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PART 2 IS OUT, INCLUDING THE DISCLOSURE OF A GLOBAL FEDERATION DATA LEAK, AND THE ANATOMY OF A GDPR DATA REQUEST HANDLED BY MATRIX.ORG. SEE THE REPOS ABOVE.
You are accusing me of "purposefully lying for years" in paragraphs of shouty bold text, while simultaneously acknowledging that I've been promoting mxisd and its capabilities in my talks. (And for that matter we've also been promoting it on matrix.org/blog). This is an almost farcical paradox. It's also starting to sound as if the root of all your unhappiness here may be due to feeling upset that mxisd doesn't get more recognition...
I maintain that the point of an IS is to discover people to talk to on Matrix based on 3PID, and the only way today to usably publish yourself as discoverable is by using the logically centralised sydent servers at vector.im/matrix.org. You can of course run a local IS like mxisd, but it will only render you discoverable to users on the same identity server (unless it delegates to the central servers), which is of very limited usage. The mxisd could try querying other ISes based on the domain of the 3pid (if it has a domain), but this relies on the 3pid having the same domain as the mxid, which is pretty unusual in the real world.
I would much rather (as I said to you years ago when trying to provide input into your IS work) that we spent the time instead providing a reliable and privacy-preserving way of letting users globally publish their 3PID->mxid mappings (if they want to), which doesn't depend on centralised servers at all - which is why we haven't prioritised the federated bodge.
An alternative approach would be to use DNS itself or a DNS-equivalent architecture, similar to ENUM, to let servers recurse identity lookups to a root server and then back down to a given deployment-specific server. But as far as I know, mxisd doesn't support that, nor has anyone proposed it as a design. Plus it would still depend on root servers being a SPOF/SPOC, and would suffer all the same attacks as DNS itself - and be tantamount to reinventing the DNS.
This is why we'd rather pursue an approach which is fully decentralised - i.e. a signed shared datastructure of hashed-3pid -> mxids, scoped to whatever visibility the publisher desires, which anyone can participate in hosting, rather than depending on centralised ISes for global lookups to function.
I'm sorry you consider this slander(!)
This sort of hyperbolic rhetoric is why we gave up trying to work with you months ago.
No, the word oversight means "an unintentional failure to [...] do something." - i.e. the issue in question is an unintentional failure, and one which we haven't solved yet.
Yup, the bug is still open, and Google STUN is still hooked up as a last resort to help people who have failed to configure their own VoIP servers:
https://github.com/matrix-org/matrix-ios-sdk/blob/develop/MatrixSDK/VoIP/MXCallManager.m#L34
https://github.com/matrix-org/matrix-android-sdk/blob/master/matrix-sdk/src/main/java/org/matrix/androidsdk/call/MXWebRtcCall.java#L602
This is a good example of where a relatively low priority (for us) issue has not been higher prioritised, as it only affects people who have failed to configure TURN servers on their homeservers.