Post-quantum cryptography encompasses the algorithms that are allegedly immune to quantum computing. In 2017, NIST initiated the process of selecting and standardizing a set of post-quantum cryptosystems. In 2020, NIST started the third round with 15 remaining candidates.
NIST announced the four winners. CRYSTALS-KYBER is the new key establishment protocol for post-quantum.
“Among its advantages are comparatively small encryption keys that two parties can exchange easily, as well as its speed of operation. ”
CRYSTALS-DILITHIUM, Falcon, and SPHINCS+ are the new digital signature systems.
“ Reviewers noted the high efficiency of the first two, and NIST recommends CRYSTALS-Dilithium as the primary algorithm, with FALCON for applications that need smaller signatures than Dilithium can provide. The third, SPHINCS+, is somewhat larger and slower than the other two, but it is valuable as a backup for one chief reason: It is based on a different math approach than all three of NIST’s other selections.”
Interestingly, version 9.0 of OpenSSH proposes a post-quantum algorithm. It is NTRU prime and not CRYSTALS-KYBER.