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When the data is in transit between devices, what encryption is being used? I mean I could speculate a manner in which it’s possible to restrict this between tw

When the data is in transit between devices, what encryption is being used? I mean I could speculate a manner in which it’s possible to restrict this between two devices and their respective secure enclaves, but is Apple doing that? This would mean that when backed up in Apple’s servers l, they’d have to backup per device... maybe they do?

karlshea 9y ago
They do all sorts of device key exchange, if you haven't watched the talk at Black Hat I'd highly recommend it: https://youtu.be/BLGFriOKz6U?t=6m55s https://youtu.be/BLGFriOKz6U?t=6m55s (link goes to beginning of Secure Enclave content, and later on in the talk he discusses iCloud which uses the SEP keys)
- bluejekyll 9y ago
  Excellent. I’ll take a look at that, thanks for the post.
abalone 9y ago
The white paper goes into some detail on the encryption and key exchange mechanisms. Basically devices exchange public keys so their private keys never have to (and physically can’t) leave the SEP. Backups are different. Those are not encrypted with device keys because obviously you want to recover from loss of device and restore to a brand new one. But if you’re not comfortable with that, you can do local encrypted backups with your own password via iTunes. And as noted the most sensitive data like HealthKit is only included in encrypted backups. White paper also discusses a special escrow service for backing up your keychain, incidentally.
- karlshea 9y ago
  > White paper also discusses a special escrow service for backing up your keychain, incidentally. My foggy understanding is that iCloud backups are encrypted with a key stored in iCloud Keychain, which is encrypted within the hardware security module escrow service they run, so after iOS 10 they can't actually decrypt your backup. Edit: oh, I replied to you below as well. That video has the details but it's been awhile since I watched it.
  - comstock 9y ago
    This contradicts statements made by Apple, most information in iCloud backups is not encrypted end-to-end. https://support.apple.com/en-us/HT202303 https://support.apple.com/en-us/HT202303
    - karlshea 9y ago
      See the iOS Security Guide page 55: https://www.apple.com/business/docs/iOS_Security_Guide.pdf https://www.apple.com/business/docs/iOS_Security_Guide.pdf It sounds like (although I'm not an expert) that it would still be impossible for them to encrypt files in higher data protection classes, since the iCloud backup keys are stored within iCloud Keychain, which is end-to-end encrypted. Edit: and honestly if I'm misinterpreting that and it's an issue for a specific person, they should just use iTunes encrypted backups and not rely on iCloud.
      - comstock 9y ago
        The statements only refer to: “When files are created in Data Protection classes that aren’t accessible when the device is locked” So not photos, most data.

karlshea 9y ago

They do all sorts of device key exchange, if you haven't watched the talk at Black Hat I'd highly recommend it: https://youtu.be/BLGFriOKz6U?t=6m55s https://youtu.be/BLGFriOKz6U?t=6m55s (link goes to beginning of Secure Enclave content, and later on in the talk he discusses iCloud which uses the SEP keys)

bluejekyll 9y ago
Excellent. I’ll take a look at that, thanks for the post.

abalone 9y ago

The white paper goes into some detail on the encryption and key exchange mechanisms. Basically devices exchange public keys so their private keys never have to (and physically can’t) leave the SEP. Backups are different. Those are not encrypted with device keys because obviously you want to recover from loss of device and restore to a brand new one. But if you’re not comfortable with that, you can do local encrypted backups with your own password via iTunes. And as noted the most sensitive data like HealthKit is only included in encrypted backups. White paper also discusses a special escrow service for backing up your keychain, incidentally.

karlshea 9y ago
> White paper also discusses a special escrow service for backing up your keychain, incidentally. My foggy understanding is that iCloud backups are encrypted with a key stored in iCloud Keychain, which is encrypted within the hardware security module escrow service they run, so after iOS 10 they can't actually decrypt your backup. Edit: oh, I replied to you below as well. That video has the details but it's been awhile since I watched it.
- comstock 9y ago
  This contradicts statements made by Apple, most information in iCloud backups is not encrypted end-to-end. https://support.apple.com/en-us/HT202303 https://support.apple.com/en-us/HT202303
  - karlshea 9y ago
    See the iOS Security Guide page 55: https://www.apple.com/business/docs/iOS_Security_Guide.pdf https://www.apple.com/business/docs/iOS_Security_Guide.pdf It sounds like (although I'm not an expert) that it would still be impossible for them to encrypt files in higher data protection classes, since the iCloud backup keys are stored within iCloud Keychain, which is end-to-end encrypted. Edit: and honestly if I'm misinterpreting that and it's an issue for a specific person, they should just use iTunes encrypted backups and not rely on iCloud.
    - comstock 9y ago
      The statements only refer to: “When files are created in Data Protection classes that aren’t accessible when the device is locked” So not photos, most data.