Algorithms face different risks
A sufficiently capable fault-tolerant quantum computer could apply Shor’s algorithm to undermine common RSA and elliptic-curve public-key assumptions. Grover’s search gives a quadratic speedup against ideal brute-force symmetric search, which is different from instantly breaking every AES key. Do not claim today’s ordinary devices can decrypt all protected traffic.
Post-quantum cryptography
Post-quantum cryptography uses mathematical schemes designed to resist known classical and quantum attacks. NIST standards include ML-KEM for key establishment and ML-DSA/SLH-DSA for signatures. These are not quantum key distribution or encryption carried out by a quantum computer. Protocol integration and implementation security remain important.
Migration planning
Inventory public-key algorithms, certificates, libraries, hardware dependencies and data confidentiality lifetimes. Long-lived sensitive data creates harvest-now/decrypt-later risk. Plan interoperability testing, crypto agility and staged provider-supported migration rather than inventing custom cryptographic protocols.
Operational tradeoffs
New key/certificate/signature sizes and handshake patterns can affect network capacity, MTU and application compatibility. Validate performance and fallback behavior with approved implementations. A PQC label is not proof that the entire authentication path, random-number generation or endpoint is secure.
Signal / protocol flow
- 1Crypto inventory
- 2Data lifetime risk
- 3Approved algorithms
- 4Interoperability test
- 5Staged migration
Technical terminology
- PQC: post-quantum cryptography
- KEM: key encapsulation mechanism
- Crypto agility: ability to replace algorithms
- Harvest now/decrypt later: store ciphertext for future attack
Worked example
A service protects records requiring decades of confidentiality with a conventional public-key key exchange. Inventory that exchange and dependencies, assess approved hybrid/PQC support and test protocol compatibility; do not merely increase a subnet prefix or disable certificate validation.
Configuration reference
# Migration inventory reference; no cryptographic implementation here Service / owner Key exchange and signature algorithm Library and firmware support Data confidentiality lifetime PQC / hybrid deployment test and rollback
Troubleshooting scenario
A larger approved handshake fails on one path while small packets succeed. Investigate MTU, fragmentation and middlebox behavior with evidence. Never bypass authentication to force completion.
Knowledge check
Which statement is accurate about NIST ML-KEM?
Related practice
References
Educational model — not real hardware, traffic or official certification.