The most commonly used feature in windows system is the ability to lock your desktop by pressing a combination of windows key + L, but what if you want to secure your MAC system ? There is a simple tool found on the web which helps you lock your desktop (same as windows) with a help of a screen saver.
ScreenLock is small handy application which locks your MAC screen, you just have to download the zipped file and extract on your desktop (proffered for easy access), know when ever you want to lock your desktop just double click the file placed on your desktop. To retrieve back or unlock you have to provide the login information simple.
Download ScreenLock via [Addictive Tips]