HQC-128 Threat Model
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.
Algorithm Family: Code-based (Hamming)
Security Level: 128-bit
Standardization: NIST Round 3
Last Updated: 2025-01-02
Executive Summary
This document provides a comprehensive threat analysis for HQC-128, a Code-based (Hamming) algorithm standardized under NIST Round 3. The algorithm provides 128-bit security against both classical and quantum adversaries.
Algorithm-Specific Threats
Mathematical Foundation
- Hard Problem: Code-based (Hamming)-based security assumptions
- Classical Hardness: Exponential in security parameter
- Quantum Hardness: Resistant to known quantum algorithms
- Cryptanalytic Progress: Continuously monitored
Known Attack Vectors
Lattice Attacks (if applicable)
- BKZ lattice reduction algorithms
- Sieving algorithms
- Dual attacks
- Primal attacks
Implementation Vulnerabilities
- Side-channel leakage points
- Fault injection targets
- Timing variations in operations
- Memory access patterns
Parameter-Specific Security
| Parameter Set | Classical Security | Quantum Security | NIST Level |
|---|---|---|---|
| HQC-128 | 128-bit | 128-bit | Comparable |
Implementation Threats
Side-Channel Vulnerabilities
- Timing Attacks: Polynomial multiplication timing
- Power Analysis: Key-dependent operations
- Cache Attacks: Table lookup patterns
- Fault Attacks: Signature/decryption faults
Common Implementation Errors
- Improper randomness in key generation
- Incorrect parameter validation
- Missing constant-time implementations
- Inadequate error handling
Deployment Considerations
Hybrid Mode Threats
- Algorithm negotiation attacks
- Downgrade vulnerabilities
- Cross-algorithm dependencies
- Performance-based DoS
Migration Risks
- Backward compatibility issues
- Key management complexity
- Interoperability challenges
- Performance impacts
Countermeasures
Algorithm Level
- Parameter selection for security margin
- Proper randomness requirements
- Validation of all inputs
Implementation Level
- Constant-time operations mandatory
- Memory sanitization required
- Side-channel countermeasures
- Fault detection mechanisms
Protocol Level
- Authenticated algorithm negotiation
- Binding security parameters
- Version enforcement
- Monitoring and logging
Compliance Requirements
- NIST Standards: NIST Round 3 compliance
- CNSA 2.0: Quantum resistance timeline
- Industry Standards: Ongoing standardization
Testing and Validation
Security Testing
- Known Answer Tests (KAT)
- Side-channel resistance testing
- Fault injection testing
- Fuzzing and stress testing
Interoperability Testing
- Cross-implementation testing
- Protocol integration testing
- Performance benchmarking
- Backward compatibility testing
Real-World Deployment Status
- Adoption Level: Early adoption/Research/Production
- Known Implementations: Reference, optimized, hardware
- Deployment Scenarios: TLS, VPN, PKI, messaging
References
- [NIST PQC Standards]
- [Algorithm Specification]
- [Security Analysis Papers]
- [Implementation Guidelines]