The data in the keychain item cannot be accessed after a restart until the device has been unlocked once by the user.
- iOS 4.0+
- macOS 10.9+
- tvOS 9.0+
- watchOS 2.0+
After the first unlock, the data remains accessible until the next restart. This is recommended for items that need to be accessed by background applications. Items with this attribute do not migrate to a new device. Thus, after restoring from a backup of a different device, these items will not be present.