CIF: Small: Everlasting Security for Disadvantaged Wireless Communications

该项目开发技术，为无线通信系统中传输的消息提供信息论保密，以应对窃听者接收到比预期接收者更强的信号的挑战性场景：例如，窃听者可能比预期接收者更接近发射器。本项目中考虑的方法首先是发射器和预期的接收器共享一个短暂的加密密钥，然后发射器使用该密钥故意扭曲传输的信号。有了密钥的知识，预期的接收者在减少模数转换和信号记录之前的这种故意失真方面比窃听者具有显著的优势。即使窃听者在稍后的时间获得了密钥，模数转换的非线性和非线性算子不一定是可交换的这一事实意味着窃听者无法消除有意的失真。通过这种方式，获得了信息论的保密性。该项目将考虑通过这种技术最大化秘密通信速率的方法。首先，将开发采用基于共享密钥的加性干扰信号的窄带系统方法。接下来，将注意力转向宽带系统，在宽带系统中，共享密钥可以用来额外隐藏发送器的操作频带，从而进一步抑制窃听者。考虑宽带系统的关键是为窃听者考虑广泛的新兴接收能力。最后，该项目将以最新的分析技术为基础，考虑在必须考虑不同系统节点传输交互的网络场景中提供保密性。保护无线通信系统中的信息不被窃听具有明显的社会效益。标准采用的密码学方法对窃听者当前和未来的计算能力做出了关键假设，窃听者可能会记录传输的消息并试图在很长一段时间内破解它；因此，信息论技术对提供永久的保密性很感兴趣。然而，信息论的保密通常要求预期的接收者比窃听者有优势，这在无线通信系统中很难保证，导致消息内容立即被泄露的重大风险。这里考虑的技术利用了密码学方法和信息论方法的优势，前者不容易受到靠近发送者的窃听者的影响，后者在接收方比窃听者获得所需优势的情况下提供永久保密。其结果是一种具有潜力的方法，通过无线通信系统中可靠的永久保密技术，提供了显著的广泛的社会效益。该项目还具有重要的教育主题，为K-12学生提供拓展服务，并为马萨诸塞大学的各种学生提供重要的项目和研究机会。

This project develops techniques to provide information-theoretic secrecy for messages transmitted in a wireless communication system for the challenging scenario where an eavesdropper receives a stronger signal than the desired recipient: for example, the eavesdropper might be significantly closer to the transmitter than the intended receiver. The approach considered in this project starts with the transmitter and intended receiver sharing an ephemeral cryptographic key, which the transmitter then employs to intentionally distort the transmitted signal. With knowledge of the key, the intended receiver has a significant advantage over the eavesdropper in reducing this intentional distortion before analog-to-digital conversion and the recording of the signal. Even if the eavesdropper obtains the key at some later time, the nonlinearity of the analog-to-digital conversion and the fact that non-linear operators are not necessarily commutative implies the eavesdropper cannot remove the intentional distortion. In this manner, information-theoretic secrecy is obtained. The project will consider methods of maximizing the rate of secret communications through this technique. First, approaches to narrowband systems that employ an additive jamming signal based on the shared key will be developed. Next, attention will turn to wideband systems, where the shared key can be used to additionally hide the band of operation of the transmitter, hence further inhibiting the eavesdropper. Critical to the consideration of wideband systems is considering broad classes of emerging receiver capabilities for the eavesdropper. Finally, the project will build on recent analytic techniques to consider the provisioning of secrecy in network scenarios where the interaction of the transmissions of different system nodes must be considered.The protection of messages in wireless communication systems from eavesdropping has clear societal benefit. Standardly employed cryptographic approaches make critical assumptions on the current and future computational capabilities of the eavesdropper, who may record a transmitted message and attempt to break it over a long time period; hence, information-theoretic techniques are of interest for the provisioning of everlasting secrecy. However, information-theoretic secrecy generally requires an advantage for the intended recipient over the eavesdropper, which, per above, is difficult to guarantee in wireless communication systems, leading to a significant risk that the contents of a message will be immediately compromised. The technique considered here exploits the strengths of both cryptographic approaches, which are not susceptible to an eavesdropper close to the transmitter, and information-theoretic approaches, which provide everlasting secrecy if the required advantage is available for the recipient over the eavesdropper. The result is a method with the potential to provide significant broad societal benefit through a technique for robust everlasting secrecy in wireless communication systems. The project also has a significant educational theme, providing both outreach to K-12 students and significant project and research opportunities to a diverse set of University of Massachusetts students.