Leave the computer unattended - not a good idea, especially if you keep it relevant information. However, be near Mac 24 hours is impossible, and permanently block access to OS X is very inconvenient. For such cases, the studio Fi a Fo Ltd has developed iOS-app Tether, which automatically locks the Mac, if the user leaves the workplace, and unlocks it when you return.
Free app of about 4 MB is available on the iPhone 5, 5s, 6 and 6 Plus with operating system iOS 8.0 and above. Tether uses a built-in computers and laptops module Bluetooth 4.0 LE.The list of compatible models - MacBook Air release no earlier than 2011, MacBook Pro 2012 and 2013, iMac 2013 and Mac mini until 2011
Tether performs its task using the built-in OS X screen saver password protected. Using proprietary application, the user can specify the distance at which the screen saver should work. In addition, you can use two-factor authentication when after approaching the Mac user must enter a password to login.
Tether can free download from the App Store at this link . Desktop companion is available for download on the website of the developers.