This is a proposal to the Ubuntu phone developers about phone app locking.
Having to unlock your phone every time you turn it on can be too much hassle. Many users, including myself, disable the lock because of this, leaving a phone with absolutely no security. What’s the point of security features if they’re not used? I believe the solution is to only require unlocking the phone when trying to access restricted features, not every time you look at your phone.
Opening a locked app
This shows opening a locked app from the launcher, when the keyring is still locked.
Accessing a running app
To improve the usability, this should also work for apps left running in the background. This could be achieved by adding a lock layer over the running app when the keyring is locked.
I think the ultimate goal should be to have an infrastructure for fine-grained lock controls. This would allow an app to be used without unlocking, but still stop unauthorised users using restricted features, such as sending email or replying to messages. Here is a mockup of the settings page for such a design: