[maxtaco]

An attack that might be of concern with this configuration is the server suppressing updates to this JSON file, or showing different versions of the JSON file to different clients. What you're describing is pretty close to what FOKS is getting at with signature chains and Merkle Trees, but maybe it's overkill for this particular application.

I wonder if the policy you describe could be implemented as world-visible team with world-visible users. Others have commented on the need for something like this, so I think it should be pursued with high priority. What's slighlty fuzzy to me is how these totally world-viewable teams and users would interact with more closed-down users on other servers.

[raphinou]

Although I didn't consider this attack possibility (thanks for raising it!), I think we are reasonably immune to it or able to detect it with the way we manipulate and store the JSON (though completely avoiding it seems not attainable, at one point the client has to trust the response it gets from a server, am I right? Otherwise I'm very interested in pointers to learn more!)

World visible teams and users might be a way to define our multi-sigs members. But we would still need a JSON file for others characteristics of the multi-sig. I'll keep an eye on foks as if it becomes a good fit, it might let us concentrate on our service and not on key management intricacies. My email is on my HN profile, in case you want to notify me of advancement fitting our use case.