Post-Quantum Cryptography Key Exchange to Extend a High-Security QKD Platform into the Mobile 5G/6G Networks

This paper presents a way to integrate a Post-Quantum Cryptography key exchange mechanism based on the encryption and signature algorithms currently being standardized by the National Institute of Standards and Technology into a Quantum Key Distribution platform. In contrast to Quantum Key Distribution, the security of Post-Quantum Cryptography is based on the mathematical complexity of the cryptographic algorithms. The unique feature of the presented solution is that the Post-Quantum Cryptography key exchange mimics a Quantum Key Distribution system. As implemented, the encryption keys are continuously exchanged between the nodes that are part of the OpenQKD testbed Berlin and then stored in a secure key store. The testbed’s key management can distinguish between Quantum Key Distribution and Post-Quantum Cryptography keys based on metadata information, allowing applications to select the appropriate key type. This architecture enables interoperability between the two technologies and may also provide a means to deliver quantum-secure keys to the end user by leveraging Post-Quantum Cryptography to secure the last mile.