This paper examines the security vulnerabilities and threats imposed by the
inherent open nature of wireless communications and to devise efficient defense
mechanisms for improving the wireless network security. We first summarize the
security requirements of wireless networks, including their authenticity,
confidentiality, integrity and availability issues. Next, a comprehensive
overview of security attacks encountered in wireless networks is presented in
view of the network protocol architecture, where the potential security threats
are discussed at each protocol layer. We also provide a survey of the existing
security protocols and algorithms that are adopted in the existing wireless
network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term
evolution (LTE) systems. Then, we discuss the state-of-the-art in
physical-layer security, which is an emerging technique of securing the open
communications environment against eavesdropping attacks at the physical layer.
We also introduce the family of various jamming attacks and their
counter-measures, including the constant jammer, intermittent jammer, reactive
jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the
integration of physical-layer security into existing authentication and
cryptography mechanisms for further securing wireless networks. Finally, some
technical challenges which remain unresolved at the time of writing are
summarized and the future trends in wireless security are discussed.

本文针对无线通信的开放性所带来全部安全漏洞和威胁，通过提出有效的防御机制来提高 了无线网络的安全性；全面总结了无线网络的安全需求，包括认证、机密性、完整性和可用性问题，并对各种潜在的安全威 胁在网络协议体系结构层次上进行了详细的讨论。同时，本文还提供了各种现存的蓝牙、Wi-Fi、WiMAX 以及长 期演进（LTE）系统这些无线网络标准所使用的安全协议和算法的综述；此外，本文还探讨了物理层安全中对物理 信息进行加密来保证开放通信环境不受窃听攻击的新技术，以及来自不同类型的干扰攻击及其相应的对抗措施。最后， 文章总结了一些在撰写本文时仍未解决的技术难题，并讨论了未来无线安全的发展趋势。