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A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

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Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#11

Post by modeless »

londons_explore wrote: post #10
modeless wrote: post #5

Earlier quoted context omitted.

I'm glad ADP exists now, but you have to make sure everyone you message has it enabled too, or your messages are still Apple's to read whenever they choose. Meanwhile Google's equivalent backup feature (whatever other faults it may have) has been end-to-end encrypted by default for everyone since long before ADP was even available at all. The risk of losing access is practically nonexistent because the password is yo…

> the password is your screen lock code You mean the one that by default is a 4 digit number and therefore trivially brute forcable? And neither android hardware nor the google servers have any kind of secure element enforcing brute force protections like '3 tries then we wipe the keys'.

> neither android hardware nor the google servers have any kind of secure element enforcing brute force protections

I don't know why you would say this when it is obviously false. https://security.googleblog.com/2018/10/google-and-android-h...

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#12

Post by Jtsummers »

xvector wrote: post #8
ls612 wrote: post #3

Earlier quoted context omitted.

The more charitable interpretation is that for most people losing their photos and messages is a bigger threat than the government spying on them. For those who might have a different tradeoff there is Advanced Data Protection.

ADP is a total joke if it doesn't also disable plaintext backups for the people you're talking to

> ADP is a total joke if it doesn't also disable plaintext backups for the people you're talking to

Do you consider all security to be a joke then? If you send me a message, how will you actually guarantee that I do not make a copy of it once it's on my own computer?

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#13

Post by modeless »

Jtsummers wrote: post #12
xvector wrote: post #8

Earlier quoted context omitted.

ADP is a total joke if it doesn't also disable plaintext backups for the people you're talking to

> ADP is a total joke if it doesn't also disable plaintext backups for the people you're talking to Do you consider all security to be a joke then? If you send me a message, how will you actually guarantee that I do not make a copy of it once it's on my own computer?

There's no guarantee, but some apps intended for security actually make at least a minimal effort to be excluded from plaintext backups, rather than intentionally sending their encryption keys to the backup service that just happens to be run by the same company...

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#14

Post by snowwrestler »

modeless wrote: post #2

All that security, and then by default Apple literally just sends themselves a copy of your encryption keys to store in iCloud backup, the only cloud backup solution Apple allows you to use. "to help you recover your data" [1] (oh and also to send law enforcement your message history in plaintext on request, but we don't talk about that). [1] https://support.apple.com/en-us/102651#:~:text=in%20iCloud%2...

Only if you have “Messages in iCloud” turned on, which is optional.

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#15

Post by modeless »

snowwrestler wrote: post #14
modeless wrote: post #2

All that security, and then by default Apple literally just sends themselves a copy of your encryption keys to store in iCloud backup, the only cloud backup solution Apple allows you to use. "to help you recover your data" [1] (oh and also to send law enforcement your message history in plaintext on request, but we don't talk about that). [1] https://support.apple.com/en-us/102651#:~:text=in%20iCloud%2...

Only if you have “Messages in iCloud” turned on, which is optional.

This is false. If you turn off the "Messages in iCloud" feature then your messages are included in your regular iCloud backup which Apple has the keys to decrypt, as disclosed.

Of course iCloud backup is itself optional. But Apple gives you and the people you're messaging no other option for cloud backups. ADP actually encrypts your backups, but since it defaults to off your messages are almost certainly still readable by Apple thanks to the keys stored in other peoples' backups.

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#16

Post by tgma »

snowwrestler wrote: post #14
modeless wrote: post #2

All that security, and then by default Apple literally just sends themselves a copy of your encryption keys to store in iCloud backup, the only cloud backup solution Apple allows you to use. "to help you recover your data" [1] (oh and also to send law enforcement your message history in plaintext on request, but we don't talk about that). [1] https://support.apple.com/en-us/102651#:~:text=in%20iCloud%2...

Only if you have “Messages in iCloud” turned on, which is optional.

Actually it is the opposite. If you have Messages in iCloud, they do not store messages in "iCloud Backup" but keep it separate with some client-side device-to-device encryption key (UPDATE: which they also store a copy of inside iCloud backup unless ADP is on; thanks to 'modeless). If you enable iCloud Backup and Messages in iCloud is turned off, it will backup all your messages in a way visible to Apple servers. Of course, that is unless you enable Advanced Data Protection (the thing that UK hates).

The fact that this is so unintuitive that I had to explain it and I am only 95% sure I got it right is precisely the problem.

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#17

Post by conradev »

modeless wrote: post #2

All that security, and then by default Apple literally just sends themselves a copy of your encryption keys to store in iCloud backup, the only cloud backup solution Apple allows you to use. "to help you recover your data" [1] (oh and also to send law enforcement your message history in plaintext on request, but we don't talk about that). [1] https://support.apple.com/en-us/102651#:~:text=in%20iCloud%2...

Not if you have "Advanced Data Protection" turned on: https://support.apple.com/en-us/108756

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#18

Post by modeless »

tgma wrote: post #16
snowwrestler wrote: post #14

Earlier quoted context omitted.

Only if you have “Messages in iCloud” turned on, which is optional.

Actually it is the opposite. If you have Messages in iCloud, they do not store messages in "iCloud Backup" but keep it separate with some client-side device-to-device encryption key (UPDATE: which they also store a copy of inside iCloud backup unless ADP is on; thanks to 'modeless). If you enable iCloud Backup and Messages in iCloud is turned off, it will backup all your messages in a way visible to Apple servers. Of…

Yes but when Messages in iCloud is enabled that "client-side" encryption key is itself included in your iCloud backup (that Apple can read), as disclosed. So Apple can read your messages regardless of whether you enable or disable Messages in iCloud. The only things that prevent it are disabling cloud backups entirely, or enabling ADP. But even those don't really prevent it because unless everyone you message also does the same, Apple can still read your messages.

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#19

Post by tgma »

modeless wrote: post #18
tgma wrote: post #16

Earlier quoted context omitted.

Actually it is the opposite. If you have Messages in iCloud, they do not store messages in "iCloud Backup" but keep it separate with some client-side device-to-device encryption key (UPDATE: which they also store a copy of inside iCloud backup unless ADP is on; thanks to 'modeless). If you enable iCloud Backup and Messages in iCloud is turned off, it will backup all your messages in a way visible to Apple servers. Of…

Yes but when Messages in iCloud is enabled that "client-side" encryption key is itself included in your iCloud backup (that Apple can read), as disclosed. So Apple can read your messages regardless of whether you enable or disable Messages in iCloud. The only things that prevent it are disabling cloud backups entirely, or enabling ADP. But even those don't really prevent it because unless everyone you message also do…

Good to know, hence my 95% certainty. Fortunately for me, each new device starts with DFU restore and installation of my own Configuration Profile which supervises the device, disable automatic pairing with new devices, disables useless apps like Game Center, and most importantly disables iCloud Backup entirely, etc.

Re: A Formal Analysis of Apple's iMessage PQ3 Protocol [pdf]

#20

Post by modeless »

conradev wrote: post #17
modeless wrote: post #2

All that security, and then by default Apple literally just sends themselves a copy of your encryption keys to store in iCloud backup, the only cloud backup solution Apple allows you to use. "to help you recover your data" [1] (oh and also to send law enforcement your message history in plaintext on request, but we don't talk about that). [1] https://support.apple.com/en-us/102651#:~:text=in%20iCloud%2...

Not if you have "Advanced Data Protection" turned on: https://support.apple.com/en-us/108756

Unlike Google's comparable backup encryption feature, ADP is off by default. And ADP protects your messages from Apple only to the extent that everyone you message also turns on this non-default option; otherwise your messages are still Apple's to read as they please with no notification to you.
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