Types of PostQuantum Cryptography
Postquantum cryptography (PQC) research is currently mostly focused on these 6 approaches listed below.
Hashbased cryptography
Leslie Lamport invented hashbased signatures in 1979. The XMSS (eXtended Merkle Signature Scheme) and SPHINCS hashbased signature schemes were introduced in 2011 and 2015, respectively^{1}.
Hashbased cryptography has been thoroughly studied. It has been around for a long time.
Popular Scheme: The Merkle signature scheme, XMSS.
Latticebased cryptography
First introduced by Miklos Ajtai in the year 1996, whose security was based on lattice problems.
Popular Scheme: NTRU, CRYSTALSDilithium (digital signature algorithm) and CRYSTALSKYBER (public key encryption and key establishment algorithm).
TODOs below
Multivariate cryptography
Codebased cryptography
Isogenybased cryptography
Symmetric key quantum resistance

https://en.wikipedia.org/wiki/Hashbased_cryptography ↩︎