NIST Post-Quantum Migration Checklist

The Migration
Checklist.

Related · tier-1 reading. For how to migrate before the NIST deadline and stay verifiable, see Post-Quantum.

Six steps from quantum-vulnerable to quantum-safe. A practical, actionable checklist for enterprises migrating to NIST FIPS 203/204/205 post-quantum cryptography. No theory. No speculation. Just the steps.

Inventory

Catalog every cryptographic algorithm in your infrastructure. You cannot migrate what you have not mapped.

TLS configurations: List every server's TLS cipher suites. Identify RSA, ECDHE, and DHE key exchange. Record key sizes and certificate authorities.
Certificate chains: Map every certificate from leaf to root. Record the signing algorithm (RSA-SHA256, ECDSA-P256, etc.) at each level.
API authentication: Document how API keys, JWTs, and tokens are signed. Record the algorithm (RS256, ES256, etc.) and the signing library.
Data-at-rest encryption: List every encrypted data store. Record the encryption algorithm (AES-256 is quantum-safe) and the key wrapping algorithm (RSA key wrapping is not).
VPN and remote access: Document the key exchange algorithms used by VPN concentrators, SSH servers, and remote access gateways.
Code and document signing: Record the algorithms used to sign software releases, firmware updates, and legal documents.
Third-party dependencies: Identify cryptographic dependencies in third-party libraries, cloud services, and SaaS integrations.

Prioritize

Not all systems have equal quantum risk. Prioritize based on data sensitivity lifespan and exposure to harvest-now-decrypt-later threats.

Highest priority: Systems transmitting data with 10+ year sensitivity lifespans (healthcare records, legal communications, classified information, financial records with long retention).
High priority: Authentication systems, certificate authorities, and key management systems. These are the foundation of trust for everything else.
Medium priority: Session-based encryption for internal services. The data sensitivity is lower but the systems may handle aggregated sensitive data.
Lower priority: Non-sensitive communications, public-facing content delivery, and systems where data has a short sensitivity lifespan.
Document the rationale: For each system, record why it was assigned its priority level. This documentation supports compliance and insurance conversations.

Test

Validate your PQC implementation before deploying to production. Testing must include correctness, interoperability, and performance.

KAT validation: Run NIST Known Answer Test vectors for every PQC algorithm on every target platform. All KAT vectors must pass. No exceptions.
Interoperability testing: Test your implementation against at least two independent PQC implementations. Verify that keys, signatures, and ciphertexts are compatible.
Hybrid mode testing: Verify that hybrid key exchange correctly combines classical and PQ shared secrets. Test fallback to classical-only. Test downgrade attack resistance.
Performance benchmarking: Run sustained benchmarks (120+ seconds) on target hardware. Measure key generation, signing, verification, encapsulation, and decapsulation latencies.
Regression testing: Verify that PQC deployment does not break existing functionality. Run your full test suite with PQC enabled.
Certificate chain validation: Verify that quantum-safe certificate chains validate correctly end-to-end, from leaf to root.

Deploy

Deploy PQC to production using the overlay approach. Start with hybrid mode for backward compatibility.

Deploy the H33 Gateway: Install as a reverse proxy in front of your highest-priority systems. Configure hybrid TLS (ECDH + ML-KEM).
Enable monitoring mode: Run for 3-5 days with PQC headers but no enforcement. Verify that all requests proxy correctly.
Enable hybrid TLS: Allow clients that support ML-KEM to negotiate quantum-safe connections. Monitor the percentage of hybrid connections.
Enable PQ signatures: Add ML-DSA signatures to API responses. Verify that signatures are correct and that legacy clients are not affected.
Deploy incrementally: Start with one service, validate for a week, then expand to additional services. Do not deploy to all services simultaneously.
Document the rollback procedure: For each deployment, document the exact steps to revert to classical-only operation. Test the rollback before relying on it.

Verify

Validate that your PQC deployment is working correctly and providing the expected quantum-safe protection.

TLS handshake verification: Use protocol analysis tools to confirm that hybrid key exchange is negotiated. Verify that both ECDH and ML-KEM shared secrets contribute to the session key.
Signature verification: Verify ML-DSA signatures on API responses using the H33 verification API or the open-source verifier CLI.
Attestation chain verification: Confirm that H33-74 attestations are being generated and anchored correctly. Verify the attestation chain for completeness and consistency.
Performance monitoring: Compare latency and throughput metrics before and after PQC deployment. Confirm that overhead is within expected parameters.
Penetration testing: Conduct a focused penetration test on the PQC deployment. Test for downgrade attacks, implementation vulnerabilities, and configuration errors.

Attest

Establish continuous attestation to prove that your PQC deployment remains operational over time.

Deploy HATS monitoring: Configure continuous attestation for your PQC-protected systems. Monitor algorithm usage, certificate validity, and key rotation compliance.
Establish the attestation record: Begin building the longitudinal attestation record that demonstrates continuous PQC compliance.
Share with stakeholders: Provide attestation records to auditors, insurers, and regulators. Use the records to support compliance certifications and insurance renewals.
Monitor for drift: Configure alerts for any deviation from PQC-required configurations. Respond to drift events within your defined remediation timeline.
Review and update quarterly: Review your cryptographic inventory quarterly. Add new systems to the PQC overlay as they are deployed. Update your attestation scope as your infrastructure evolves.

The MigrationChecklist.