Yubico Forum

I got an e-mail question today regarding the Yubikey NEO NDEF configuration, so I would like to describe how this works a bit more in detail.

First - everyone who wants to dig deeper into the concept of NDEFs, please visit the NFC Forum - http://www.nfc-forum.org/home/

The NDEF URI type allows a URL/URI to be written to a Yubikey NEO. Once scanned with an NFC reader, the NEO concatenates this URI/URL with the OTP output of the configuration. In order to save bytes in the field, some known types are compressed into an "URI Identifier code". http://www. is for example equivalent to the value 1, https://www. is equivalent to 2 etc. A value of 0 means "no predefined prefix", and the string is then not compressed. This means that http://www.foobar.com could either be stored as 1 + foobar.com (=11 bytes) or uncompressed (=21 bytes).

A typical custom login string could then be http://www.foobar.com/login?id=<otp-value-here>

1. Set type to http://www.
2. Enter URI string foobar.com/login?id=

The Yubikey will then output a NDEF string like http://www.foobar.com/login?id=ccccclct ... virgkkiurc and you'll then get an out-of-the-box experience, allowing an instant navigation to this URL by simply tapping the Yubikey with your NFC phone.

A full description of the URI record type, read the NFC forum document "NFCForum-TS-RTD_URI_1.0"


The NDEF text type is simpler and just stores an arbitrary text element. Please read the NFC forum document "NFCForum-TS-RTD_Text_1.0" for more information


Best regards,

JakobE
Hardware- and firmware guy @ Yubico