xscreensaver + light-locker should be okay, there is no virtual keyboard. There is also xsecurelock [1] by Google. [1] https://github.com/google/xsecurelock h

xscreensaver + light-locker should be okay, there is no virtual keyboard. There is also xsecurelock [1] by Google. [1] https://github.com/google/xsecurelock https://github.com/google/xsecurelock