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Comment by hopler | Hacker News Reader

What's the point of using an encrypted chat at all if you don't care if it's hacked?

The proper question is: what's your threat model?

I use signal to chat with my wife. I'm glad it offers good enough protection that my country's secret service is whining endlessly that it can't get in. I'm glad our inappropriate jokes don't easily become public.

At the same time, I'm sure that a determined and competent adversary could compromise my phone without needing to break signal's encryption or engineer fairly sophisticated mitm attacks.

I'm fine with that level of security, and don't want a more annoying UI when a device is reset. Because even with the current setup, the chat protocol isn't the weakest link anymore.

A big benefit of end-to-end encryption is that it makes it impossible for the service provider to suddenly start doing silent mass surveillance of their userbase. A solution doesn't need to be 100% perfect to achieve this goal.

Somehow, nearly every article on the subject completely misses this, and instead keeps moving goalposts on reasonable endpoint security.

I'm happy that I found this subthread here, which in a sea of comments talks about the really relevant point: Signal's goal is not to provide the most secure communication channel ever to targeted individuals. It's to mitigate passive eavesdropping on a whole population. This creates the smokescreen that the actual targets require, and prevents people from actually becoming a target in the first place.

Exactly. I only use signal for chat, and I tell my family and friends that they must install it if they want to send me text messages. It's not because I fear being hacked, it's because I don't want highly personal conversations about sex, drugs, chronic illness, and skeletons in the family closet getting picked up by global passive surveillance.

Yep. And Signal is as good as it gets for end users with zero technical knowledge. I've had many family members and friends install it on their own and not skip a beat.

This is a very underrated point.

It also means that an adversary can't go in long after the fact and dig up a message history from a server god knows where.

A lot of the eavesdropping scenarios concocted around key change in particular are fanciful. Practically speaking, end-to-end encrypted chat is often replacing email, not trying to protect secret agents hiding from the Reptilian Council.

>A big benefit of end-to-end encryption is that it makes it impossible for the service provider to suddenly start doing silent mass surveillance of their userbase.

Mass surveillance no, but if everybody blindly trusts any key provided (which seems to be the default "setting" for Signal and WhatsApp) then it's easy to start MITM'ing any connection at any point. You'll just get an innocuous-looking "your safety number has changed" and nothing else.

I do agree that it's still much better than nothing but I also agree with TFA when they say that "Signal cut a big corner by not planning device management properly", there are many ways Signal could make it massively easier for users to transfer their keys from one device to an other (for instance by deriving the master key from a passphrase bitcoin-wallet-style, or simply by making it easier to transfer your keys and history from device to device).

Because they didn't do this they probably considered that having an SSH-style intrusive "SOMETHING IS GOING WRONG HERE" message was too annoying and got rid of it. But really, they're fixing the symptom, not the problem.

Normalize end-to-end encryption, increase the amount of encrypted target traffic for attackers.

And I think it's not so binary as care/don't-care about being hacked. You might care a bit, but how much do you care? Just as important, what is your threat model?

MITM is an active/directed hack; encrypted chat covers all the passive hacks. My friend's arch-nemesis won't be thwarted, but a voyeuristic sysadmin will be. And my friends don't have arch-nemeses (that I know about anyway), but I know lots of people who would eavesdrop at any opportunity.

Protection against passive scanners and the unskilled is complete enough protection for 99% of people.

It's not care vs not care, it's a cost-benefit analysis.

This is a great point, however as many security researchers will tell you, the cost of an exploit goes down exponentially over time.

Yesterday's hash attack that required $100m supercomputer will require a $10k GPU, which is 5 years will require a $100 GPU. (Not talking about the math changing, but it's been more about weaknesses in S-boxes and other parts of older hash functions that get slowly chipped away)

Similarly, yesterday's system that takes an attacker 3 days to MITM your machine, will take 3 hours, and then will be somebody's python script that installs and aggregates millions of exploits.

So in general, the cost and benefit variables are constantly changing under us.

Actually I was referring to the cost to the user who wishes to protect themself. Signal is designed to be fairly low "cost" i.e. easy to use. If they can find a way to make it more secure without making it harder to use they should and probably will do it. For most cases, the benefit of privacy probably doesn't warrant going through more trouble than this.

For those cases where somebody needs more protection, there's a way to go through a little more trouble to use Signal more diligently (agree with important parties not to change keys for a period of time).

To your point though: the cost of executing MITM doesn't just include the equipment, it includes showing ones hand by being discovered.

>Similarly, yesterday's system that takes an attacker 3 days to MITM your machine, will take 3 hours, and then will be somebody's python script that installs and aggregates millions of exploits.

The big cost of a MITM attack is getting in the middle. The cost of doing the actual attack is minimal.

By not knowing which peers have verified numbers, the risk of getting caught that you're in the middle is very high, so that big cost for getting there will be for nothing (and actually get way more costly because you alerted the subjects).

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