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You're really missing the point here. The core Matrix protocol doesn't handle contact discovery at all. An entirely separate system exists to facilitate contac

by Reelin 6y ago

You're really missing the point here. The core Matrix protocol doesn't handle contact discovery at all. An entirely separate system exists to facilitate contact discovery. You have to explicitly choose to publish an identifier to it. You choose the server you want to publish to. You choose if, which, and when to query such servers. You choose what to query them with. A server implementation can (in theory) support whatever arbitrary thing it wants to for an identifier. The fact that email addresses are commonly supported is already _significantly_ better than being forced to use a phone number.

akerl_ 6y ago
In the interest of being an informed member of this discussion, I went to try out Matrix. Per the top recommendation from matrix.org, I downloaded the Elements app for iOS. When I opened it, the very first thing it did was ask me if it could access my contacts for sharing them with my (as yet unchosen?) identity server. Then, I registered an account and clicked the “People” tab. I was immediately prompted to enable contact discovery, via a modal called “Contact Discovery”. It specifically calls out finding contacts by email and phone number. There was never an option presented to select my own identity server, or change what info is published. If “contact discovery” isn’t part of the core offering, it certainly makes a great attempt to look like it is. The only choice I had available to me is to decline sharing my metadata, which is the same option Signal makes available for SGX. I get that due to the magic of open source and federation, Matrix implementations could technically use random numbers or favorite colors or some other identifier, and I’m sure there are other less recommended clients which let me pick my own identity server or only share certain slices of data. But if we can’t agree that the flow recommended on the website is the one that the vast majority of users are going to follow, there’s not much room for a productive discussion.
- Reelin 6y ago
  > If “contact discovery” isn’t part of the core offering, it certainly makes a great attempt to look like it is. You are looking at only a single implementation here. The point is that this is a set of federated protocols that has been specifically designed to provide freedom of implementation in this regard. > But if we can’t agree that the flow recommended on the website is the one that the vast majority of users are going to follow, there’s not much room for a productive discussion. I never claimed otherwise? We seem to be talking past each other. You say you followed the top recommendation provided to you and that the end result was essentially equivalent to Signal. Since you appear to approve of how Signal handles things, that hardly seems like a complaint to me? The key difference, of course, is that for Signal that's the only option. If the central authority changes it tomorrow, then tough. Matrix, on the other hand, provides you the freedom to select (or build, or patch, or whatever) a client that meets your needs. It's providing a superset of what Signal is offering.
  - akerl_ 6y ago
    Except this isn’t the same as how Signal handles things. Signal uses SGX specifically so that they can store metadata without exposing it to the server. Matrix’s contact discovery spec doesn’t. My initial question, earlier up the chain, was in regards to this dilemma: Signal didn’t upload contact metadata to their servers for years, until they implemented SGX to allow them to do so securely. By contrast, every other messaging platform (Matrix included) just wrote up a spec for contact metadata storage that doesn’t address protections from the server operator. We’ve got back and forth about the upsides of federation and open source clients and such, but as I’ve tried to point out, none of that is relevant to the actual question I asked, or the upstream point in the thread: that Signal’s spec didn’t include contact uploads at all until there was a way they could store them securely, and other message platforms just skipped straight to storing them.
    - Reelin 6y ago
      You can't control the server operator though. In practice I have no way of preventing Signal from turning off SGX any time they feel like it because they aren't open and federated. They could push a software update and I'd be none the wiser until a security researcher noticed and pointed it out! I guess it would be nice if Matrix integrated some sort of remote attestation support into the identity server protocol. Maybe they should have done so from the start, maybe not. At this point I don't see their offering as being less secure than Signal's though, just slightly different. It's also worth noting that SGX (and AMD's competitive offering) has been broken an embarrassing number of times at this point. From my perspective, secure storage by the server is more or less orthogonal to any given spec or implementation. You either provide data to a server as cleartext or ciphertext. The server does with it what it will - you as the user have effectively no control over that.

by Reelin 6y ago

akerl_ 6y ago

In the interest of being an informed member of this discussion, I went to try out Matrix. Per the top recommendation from matrix.org, I downloaded the Elements app for iOS. When I opened it, the very first thing it did was ask me if it could access my contacts for sharing them with my (as yet unchosen?) identity server. Then, I registered an account and clicked the “People” tab. I was immediately prompted to enable contact discovery, via a modal called “Contact Discovery”. It specifically calls out finding contacts by email and phone number. There was never an option presented to select my own identity server, or change what info is published. If “contact discovery” isn’t part of the core offering, it certainly makes a great attempt to look like it is. The only choice I had available to me is to decline sharing my metadata, which is the same option Signal makes available for SGX. I get that due to the magic of open source and federation, Matrix implementations could technically use random numbers or favorite colors or some other identifier, and I’m sure there are other less recommended clients which let me pick my own identity server or only share certain slices of data. But if we can’t agree that the flow recommended on the website is the one that the vast majority of users are going to follow, there’s not much room for a productive discussion.

Reelin 6y ago
> If “contact discovery” isn’t part of the core offering, it certainly makes a great attempt to look like it is. You are looking at only a single implementation here. The point is that this is a set of federated protocols that has been specifically designed to provide freedom of implementation in this regard. > But if we can’t agree that the flow recommended on the website is the one that the vast majority of users are going to follow, there’s not much room for a productive discussion. I never claimed otherwise? We seem to be talking past each other. You say you followed the top recommendation provided to you and that the end result was essentially equivalent to Signal. Since you appear to approve of how Signal handles things, that hardly seems like a complaint to me? The key difference, of course, is that for Signal that's the only option. If the central authority changes it tomorrow, then tough. Matrix, on the other hand, provides you the freedom to select (or build, or patch, or whatever) a client that meets your needs. It's providing a superset of what Signal is offering.
- akerl_ 6y ago
  Except this isn’t the same as how Signal handles things. Signal uses SGX specifically so that they can store metadata without exposing it to the server. Matrix’s contact discovery spec doesn’t. My initial question, earlier up the chain, was in regards to this dilemma: Signal didn’t upload contact metadata to their servers for years, until they implemented SGX to allow them to do so securely. By contrast, every other messaging platform (Matrix included) just wrote up a spec for contact metadata storage that doesn’t address protections from the server operator. We’ve got back and forth about the upsides of federation and open source clients and such, but as I’ve tried to point out, none of that is relevant to the actual question I asked, or the upstream point in the thread: that Signal’s spec didn’t include contact uploads at all until there was a way they could store them securely, and other message platforms just skipped straight to storing them.
  - Reelin 6y ago
    You can't control the server operator though. In practice I have no way of preventing Signal from turning off SGX any time they feel like it because they aren't open and federated. They could push a software update and I'd be none the wiser until a security researcher noticed and pointed it out! I guess it would be nice if Matrix integrated some sort of remote attestation support into the identity server protocol. Maybe they should have done so from the start, maybe not. At this point I don't see their offering as being less secure than Signal's though, just slightly different. It's also worth noting that SGX (and AMD's competitive offering) has been broken an embarrassing number of times at this point. From my perspective, secure storage by the server is more or less orthogonal to any given spec or implementation. You either provide data to a server as cleartext or ciphertext. The server does with it what it will - you as the user have effectively no control over that.