SWIFT: SMALL: Exploiting Co-Existence for Verifiable Everlasting Security in Wireless Communication Systems: Hardware and Protocols

拥挤的无线电频谱激发了人们对在同一频段上操作雷达系统和无线通信系统更有效地使用频谱的极大兴趣。传统上认为这种共存对两个系统都是中立或有害的，但这种观点正在演变，特别是在系统之间存在信息共享的情况下。本项目利用一种共存雷达来解决通信中一个长期存在的问题：保护无线通信系统（如蜂窝电话、WiFi系统和公共安全无线电）中的信息内容。标准方法是基于加密密钥对消息进行编码，该密钥由消息发送方和预期接收方共享，但攻击方不知道；预期的接收者可以很容易地解码信息，但攻击者面临着一个棘手的计算任务。然而，如果目标是永久安全，攻击者可能会记录编码的消息，然后在将来使用先进的计算技术或在获得密钥后解码该消息，这意味着加密方法是不够的。该项目将对一种永久安全技术进行实验验证和改进，该技术利用两种不同安全方法的优势，如下所述，利用共存的雷达信号阻止对手的接收器记录无线通信信号，从而可以从中提取信息内容。该项目的实验性推力也将成为以项目为基础，加强不同学生教育的沃土。该技术将经典密码技术与现代信息理论安全技术相结合。信息论的安全方法在消息传输时只要具备适当的条件，就能永远保护消息内容；然而，试图保证这样的条件是具有挑战性的，特别是在无线通信环境中，因此信息理论技术在实际系统中的渗透有限。该项目将采用一个共存的雷达，以提供永久的安全，如下所示。通信双方和雷达系统的操作员建立一个加密密钥，然后使用该密钥为预期接收方提供所需的雷达干扰消除优势，以建立信息论的安全通信。即使密钥在消息传输后立即被泄露，攻击者也无法存储可以从中提取消息的信号版本，因此提供了永久的安全性。其优点是预期的接收方采用用于接收机前端自适应的密钥来减小接收信号的动态范围。然而，这样的适应可能是具有挑战性的，并且在目前所提出的技术的研究中仅通过简单的模型进行了考虑。在过去几年中出现的全双工通信方法的支持下，该项目展示了在宽频带上的干扰消除，该项目解决了该技术的具有挑战性的硬件实现，并对建模和协议进行了改进，从而产生了持久安全的强大形式。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The crowded radio spectrum has motivated significant interest in using spectrum more efficiently by operating radar systems and wireless communication systems in the same frequency band. Traditionally such coexistence is viewed as neutral or detrimental to both systems, but this view is evolving, particularly if there is information sharing between the systems. This project exploits a coexisting radar to solve a longstanding problem in communications: protecting the message contents in wireless communication systems, such as cellular phones, WiFi systems, and public safety radios. The standard approach is to encode the message based on a cryptographic key, which is shared by the message sender and intended recipient but unknown to the adversary; the intended recipient can readily decode the message, but the adversary is faced with an intractable computational task. However, the potential for an adversary to record the encoded message and then work to decode the message in the future using either computational advances or after obtaining the key means cryptographic approaches are insufficient if the goal is everlasting security. This project will perform experimental validation and refinement of a technique for everlasting security that exploits the strength of two different approaches for security, as described below, to exploit the coexisting radar signal to block the adversary's receiver from making a recording of a wireless communications signal from which the message content can ever be extracted. The experimental thrust of the project will also serve as fertile ground for project-based enhancement of the education of a diverse set of students.The proposed technique combines classical cryptographic techniques with contemporary information-theoretic security techniques. Information-theoretic security approaches protect the message content forever if the proper conditions are present at the time of message transmission; however, trying to guarantee such conditions is challenging, particularly in the wireless communications environment, and hence information-theoretic techniques have seen limited penetration in practical systems. This project will employ a coexisting radar to provide everlasting security, as follows. The communicating parties and operator of the radar system set up a cryptographic key, which is then employed to provide the required advantage in radar interference cancellation for the intended recipient over the adversary to establish information-theoretic secure communications. Even if the key is compromised immediately after message transmission, the adversary will not have been able to store a version of the signal from which the message can ever be extracted, hence providing everlasting security. The advantage is obtained from the intended recipient employing the key for receiver front-end adaptation to reduce the dynamic range of the received signal. However, such an adaptation can be challenging and has been considered only through simple models in the studies of the proposed technique to this point. Buoyed by full-duplex communication approaches that have emerged over the last few years and demonstrate interference cancellation over a wide frequency band, this project addresses the challenging hardware implementation of this technique jointly with the refinement of the modeling and protocols so as to yield a robust form of everlasting security.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.