CIF: Small: Everlasting Security for Disadvantaged Wireless Communications

该项目开发技术，以提供信息理论的保密性，在无线通信系统中传输的具有挑战性的情况下，窃听者接收到比所需的接收者更强的信号：例如，窃听者可能会显着更接近发射机比预期的接收器。在这个项目中考虑的方法开始与发射机和预期的接收器共享一个短暂的加密密钥，然后发射机使用故意失真的传输信号。 由于知道了密钥，预期的接收者在模数转换和记录信号之前减少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某个时间获得密钥，模数转换的非线性以及非线性算子不一定是可交换的这一事实意味着窃听者不能消除有意的失真。 以这种方式，获得信息理论保密性。该项目将考虑通过这种技术最大限度地提高秘密通信速率的方法。 首先，将开发基于共享密钥采用附加干扰信号的窄带系统的方法。 接下来，注意力将转向宽带系统，其中共享密钥可以用于另外隐藏发射机的操作频带，从而进一步抑制窃听者。 考虑宽带系统的关键是考虑广泛的新兴接收机的窃听能力。 最后，该项目将建立在最新的分析技术，考虑在网络场景中的保密性，其中必须考虑不同系统节点的传输的相互作用。保护无线通信系统中的消息免受窃听具有明显的社会效益。 标准采用的加密方法对窃听者当前和未来的计算能力做出关键假设，窃听者可能会记录传输的消息并试图在很长一段时间内打破它;因此，信息理论技术对提供永久保密感兴趣。 然而，信息理论保密性通常要求预期接收者优于窃听者，如上所述，这在无线通信系统中难以保证，导致消息的内容将立即被泄露的重大风险。 这里考虑的技术利用两种加密方法的优势，这是不容易接近发射机的窃听者，和信息理论的方法，提供永久的保密性，如果所需的优势是可用于接收者的窃听者。 其结果是一种方法，通过在无线通信系统中的鲁棒永久保密技术，有可能提供显着的广泛的社会效益。 该项目也有一个重要的教育主题，既为K-12学生提供外展，也为马萨诸塞州大学的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.