The PQC migration master checklist
A reusable, phase-by-phase checklist you can copy into your program tracker — covering discovery through validation, plus per-domain and per-wave gates. Adapt it; don't treat it as gospel.
One checklist, six phases, reusable per wave
This is a working checklist for a post-quantum migration, organized by the lifecycle phases and by domain. Copy it into your tracker and adapt it — every estate differs. The phase checklists run once per wave; the readiness gates decide whether a wave may cut over.
Discover
- Source and dependency scanning integrated into CI for in-scope repositories.
- Network/TLS scanning of external and internal endpoints complete.
- Certificate and key-store discovery run across CAs, load balancers, and secret stores.
- Configuration analysis done for servers, VPNs, and applications.
- HSM and key-store review complete.
- Coverage explicitly tracked; unscanned estate flagged as unknown-risk.
- Findings consolidated into a machine-readable CBOM.
Assess
- Each asset classified as quantum-vulnerable (RSA/ECC/DH) or not.
- Symmetric key sizes confirmed adequate (AES-256, SHA-384+).
- Data-context recorded per asset: what it protects and that data's shelf life.
- Harvestability noted: is the traffic reachable by an adversary who can record it?
Prioritize
- Mosca's inequality applied per data class (X + Y > Z).
- Scoring model applied consistently: shelf life, exposure, function, blast radius, cost.
- Assets grouped into risk-tiered waves.
- Scoring model versioned alongside the inventory.
Plan
- Dependency graph drawn; blocked desires split into ordered steps.
- Each roadmap item names system, from/to algorithm and mode, owner, validation gate, rollback trigger, and window.
- Hybrid-vs-pure decision recorded per wave with rationale.
- Roadmap stored in the same system as the inventory so they cannot drift.
Execute (by domain)
- TLS/network: hybrid key exchange at the edge, classical fallback retained.
- PKI: validators PQC-aware before issuance; parallel PQC hierarchy stood up; HSM support confirmed.
- Data-at-rest: key wrapping on a PQC path; ciphertext carries algorithm tags.
- Code/firmware signing: verifiers accept new format; verification horizon accounted for.
- Secrets/KMS: PQC key wrapping; central algorithm policy defined.
- Identity: issuer and all verifiers support the target signature algorithm.
Validate — the per-wave cut-over gate
A wave may cut over only when all of these are true
Interoperability matrix passes end to end across the real network path, including oldest supported clients and middleboxes. Non-PQC fallback verified; no silent downgrade of PQC-capable peers. Performance within the pre-agreed budget (handshake latency, CPU, bandwidth; signature size and verification cost). Rollback path tested. Test evidence attached to the roadmap item. Owner and reviewer signed off.
A checklist is a floor, not a ceiling
Copying this list and ticking boxes does not make a migration safe — it makes it legible. Your estate has specifics this generic list cannot know: a bespoke protocol, a regulated data class, a fragile legacy dependency. Add the checks your context demands, and treat any item you cannot honestly tick as an open risk with an owner, not a box to fudge.