HQC-128 Security API
Side-channel claim limit. Nothing on this page claims constant-time behaviour or side-channel resistance for any target: the side-channel harness covers nothing (finding A48) and no measurement exists. The Rust and C cores are designed for constant time and unmeasured; managed runtimes (JIT, GC, bounds checks) make no timing claim. Where this page names constant-time or side-channel techniques, in prose or in code, they are design intent or recommendations, not measured properties.
Version: 1.0.0
Last Updated: 2025-01-02
Security Classification: Code-Based KEM
Author: MetaMUI Security Team
Overview
HQC (Hamming Quasi-Cyclic) is a code-based KEM using quasi-cyclic codes, providing an alternative to lattice-based schemes.
- Algorithm Family: Code-based KEM
- Security Level: NIST Level 1 (128-bit)
- Key Sizes:
- Public Key: 2249 bytes
- Secret Key: 2289 bytes
- Ciphertext: 4481 bytes
- NIST Round: Round 4 candidate
Security Warnings ⚠️
- Code-Based: Different assumption than lattice schemes
- Large Keys: Larger than lattice-based alternatives
- Decoding Failures: Small probability of decoding failure
- Side Channels: Requires constant-time decoding
API Functions
Standard KEM interface with code-based construction.
Security Analysis
Threat Model: HQC-128 Threat Model
The comprehensive threat analysis covers:
- Algorithm-specific attack vectors
- Implementation vulnerabilities
- Side-channel considerations
- Quantum resistance analysis (where applicable)
- Deployment recommendations
For complete security analysis and risk assessment, see the dedicated threat model documentation.