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Comment by atoav | Hacker News Reader

I get what signing is — but to the ordinary person it solves a problem they didn’t even knew they had. When you explain it like you did my first question would be why emails are not signed automatically if it is just about the press of a button?

With things like signal or whatsapp you get encryption and signing automatically and everybody uses it.

Why don’t people use signing with email then? Because it is not the default, not built in and not the standard everywhere. Blaming those people for it is wrong. Blame those who didn’t manage to implement the standards and stand in the way of making it the default

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In either Signal or WhatsApp you have no verification whatsoever of the true sender unless you meet them out of band (preferably in person) and compare codes that summarise the public key identity value.

Signal does make a bigger deal about trying to get you to verify, but in practice for both systems casual users don't do it. Most of my Signal contacts aren't verified.

Without this step an attacker can MITM these protocols because the identity problem is hard and cannot be waved away.

Most of my signal contracts are also unverified (my nerd friends are). However, I am notified if their key changes, so unless our connection was MITM'd on first contact, I would at least have a warning and know to be more suspicious. Usually I'll follow up with people out of band to verify that they got a new phone or something. This happens infrequently enough that it is not a hardship.

I'd prefer to verify all of my contacts but, given my security model, this is good enough and a huge step up from email.

All of my Signal/Telegram/WhatsApp contacts are unverified in the app itself, but almost all of them are de facto verified by other means; we plan meeting up at bars and I know who I'm chatting with because the person I expect shows up. Or we send emails or communications via other means and the conversations match.

I don't need to verify the code because everything else about the communication matches.

None of that ensures you have message privacy. If you haven't verified the key, you have no assurance that the connection hasn't been MITM'd.

What's worse is that Whatsapp doesn't tell you if they changed the key, so there is no protection against MITM.

WhatsApp used to. Did they stop?

I don't use Whatsapp, so I don't actually have first-hand knowledge. Now that I think about it, it may be that I was told that it automatically regenerates the key more often than they need to, which would have the same effect.

I don't believe this is true. Every time I've asked about a key change, it has been because someone either got a new phone, reinstalled the app, or reset their phone.

It's a setting which is off by default.

You need to enable security notifications, and you will be notified of key changes.

> Turn on this setting to receive notifications when a contact's security code has changed. Your messages and calls are encrypted regardless of this setting.

> but to the ordinary person it solves a problem they didn’t even knew they had.

Or more so, DON'T have. I don't know if I'd qualify for "ordinary person" here but regardless, of the emails I went through this morning I don't think I can think of ONE that I cared about actually being from the sender it said it was from. There are very few that matter that much.

If your bank is any good, it doesn't send you emails about your account activity or problems. Yet, it could, if everybody was signing their emails.

It already could using DKIM: https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail

This has already been touched on in the article and the comments. DKIM isn't any good when it tells you that the email from fraudulent mybankk.com is verified just because the phishers were clever enough to set up DKIM on their site.

That's true. I guess we need something like https://en.wikipedia.org/wiki/Extended_Validation_Certificat... for email then.

I'm not sure how PGP would help though, as the user also has to check, if the email from his bank was signed with the correct key. Checking the exact domain name is something he can already do and I guess is also easier to understand.

My bank and broker send an email or text telling me to log in and check the "secure email" system on the bank's site.

One difference is that Signal and Whatsapp are synchronous so they are able to use deniable authentication. That's in contrast with asynchronous email where signing a message can then be proven to have come from the sender to a third party - not always desirable.

https://en.wikipedia.org/wiki/Deniable_authentication etc. Perhaps you can do it with asynchronous protocols too, though it seems harder.

> Blame those who didn’t manage to implement the standards and stand in the way of making it the default

Well, some of the oldest corporate systems (Lotus Notes, MS Exchange) did (and I think still do) have the capability for transparent secure messaging. Still, sysadmins rarely ever bother to use it. I believe the cause is that nobody wants to operate a certificate authority if they can avoid it, and when they can't, they'd rather restrict it to the bare minimum (servers that are absolutely necessary).

If corporate sysadmins can't be bothered to look after keys, you can imagine how motivated the average user will be to do the same.

The truth is that X509 remains a clusterfuck: it's just too burdensome. LetsEncrypt is a first step in the direction of replacing it with something better and more automated. "LetsEncrypt for email" would be very welcome - although I bet the security services of the world would be really pissed off.

How do you explain locks to someone who's never had their shit stolen?

> I get what signing is — but to the ordinary person it solves a problem they didn’t even knew they had.

It's not just people are not learning. I don't see any ordinary email client is encouraging people to use signing or encryption. Which is very odd to me.

Just imagine what if all the email client start asking their user to sign their email, and mark unsigned email as "Untrustful".

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