ML-KEM
The quantum-safe replacement for key exchange in TLS — formerly CRYSTALS-Kyber, now FIPS 203.
NIST concluded its selection process in August 2024 and made the algorithm a standard under the name Module-Lattice-based Key-Encapsulation Mechanism. It does not replace data encryption, but the step where two parties agree on a session key — precisely the step Shor's algorithm breaks in today's Diffie-Hellman and elliptic curves.
Deployment has been unusually quick. Chrome and Firefox support it, as do Cloudflare and OpenSSH. Throughout, hybrid mode is used: ML-KEM is combined with classical X25519 so the key stays secure even if a classical weakness were found in the new and still young algorithm.