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,, E2EE is pretty useless if you don't verify the identity of keys, as you could be just talking to a MITM (e.g. a malicious server admin could add a 'ghost' de

,, E2EE is pretty useless if you don't verify the identity of keys, as you could be just talking to a MITM (e.g. a malicious server admin could add a 'ghost' device onto your account in order to sniff the messages people are sending you).'' This is just not true. The amount of passive listening is so much more than the amount of MITM, as most middle men don't want people to know that they are listening. It's just too easy to catch them if they do it on a massive scale, as long as just 0.1% of users verify the E2E keys. This way the remaining 99.9% gets a part of the security benefit as well.

Arathorn 7y ago
I think there's a misunderstanding here - I was sloppily conflating together MITM (a malicious server admin who has created a false device eclipsing a real one, who forwards traffic onto the real one, having reencrypted it) and a "ghost device" (a malicious party who has added a new device to your account which is sniffing your messages). My point was that to mitigate both attacks, it's vital to verify key identity out of band. I agree MITM is much less likely than passive listening via a ghost device: we haven't seen MITM in the field, but we have seen attackers try to add ghost devices to spy on accounts (by acquiring a login password, adding a new device, and hoping the victim doesn't notice they've sprouted a new E2E device and that nobody verifies devices).
upofadown 7y ago
Perhaps it would be more illuminating to say that E2EE is mostly pointless if you don't verify keys. Then all you have to do is encrypt on the network links to get the same level of security for a lot of these things that claim E2EE as they have the power to do trivial MITM.
- xiphias2 7y ago
  The point is that instead of requiring end users to verify public keys, it's better UX to give them the ability if they want, but not require. I remember an email standard that sent public keys inside the emails, and the replies are encrypted with that public key. Sure, MITM is possible, but it's easy to detect, at the same time the UX is easy to scale to billions of people.
  - upofadown 7y ago
    That's autocrypt. It is awesome and should be default on all email clients. As part of the autocrypt standard MITM is not detectable as that would just provide users with information they could do nothing about. Autocrypt is fine just as long as the users are made to understand that the privacy protection is a lot less than the protection they would get from a PGP key they actually got from someone directly. No UX in the world can overcome that incontrovertible fact.

Arathorn 7y ago

I think there's a misunderstanding here - I was sloppily conflating together MITM (a malicious server admin who has created a false device eclipsing a real one, who forwards traffic onto the real one, having reencrypted it) and a "ghost device" (a malicious party who has added a new device to your account which is sniffing your messages). My point was that to mitigate both attacks, it's vital to verify key identity out of band. I agree MITM is much less likely than passive listening via a ghost device: we haven't seen MITM in the field, but we have seen attackers try to add ghost devices to spy on accounts (by acquiring a login password, adding a new device, and hoping the victim doesn't notice they've sprouted a new E2E device and that nobody verifies devices).

upofadown 7y ago

Perhaps it would be more illuminating to say that E2EE is mostly pointless if you don't verify keys. Then all you have to do is encrypt on the network links to get the same level of security for a lot of these things that claim E2EE as they have the power to do trivial MITM.

xiphias2 7y ago
The point is that instead of requiring end users to verify public keys, it's better UX to give them the ability if they want, but not require. I remember an email standard that sent public keys inside the emails, and the replies are encrypted with that public key. Sure, MITM is possible, but it's easy to detect, at the same time the UX is easy to scale to billions of people.
- upofadown 7y ago
  That's autocrypt. It is awesome and should be default on all email clients. As part of the autocrypt standard MITM is not detectable as that would just provide users with information they could do nothing about. Autocrypt is fine just as long as the users are made to understand that the privacy protection is a lot less than the protection they would get from a PGP key they actually got from someone directly. No UX in the world can overcome that incontrovertible fact.