LMS 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: Stateful Hash-Based Signature
Author: MetaMUI Security Team
Overview
LMS (Leighton-Micali Signature) is a stateful hash-based signature scheme standardized by NIST, providing quantum-resistant signatures.
- Algorithm Family: Hash-based signature (stateful)
- Security Levels: 128/192/256-bit
- State Management: Critical for security
- Tree Variants: Multiple parameter sets
- Standard: RFC 8554, NIST SP 800-208
Security Warnings ⚠️
- STATE REUSE IS FATAL: Never reuse any portion of the state
- Sequential Signing: Must maintain strict ordering
- Limited Signatures: Fixed number of signatures per key
- HSS Option: Hierarchical variant available for more signatures
API Functions
Similar to XMSS with LMS-specific parameters.
Security Best Practices
- Implement hardware security module for state
- Use HSS for increased signature capacity
- Monitor signature count
- Plan for key exhaustion
Security Analysis
Threat Model: LMS 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.