It hides the destination from someone watching the depot line, yes, Rahul. But the destination was never the secret, and Tor costs you real things on the Hermetry side.
What actually protects you today: the MQTT session is TLS 1.2 minimum with forward-secret suites, so contents and the device token aren’t readable on the wire. Someone sniffing the depot uplink learns there’s a device talking to a broker every N seconds. Tor hides the broker name and adds a lot of latency and connection churn.
Now the costs. Every Tor circuit exits from a different address. Hermetry sends your admins a notice when a device logs in from a new network (at most once an hour per device), so 9 nodes hopping exits means a steady stream of those, and you train people to ignore exactly the warning that would tell them a token was stolen. You also lose the profile’s Allowed networks option, which is one of the best controls you have for fixed-site devices: list the depot’s public address and a stolen token used from anywhere else gets CONNACK 5. Plus repeated failed logins block an address for every device behind it, and on shared exits that’s not under your control.
If the boss wants more, I’d do this instead, all on the device profile:
- Allowed networks: the depot’s public IP
- TLS only, Token in the URL off, Commands allowed without TLS empty
- move from access tokens to X.509 if your firmware can, otherwise MQTT basic, one credential per device
- lower the profile Limits to what the nodes really send so a hijacked one gets cut off fast
And put the ESP32s on their own VLAN so a compromised node can’t reach the office PCs. Checklist is on Device transport security.