Our Premium-range models are expected to have the upgrade available from November, meaning owners of the Xperia XZ2, XZ2 Premium, XZ2 Compact, Xperia XZ Premium, XZ1 and XZ1 Compact will be among the first to get their hands on the new tech.
Owners of XA2, XA2 Ultra and XA2 Plus devices can expect to access the upgrade early 2019.
Starting in Android Pie, devices can take advantage of a new capability where backed-up application data can only be decrypted by a key that is randomly generated at the client. This decryption key is encrypted using the user's lockscreen PIN/pattern/passcode, which isn’t known by Google. Then, 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.