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Comment by wruza | Hacker News Reader

WhatsApp vs Telegram E2E encryption seems to be a hot topic here, so I’m not sure in which subthread to ask.

The question is how WhatsApp is E2E by default, if I can open a browser, read the QR-code and see all my E2E chats in there instantly? WA either has them unencrypted or can see my phone’s secret key in transit. Isn’t the whole point of END to END messaging being undecipherable on devices other than these two?

Or how does that work? Is my browser establishing e2e to my phone and downloading all chats? This seems unlikely. Does it synchronize the secret key? Then I see it as a security hole — I don’t want my secret chats to leak to other devices that may be not as protected as a phone.

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> Isn’t the whole point of END to END messaging being undecipherable on devices other than these two?

That’s how it should be. WhatsApp’s desktop apps are technically another front-end to your secured database on your phone. I’m searching for the tweet of one of iOS security researcher that confirmed this. That’s also the reason that your WhatsApp desktop client stops working when you are out of range. That’s being said, I’ve noticed that recently this is changing and somehow the desktop app maintains the data a bit longer. It’s still not completely independent but I think it’s in the transition period. If that happened, then their E2E has to be different.

By the way, I think the security code from one of your devices, probably your phone, can be encoded to the QR code and transfer to the client.

I assume WhatsApp implementation is a hybrid between mirroring the information and some sort of secure handshake via the QR code.

I think what you observed is just some smart caching behavior and application code expecting frequent network issues. I can read already synchronized messages and queue messages for being sent on reconnect. I dont see why this would change anything with their encryption scheme...

If anyone has led you to believe that E2E means one specific device to another specific device at all times, they don't know what they're talking about.

There are different ways keys can be exchanged between devices (of the same user). All of them are E2E and secure. WhatsApp forces you to keep the phone around because the phone is the conduit for all communication even when you use it on the desktop. Signal has a desktop client that you need to link once to your phone, and works as a standalone client even when your phone is not around. Wire has E2E by default (like WhatsApp and Signal) and message synchronization across devices and platforms.

I always heard that telegram encryption was disabled by default. If you want security use signal, if you wants stickers and the like, use telegram.

Telegram is still a step up from what most people use (Facebook Messenger, WhatsApp). And if you really want a chat to be secure it's easy to set one up. I find it to be a perfect blend of security and usability. Saying it's only good for stickers is pretty disingenuous

Seeing that WhatsApp is using the signal protocol and encrypts all communications by default, I contest the notion that Telegram with its home-grown protocol and clear text by default is a step up.

I thought Telegram was sending messages encrypted (though not E2E) per default?

It isn't by default. You have to enable it yourself.

This is wrong. All communication is encrypted in transit, even for non-secret chats.

Is it also E2E encrypted though? If not, wouldn't that mean that Telegram servers could snoop in on the non-E2E conversations?

You're talking about "secret chats", the Telegram way of doing E2E, but it doesn't mean that all other communications are sent or stored plain text. And there is no setting in the app to enable encryption (I just checked), because there is no way to disable it. "Not E2E" != "not encrypted"

And you just trust Facebook to somehow really encrypt everything in this black-box? I think this is naive as Facebook has always lied to us and proved it isn't a trustworthy entity.

WA used to steal your contacts by default to improve Facebook's data set and probably still does.

The Telegram guy however left his country because he didn't want to cooperate with such entities (like the Kremlin which for me is kind of another organization that seeks to harm your privacy among other goals and is therefor comparable to FB and other spy-companies).

Seeing that WhatsApp is not prohibited in Russia is a big concern of itself. This country has a law that requires you to pass ‘master key’ (or a backdoor, if you read between the lines) to special agency, or be banned by all ISPs. When my friend researched the topic, some interesting guys told him few years ago that whatsapp is a no-brainer for them to read, but tg+secret is opaque. Subsequent events shown that it was probably true.

All this is full of false negatives and positives, but concerns too much to ignore, if you’re after secrecy that puts your welfare at stake. If you just hide your pics from a corporate big brother, I admit that whatsapp and regular tg chats may have different weights on scales.

This kind of oversimplification and hyperbole with an attitude is what I dislike in such conversations. Telegram is far, far better in speed, reliability, features and UX than Signal has been and is. Signal cannot even get messages delivered reliably as of today and has a whole bunch of UX issues that aren't addressed (two examples among many: can't restore conversations to a new device on iOS, and can't join past conversations and groups on a new device without going through some additional steps and still struggling to get it working). I appreciate that Signal (team invented and) uses reputed E2E, but there's a whole lot more to communicating with other people than security alone.

i think it could be done securely by transmitting the key material via a secure channel directly from the phone to the browser or transmit messages directly encrypted with the probably ephemeral key used for this secure channel. The secure channel could actually be build upon the the QR code you would give the app on your phone. No idea what is actually done though, just saying it could or should ^^

WhatsApp would of course still serve the whole browser application and could do whatever they intend to including leaking key material back home :) Not to mention that even if you opt to trust them not to do something shady or stupid like this you still have to trust DNS, certificate authorities, BGP routing policies, browser and platform security and likely a bunch of other stuff :P

It piggybacks off your cell phone app, I believe. It basically mirrors what's on your app, and if the connection severs at all then the data is wiped from the browser. You do bring up a good point on how it can be an attack vector, though.

> Or how does that work? Is my browser establishing e2e to my phone and downloading all chats?

More or less. It interfaces with your phone, which has a number of caveats. You can’t use the web interface without your phone.

WhatsApp desktop proxies through your phone over HTTPS. The Desktop to phone session is TLS, but not E2E.

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