposed in 1973 by Lampson, it is defined as: not designed or intended communication channel that used to transfer information.With the development of computer networks, network data stream in the use of covert channels for illegal communication has gradually become an important means of the threat of network and information security.Many researchers have studied the transport layer and the network layer, constructed a large number of network covert channel.However, with the widespread use of firewalls and NAT devices, the simple use of this two-layer structure covert channel becomes difficult.More researchers turn their gaze to study the network application layer protocols such as HTTP covert channel.This article discusses the method of network covert channel based on the application layer HTTP protocol structure, the first letter of a use HTTP-sensitive transition structure covert channel implementation and performance analysis.The main work completed as follows:

（1）Collate and summarize the related technologies about network Covert Channels.

（2）Research and analysis the needs of the project.

（3）Analysis the feasibility programs that use HTTP header letter case conversion to construct network covert channel .

（4）On Windows platform, programming realization of each functional module.

Keywords  Covert channel  HTTP protocol  Network information hidden

摘    要 I

目    次 I

1 引言 1

1.1 信息隐藏技术研究背景 1

1.2 信息隐藏技术的概念和特点 1

2 网络隐蔽信道 2

2.1 网络隐蔽信道的发展情况 2

2.2 网络隐蔽信道与网络安全 3

3 NDIS驱动程序 4

3.1 开发环境配置 4

3.2 NDIS驱动概述 5

3.3 NDIS小端口驱动和协议驱动 7

3.4 NDIS中间层驱动 8