Mac/iOS: Have a relatively recent Mac and an iPhone, iPad, or Apple Watch equipped with TouchID, Apple's fingerprint-reading security feature? MacID lets you turn your mobile device into a key that can unlock your Mac when you're nearby.
Once installed, you'll pair your device with your Mac though the app. From there, you can tell MacID to automatically lock your Mac when you're not in immediate proximity to it, to auto lock and unlock when you move away or come back, or just manually lock or unlock your device from your iPhone, iPad, or Apple Watch. Once you get back to your computer, instead of typing out your password, you can use TouchID on your mobile device to authenticate, unlock your Mac, and get back to work.
MacID can pair with your iOS device with multiple Macs if you want it to, send clipboard text from your Mac to your iOS device, and control your Mac's audio. You can even set a custom unlock pattern for your Mac if you prefer, meaning you have to tap a specific pattern on your trackpad before your computer will unlock.
You can grab the iOS app from the iTunes App Store (linked below) for $4.99, and the companion app for your Mac for free. Remember, you have to have a Mac that supports Bluetooth LE for MacID to work. Hit the link below to try it out.