Even with end-to-end encryption on board, WhatsApp can do little to stop people from reading your messages should they manage to get into your phone. According to a report by Android Authority, a future update to the app will permit users to enter a six-digit passcode should they wish to shore up local defense against intrusion.
Apparently spotted within a WhatsApp translation program, strings include references such as 'Enter the current six-digit passcode', 'Passcodes don’t match. Try again', and 'Enter a recovery email address'. The recovery email part may be optional, notes the report, as a way for users to recover account access should they accidentally lock themselves out.
Of course, just because the feature is being tested, this doesn't necessarily mean that it will roll out soon, if at all. But with Facebook / WhatsApp clearly ramping up efforts to make these services as watertight as possible, it's difficult to see why it would be held back.