The entities most harshly critical of Signal are supporters of other messaging applications and protocols.
I think the most important thing to understand about secure messengers is that messaging in general is a back-ally knife fight of a market, one of the most vicious I've seen in my career. Perhaps it's because of the WhatsApp outcome and a general belief that there's another such outcome for some other messaging app. Or it could just be the network affect. Messaging applications themselves are interesting UX challenges, but as programming challenges they're pretty close to socket projects. So there are a lot of entrants in the market. Whatever the reason, the knives are out for Signal.
I don't so much care what messaging system you use to talk to your friends or chat with your gaming guild. But if you have real adversaries, the security part of your messaging system has to work, even more than the messaging part. For that situation, Signal is the only messaging system I'd recommend unreservedly.
Sorry, but I am still yet to see the proclaimed unanimous support for Signal as a messenger. As a protocol – sure, most infosec professionals obviously support Axolotl, but this does not imply your statement in any way.
> The entities most harshly critical of Signal are supporters of other messaging applications and protocols.
So the support for Signal isn't that “unanimous” after all, is it?
Otherwise, of course they will if they think that Signal has lost the proper direction for some reason (according to their view). Even many protocol supporters prefer using something like WhatsApp or Wire, the former due to its purported network effect and the likes of the latter because of features like E2E encrypted file transfers, 1:1 video or group calls w/o apparent security trade-offs compared to Signal.
> I don't so much care what messaging system you use to talk to your friends or chat with your gaming guild. But if you have real adversaries, the security part of your messaging system has to work, even more than the messaging part. For that situation, Signal is the only messaging system I'd recommend unreservedly.
In the end, it turns out that this is your personal opinion, not that of the security community as a whole (hint: there is none), which is fine if you didn't misrepresent it in most of your post. The networks of other people may or may not choose to go a different way, although some (or even many) of them may support the same core technologies, just because they do not agree with some decisions OWS made along the way and don't want to reconsider for any reason opposing parties have presented, e.g. in articles like the one we are commenting under.
To sum up, feel free to suggest Signal as an instant messenger, but please be careful with your supporting claims because there are other great and upcoming messengers out there like Matrix, Wire, Onion.chat, GNU Ring, any of the mentioned elsewhere Telegram and WhatsApp, or many, many others. Signal has legitimate reasons on its side that will make your argument weigh more than unjustified claims that it should apparently be the end-all and be-all of one's instant messaging needs.
A good way to rebut my claim would be to cite the most high-profile security engineer or security professional or crypto engineer or crypto scientist you can think of who recommends some other system over Signal.
If you believe people with state-level adversaries should exclusively use transparent and open hardware, that's fine; you should see Moxie's comment on this thread to learn how you might go about ensuring that the tiny minority of users with that hardware have access to Signal on it.
That's because when it comes to security often theoretical vulnerabilities end up being protocol-destroying vulnerabilities in practice. Security folks are notorious for saying, 'that won't work,' being ignored — and then everyone being surprised when indeed it doesn't work.
> phone numbers allow for signal to be a drop in replacement for other messaging apps with minimal to no registration required
The issue is not allowing phone numbers as identifiers: the issue is in not allowing other identifiers. There's already a URN scheme for telephone numbers, and there are URN schemes for many other identifiers, to include email addresses, and there are even ways to add additional schemes. If Signal used URNs rather than telephone numbers, then users could continue to use telephone numbers but advanced users could use other identifiers, as they wish.
> lack of federation means ows can control spam better unlike in a federated environment where lazy/malicious operators can cause lots of problems
A spammer cannot spam someone whose public key he does not know. If there is no central directory of identifiers to public keys, there's no way for a spammer to send spam. It is possible for someone who knows one's public key to spam one, but since the sender's public key is tied to a public identifier, one knows who sent the spam.
Does Signal perform any anti-spam activity anyway?
we're not talking about protocol destroying bugs, were talking about things firmly in the realm of trade offs between marginal security gains and usability with security folks tending to be far too focused on marginal security gains while loosing sight of the big picture of less then perfect security that people use is better then perfect security that nobody uses.
I.E. ChaCha is better then AES because it is more resistant to side channel attacks among other things, but if you are creating a TLS server and can only choose one algo, you probably want to choose AES because more browsers support it compared to ChaCha and the marginal gains from ChaCha probably don't justify excluding those users that don't support it.
> If there is no central directory of identifiers to public keys, there's no way for a spammer to send spam
If there is no central directory of identifiers to public keys, there's no way my mom will use it to send me anything
She'd never use an app where you two bump phones with NFC?
I think an IM which relied on in-person seeding and then bootstrapped with mutual contacts could be quite powerful, and easy to use for newbies too.
I still have the biggest difficulties to persuade my "normal" friends and relatives to prefer signal over whatsapp.
Everybody thinks whatsapp is more user friendly and convenient. In the end this is the key to adoption we should not forget that.
The criticism of signal's closed ecosystem is not new, this is just another write-up of what has been criticized numerous times before.
- phone numbers allow for signal to be a drop in replacement for other messaging apps with minimal to no registration required, I doubt I could have gotten my mother to use signal without switching from texting being so low-friction.
- lack of federation means ows can control spam better unlike in a federated environment where lazy/malicious operators can cause lots of problems. Take a look at the 2 big federated protocols email and irc where due to spam and other issues they are both increasingly centralized.