4 ms·

For comparison, Google end-to-end encrypts Android backups with your lock screen PIN/pattern (which isn't known to Google). Source - https://security.googleblo

by skrowl 7y ago

For comparison, Google end-to-end encrypts Android backups with your lock screen PIN/pattern (which isn't known to Google). Source - https://security.googleblog.com/2018/10/google-and-android-have-your-back-by.html https://security.googleblog.com/2018/10/google-and-android-h...

Shank 7y ago
Offline attacks for a motivated adversary, like NSA, are trivial on low strength security measures, like a standard PIN, numeric only PIN, or pattern. Only a strong passphrase would really help you.
- deleted 7y ago
  [deleted]
- modeless 7y ago
  This is false. This concern is addressed in the second paragraph of the linked article: > this passcode-protected key material is encrypted to a Titan security chip on our datacenter floor. The Titan chip is configured to only release the backup decryption key when presented with a correct claim derived from the user's passcode. Because the Titan chip must authorize every access to the decryption key, it can permanently block access after too many incorrect attempts at guessing the user’s passcode, thus mitigating brute force attacks. The limited number of incorrect attempts is strictly enforced by a custom Titan firmware that cannot be updated without erasing the contents of the chip. By design, this means that no one (including Google) can access a user's backed-up application data without specifically knowing their passcode.
  - ran3824692 7y ago
    But the source code of many important parts of android are nonfree, so google can update it to send your cleartext password and you would never know.
    - modeless 7y ago
      This is true for iOS as well as every other widely used computing platform. Android is better; unlike iOS you can build AOSP yourself without the Google proprietary parts, and unlike iPhones, Pixel phones have unlockable bootloaders so you can install your own OS builds. Even most PCs running Linux have plenty of nonfree binaries in various firmwares and common peripheral drivers. I support efforts to make devices with fully open firmware on which you could run Android's AOSP or other open source operating systems.
robocat 7y ago
So backups are insecure because they can be brute forced then? Most PINs are 4 digits, and 50% of people use the most popular 25 PINs. Pattern has 9! combinations (= 51840) but most people use four dots (987*6 combos) and most of those probably use one of a few popular patterns.

by skrowl 7y ago

Shank 7y ago

Offline attacks for a motivated adversary, like NSA, are trivial on low strength security measures, like a standard PIN, numeric only PIN, or pattern. Only a strong passphrase would really help you.

deleted 7y ago
[deleted]
modeless 7y ago
This is false. This concern is addressed in the second paragraph of the linked article: > this passcode-protected key material is encrypted to a Titan security chip on our datacenter floor. The Titan chip is configured to only release the backup decryption key when presented with a correct claim derived from the user's passcode. Because the Titan chip must authorize every access to the decryption key, it can permanently block access after too many incorrect attempts at guessing the user’s passcode, thus mitigating brute force attacks. The limited number of incorrect attempts is strictly enforced by a custom Titan firmware that cannot be updated without erasing the contents of the chip. By design, this means that no one (including Google) can access a user's backed-up application data without specifically knowing their passcode.
- ran3824692 7y ago
  But the source code of many important parts of android are nonfree, so google can update it to send your cleartext password and you would never know.
  - modeless 7y ago
    This is true for iOS as well as every other widely used computing platform. Android is better; unlike iOS you can build AOSP yourself without the Google proprietary parts, and unlike iPhones, Pixel phones have unlockable bootloaders so you can install your own OS builds. Even most PCs running Linux have plenty of nonfree binaries in various firmwares and common peripheral drivers. I support efforts to make devices with fully open firmware on which you could run Android's AOSP or other open source operating systems.

robocat 7y ago

So backups are insecure because they can be brute forced then? Most PINs are 4 digits, and 50% of people use the most popular 25 PINs. Pattern has 9! combinations (= 51840) but most people use four dots (987*6 combos) and most of those probably use one of a few popular patterns.