(PrivateInternetAccess) Post Quantum Cryptography is encryption that can resist cracking by quantum computers. The pace of research suggests that quantum computers with the capability to break current encryption algorithms could be built sometime in the next decade. These systems are particularly adept at breaking asymmetric encryption like RSA and Diffie-Hellman which are used for secure handshakes. Post-Quantum research delves into finding the best algorithms for replacing RSA and Diffie-Hellman. The criteria are a combination of security and practicality.
NIST is looking for algorithms that remain resistant to all known methods of classical attacks, but that are also resistant to quantum attacks. The Candidates that have Advanced to Round Two and 26 have been identified.