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Comment by dylkil | Hacker News Reader

Signal is open source, you and anyone else can inspect the code. You can then build it from source and install on your android directly avoiding the play store.

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That is a somewhat misleading statement, you may know what's on your device but you don't know what is happening on the servers

Its end to end encrypted chat. They could store the encrypted messages sure. I think the biggest fear people should have with signal is the client side encryption.

Because of public-key crypto, it doesn't matter if the servers are malicious.

not true with respect to meta data

which I don't think is as concerning, but is there a particular piece of metadata that concerns you?

I do think it is a valid concern. Over the years, various sources reported that intelligence agencies mostly use metadata (who's talking to whom, i.e. the social network) in their analysis because message content is harder to parse and understand (and, outside of email traffic, harder to obtain in the first place).

https://www.sciencemag.org/news/2016/05/your-call-and-text-r...

Metadata can be as damning as the actual message data, and in a lot of places you don't want the authorities to know that you are even communicating at all.

Certain parts of the world, people get bombed on metadata alone.

Assuming you have:

- read the source code and are satisfied that it's secure

- compiled that version of the code

- installed it on your mobile or desktop

You're still only as secure as the client on the other side of the conversation.

If that one is compromised (has not gone throught the steps above) it could very well be sending all messages in clear text to a malicious party.

Edit: formatting

Ok, sure. But what do you propose? It's still a much better situation than what we have with Whatsapp. Is there something that the Signal Foundation could do to alleviate that concern you have? There's no technical solution in any technology for preventing the other side being compromised, as far as I can see.

At present I'm choosing to trust Signal.

That doesn't mean I blindly trust them, only that despite seeing potential for abuse I judge that they have more incentive to be telling the truth than not.

Also check the comment by user faitswulff where they mention how they have been subpoenaed "and could only supply account creation time and last connection time".

Matrix since you can self-host and have control while still being able to communicate to other people on it through federation

>>> You're still only as secure as the client on the other side of the conversation. If that one is compromised ... it could very well be sending all messages in clear text to a malicious party.

>> There's no technical solution in any technology for preventing the other side being compromised, as far as I can see.

I don't know Matrix, but I can guarantee that it doesn't solve the problem of a compromised client obtaining the messages willingly sent to it.

Yeah and since you have the possibility of dealing with state actors with deep pockets, you have to wonder if Android or iOS doesn't have the ability to copy your private keys and send those off somewhere for storage. Because of signal's popularity, it feels pretty possible to me.

If the NSA did have it backdoored somehow through the OS, it's a good bet they'd force LE agencies to use parallel construction to keep that information top secret.

That is why we really need open source hardware and OS's. A good (or even functional) open linux phone can't come fast enough.

If your adversary is state actors with deep pockets or the NSA, you've lost already. No amount of opsec cosplay is going to save you.

Your solution?

* Magical amulets?

* Fake your own death, move into a submarine?

* YOU’RE STILL GONNA BE MOSSAD’ED UPON

https://www.usenix.org/system/files/1401_08-12_mickens.pdf

AOSP (Vanilla, GrapheneOS, CalyxOS) doesn't have this capability.

The Google Play Services app/package? Heh...

The server can MITM the public keys, providing you with a key from the server instead of the key from your conversation partner.

It very much does matter if the server is malicious.

Not if the keys are generated by the client.

Signal also offers to label contacts for which you could verify the authenticity by another way.

Doing a video call with the contact can be a simple way to clear doubts, even if it is not a proper different channel.

This is false. A video call will not prevent or detect MITM. You may be suggesting that a video call is used to authenticate the key, which is certainly a step in the right direction, but I don't think Signal supports this.

It will, because it will prove (or give you a lot of confidence) that the agent who sent you their public key is your legit correspondent.

This uses the fact that the client on each side is open source and inspectable, so that each side knows that they sent only the public key that they generated on their own device.

PS: to answer your last sentence, Signal allows you to flag specifically contacts that you managed to verify. Which is technically equivalent to say that you verified that the public key is theirs.

Yes, but it doesn't support doing that whilst in a video call with them.

[edited]

Indeed it is far from straightforward that merely doing a video call suffices to check the keys.

Signal is famously using a special protocol for secure key sharing through the server, which I have not studied.

But as said by another comment, there is no way around verifying explicitly the public key using an independent channel.

Video calls alone won't stop a MITM attack. They would just send both video streams along, and record both sides.

Signal does have the capability to have a verification phrase displayed, which is generated from the session key. Reading that off can make the video more difficult to MITM, because then they'd have to morph the audio to match the phrase, and if it's done after the video is setup, morph the video as well. Not impossible, but difficult.

If you are paranoid, you can do public key verification through another channel. People with high risk profiles should do this.

Key authentication is not for the "paranoid" or simply those with "high risk profiles", otherwise every web browser in the universe wouldn't do it by default on every single connection to every single website. It is a normal, routine thing that is expected in all modern secure communications systems.

Please don't spread this harmful meme.

We've got certificate authorities to centralize trust for server public keys. And those require trusting organizations that lots of people don't want to trust. We don't have an equivalent system for individuals. There is no trivial push-button key verification process for peer-to-peer communications. Key signing parties suck and never worked. Key validation for things like Signal is nicely automated if you are physically near the other person. But beyond that it is tricky.

It is hard enough to get my parents to use a secure messenger. If I told them they needed to do a key verification process for every person they ever communicate with... they'd just go back to facebook messenger or sms.

I think it is completely reasonable for somebody to say "I don't care enough to worry about validating public keys" while also educating people like journalists about how to do that correctly.

Right! the keyword here is "Reproducible Builds". Basically once there is documentation about how to produce the release build, you can do it yourself and compare the resulting hash with the build distributed in the Store. Generally speaking it does no come for free, but once you find a way (e.g. for iOS compiling with a specific Xcode version in a specific OS with some adjusted config) is kind of doable (except that Apple encrypts your build server side for DRM purposes, so you'll need a jailbroken phone to do something about it)

For Signal there is an open issue here for iOS [1] and some documentation for Android [2]

Some nice work about it has already be done by telegram https://core.telegram.org/reproducible-builds

[1] https://github.com/signalapp/Signal-iOS/issues/641

[2] https://github.com/signalapp/Signal-Android/blob/fab24bcd1e5...

This has nothing to do with the comment you replied to, as you have no idea what software is running on their server, so what would it even mean to reproduce it in the first place? The correct answer is merely "the server never received much in the first place so it doesn't matter as much if they stored all of it".

right, I think I messed up with the reply while I was reading other comments.

While this is a great way to build trust, there is obviously no way to confirm the App Store version is the same as one built from their public source. In fact, due to the way Apple optimizes apps for each device, this becomes even harder. Furthermore, just because you compile it from source and put it on your phone does not mean that you can reasonably stay aware of or understand all the internal workings that happen inside the app.

I know that developers can post LLVM bitcode to the App Store instead of a binary, which allows Apple to recompile it for architectural changes. I'd be surprised if Apple optimized per device. Creating separate builds with optimizations for different iPhone models would make more sense. Do you have more details on that?

I think he meant "iPhone models" when he said "devices". I'm not the op, but they definitely do optimize per model, not individual device.

Per model is what I meant.

> Furthermore, just because you compile it from source and put it on your phone does not mean that you can reasonably stay aware of or understand all the internal workings that happen inside the app.

Can you elaborate on this? That's exactly what I'd expect of an app I compiled from source.

Are you going to read every commit and fully explore the entire app to know your messages and encryption are being handled securely? And keep doing this every time you update? If so, you have more time than I do. :-)

As much as it is open source, there's no way to know for sure that the software running on their servers is the same that's published on Github.

The software on the server doesn't matter, as long as the encryption is solid on the device. That's the whole point, the devices handles all encryption/decryption so the server can't understand any of the data coming and going. The reason they don't store the data is because it would be pointless. The Github repos contain the device source code which, for most platforms, can be verified.

> You can then build it from source

To be secure you would HAVE to build and install it from source.

But then again your OS could possibly inject code to get the keys. Or a keystroke logger may have been installed.

So how do I build the Signal server and confirm it's identical to the one they're running?

It doesn't matter if it's not. Security should depend completely on the clients. Public-key crypto allows private communication through insecure channels.

That's not going to be true of metadata, though. A malicious server could keep a lot of valuable metadata about you.

No, it does. In some cases (think dictatorship) - you not only want the secret police to not read your messages - you don't want them to know at all, who are you talking to(and how often and when!). Otherwise you might all go to jail (or worse), if they are after one contact of yours. And then you can try to feel save, that they don't know your encryption password.

https://xkcd.com/538/

here https://www.deccanherald.com/national/north-and-central/jk-a...

not allowed to use VPNs because national security issues.

https://www.aa.com.tr/en/asia-pacific/india-launches-fresh-c...

"social media muisuse"

i remember last year this word was so much used, "misuse" which translates to criticizing the ruiling dictator government. it still is,

https://thenextweb.com/in/2020/01/08/kashmirs-police-want-pe...

here. a whatsapp group needs to be "registered" with police.

and lastly more recently, https://theintercept.com/2020/12/06/kashmir-social-media-pol...

this is a reason why i never signed up for whatsapp, havent joined signal, don't tweet or post on facebook. Why? because PII

the danger is real and i am living it. people better realize it

Well, if a government goes authorian, than it does not matter much, what service you use, if you have to assume your phone has spyware on it.

If the main danger is, police scanning the phone for compromised material (without a police spyware on it), then there are some ways to deal with it technically, by using services that don't leave a trace. Telegram for example has a "secret chat" function, which won't save the messages, meaning someone scanning your phone later, won't find them.

(which I head is also a main reason for many people to join telegram, because so they can chat with their affairs and not have their wifes read it)

Then there are simply private tabs of chrome or ff, from where you can use chat-services without trace. (if the chat services are not cooperating with the police, or are decentralised by default, I think in that scenario I would use matrix)

Anyway, you live in kashmir?

I know mainly of the conflict by reading Shalimar the Clown, from Rushdie. Just curious about your opinion, if you know the book. I heard it was not well received in Kashmir itself? I think it was very well written, but I don't know how accurate it is.

Yeah. Just last year I had to teach neighbours and such to use a launcher like Evie which lets you hide apps. Many were stopped during random street checks and that saved their Turkey. Heh.

8 months or so ago I was stooped because it looked like I was "recording a video" on my phone when actually I was. Took a slow turn, double press power button and pickachu face that I wasnt. Still a couple guys around helped or I was history.

No. I havent read Rushdie. It has that whole demon verse thing around him, he isnt liked

The problem with telegram as with WhatsApp and signal is phone numbers. India has had this network analyzer on isp level for like 6-7 years, called "netra". So all unencrypted traffic goes through it. Same for all encrypted traffic. This is the reason why I stopped using tor, because my traffic would show up uniquely than rest and that gets them suspicious quickly.

There is a lot of text written on the conflict which actually is more than 500 years old. Kashmir has been under foreign oppressive occupation for over 500 years constantly and even today is under 3 nations. Its not like the occupation wont affect the people.

I am trying to get people I know on matrix because there is no PII, waiting for dendrite to come out of beta so that I can set up my own server and such.

The joys of living in an open air prison.

"No. I havent read Rushdie. It has that whole demon verse thing around him, he isnt liked"

Well, he did made many people aware of the conflict, which created attention, which results in indian police having to give interviews to the intercept for example, which helps in some ways. Things would probably be darker without.

How is your opinion on a political solution?

Do you think independence would work out (if your big neigbhours would let you)?

My understanding is, that the kashmir population in itself is divided?

Anyway, hope you stay safe.

i "think" i am safe. Recently a prominent lawyer was assassinated in broad daylight, that has gotten me scared. other than that this place is actually safer for non combatants than rest of the subcontinent and i can say that with authority. the governments otoh are not safe for people.

from what i have observed and from facts, at least on the indian occupied side, india spend like millions to convince entire generations about a local hero who happened to be pro india.

https://zeenews.india.com/india/at-2-3-per-cent-turnout-srin...

this was a couple years ago.

yeah so its not like people are not protesting, we just don't see a point in the conventional protests. kashmir has been fighting foreign invaders for over 500 years so its kinda in the system, to oppose.

as a kashmiri, i see no alternative other than complete independence. there is no other way forward, will that take 20 years or 500. Doesn't matter

personally i think all three of these nations have to let go of kashmir, not because of some altruistic reason but because of CPEC. india and pakistan "need" to pass through kashmir to access it. china cannot afford jeopardizing their project because of indo-pak squabbles. for them business is king and the sooner things settle down, the easier.

for us kashmiris, we could practically live off of port fees for all the goods passing through our borders so yeah, i am hopeful

"personally i think all three of these nations have to let go of kashmir, not because of some altruistic reason but because of CPEC. india and pakistan "need" to pass through kashmir to access it. china cannot afford jeopardizing their project because of indo-pak squabbles. for them business is king and the sooner things settle down, the easier."

I would be more afraid, that those big powers next to you don't want to let you go exactly for that reason. They want to use your land.

But yeah, I hope that they can settle for that. Leave you in the middle. A buffer between them.

Good but currently the land is divided between 3 and there is fighting. Unless status quo changes, fighting will continue. Its not like if any of the three forces its way on others territory and the two will stay quiet. Either all can have it like now and keep fighting or all let go and no one fights.

Well a man can dream. Right?

My sympathies are with Kashmiris but you have to admit Mirwaiz who sees a Qadiani behind every corner and Syed Ali Shah Geelani are not good PR for you.

Session is a signal-derived app that attempts to mitigate these types of information leaks.

https://getsession.org/

Edit: see discussion here: https://news.ycombinator.com/item?id=25690036

Other than literally showing up at somebody's datacenter and taking their machines away you won't be able to do this with any service ever.

and how does this proof that they don't save what you send them?

what use are my encrypted messages to them?

Building social graphs and activity logs, for one.

1) Meta data 2) Decrypt in case of security breach or more advanced computing

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