/cc @Duansg @Aias00 @tomsun28 @zqr10159

The implementation direction addresses the secret-distribution path, but this is a breaking manager/collector contract change and the PR is still draft. Before release approval, please document mixed-version behavior and the upgrade order, prove the required common.secret failure mode is actionable, and run the manager/collector compatibility and packaging checks. Once the PR is ready and those upgrade guarantees are recorded, I can re-review it.

I rechecked the current head (14382ff). This change protects the key-distribution path, but it does not authenticate the Netty peer or any ClusterMsg.Message: unsigned GO_ONLINE, heartbeat, and collection-result messages still reach their processors. In particular, GO_ONLINE can still replace the identity-to-channel mapping, and cyclic results still enter the data queue without a message-integrity check.

I opened the dependent follow-up #4294. It signs the complete message envelope, enforces timestamp freshness and replay rejection, and closes invalid connections before processor dispatch. For this transport boundary, I would only treat #4263 plus #4294 (or an equivalent combined implementation) as complete. The rollout remains intentionally breaking: manager and standalone Collector must be upgraded together, share common.secret, and keep clocks synchronized.

Superseded by #4294, which preserves the local-only AES secret change and adds complete challenge-bound message authentication, required-by-default configuration, rotation support, executable Manager/Collector configuration, mixed-version rollout guidance, and packaging/startup regression coverage. Keeping both PRs open would duplicate the same transport-boundary change; continuing review on #4294.