On March 11, 2025, NIST announced the selection of HQC (Hamming Quasi-Cyclic) as the fifth algorithm for post-quantum encryption standardization. HQC is a code-based key encapsulation mechanism that will serve as a backup for ML-KEM, the primary standard for general encryption published in FIPS 203.
Unlike ML-KEM, which is built on structured lattice mathematics, HQC uses error-correcting codes, providing algorithmic diversity in the event a vulnerability is discovered in lattice-based schemes. NIST project lead Dustin Moody stated that HQC’s clean and secure operation convinced reviewers it would make a worthy backup, despite requiring more computing resources than ML-KEM. A draft standard incorporating HQC is expected in early 2026, with finalization anticipated in 2027.