I've read a lot of your replies on the forum and it's clear you spend a lot of time thinking about architecture of Syncthing. Thank you. However, you're out ahead of my brain. Can you tell me a bit more about no shared secrets?
"Folders only" in BTSync are not shared secrets any more than folders and devices are in Syncthing. In both bases, they're simply unique identifying hashes. Of course, if you don't have the hash, I guess it could be called a "secret", but they're still both the same in that way.
It just seems the overlaying of both concepts (devices and directories) seems redundant. You can't ever have a directory sync without a device, so what's the point of specifying a device? And you can't specify a device only without knowing what directory to sync, so devices can't stand alone. Directories ~can~ stand alone without specifying a device. Directories are ideological data sets, which is what we're trying to share. Forcing knowledge of what device syncs the data is sort of the antithesis of "the cloud".
What is accomplished with device ID#s that can't be done with only directory ID#s?
Wweich (@Community MVP), ..yes.. I noticed the changes in BTSync v2, so somebody did think this was a good idea over there, but my understanding is still missing what feature or capability this ads.