Algorithms
What is HQC?
Hamming Quasi-Cyclic. NIST-selected code-based KEM (March 2025) — second pillar alongside ML-KEM in NIST's PQC migration plan. Three parameter sets (128, 192, 256). Used by QNSP as the second KEM in defense-in-depth hybrid mode on Maximum and Government tiers.
Deep dive
HQC on QNSP
Code-based KEM selected by NIST in March 2025 as a fifth-round alternate KEM standard, providing an independent cryptographic assumption (coding theory, not lattices) as defence-in-depth against ML-KEM cryptanalysis.
For parameter sets, key and signature sizes, NIST ACVP conformance status, and when to use it, see the full HQC algorithm reference.
FAQ
Common questions
What is HQC?
Hamming Quasi-Cyclic. NIST-selected code-based KEM (March 2025) — second pillar alongside ML-KEM in NIST's PQC migration plan. Three parameter sets (128, 192, 256). Used by QNSP as the second KEM in defense-in-depth hybrid mode on Maximum and Government tiers.
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