Currently deployed key exchange protocols such as Diffie-Hellman (DH), Elliptic Curve Diffie-Hellman (ECDH), and Rivest-Shamir-Adleman (RSA) are vulnerable to attack by future quantum computers due to the discovery of Shor's algorithm.
New protocols are under development to make key exchange quantum-safe. The best-known two methods are Post-Quantum Cryptography (PQC) and Quantum Key Distribution (QKD).
Most people are less familiar with Distributed Symmetric Key Establishment (DSKE) which is a completely different approach for quantum-safe key exchange.
The DSKE approach is described in IETF Internet Draft draft-mwag-dske and in arXiv paper arXiv:2205.00615 Distributed Symmetric Key Establishment: A scalable, quantum-proof key distribution system. It has been commercialized by Quantum Bridge (who are not involved with this open source project).
This repository contains an open source implementation of DSKE inspired by the IETF draft. I say "inspired by" because the draft only describes the general approach and not a detailed protocol and because my implementation differs from the draft in some aspects.
Documentation: