HQC
Code-based · QCSD · pqc-hqc.org(opens in a new tab)
- Programmes
- Std pending
- Status
- To be standardized
- Security flags
- None on current sets
Parameter sets
| Parameter set | Level | pk (B) | ct (B) | pk+ct (B) | Keygen | Encaps | Decaps |
|---|---|---|---|---|---|---|---|
| HQC-128 Note | 1 | 2,241 | 4,433 | 6,674 | 19.0 µs | 35.7 µs | 87.5 µs |
| HQC-192 Note | 3 | 4,514 | 8,978 | 13,492 | 42.8 µs | 81.6 µs | 191.0 µs |
| HQC-256 Note | 5 | 7,237 | 14,421 | 21,658 | 83.9 µs | 162.6 µs | 377.6 µs |
Wall-clock times vary between runs and machines (CPU frequency scaling, other tenants on cloud VMs); cycle counts are the steadier basis for comparison.
Security flags
- Note (all parameter sets): Selected by NIST for standardisation (March 2025). Sizes from the v5.1 specification.
History
- added to site Update
HQC v5.1 (specification, 2026-10-12, revised 2026-11-09; announcement by Bidoux) refines the decryption-failure analysis and raises the weights: ω by 1 for HQC-1, -3 and -5, and ωr by 1 for HQC-1 and -5, to offset minor cryptanalytic improvements. The decapsulation key becomes the 32-byte seed (previously 2,321, 4,602 and 7,333 bytes), the F28 polynomial changes and the XOF domain separator changes. Public keys and ciphertexts keep their sizes. We now build the v5.1.0 release (upstream KATs pass) and benchmarked it on AWS c8i.4xlarge on 2026-11-12. Key generation and encapsulation keep their speed; decapsulation is 10–17% slower (79.8→87.5, 166.9→191.0 and 322.7→377.6 µs), because it now expands the 32-byte key first.