Mysterious White Dogtag

I have been playing BF4 and every now and then I come across these players with these cool-looking, white, complex dogtags, nothing like the usual. These tags have a barcode looking thing on them, and they seem to have a sphere shaped thing as the background picture. This tag looks more like a keycard, to be honest. I don't think it's anything to do with the Phantom project, as I have completed that.
I really want it, but don't know how to get it. Please help.
Best Answer
Without an image of the dog tag in question I can't be sure which one you are referring to, but it sounds like the "4th floor dog tag":
You can see it on your Battlelog profile in the section for right dog tags under the "exclusive" category.
There is a lot of speculation on how to get the dog tag, but it appears that there is nothing you can do anymore to get it. An answer from user MorningTimeCloud on the EA forum suggests that you needed to play the Battlefield Hardline beta:
If you played the [Battlefield Hardline] beta, you get the dogtag.
If you didn't then you won't get it.
I also found a Google Doc about the 4th floor dog tag which contains a lot of research about obtaining the tag and agrees with the EA forum. Here are the most relevant quotes:
just got off the phone to EA support
anyone else can freely do this to confirm
the 4th floor dogtag is NOT premium related and is NOT phantom program related, however it is HARDLINE related, they could not specify how its hardline related as it's something you need to do, and they will not reveal spoilers.
and
This isn't really new, but I asked on the Battlefield FB page and they responded with this:
"The 4th Floor Dog Tag awarded to Battlefield 4 players is from the Battlefield Hardline Beta. Those who successfully signed up for the Battlefield Hardline beta through the beta sign-up site were awarded the tag. If you received a code from a different source and did not sign up through the site you will not receive the dog tag."
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Answer 2
Seems that the QR code points to battlefield.com/4thfloor. If you visit the site while you're logged into Battlelog, it will take you back to your emblem editor. When you return to your 'Customize Dogtag' page, it should be selectable. (from mpgh.net)
It might require that you had participated in the Battlefield Hardline beta.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Pedro Figueras, Eman Genatilan, Eman Genatilan, Griffin Wooldridge