A New App Lets You Knock Twice On Your iPhone To Unlock Your Password-Protected Mac

Knock is a new app that retails for $3.99 and promises a more secure way to log-in to your computer.

Instead of typing in a password, Knock lets you rap your knuckles twice on your iPhone to unlock your Mac.

Knock uses Bluetooth technology to connect both devices once the sound is made. A phone can be knocked through a pocket or directly. It is compatible on MacBook Pros, Airs, iMacs, Mac minis and Mac Pros.

Eventually, the company wants to let users unlock much more than just computers with a knock.

William Henderson and Jon Schlossberg founded the company and tell TechCrunch they built the app in just a few weeks. Henderson previously worked at Square on its Wallet product; Schlossberg worked for Bonobos.

It's a cool concept, but it doesn't seem much easier than typing in a password. There are a lot of other companies trying to build password hacks too. Unikey, for example, uses fingerprints to unlock front doors. NYU professor Nasir Memon is turning gestures into passwords on touchscreen devices.

Still, when you see Knock in action it's unbelievable. Here's the video that demonstrates how to knock and unlock your Mac.