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Ask HN: How can I verify that WhatsApp uses E2E encryption?

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31–40 of 48 posts

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#31
post #29
post #27

I think a lot of people here have missed the point a little. It's very easy to subvert E2E encryption of this sort, because no Whatsapp user has any way of verifying that they're talking to another Whatsapp user beyond the Whatsapp servers saying so. The actual apps could carefully perform the E2E encryption, but Whatsapp could easily MITM the data if (say) requested to by an outside agency, without the app being any…

If WhatsApp integrated everything they had in `Axolotl` [0] protocol specification, this wouldn't be the case. If WhatsApp would attempt to MITM, they would have to know someone's private-key (or break the crypto) which never leaves the phone, hence the E2E property. [0] https://github.com/trevp/axolotl/wiki

[deleted]

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#32
post #29
post #27

I think a lot of people here have missed the point a little. It's very easy to subvert E2E encryption of this sort, because no Whatsapp user has any way of verifying that they're talking to another Whatsapp user beyond the Whatsapp servers saying so. The actual apps could carefully perform the E2E encryption, but Whatsapp could easily MITM the data if (say) requested to by an outside agency, without the app being any…

If WhatsApp integrated everything they had in `Axolotl` [0] protocol specification, this wouldn't be the case. If WhatsApp would attempt to MITM, they would have to know someone's private-key (or break the crypto) which never leaves the phone, hence the E2E property. [0] https://github.com/trevp/axolotl/wiki

You don't need to find someone else's private key. Just create your own private key and convince people to send stuff to it.

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#33
post #10

Most of the comments so far focus on the fact that WhatsApp is a closed-source system. And just to be clear, it would absolutely be better to have source code. Source code gives you a 1000-foot view of the application and lets you spot obvious problems quickly. But source code can also lie to you. To really understand what the application is doing, you need to do what security auditors do irrespective of source code…

I would at least like them to:

1) state in their Privacy Policy somewhere that they are using end-to-end encryption and they can't see the messages - this means that if they change that later and get caught, they could get in trouble with the FTC

2) show me somewhere in the app that I'm using end-to-end encryption. This should teach their users that they are using end-to-end encryption, and it would make many more angry if they find out they are "lying" if they're using that interface but without actual end-to-end encryption behind the messages

Unfortunately, Whatsapp hasn't even made an official statement about adopting end-to-end encryption. Only Moxie has. So right now Whatsapp gets all the benefits of the media attention from "using end to end encryption", without having to hold themselves to that promise at all ("hey - you didn't see us say anything anywhere about using end-to-end encryption, did you?!").

So I don't necessarily want to see the source code, but at the very least they should publicly and legally commit to using end-to-end encryption.

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#34
post #3

You cannot verify that WhatsApp isn't cheating without a source code analysis. And it's even worse, WhatsApp is a doughter company of Facebook, so WhatsApp is falling under Section 215 US Patriot Act. In short: it's not Facebook's or WhatsApp's fault, but they're forced to cheat if there is the requirement from US officials. While there may be E2E encryption in WhatsApp, there is no way to get it trustworthy.

Legally, if they indeed enabled E2E, the government shouldn't be able to force them to disclose the data. CALEA says you should decrypt the data for the government only if you have the keys. But with Axolotl E2E encryption, they're not supposed to have them.

Of course the government will try to threaten them with NSLs or tax audits or whatever, and Whatsapp could cave, but the law should be on their side.

But before we get there they actually have to put it in their privacy policy that they are doing that, so then they can show the judge later that they've legally committed to a certain level of privacy for their users.

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#35
post #3

You cannot verify that WhatsApp isn't cheating without a source code analysis. And it's even worse, WhatsApp is a doughter company of Facebook, so WhatsApp is falling under Section 215 US Patriot Act. In short: it's not Facebook's or WhatsApp's fault, but they're forced to cheat if there is the requirement from US officials. While there may be E2E encryption in WhatsApp, there is no way to get it trustworthy.

Legally, if they indeed enabled E2E, the government shouldn't be able to force them to disclose the data. CALEA says you should decrypt the data for the government only if you have the keys . But with Axolotl E2E encryption, they're not supposed to have them. Of course the government will try to threaten them with NSLs or tax audits or whatever, and Whatsapp could cave, but the law should be on their side. But before…

it's not a case of threatening anyone.

they just pay them to include the additional primes in the public key system. users are still more or less secure. not just whatsapp. pretty much all the public key systems use it. it's still effectively 1024 bit plus keys for everyone but the nsa and ghcq.

latest snowdon leaks include everything you need for confirmation now you know what to look for.

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#36
post #10

Most of the comments so far focus on the fact that WhatsApp is a closed-source system. And just to be clear, it would absolutely be better to have source code. Source code gives you a 1000-foot view of the application and lets you spot obvious problems quickly. But source code can also lie to you. To really understand what the application is doing, you need to do what security auditors do irrespective of source code…

mmh

1. having a public repo of the official source code

2. hashing the executable you have on your phone

3. the repo publishes a hash of its compiled executable release

4. the repo approves or reject the binary, based on the decompiling of the application and its comparison with the original source code

5. your os cannot run code that is rejected, or will just warn the user

don't know if a digital signature could be used somewhere in there.

would be much simpler to let system download source code and compile it instead of an executable I guess, but that would require to have much lighter libraries...

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#37
post #21

Earlier quoted context omitted.

How can I (developer, no security knowledge) verify that does encryption properly?

You should assume it can't. The track record is very, very poor.

That's a funny statement, considering PGP and OTR is the go-to and has held up for all of these years.

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#38
post #37
post #21

Earlier quoted context omitted.

You should assume it can't. The track record is very, very poor.

That's a funny statement, considering PGP and OTR is the go-to and has held up for all of these years.

What's the next example?

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#39
post #16

Several people have already raised the very good point that ultimately, we need the source code to be certain. However, can we really be sure when we have the source? I don't think so. The codebase is likely to be large, especially when you start looking at dependencies such as the crypto libraries they may be using (unless you want to assume they are safe themselves), and it has been shown that humans are actually q…

Would someone actually looking through those entries trying to find a problem fail? Or is it just "first glance doesn't show any problems" stuff? I thought it was 2.

It would be great to throw entries at actual security auditors, mixed with innocent versions, and see how they fare.

Re: Ask HN: How can I verify that WhatsApp uses E2E encryption?

#40

Several people have already raised the very good point that ultimately, we need the source code to be certain. However, can we really be sure when we have the source? I don't think so. The codebase is likely to be large, especially when you start looking at dependencies such as the crypto libraries they may be using (unless you want to assume they are safe themselves), and it has been shown that humans are actually q…

"we need the source code to be certain."

The source and a lot of effort, or just a tremendous amount of effort.

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