- what the key is used for: signing critical operations, most notably print and gcode commands: https://git.devminer.xyz/archive/bambu-connect/src/commit/47..., list of known MQTT commands: https://github.com/Doridian/OpenBambuAPI/blob/main/mqtt.md

- what the firmware does: verify these operations, meaning it can reject MQTT messages with an invalid/missing signature from third party software

- the big flaw with that approach: by extracting the key, third party software can get full access again

- improvement to security: none (that obfuscation layer doesn't prevent anything if the printer/cloud were vulnerable)

authentication stays the same as before: https://git.devminer.xyz/archive/bambu-connect/src/commit/47...