4 ms·
In general, I totally agree with the article, however, there is one thing: > From what I can tell, the iMessage app gives the sender no indication of how many
by pilif 13y ago
In general, I totally agree with the article, however, there is one thing:
> From what I can tell, the iMessage app gives the sender no indication of how many keys have been associated with a given iMessage recipient, nor does it warn them if the recipient suddenly develops new keys.
iMessage does warn you on all devices when a new device gets added to the account. Of course that's during normal operations. Unless somebody reverse-engineers one of the apps, we can't know whether the protocol has a provision for "please add this key but don't warn the user".
That's the thing with crypto in closed source software: it's completely useless because you have to trust the software vendor not to put any backdoors in.
And since two weeks, unfortunately, the only think we can trust is that the vendor actually DID add a backdoor.
- mrmaddog 13y agoThe problem here is that you need to know the other person's encryption key. Since I'm not warned whenever you get a new device, I have no idea how many keys are assigned to you. Hence, the key distribution problem still remains.
- pilif 13y agoOh I agree with you. The public key directory thing breaks the whole system. No question there. I totally agree with the original article. I just wanted to highlight the fact that devices DO inform the user when a new key gets added. So if the directory didn't serve fake public keys and if the devices didn't have code to not warn if certain keys were added, then you would have the guarantee to only talk to me. Sure: I could add more devices, but I have the full control over them, so it doesn't matter to you how many devices your client encrypts the message for because I have the full control over what devices I authorize or not. That of course would be the perfect world, when in fact, Appke probably adds surveillance keys to the directory server and doesn't warn the user as such keys are added. Don't use iMessages for anything you would not want Apple or the NSA or any other law enforcement agency to read. But then again, don't use any of email (envelope in the clear), SMS (your carrier can read it), any other IM service (same issue as iMessage), snail mail (can be read by the post office and anybody opening your letter box when you aren't there).
- sneak 13y ago> I just wanted to highlight the fact that devices DO inform the user when a new key gets added. This is totally false. When you are sending iMessages to someone, you get no UI indication at all when they buy new devices and add them to their Apple ID. You are confusing it with adding devices to your own account. We're talking about RECIPIENT keys.
- msh 13y agoI would not want the sender of messages to me to be notified about my devices.
- sneak 13y agoWell, they are now—if they MITM their connection to the APNS. Messages they send get encrypted to all the devices associated with your iMessage account. The data's available to them from Apple, though there is no UI for it.
- sneak 13y agoNot you, the recipient. Nobody iMessaging me gets an alert when I buy a new iPad - only my other devices.
- pilif 13y agoI would hope so. It's none of their business if I buy a new device. This is plain respecting my privacy. BUT: If I can be sure that only my devices can decrypt data sent to them and you know that my account will only announce keys to devices I actually own, then you don't need a notification when I add a new device because however many devices I have, only I will be able to read your messages. Of course because we can't trust apple to not silently add more keys to an account, all of this is moot anyways.
- sneak 13y ago> I would hope so. It's none of their business if I buy a new device. This is plain respecting my privacy. What about THEIR privacy? End-to-end encryption to device-specific keys means that they have no idea which devices THEIR messages to you are being encrypted to.