[HN Gopher] An anonymous hacker reverse engineered my E2EE
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An anonymous hacker reverse engineered my E2EE
Author : collaborative
Score : 13 points
Date : 2021-08-15 20:27 UTC (2 hours ago)
(HTM) web link (www.groupsapp.online)
(TXT) w3m dump (www.groupsapp.online)
| saurik wrote:
| FWIW, I was expecting something like "the mechanism is
| fundamentally flawed because the e2e encryption actually is
| designed in a way where the server can derive or find the key";
| but, thankfully, this is "merely" the "obvious" vulnerability in
| key exchange: "how do I know I wasn't given a forged key by the
| server?", to which the protocol generally won't have any solution
| (barring some kind of pgp-style web of trust, which protocols
| should probably adopt) and the only reasonable thing to do is to
| add a UI that shows the user the key and helps them verify it
| (preferably with a mechanism to make chats _look_ insecure
| _until_ they are verified, like Threema also gets right)... which
| thankfully this developer did--though I have no clue how well the
| UI works in context as I haven 't used it and am only glancing at
| the screenshots... probably nowhere near as good as Threema--
| instead of trying to paper over the problem and pretending it
| doesn't really exist by simply throwing certificate pinning at
| the proximal MITM problem because their server can (of course) be
| trusted like Apple does with iMessage without addressing the
| ultimate flaw [<- all of which I describe in a single run-on
| sentence, as it is _maximally fun_ :D, before y 'all get upset at
| me and leave pointless replies].
| collaborative wrote:
| Screenshots of the UI in action (light mode):
|
| https://ibb.co/T2jmBYr https://ibb.co/1dRfpxQ
| https://ibb.co/vhdsKp7 https://ibb.co/g7VBX3R
| https://ibb.co/281zqqj https://ibb.co/SNbYc7k
| SP2njsPl2WmlAwM wrote:
| > FWIW, I was expecting something like "the mechanism is
| fundamentally flawed because the e2e encryption actually is
| designed in a way where the server can derive or find the key"
|
| The mechanism wasn't intentionally designed that way. But the
| symmetric ChatKeys were created with Random(), seeded (at least
| partially) with time().
| lucgommans wrote:
| > add a UI that shows the user the key and helps them verify it
| [...] probably nowhere near as good as Threema
|
| Indeed, Threema really has to get more credit for this one.
|
| How many people verify their contacts in Signal when they
| opportunistically get the chance? Wire? WhatsApp? Matrix?
|
| My mother in law wanted to verify keys with me in Threema of
| her own volition. In Signal, which she tried for the same
| reason (securely communicating medical data between
| colleagues), she didn't even know it was possible, let alone
| that she should be doing that.
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(page generated 2021-08-15 23:02 UTC)