Knock pairs your iPhone with Mac which allows you to lock screen password more easily. Once you are done purchasing this app, you’ll need Bluetooth LE to pair your Mac and iPhone. As soon as this tricky and tedious part is over, you can start using this app to unlock your Mac with your iPhone.
With using the newer Bluetooth LE technology, it ensures that your Mac will be unlocked as soon as you knock on your iPhone. It’s as prompt and responsive as you’d expect from a paid app.
Now the question is, can your mobile phone become a replacement for manually typing in a password? Possibly no, but this paid app is well worth a try, especially if you like to keep your phone in proximity.
To know more about it and download this app, head on over to its iTunes page.
Source - Knock