How to password Protect an NFC tag

One of the many great features on consumer NFC tags are that they can be reprogrammed with new information over and over again. You could be a restaurant or coffee bar with convenient NFC tags placed so customers can easily tap to see your menu, or follow your social media. However, the ability to reprogram an NFC tag may not be so great when using in an unsupervised public environment. 
The last thing you want is a punk teenager reprogramming something undesirable onto your tags for an unknowing customer to be surprised when they are redirected to something other than your menu. 
Luckily many consumer NFC tags (NTAG213, and NTAG215) including all Tap Tag products offer the ability to password protect your NFC tag. Password protecting your NFC tag can be done with many free apps from the Apple and Android app store. We are going to be using an app called NFC Tools. 
Before we start, I want to answer a few common questions regarding this topic.

What are the password requirements for an NFC tag?

The password can be anything, even just one character. Make it easy because it is impossible to recover if forgotten which will leaved the tag permenently locked. There are no hints either. However, you can guess the password infinite times without being locked out. 

If an NFC tag is password protected, can it still be scanned?

Yes! the password protection only stops one from reprogramming the tag. All other features are still accessible such as scanning the tag.

What are the password requirements for an NFC tag?

There are none! You can do any size password using any characters on the keyboard. Even just one character if you wanted... your password could be "p"

Does a password take up memory on an NFC tag?

Yes it does. So try to make it as short as possible to save up valuable memory. A typical NFC tag can only hold about 45-85 characters of info which includes the password. Referring to the question before this, you can make a password just 1-2 characters long

Can someone hack my NFC tag?

NFC tags are closed circuit, meaning they are not hooked up to the internet or any outside source further than a few inches away. Yes, someone could technically guess your password especially because they are allowed infinite try's. However, just having a 2-character password like "b>" would take someone millions of tries to guess right assuming they would not know its just 2 characters. They would also have to be within a few inches the entire time they are trying. Additionally, even if they did successfully hack the only thing they could do is reprogram its contents, they do not gain access to personal information whatsoever, just the ability to change the information on the tag. 

What if I forget my password?

There is absolutely no way to recover. There are no hints, no 2FA, no email-me-a-reset-link, no way to recover. If you forgot the password the tag is permanently locked. Luckily the tag is still scannable and therefor still usable, but the info stored on it will be set in stone until the tag is destroyed. 

How do you remove password off an NFC tag?

Simply download an app like NFC Tools. Under more options hit "Remove Password," type in the correct password and hit okay, tap the chip. If the password is correct you will get a blue check mark, if it is incorrect you will get a red exclamation point. The password will be removed completely if correct. If you wish to reactivate the password you will have to hit "Set Password" to create a new one and tap the chip to re-lock.

How do I program an NFC tag?

We have written an entire Step by Step Guide on how to do this complete with text, pictures, and videos.

How do I password protect an NFC tag?

Password protecting your tag is incredibly easy. First open the app NFC Tools on App Store  or Google Play Store
Upon opening the app you are greeted with 4 options: Read, Write, Other, and My Saved Tags.
Hit the "Other" option
From here you will see the options "Set Password" and "Remove Password"
To set a password click that option and type in any length password, after doing so click "Set" and tap the chip. A blue exclamation shows it worked, and a red exclamation means it did not. To remove the password, hit the appropriate button, type in the correct password and tap the chip again. This will remove the password all together.