Faster and safer than typing a password， for iOS and Mac.
You keep your iPhone with you all the time. Now you can use it as a password. You never have to open the app— just knock on your phone twice， even when it’s in your pocket， and you’re in.
Using Knock won’t drain your iPhone’s battery， even if you use it all day every day. Knock securely communicates with your Mac using Bluetooth Low Energy， a new technology that draws very little power.
Knock works with any Mac that supports Bluetooth 4.0.