...
- https://support.apple.com/en-us/HT204379 (requiring a password after screen saver or sleep)https
- http://support.appleosxdaily.com/kb/PH21782?locale=en_US&viewlocale=en_US/2013/03/23/automatically-log-out-of-a-mac-after-a-period-of-inactivity/ (setting your Mac to log out after inactivity)
...