Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

iMessage Key Verification

support.apple.com

Post reply on HN
Print view View original

31–40 of 127 posts

Re: iMessage Key Verification

#31

Post by _8j50 »

danShumway wrote: post #11

This seems somewhat similar to Matrix's (and other apps') approach of comparing keys to verify identity (plus with I guess some extra hardware requirements and attestation). I'm interested to see what the uptake is among users, because even though Matrix has done a fair amount to smooth this process, verification is still a pretty large source of friction from what I can tell, and I'm not completely sure how it could…

I don't like how matrix does it. I tried to get very technical people to use it and they struggled. Plus, they assume you have enough trust with your contacts to share with them your device details instead of just a unique identifier.

Re: iMessage Key Verification

#32

Post by 0x0 »

Sucks that it requires iCloud Keychain enabled, and also removing your appleid from any legacy macs and iphones. Wish they explained the reasons for this, because I'm having a hard time seeing one.

Re: iMessage Key Verification

#33

Post by grgar »

thamer wrote: post #16
poorman wrote: post #15

How safe is the contact that is uploaded to the iCloud? How safe is the contact from being modified by some app on your iPhone? The contact containing the verification code seems to be one of the weaker link in this whole thing. If Mallory can change the verification code in the contact to their own, the communication between Alice and Bob is no longer protected.

They can't just change the verification code, and it's not based on the fields of the contact card. You can think of it as a fingerprint for their iMessage public key, the one used to encrypt messages end-to-end. If the key with which your phone encrypts iMessage payloads has changed, it indicates that the conversation is being intercepted. WhatsApp supports this too, see "Verify Security Code" on this page: https://…

But the verification code is stored in the contact card, so the parent comment still stands. Anything that can access contacts, e.g. apps or iCloud (since Contacts are not part of Advanced Data Protection i.e. E2E encryption), can modify the verification code in the contact used by Messages for validation.

Re: iMessage Key Verification

#34

Post by teaearlgraycold »

0x0 wrote: post #32

Sucks that it requires iCloud Keychain enabled, and also removing your appleid from any legacy macs and iphones. Wish they explained the reasons for this, because I'm having a hard time seeing one.

Probably requires a hardware-security-module for generating secure attestation keys.

Re: iMessage Key Verification

#35

Post by epolanski »

aaomidi wrote: post #25

There is a huge opportunity here for Apple to do a proper chain of trust. “You want to talk to Adam, but you haven’t verified their keys yet. However your contacts Anna and Derek have confirmed Adam’s identity”

I'm always confused by this. This merely validates that Anna at the time thought that was Adam's number, what else?

Does not guarantee it's Adam reading.

Re: iMessage Key Verification

#36

Post by cheeze »

0x0 wrote: post #32

Sucks that it requires iCloud Keychain enabled, and also removing your appleid from any legacy macs and iphones. Wish they explained the reasons for this, because I'm having a hard time seeing one.

Removing appleid from legacy mac and iphone because they don't have the hardware security module. So rather than having a broken imesssage experience on those devices, they decided its better for you to just unregister.

Re: iMessage Key Verification

#37

Post by comex »

0x0 wrote: post #32

Sucks that it requires iCloud Keychain enabled, and also removing your appleid from any legacy macs and iphones. Wish they explained the reasons for this, because I'm having a hard time seeing one.

Because iCloud Keychain sync is how each person can have one key for others to verify, rather than a separate key for every device they are logged into iMessage with.

It’s described in more detail here:

https://security.apple.com/blog/imessage-contact-key-verific...

(This is end-to-end encrypted, by the way; Apple can’t get at people’s private keys.)

And this is a new protocol, so no surprise it doesn’t work with older operating systems. (It doesn’t say you have to remove your Apple ID completely, just log out of iMessage.)

Re: iMessage Key Verification

#39

Post by toomuchtodo »

epolanski wrote: post #35
aaomidi wrote: post #25

There is a huge opportunity here for Apple to do a proper chain of trust. “You want to talk to Adam, but you haven’t verified their keys yet. However your contacts Anna and Derek have confirmed Adam’s identity”

I'm always confused by this. This merely validates that Anna at the time thought that was Adam's number, what else? Does not guarantee it's Adam reading.

If you have a cryptographic primitive and a robust system to protect it (secure hardware, biometric auth), if you can confirm digital identity in real life you can be reasonably assured Adam is reading. Chain of integrity.

Re: iMessage Key Verification

#40

Post by rootsudo »

poorman wrote: post #15

How safe is the contact that is uploaded to the iCloud? How safe is the contact from being modified by some app on your iPhone? The contact containing the verification code seems to be one of the weaker link in this whole thing. If Mallory can change the verification code in the contact to their own, the communication between Alice and Bob is no longer protected.

It doesn’t matter, the keyword is “in transit” but since it requires iCloud Keychain - it also means it’s compromised with LE. Also the fact that most people they have iCloud also will backup their messages….

So it’s nice that it’s encrypted in transit but since iMessage is apple only and requires.. see above!

Post reply on HN