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My understanding is that the notification on phones when a new key is added is built into the OS and can't be easily bypassed. That notification shows up when t

My understanding is that the notification on phones when a new key is added is built into the OS and can't be easily bypassed. That notification shows up when the key is added. If the key isn't added on the device then messages won't be signed for it. Also, I thought the consensus was that Apple was 'backdooring' iMessage by giving LE access to iCloud backups which include iMessage, not compromising iMessage directly?

9fb29947 11y ago
> Also, I thought the consensus was that Apple was 'backdooring' iMessage by giving LE access to iCloud backups which include iMessage, not compromising iMessage directly? Can you please expand on this? How would access to iCloud backup not compromise iMessage?
- delinka 11y ago
  The backups store messages as plaintext within the [encrypted?] backup. This compromises the messages themselves, but not the iMessage protocol nor systems.
- citruspi 11y ago
  iCloud backups are not encrypted, and they include iMessage conversations. So the backups don't compromise the iMessage "service" or "application," but simply provide access to messages sent and received before the backup was made.
benihana 11y ago
>Also, I thought the consensus was that Apple was 'backdooring' iMessage by giving LE access to iCloud backups which include iMessage, not compromising iMessage directly? Consensus? First I've heard of this being a consensus. I've heard people say if Apple is backdooring, this is the way they'd do it, but no consensus on this actually happening. Care to go into this a bit more?
- dantiberian 11y ago
  Consensus may have been the wrong word to use, but I've heard the same as you, that backups are a weak point in iMessage security, and a very plausible way for LE to get access.
  - BBlarat 11y ago
    is it required to have an iCloud backup when using iOS? Or is it something that can be opted out of? I'm just curious.
    - dantiberian 11y ago
      You can opt out, but I think it will be the default.
    - deleted 11y ago
      [deleted]
    - hutattedonmyarm 11y ago
      Not required. You can choose between iCloud backup, iTunes backup (even encrypt if you want) and no backup at all. iCloud is the most convenient though
    - smackfu 11y ago
      Just have more than 5 GB of data and you can't backup to iCloud without paying monthly.
      - hutattedonmyarm 11y ago
        Photos are not included, Apps aren't (only their data), I'm not sure about music. It's gonna be hard to exceed the 5GB this way
        smackfu 11y ago
        Photos may be included. "Here’s what iCloud backs up: Photos and videos on your iOS devices, unless you turn on iCloud Photo Library on your iOS device (iOS 8.1 or later)." https://support.apple.com/kb/PH12519?locale=en_US https://support.apple.com/kb/PH12519?locale=en_US The photos hit the same 5 GB limit, so it's not like excluding or including them really changes anything. Photos are the #1 reason people hit the backup limit.
ejdyksen 11y ago
I've upgraded to iOS 9 GM and El Capitan GM, and I saw some new items show up in my iCloud Keychain, titled: PCS Backup PCS CloudKit PCS Escrow PCS FDE PCS iCloudDrive PCS iMessage PCS Maildrop PCS MasterKey PCS News PCS Notes PCS Photos (They also have what looks like a base64 string in there, but I'm excluding that just in case it might be secret) Just a guess, but between this and the fact that iCloud Backups were broken during the iOS 9 beta period, it seems like they might be encrypting backups now, as well.
- dantiberian 11y ago
  The problem with encrypting backups is what do they use as the encryption key? You have to have some route back to the users password, as that's what they'll be using to restore. That leaves it vulnerable to a LE password reset even if the backup is encrypted.
  - ejdyksen 11y ago
    iCloud Keychain solves this problem, if you use a complex passphrase: http://www.slideshare.net/alexeytroshichev/icloud-keychain-38565363 http://www.slideshare.net/alexeytroshichev/icloud-keychain-3...
0x0 11y ago
The key could be added to the appleid on the server, without telling the phone about it. Others sending messages to you would then also encrypt with the new backdoor key. Likewise, you don't get notifications about your friends' keys updating (in fact there's not even any UI to show the current keys for a contact), so your phone would start encrypting messages to the recipient's additional backdoored key silently too. :(

9fb29947 11y ago

> Also, I thought the consensus was that Apple was 'backdooring' iMessage by giving LE access to iCloud backups which include iMessage, not compromising iMessage directly? Can you please expand on this? How would access to iCloud backup not compromise iMessage?

delinka 11y ago
The backups store messages as plaintext within the [encrypted?] backup. This compromises the messages themselves, but not the iMessage protocol nor systems.
citruspi 11y ago
iCloud backups are not encrypted, and they include iMessage conversations. So the backups don't compromise the iMessage "service" or "application," but simply provide access to messages sent and received before the backup was made.

benihana 11y ago

>Also, I thought the consensus was that Apple was 'backdooring' iMessage by giving LE access to iCloud backups which include iMessage, not compromising iMessage directly? Consensus? First I've heard of this being a consensus. I've heard people say if Apple is backdooring, this is the way they'd do it, but no consensus on this actually happening. Care to go into this a bit more?

dantiberian 11y ago
Consensus may have been the wrong word to use, but I've heard the same as you, that backups are a weak point in iMessage security, and a very plausible way for LE to get access.
- BBlarat 11y ago
  is it required to have an iCloud backup when using iOS? Or is it something that can be opted out of? I'm just curious.
  - dantiberian 11y ago
    You can opt out, but I think it will be the default.
  - deleted 11y ago
    [deleted]
  - hutattedonmyarm 11y ago
    Not required. You can choose between iCloud backup, iTunes backup (even encrypt if you want) and no backup at all. iCloud is the most convenient though
  - smackfu 11y ago
    Just have more than 5 GB of data and you can't backup to iCloud without paying monthly.
    - hutattedonmyarm 11y ago
      Photos are not included, Apps aren't (only their data), I'm not sure about music. It's gonna be hard to exceed the 5GB this way
      - smackfu 11y ago
        Photos may be included. "Here’s what iCloud backs up: Photos and videos on your iOS devices, unless you turn on iCloud Photo Library on your iOS device (iOS 8.1 or later)." https://support.apple.com/kb/PH12519?locale=en_US https://support.apple.com/kb/PH12519?locale=en_US The photos hit the same 5 GB limit, so it's not like excluding or including them really changes anything. Photos are the #1 reason people hit the backup limit.

ejdyksen 11y ago

I've upgraded to iOS 9 GM and El Capitan GM, and I saw some new items show up in my iCloud Keychain, titled: PCS Backup PCS CloudKit PCS Escrow PCS FDE PCS iCloudDrive PCS iMessage PCS Maildrop PCS MasterKey PCS News PCS Notes PCS Photos (They also have what looks like a base64 string in there, but I'm excluding that just in case it might be secret) Just a guess, but between this and the fact that iCloud Backups were broken during the iOS 9 beta period, it seems like they might be encrypting backups now, as well.

dantiberian 11y ago
The problem with encrypting backups is what do they use as the encryption key? You have to have some route back to the users password, as that's what they'll be using to restore. That leaves it vulnerable to a LE password reset even if the backup is encrypted.
- ejdyksen 11y ago
  iCloud Keychain solves this problem, if you use a complex passphrase: http://www.slideshare.net/alexeytroshichev/icloud-keychain-38565363 http://www.slideshare.net/alexeytroshichev/icloud-keychain-3...

0x0 11y ago

The key could be added to the appleid on the server, without telling the phone about it. Others sending messages to you would then also encrypt with the new backdoor key. Likewise, you don't get notifications about your friends' keys updating (in fact there's not even any UI to show the current keys for a contact), so your phone would start encrypting messages to the recipient's additional backdoored key silently too. :(