Hi everyone. I was curious about how private messages work in regards to private meshtastic channels. If clients all have the default long fast primary channel, but also have another channel with a private PSK, what channel does private messages use? Will it still use the primary long fast channel, or will it know to use a more secure channel that is available?
Thanks!
It will use the channel where it most recently heard a Node Info packet from the destination on. That’s most likely the destination’s primary, but can be a secondary.
If you want to make sure it will use your private one, only one side can also have the public channel, not both sides.
I’ve been curious about that for awhile.
I have to say that seems like an inconvenient way to manage privacy. How can one tell what channel nodeinfo came from in practice?
It will be shown in the node list if it’s not index 0.
Direct messages to secondary channels wasn’t designed for privacy, see the discussion in the original pull request.
Thanks for the information. I have to admit, I am not really pleased with this design choice, but I understand why it was made. Ideally you should be able to set which channel a direct message should use, if privacy is desired. I think a lot of people are under the false impression that as it is, direct messages are private and secure. That has the potential to get someone in trouble, since it doesn’t appear documented anywhere.
This is where having only some radios with an additional channel Key is helpful. Then only those radios will display the encrypted messages. It’s not so much a private message but is not readable from other devices on the mesh that do not have the channel added with the key. You will need to make sure ALL traffic is forwarded on instead of local only.
