Can we skip hybrid and go pure-PQ?

Not recommended. Hybrid is the conservative path; if Kyber is later weakened, classical X25519 still protects you. Pure-PQ is reasonable around 2030, after libraries have matured 5+ years in production.

How much does this cost?

Mostly engineering time, not direct cost. New libraries are open-source. HSMs may need replacement or firmware update (cost depends on vendor). For a 1000-employee organisation: estimate ~10-20 person-months of senior engineering effort spread over 24 months.

Will old clients break?

Hybrid TLS is backwards-compatible — old clients fall back to classical. Don't break old clients with mandatory PQ; let them age out naturally.

Should we wait for vendors to ship before starting?

No. Inventory and prioritisation can happen now. By the time your inventory is complete (3-6 months), vendors will have shipped. Start the work; vendor-readiness aligns naturally.

How do we measure success?

Percentage of TLS handshakes negotiating hybrid PQ. Percentage of internal-CA-issued certs using ML-DSA. Percentage of JWT signing using hybrid alg. Plot trends; aim for >80% hybrid by month 18.

Migrating to Post-Quantum Cryptography in Production — TLS, SSH, JWT, S/MIME (24-Month Playbook)

Read as

Migrating production systems to post-quantum cryptography means inventorying every cryptographic dependency, prioritising by data lifetime and criticality, and rolling out hybrid then pure-PQ in stages. The work is largely engineering hygiene — discovering what algorithms you actually use, replacing libraries, regression-testing performance — rather than novel cryptographic complexity. This module is the operational playbook for a 24-month enterprise PQ migration program.

Most enterprises don’t know which TLS libraries their dependencies use, which JWT alg their microservices accept, or which signature algorithm their internal CA issues. The PQ migration is, more than anything, a forced cryptographic inventory exercise. Treat it as that, and the algorithm changes become the easy part.

Phase 1 — Discovery (Months 1-3)

Inventory every cryptographic primitive in production. The categories:

TLS endpoints: every load balancer, every internal-mesh proxy, every API gateway. Audit cipher suites in use; flag ones using ECDHE_*, RSA_*, DH_*.
SSH: every server’s /etc/ssh/sshd_config KexAlgorithms, HostKeyAlgorithms, PubkeyAcceptedAlgorithms.
VPN / IPsec: site-to-site VPN configs, employee remote-access configs.
JWT signing keys: every microservice that issues or verifies JWT — what alg (RS256? ES256?). Centralised auth services?
S/MIME and PGP: anyone sending signed/encrypted email? Internal or external?
Code signing: software releases, JAR signing, RPM/DEB signing, Authenticode.
Internal CA: which algorithm does your internal root CA use? Intermediate? Issued certs? Lifetime?
Database TDE: SQL Server, Oracle, PostgreSQL transparent data encryption — what’s the encryption key wrapped with?
Backup encryption: tape backup, S3 KMS, etc.
HSM-resident keys: AWS CloudHSM, Thales, Gemalto — what algorithms are supported and used?
Certificate transparency: SCT signatures from CT logs (these will need to migrate).

Output: a spreadsheet with every cryptographic dependency, library version, current algorithm, ownership team. This is your migration backlog.

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Migrating to Post-Quantum Cryptography in Production — TLS, SSH, JWT, S/MIME (24-Month Playbook)

Phase 1 — Discovery (Months 1-3)

Custom team training + practitioner advisory

Other modules in this track

What is Quantum Computing — Qubits, Superposition, Entanglement (Beginner)

Why Quantum Matters for Cybersecurity — The Post-Quantum Threat in Plain English

Shor’s Algorithm Explained — Why RSA and ECC Will Break