Opening the iTunes Store.If iTunes doesn't open, click the iTunes application icon in your Dock or on your Windows desktop.Progress Indicator

iTunes is the world's easiest way to organize and add to your digital media collection.

We are unable to find iTunes on your computer. To buy and download Knock – unlock your Mac without a password using your iPhone by Knock Software, Inc, get iTunes now.

Already have iTunes? Click I Have iTunes to open it now.

I Have iTunes Free Download
iTunes for Mac + PC

Knock – unlock your Mac without a password using your iPhone

By Knock Software, Inc

Open iTunes to buy and download apps.


Knock to unlock. Faster and safer than typing a password, for iOS and Mac.

PLEASE CHECK TO SEE IF YOUR MAC IS COMPATIBLE BEFORE PURCHASING. Compatible Macs are listed in the screenshot below.

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. Have a question? Email us at and we'll get back to you within a day.

What's New in Version 1.0.3

- New app icon
- Knock shows which Mac and account you are paired with
- Fixed an issue that could cause Knock to never pair

iPhone Screenshots

iPhone Screenshot 1
iPhone Screenshot 2
iPhone Screenshot 3
iPhone Screenshot 4

Customer Reviews

Excellent app & the best response I've ever had

This app is amazing. True, it does one, simple thing, but for once, it's an app that actually does it right.
A few versions ago, I just happened to find a very rare bug with it. I contacted them and the response was fast. They continued to work with me on it, and within about a week, the fix was pushed out in an upgrade.
I have been a part of teams developing IT security software (not for apps) so I completely understand the process of involving the Dev & Eng teams as customer service goes between them and the customer. I've seen it from inside so many times.
All I can say is that these people who created this app, did it right and they support it the way it should be done.
There was NONE of the usual "let's make a lot of crappy apps so we can just grab a few bucks and run." with this one.
I'm not sure how many people work on this one, all of you are awesome! And I apologize it took me so long to write this review, guys!

Useful, but I’d like more security

The app is very intuitive and clever. I like it! However, I have a number of security concerns.
First, I’ve tested the signal strength, and I can be two floors below my computer, with multiple closed doors between, and Knock still shows a connection to the desktop. This is worrying. Granted, I need to knock on my phone for someone upstairs to access my computer, and it’s difficult to do by accident, but range is worrying nonetheless. I’d like to see range reduced to a few meters at most (I measured more than 10).
Second, 1024-bit RSA is just not strong enough! 2048 is the current *lowest* best-practice key length. Further, not much is documented about the authentication protocol. Is it challenge-response, or something simpler? Some clarification (and a longer key) would alleviate my concerns.

so far so good, read their FAQ

Works very well for me. Follow the instruction for the first time installation and it will work nicely. No, you don’t need to lock with their program to “knock to unlock” although their program has to be running at all time. When my mac lock after wake up, I can use this to unlock it. No, it does not use their own lock screen. This works with default lock screen. If you worry about the location service on your iPhone, read their FAQ and they explain why they need the location services. I have a 10-digit password and it take about the same time to pair+knock+unlock than I type my password. You might have to wait about 1-2 sec if you have short password. I suppose 1-2 sec is eternity in this digital age.

Knock – unlock your Mac without a password using your iPhone
View In iTunes
  • $3.99
  • Category: Utilities
  • Updated: Dec 24, 2013
  • Version: 1.0.3
  • Size: 1.9 MB
  • Language: English
  • Seller: Knock Software, Inc

Compatibility: Requires iOS 7.0 or later. Compatible with iPhone 4S, iPhone 5, iPhone 5c, iPhone 5s, iPad Wi-Fi (3rd generation), iPad Wi-Fi + Cellular (3rd generation), iPad Wi-Fi (4th generation), iPad Wi-Fi + Cellular (4th generation), iPad mini Wi-Fi, iPad mini Wi-Fi + Cellular, iPad Air, iPad Air Wi-Fi + Cellular, iPad mini with Retina display, iPad mini with Retina display Wi-Fi + Cellular, and iPod touch. This app is optimized for iPhone 5.

Customer Ratings

Current Version:
All Versions:

Become a fan of the iTunes and App Store pages on Facebook for exclusive offers, the inside scoop on new apps and more.