Foundations
Post-quantum cryptography: the starting point
What you will understand
Distinguish algorithms, protocols, and systems before planning a transition.
Last reviewed:
Understand the context
Post-quantum cryptography (PQC) uses mathematical constructions intended to resist attacks by both classical and quantum computers. It runs on ordinary computing platforms. Quantum key distribution (QKD) instead uses physical quantum communication mechanisms and has different equipment, distance, authentication, and operational requirements. These are distinct technologies; a PQC migration is not a requirement to install a quantum network.
Plan the work
Begin with a business service and its cryptographic purpose. Key establishment, digital signatures, and bulk encryption are different jobs. Replacing the name of an algorithm in a configuration file is not a complete migration: protocol negotiation, key formats, providers, certificates, and peer systems may all constrain what is possible.
Evidence to review
For every proposed change record the applicable standard, the exact implementation and version, the protocol profile, and the environment where it was tested. Ask which component terminates the protected connection and whether a managed provider controls that boundary. Keep observed behavior separate from a vendor roadmap or a laboratory demonstration.
Limits and next steps
NIST FIPS 203 specifies ML-KEM for key encapsulation; FIPS 204 and 205 specify ML-DSA and SLH-DSA signatures. An algorithm standard does not certify the application that uses it. Continue with the threat and data-lifetime guide, then identify a bounded system to inventory.
Evidence and limitations
Educational guidance with referenced standards; no customer system has been assessed for this article. Implementation and protocol support must be verified for the selected environment.