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Is Telegram really an encrypted messaging app?

blog.cryptographyengineering.com

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Re: Is Telegram really an encrypted messaging app?

#121

Post by fsflover »

lxgr wrote: post #71
ziofill wrote: post #65

> One of the biggest privacy problems in messaging is the availability of loads of meta-data — essentially data about who uses the service, who they talk to, and when they do that talking. […] the same problem exists with virtually every other social media network and private messenger. Is this true for Signal too? I thought it wasn’t.

Avoiding any metadata leaks without generating tons of cover traffic (to frustrate timing correlation attacks) is very hard. Signal does indeed use an architecture (at least for chats with contacts, or optionally everyone when you enable the "sealed sender" option that makes you a bit more prone to receiving spam) where Signal doesn't know who's sending a given message from a given IP address, and only which account…

> But any entity in position to globally correlate traffic

Also, Signal relies on AWS, which could also perform such an attack it seems.

Re: Is Telegram really an encrypted messaging app?

#122

Post by pandog »

alerighi wrote: post #118
bryanlarsen wrote: post #34

Try the mud puddle test: log into your account on a new device using the password recovery flow. Can you see your old messages? If the answer is yes then law enforcement can too. https://www.forbes.com/sites/anthonykosner/2012/08/05/how-se...

Well of course, but this is a feature of Telegram. It's the only messaging app where messages are stored on the cloud. This of course has security implications, but also allows you to have a big number of chats without wasting your device memory like WhatsApp does, or having to delete old conversations, and allows you to access your chats from any device. By the way you can also set a password to log in from another…

I think a high definition photo taken on a recent phone takes up an awful lot more device memory than a "big number of chats"

Re: Is Telegram really an encrypted messaging app?

#123

Post by alerighi »

tamimio wrote: post #68
sharpshadow wrote: post #15

Only the secret chat is e2e encrypted. All the other chat options are not. I think calls are also not encrypted since they appear in the normal chat history not in the e2e chat. Obviously if your phone is compromised your e2ee chat is not safe.

> Obviously if your phone is compromised your e2ee chat is not safe. Pretty much, a lot of people think that seeing E2EE means everything is safe, which I believe gives a false sense of security. You can have your phone compromised (especially when I know your phone number, Signal I’m looking at you) or be subject to other means of attacks, exposing everything. I would rather know that this app is not secure so I don…

Not only that. If they want to intercept e2e chats it's possible with a MITM attack, that if you control the server it's not a difficult thing to do. Of course the users if they check the keys they see they are different, but practically no one does that.

And I think WhatsApp probably does it, otherwise why the authorities never complied that WhatsApp did not let them see the conversations?

Re: Is Telegram really an encrypted messaging app?

#124

Post by kitkat_new »

yarg wrote: post #87
lxgr wrote: post #54

Earlier quoted context omitted.

Yes: End-to-end encryption is technically quite difficult, but politically and legally feasible (at least currently, at least in most countries). Simply not cooperating with law enforcement is technically moderately difficult, but politically and legally impossible. Between a difficult and an impossible option, the rational decision is to pick the difficult one.

Is there a nice solution for multiparty (n >= 3) end-to-end encryption?

MLS scales best for large n, but WhatsApp/Signal or Matrix do pretty well for < 1k people

Re: Is Telegram really an encrypted messaging app?

#125

Post by hn_throwaway_99 »

alerighi wrote: post #118
bryanlarsen wrote: post #34

Try the mud puddle test: log into your account on a new device using the password recovery flow. Can you see your old messages? If the answer is yes then law enforcement can too. https://www.forbes.com/sites/anthonykosner/2012/08/05/how-se...

Well of course, but this is a feature of Telegram. It's the only messaging app where messages are stored on the cloud. This of course has security implications, but also allows you to have a big number of chats without wasting your device memory like WhatsApp does, or having to delete old conversations, and allows you to access your chats from any device. By the way you can also set a password to log in from another…

But that's literally the entire point of this article. That is, in this day and age, when people talk about "secure messaging apps" they are usually implying end-to-end encryption, which Telegram most certainly is not for the vast majority of usages.

Re: Is Telegram really an encrypted messaging app?

#126

Post by EGreg »

tsimionescu wrote: post #109
EGreg wrote: post #76

Earlier quoted context omitted.

[flagged]

> On the question of balancing privacy and security, there are in fact solutions, but you have to get away from the idea of a centralized police force / centralized government, and think in terms of a free market of agencies, that can decrypt limited evidence only with a warrant and only if they provide a good reason. The warrant could be due to an AI at the edge flagging stuff, but the due process must be followed a…

Have you read the article I link to in that point? After you read it, you'll have a better idea, and then if you have a specific point, we can discuss.

Re: Is Telegram really an encrypted messaging app?

#127

Post by SonOfLilit »

pandog wrote: post #122
alerighi wrote: post #118

Earlier quoted context omitted.

Well of course, but this is a feature of Telegram. It's the only messaging app where messages are stored on the cloud. This of course has security implications, but also allows you to have a big number of chats without wasting your device memory like WhatsApp does, or having to delete old conversations, and allows you to access your chats from any device. By the way you can also set a password to log in from another…

I think a high definition photo taken on a recent phone takes up an awful lot more device memory than a "big number of chats"

Yeah, but Whatsapp chats tend to be full of those... and videos.

Re: Is Telegram really an encrypted messaging app?

#128

Post by ziofill »

lxgr wrote: post #71
ziofill wrote: post #65

> One of the biggest privacy problems in messaging is the availability of loads of meta-data — essentially data about who uses the service, who they talk to, and when they do that talking. […] the same problem exists with virtually every other social media network and private messenger. Is this true for Signal too? I thought it wasn’t.

Avoiding any metadata leaks without generating tons of cover traffic (to frustrate timing correlation attacks) is very hard. Signal does indeed use an architecture (at least for chats with contacts, or optionally everyone when you enable the "sealed sender" option that makes you a bit more prone to receiving spam) where Signal doesn't know who's sending a given message from a given IP address, and only which account…

How accurate does the timing need to be? I imagine there must be many Bobs getting notifications around the same time. Also, if I use Signal behind a VPN is it still known that I’m talking to the Signal servers?

Re: Is Telegram really an encrypted messaging app?

#129

Post by tptacek »

baxtr wrote: post #116
bryanlarsen wrote: post #34

Try the mud puddle test: log into your account on a new device using the password recovery flow. Can you see your old messages? If the answer is yes then law enforcement can too. https://www.forbes.com/sites/anthonykosner/2012/08/05/how-se...

Would love to see a side-by-side comparison of iMessage, Signal, WhatsApp and Telegram on this.

You already know how Signal is going to come out here, because this is something people complain incessantly about (the inconvenience of not getting transcripts when enrolling new devices).

Re: Is Telegram really an encrypted messaging app?

#130

Post by kitkat_new »

dtx1 wrote: post #101
yarg wrote: post #87

Earlier quoted context omitted.

Is there a nice solution for multiparty (n >= 3) end-to-end encryption?

Have the room owner create an AES 256 key, send it to all Party members via 1:1 e2ee, encrypt room messages with that AES key.

this is pretty much what Matrix does, if I understand correctly.

Additionally the key is regularly updated to provide some degree of perfect forward secrecy and avoid encrypting for people who left the group chat

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