【作者】 郑宇；

【导师】 何大可；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2006， 博士

【摘要】 随着无线网络与Internet的不断结合,移动通信系统经历了第一代(1G)、第二代(2G)和第三代(3G)系统的发展历程,并朝着无处不在、全IP化的下一代通用无线通信系统(4G)逐步演进。由于4G系统致力于无缝融合不同无线通信技术并支撑高速率通信环境,其安全问题比以往的无线通信系统更加复杂和难于解决。因此,世界各国在推动3G移动通信系统商用化的同时,已经把研究重点转移至4G系统的先期研究。 随着无线网络环境的不断复杂,网络实体间的信任关系、有线链路的安全、安全业务的不可否认性和安全体系的可扩展性不得不重新考虑。同时,随着移动终端(ME)的计算和存储资源的不断丰富,移动操作系统和各种无线应用的问世,ME也正面临越来越多的安全威胁。而现有无线网络安全体系对以上两方面问题考虑不够深入和全面,对效率、兼容性、可扩展性和用户可移动性的综合考虑也不够充分。此外,现有无线网络安全体系基本上是通信系统构架确立之后的附属品,直接导致了很多由通信系统自身特性而造成的无法解决的安全隐患。因此,安全体系不是4G系统出现漏洞后的“补丁”,而应作为4G体系的一部分与其它核心技术齐头并进的展开研究,并最终成为技术标准中的关键部分。 本文在分析了现有无线网络安全特性和其发展历程的基础上,根据4G无线网络的特性,确定了4G系统面临的安全威胁和安全需求,讨论了可适用于4G系统的安全策略和机制。在重点研究了移动终端(ME)安全的前提下,将USIM(Universal Subscriber Identity Module)、ME和用户视为3个独立的实体来考虑用户域的安全,提出了基于可信移动平台(TMP)和PKI相结合的4G安全体系。结合当前智能手机的主流硬件构架,给出了以智能手机主流处理器为基础的TMP实施案例,并讨论了在此平台之上的三种TPM(Trusted Platform Module)构建方法。同时,利用RSA密钥封装机制(RSA-KEM)和哈希函数设计了口令、指纹和USIM相结合的用户域三因素认证方案,实现了用户、ME和USIM间的相互认证,强化了用户域的安全,并可满足TMP中安全等级3对用户认证的要求。 随后,针对单钥和公钥体制在构建无线网络安全方案时存在的缺陷,提出了一种高效的基于自验证公钥的无线网络用户接入认证方案,以提高用户接入过程的安全性。该方案包含PKBP(公钥广播协议)和SPAKA(基于自验证公钥的认证及密钥交换协议)。其中,PKBP可使ME抵抗伪基站攻击,更多还原

【Abstract】 With the development of technologies of wireless communication, mobile communication systems have gone through the 1st generation (1G), 2nd generation (2G) and 3rd generation (3G) systems and evolve into the 4th generation (4G) system step by step. The coming 4G wireless systems focus on seamlessly integrating the existing wireless technologies and providing fast and pervasive access and service for mobile user, which will raise furhter security vulnerabilities in turn.On one hand, since the architectures of wireless network will become ever more complex in the scenario of 4G system, we have to reconsider the trusted relationship among the network entities, the security of the wired link, the scalability of the security architecture and non-repudiation of the sensitive service. On the other hand, with improving compuation capability and storage, the mobile equipment (ME) has been facing increasing security threats. However, the current security architectures for wireless network, e.g. 3G security architecture, do not take the preceding two factors into account and fail to harmonize the efficiency, scalability, compatibility, mobility and security within the system. Moreover, as a compensational patch over the existing mobile communication systems, most security architectures are really hard to solve the security risk caused by the original feature of mobile communication system. Thus during the design of the 4G system we must take the security as a critical issue into account with other core technologies and research it as a part of the future standard.In this doctor dissertation, via discussing the security features of wireless networks and analyzing the development of their security architecture, the security threats, security requirements, security policies and security mechanisms are proposed for 4G system according to 4G’s feature. Then the security architecture based on Trusted Mobile Platform (TMP) and PKI is presented to provide a considerable robust platform for user’s access to sensitive service. More attention has been paid on the security of the ME in the proposed security architecture in which user, ME and USIM (Universal Subscriber Identity Module) have been regarded as three separated entities. Using mainstream smart-phone’s processor, a sample model of TMP as well as the authentication scheme based on the combination of password, fingerprint and USIM are proposed to improve the security of the user domain, which satisfies the security requirements of level 3 presented in TMP standard.Then, in order to deal with the security flaws in privacy-key and public-key based scheme, an efficient self-certified public-key based authentication scheme including PKBP (Public-Key Broadcast Protocol) and SPAKA (Self-certified Public-key based Authentication and Key Agreement Protocol) is presented for 4G systems. With the help of PKBP, ME can identify the genuine access point (AP) from the malicious ones without validating the AP’s public-key certificate before the authentication. Meanwhile, in SPAKA, without delivering its public-key certificate to the AP, ME can achieve mutual authentication with AP and implement the controllable monitor on user’s conversation to meet the legitimate requirements of government in some special occasion. Compared with other public-key based authentication protocols, with the expected security that privacy-key based protocols can not provide, the computational and communicational payloads have been greatly reduced in our scheme.Subsequently, a secure DRM scheme for wireless network based on TMP is proposed to enhance the security of OMA DRM specification v2 and provide interoperability and compatibility between Trusted Computing (TC) and OMA DRM. With the help of the trusted relationship pre-built between the user and the wireless network operator as well as the clock synchronization technology between the wireless network and ME, the presented DRM scheme can resist the possible piracy, DoS (Deny of Service) attack and replay attack remained in the original OMA DRM architecture.Finally, the pseudorandom properties of FCSR (Feedback with Carry Shift Register) sequences have been analyzed and tested with NIST STS software package. Then the pseudorandom properties of the stream cipher based on the combination of LFSR and FCSR has been analyzed and its theoretical upper bound of period and that of linear complexity are also presented. Meanwhile, the stream cipher is realized in FPGA and compared with the implementation result of other stream ciphers, which proves this stream cipher is very efficient to satisfy the requirement of 4G system and can be employed in mobile equipment.更多还原