HMAC-SHA256 Threat Model
Algorithm Type: Message Authentication Code
Security Level: 256-bit
Quantum Impact: Hash-based MAC, quantum resistance inherited from hash
Last Updated: 2025-01-02
Executive Summary
This document analyzes threats specific to HMAC-SHA256, a Message Authentication Code algorithm providing 256-bit classical security. Hash-based MAC, quantum resistance inherited from hash
Algorithm-Specific Threats
Cryptanalytic Attacks
- Best Known Attack: Complexity and requirements
- Collision Resistance: For hash functions
- Preimage Resistance: For hash functions
- Key Recovery: For ciphers and MACs
Implementation Vulnerabilities
Common Weaknesses
- Timing side-channels in implementations
- Cache-timing attacks on table lookups
- Power analysis vulnerabilities
- Fault injection points
Platform-Specific Risks
- Hardware acceleration vulnerabilities
- Software optimization trade-offs
- Language-specific implementation issues
Security Analysis
Classical Security
| Attack Type | Complexity | Practical | Mitigation | |————|————|———–|————| | Brute Force | 2^256 | No | Key size selection | | Cryptanalysis | Varies | Depends | Algorithm updates | | Side-Channel | Implementation | Yes | Countermeasures |
Quantum Security
Hash-based MAC, quantum resistance inherited from hash
Implementation Best Practices
Secure Implementation Requirements
- Constant-time operations
- Secure memory handling
- Proper initialization
- Error handling without leakage
Common Pitfalls
- Variable-time operations
- Compiler optimizations
- Memory leaks
- Weak randomness
Deployment Considerations
Use Case Specific Threats
- Protocol integration issues
- Key management challenges
- Performance constraints
- Compatibility requirements
Migration Considerations
- Quantum threat timeline
- Hybrid deployment options
- Backward compatibility
- Performance impacts
Countermeasures
Design Level
- Appropriate parameter selection
- Security margin considerations
- Mode of operation selection
Implementation Level
- Side-channel protections
- Fault resistance
- Memory protection
- Timing attack prevention
Operational Level
- Key rotation policies
- Monitoring and detection
- Incident response
- Security updates
Compliance and Standards
- NIST Recommendations: Current status
- Industry Standards: Adoption level
- Regulatory Requirements: Compliance needs
Testing Requirements
Security Validation
- Test vector verification
- Side-channel testing
- Fuzzing and stress testing
- Formal verification (where applicable)
Performance Testing
- Throughput measurements
- Latency analysis
- Resource utilization
- Scalability testing
Known Vulnerabilities
Historical Issues
- Past CVEs and fixes
- Implementation bugs
- Protocol weaknesses
Current Concerns
- Active research areas
- Potential weaknesses
- Monitoring requirements
References
- [Algorithm Specifications]
- [Security Analysis]
- [Implementation Guidelines]
- [Standards Documentation]