Abstract: Security is one of the key factors for the equipment of VANET（Vehicular Ad Hoc Network） on the military motorcade. The security, integrity and non-repudiation of VANET can be satisfied by an important technique——encryption. The traditional encryption technique, which is based on Hash function, has been proven that it can be attacked by differencing the modes. This paper presents a dynamic encryption scheme of VANET based on the compound chaotic mapping. The compound chaotic mapping is used in the image encryption transmission by constructing an experimental system of VANET. This system has the functions of multiple hop transmission and network topology display. The results indicate that the encrypted image has the feature of pseudo-randomness and initial value sensitivity. Therefore, effective encryption and higher security can be provided by this scheme.

Key words: VANET, image encryption, chaotic mapping, Lyapunov index

摘要： 安全性是决定车载自组网能否应用到军品运输车队中的一项关键因素，加密技术是满足车载自组网保密性、完整性和不可否认性等安全需求的重要技术手段。基于传统Hash函数的加密技术已被证实可通过“模差分”方法进行攻击，提出了一种基于改进复合混沌映射的车载自组网动态加密方案，并搭建了具备多跳传输能力和网络拓扑展示功能的车载自组网实验系统。将复合混沌映射加密方案应用于该车载自组网实验系统的图像加密传输，实验结果表明经加密后的图像具有较好的伪随机特性和初始值敏感性，因此该方案具有良好的加密效果和较高的安全性。

关键词: 车载自组网, 图像加密, 混沌映射, Lyapunov指数