Physical-Layer Security, Quantum Key Distribution, and Post-Quantum Cryptography.

To solve for these problems, various schemes providing the perfect/unconditional security have been proposed, including physical-layer security (PLS), quantum key distribution (QKD), and post-quantum cryptography. Authors introduce the unambiguous state discrimination measurement and the photon-number-splitting attack against PM-QKD with imperfect phase randomization, demonstrating the rigorous security of decoy state PM-QKD with a discrete-phase randomization protocol. The topics addressed in this Special Issue include physical-layer security [[2]], quantum key distribution (QKD) [[2]], post-quantum cryptography [[6]], quantum-enhanced cryptography [[7]], stealth communication [[2]], and covert communication [[8]]. In the third article paper [[13]], authors introduce an open-destination MDI QKD network that provides security against untrusted relays and all detector side-channel attacks, in which all user users are capable of distributing keys with the help of other users. [Extracted from the article]