[personal profile] mjg59
Moxie, the lead developer of the Signal secure communication application, recently blogged on the tradeoffs between providing a supportable federated service and providing a compelling application that gains significant adoption. There's a set of perfectly reasonable arguments around that that I don't want to rehash - regardless of feelings on the benefits of federation in general, there's certainly an increase in engineering cost in providing a stable intra-server protocol that still allows for addition of new features, and the person leading a project gets to make the decision about whether that's a valid tradeoff.

One voiced complaint about Signal on Android is the fact that it depends on the Google Play Services. These are a collection of proprietary functions for integrating with Google-provided services, and Signal depends on them to provide a good out of band notification protocol to allow Signal to be notified when new messages arrive, even if the phone is otherwise in a power saving state. At the time this decision was made, there were no terribly good alternatives for Android. Even now, nobody's really demonstrated a free implementation that supports several million clients and has no negative impact on battery life, so if your aim is to write a secure messaging client that will be adopted by as many people is possible, keeping this dependency is entirely rational.

On the other hand, there are users for whom the decision not to install a Google root of trust on their phone is also entirely rational. I have no especially good reason to believe that Google will ever want to do something inappropriate with my phone or data, but it's certainly possible that they'll be compelled to do so against their will. The set of people who will ever actually face this problem is probably small, but it's probably also the set of people who benefit most from Signal in the first place.

(Even ignoring the dependency on Play Services, people may not find the official client sufficient - it's very difficult to write a single piece of software that satisfies all users, whether that be down to accessibility requirements, OS support or whatever. Slack may be great, but there's still people who choose to use Hipchat)

This shouldn't be a problem. Signal is free software and anybody is free to modify it in any way they want to fit their needs, and as long as they don't break the protocol code in the process it'll carry on working with the existing Signal servers and allow communication with people who run the official client. Unfortunately, Moxie has indicated that he is not happy with forked versions of Signal using the official servers. Since Signal doesn't support federation, that means that users of forked versions will be unable to communicate with users of the official client.

This is awkward. Signal is deservedly popular. It provides strong security without being significantly more complicated than a traditional SMS client. In my social circle there's massively more users of Signal than any other security app. If I transition to a fork of Signal, I'm no longer able to securely communicate with them unless they also install the fork. If the aim is to make secure communication ubiquitous, that's kind of a problem.

Right now the choices I have for communicating with people I know are either convenient and secure but require non-free code (Signal), convenient and free but insecure (SMS) or secure and free but horribly inconvenient (gpg). Is there really no way for us to work as a community to develop something that's all three?

What about conversations?

Date: 2016-05-12 03:25 pm (UTC)
From: (Anonymous)
There is an xmpp client for android, called conversations, which at least satisfies the requirement of a negligible impact on battery.
It also has an option for end-to-end encryption.

Date: 2016-05-12 03:47 pm (UTC)
From: (Anonymous)
Not that we want an arms race here, but whether the Signal folks "like" it or not, they're not easily going to be able to stop anyone from interoperating with their servers.
From: [personal profile] mjh75
We've spent the last 1.5 years solving *exactly* this over at Matrix.org. Apologies that the below reads a bit like an ad, but the three key desirable attributes here map almost directly to what we're doing.

Convenience: glossy clients (late beta) available on web, iOS, Android such as https://vector.im with similar featureset to Slack/WhatsApp/FB Messenger etc. Interoperability with IRC, Slack and alpha bridges to things like XMPP, Lync, FB, Skype etc via libpurple.

Security: Decentralised architecture storing all conversations into a signed DAG which is replicated over all servers participating in a conversation. PERSPECTIVES for TLS cert management (not fully finished yet). Olm (https://matrix.org/git/olm) - our own independent Apache licensed C++11 implementation of the same Double Ratchet end-to-end encryption ratchet used by Signal (in late alpha)

Freedom: Built to give users the choice over which servers, services and clients they use, without sacrificing interoperability. Run your own server; run your own services; own your own data. 100% open source (Apache, for better or worse); entirely open specification with community involvement providing an open decentralised pubsub persistence building block for the web; non-profit charter; very active dev community writing all sorts of weird clients and sdks and bots and servers etc (eg weechat, pto.im, ruma.io etc :) The official Android SDK does use GCM currently by default, but can be disabled - an Fdroid distro would be *very* welcome.

So, um, sorry for the rant but we *really* think that open decentralised comms is a tractable problem and it's here today. Sure it's harder to build and maintain than a centralised service, as Moxie points out, but that is a price worth paying for maintaining independence, freedom and interoperability in our comms.

Two years ago..

Date: 2016-05-12 07:17 pm (UTC)
From: [identity profile] tincho.org
Two years ago, after a day of talks at FOSDEM, some friends and I had a conversation about similar topics. It was triggered by the then new kid on the block: Telegram. I wrote a blog post (https://blog.tincho.org/posts/Telegram/) about that shortly after.

In the next few months I kept thinking about the problem of having a user-friendly, federated, secure system for RTC. Even though it went unnoticed and I did not do any real work on it, I wrote a series of posts discussing ways in which this could be done, here (https://blog.tincho.org/tags/Yakker/).

Maybe this interests somebody who has the time and resources to make it a reality.

Date: 2016-05-12 09:21 pm (UTC)
From: (Anonymous)
There is also Ring (formerly SFLPhone), with mobile and desktop apps, however it's still in an early state. Ring supports SIP and its own protocol which is basically serverless SIP and nodes are looked up via DHT (as in torrents). Looks very interesting, is free software and uses Qt.
Also Ostel (https://guardianproject.info/apps/) is nice, multiplatfrom, free software alternative which uses SIP if I'm not mistaken.

Personally I cannot understand why new protocols are implemented when there are already SIP and XMPP, and what is lacking is good mobile apps. Current situation is horrible, with so many protocols (Skype, Whatsapp, Signal, SIP and XMPP) it's difficult to communicate. And yes, most of your friends will use Skype or WhatsApp (because it's from Facebook).

One more for the mix

Date: 2016-05-12 10:30 pm (UTC)
From: (Anonymous)
Let me throw another one on the mix, which I'd say fails the convenience test, for now at least. There is tox (https://tox.chat/) which seems to be promising.

Regarding signal, I tried and didn't find an explanation for why each of the many permissions is required. I guess I might need a tinfoil hat but apps that require lots of permissions always make me suspicious - mind you that I'm not implying signal is not secure or does nasty things.

Kontalk

Date: 2016-05-13 12:50 pm (UTC)
From: [identity profile] keverets.livejournal.com
Kontalk is another viable option, based on XMPP and PGP (but hides the underlying PGPness).

The downside there is the lack of cross platform support. It works well on Android and has a desktop client, but lacks iOS support.

Kontalk

Date: 2016-05-13 02:05 pm (UTC)
From: (Anonymous)
And you can always fall back to SMS.

Silence

Date: 2016-05-15 11:48 am (UTC)
From: (Anonymous)
I wonder whether Silence (formerly known as SMSSecure) is an option. It's a fork of Signal/TextSecure that uses only SMS as a transport.

https://silence.im/
https://github.com/SilenceIM/Silence

Date: 2016-05-15 06:27 pm (UTC)
From: (Anonymous)
Does freedom even enter the debate? It seems that Free services can be convenient and secure (well, so long as convenience isn't defined as the kind of ubiquity that only Big Daddy G can muster) at the same time as proprietary services can be inconvenient and insecure. Indeed non-freeness implies a condition where security cannot be ascertained, which from a practical standpoint is as good as known insecure.

Really the problem is that Google has a whiz-bang service built into all Android clients, and the use of this service is tied to proprietary horseshit. Consequently all alternatives will be technically inferior (i.e. wakeups, power consumption) or require rooting a handset and so forth. It's Microsoft tier secret API leverage for competitive advantage all over again.

Spose Google's itching for an antitrust action?

Date: 2016-05-15 09:47 pm (UTC)
vlion: cut of the flammarion woodcut, colored (Default)
From: [personal profile] vlion
One of the big takeaways here is that opsec is hard, and most people don't have a pressing need to operate in an opsec mode, so they opt for convenience.

Inasmuch as Moxie is looking for adoption, he's opting to shift out of an opsec mode in proportion to this. For people who have a *significant* need to operate out of the snooping ability of Google, then Signal is not an option: it relies on a friendly Google. This permeates everything in the ecosystem - friendly services such as Google or Apple (not neutral) are taken to be mandatory for user friendliness. It's important to understand that if you're concerned about Big Siblings, then you have to control the software; and most / all of the hardware.


This is of course in separate context from the Libre Software requirements, of course!


I'm not sure who Moxie is serving at this point in the game. Not people who have reasonable concern for a Big Sibling. Unsure who is paying his bills: Twitter, I think. My analysis would be that Signal is adequate for purpose when dealing with ordinary snooping concerns - family concerns, coffeeshop snooping, etc. For people dealing with Significant Security Concerns... not sure there are reliable options; all paths are fraught with risk.

OSS and the desktop/mobile

Date: 2016-05-25 07:01 pm (UTC)
From: (Anonymous)
I'd ask a deeper kind of question: Why has "open source" proven to be almost completely unable to solve the end user software (aka desktop/mobile applications) problem? And given that continued failure, is it time to go back to primarily advocating a **moral** stance for opening code rather than a technical one?

ChatSecure ?

Date: 2016-07-09 08:26 am (UTC)
From: (Anonymous)
https://github.com/guardianproject/ChatSecureAndroid/
The only problem is if a communication gets disconnected, OTR is not designed for mobile communications, but the successor OMEMO is. AFAIK ChatSecure doesn't support OMEMO yet.

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Matthew Garrett

About Matthew

Power management, mobile and firmware developer on Linux. Security developer at Google. Member of the Free Software Foundation board of directors. Ex-biologist. @mjg59 on Twitter. Content here should not be interpreted as the opinion of my employer.

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