Market data is public the instant it is published, so encrypting the payload is not the point. The session is. An adversary who records an authenticated state channel today and breaks the key exchange in ten years can replay it to forge provenance — and provenance is the one thing we sell. So LIAW state channels run a post-quantum key exchange under the existing transport.
The migration was quieter than expected. Hybrid key exchange adds a few hundred bytes to the handshake and nothing to the steady-state path, so the freshness budget is untouched after the channel is established. We pin the post-quantum suite, fall back to nothing, and stamp the negotiated suite into the lineage so a consumer can audit exactly how their session was secured. Security here is just another field in the ledger.