ML-KEM Implementation Notes

ML-KEM (formerly Kyber, standardised as FIPS 203) is the recommended key encapsulation mechanism for most use cases. These notes cover a pragmatic adoption path.

Hybrid mode first

Deploy ML-KEM alongside an existing classical algorithm so a weakness in either does not break security. Most early adopters run a hybrid handshake during transition.

Sequencing

1. Update cryptographic libraries to versions that expose ML-KEM.
2. Enable hybrid key exchange on internal services first.
3. Extend to externally facing endpoints once monitoring is in place.
4. Track performance — larger key sizes affect handshake payloads.

Treat this as a multi-quarter programme, not a single change window.