Today's information society relies on cryptography to achieve security goals such as confidentiality, integrity, authentication, and non-repudiation for digital communications. Here, public-key cryptosystems play a pivotal role to share encryption keys and create digital signatures. However, quantum computers threaten the security of traditional public-key cryptosystems as they can tame computational problems underlying the schemes, i.e., discrete logarithm and integer factorization. The prospective arrival of capable-enough quantum computers already threatens today's secret communication in terms of their long-term secrecy when stored to be later decrypted. Therefore, researchers strive to develop and deploy alternative schemes. In this work, evaluate a key exchange protocol based on combining public-key schemes with physical-layer security, anticipating the prospect of quantum attacks. If powerful quantum attackers cannot immediately obtain private keys, legitimate parties have a window of short-term secrecy to perform a physical-layer jamming key exchange (JKE) to establish a long-term shared secret. Thereby, the protocol constraints the computation time available to the attacker to break the employed public-key cryptography. In this paper, we outline the protocol, discuss its security, and point out challenges to be resolved.

翻译：当今信息社会依赖密码学来实现数字通信的机密性、完整性、认证性和不可否认性等安全目标。其中，公钥密码系统在共享加密密钥和生成数字签名方面发挥着关键作用。然而，量子计算机威胁着传统公钥密码系统的安全性，因为它们能够攻克这些方案所依赖的计算难题——即离散对数和整数分解问题。具备足够能力的量子计算机的预期出现，已对当前秘密通信的长期保密性构成威胁，尤其是当密文被存储以待未来解密时。因此，研究人员致力于开发和部署替代方案。在本工作中，我们评估了一种结合公钥方案与物理层安全的密钥交换协议，以应对量子攻击的前景。若强大的量子攻击者无法立即获取私钥，合法通信方将拥有一个短期保密窗口，可执行物理层干扰密钥交换（JKE）以建立长期共享密钥。由此，该协议限制了攻击者破解所用公钥密码的计算时间。本文概述了该协议，讨论了其安全性，并指出了有待解决的挑战。