DIY Ultralight ‘Faraday Cage’ RFID Blocking Wallet

DIY ultralight RFID blocking pouch or wallet

There has been a surge of new RFID blocking wallets and other products on the market that are designed to block cellular phone or RFID chip signals in order to prevent their transmissions or stored data from being maliciously intercepted, scanned or used to track your location. Two recent examples of these types of products that spring to mind are the LOKSAK ShieldSak ($33) and the Nemo EMFX-47 Pouch ($50).

Radio frequency identification (RFID) chips hold personal information, which can apparently be stolen by just about anyone with a radio frequency (RF) scanner. They can be found in just about everything these days including passports, ATM cards, credit cards and some of the newer state-issued driver’s license. The same technology will likely even be used in paper currency in the near future.

To address this new level of identity theft “paranoia”, manufacturers have started producing and selling products containing specially designed metal-infused fabrics that act as a miniature Faraday Cage by blocking electronic signals from passing through the material and potentially being scanned by data transponders. Just do a Google search for “RFID blocking wallets” and you’ll see what I mean.

I’m no expert in RFID technology or passive data transmission by RF devices, but the whole topic does sort of intrigue me in a conspiracy theory kind of way.  It also struck me that not only were most of these RF blocking products pretty darn expensive, they weren’t exactly light weight (the EMFX-47 for example weighs close to 4oz).  That got me to thinking about how I could make something myself to achieve the same RF shielding results but which would weigh considerably less than a store bought product.

DIY ultralight RFID blocking wallet or pouch

The lightest weight material that I have is Cuben Fiber, which depending on the thickness can weight almost nothing at all.  Many months ago I was very kindly sent a set of Cuben Fiber samples from Jon Holweger (some of which I made into ultralight stuff sacks), one piece of which was foil backed.  It was one of the lighter weight pieces, but at the time I had no idea what I would do with it.  Until I started thinking about RF shielding – eureka!

DIY ultralight RFID blocking wallet or pouch

Using my sewing machine I created a simple pouch by folding the foil coated Cuben Fiber sample in half (foil side outwards) and stitching across the bottom and up the long side.  I then turned it inside out so that the unsightly seam was on the inside.  To make the flap of the pouch I cut a simple notch out of one side of the pouch – I wasn’t too concerned with fraying because the Cuben Fiber is incredibly strong and fray resistant.

DIY ultralight RFID blocking wallet or pouch

To make my RF shielding pouch stay closed when I put my phone or items inside it, I used two small 3M self-adhesive Velcro squares.  In hindsight one set of Velcro would have been enough but I used to pairs to balance it out – these probably equate to the majority of the weight too.

DIY ultralight RFID blocking wallet or pouch

My iPhone fits inside with plenty of room to spare. The overall RF shielding pouch measures 3.5 x 6 inches when closed which means it will accommodate not only my iPhone but a Passport, several credit cards and any other items that I want to make fall off the grid :-)

But did it work?

Heck yeah!  In tests with several different cell phones I was not able to call or make any connection to the device once it was put inside the pouch. When I took a device out of the pouch it would search for a network and then be able to receive calls. Put it back inside the pouch and again it was out of signal reach.

I have no way to test the effectiveness of the passive RFID shielding, but have extremely high confidence that it will thwart any passive scanning attempts based on what I have seen with the cell phones.

Finished Weight?

My digital weighing scales go down as low as 1/8 of an oz (0.125oz) so my home-made ultralight ‘Faraday Cage’ pouch is <0.125oz including the two pairs of Velcro fasteners.  That’s pretty darn light weight :-)

Other good articles/reviews about RF shielding pouches:

Gear Links: Eastern Mountain Sports | REI | CampSaver | Patagonia | Altrec

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  • http://www.blogger.com/profile/07180571503542781921 The Odyssee

    Hi Brian,
    Good post. Interesting. Do you think that emergency space blanket material will do the same job?…Cheers Alan

  • http://www.blogger.com/profile/09628095804170935682 Brian

    Alan, I don’t see why not. It’s essentially foil backed with mylar for strength, that would be a great material to use. I just happened to have a sample piece of Cuben Fiber that was foil backed, so that was an obvious choice.

    It would be cheap and relatively easy to make a similar case out of space blanket material. In fact I bet you could make a lot of them and hand them out to any of your friends that iPhones so that Apple won’t be able to track their location :-p

    Now you have me wanting to give this a try – darn you!

  • kuku

    this is totally retarded bro. just put your phone in flight mode. phones don’t have rfid chips in them. also, your passport and shit, i mean, come on. someone gonna sit there in 3-10 feet of you with a scanner to capture your particular shit? don’t be paranoid.

  • Todd

    I’m curious, has anyone tried the emergency blanket?  I wonder how it would hold up. 

    I’m glad I found your site.  I’m going to link to it on my site and link to this post.

    Todd
    http://www.prepperwebsite.com

  • Bluedunbar

    I use 3 layer of aluminum foil in the outer bill pocket of my wallet.  Folded, it blocks all crds in the wallet from being scanned.

    • http://www.briangreen.net Brian Green

      Simple but effective. I’ve heard a lot of people using empty (and cleaned) foil crisp packets too. And for folks that don’t think this is an issue, check out the Red Team videos on YouTube to see how easily they cloned an RFID building access card that was in someone’s back pocket :-)

  • Bluedunbar

    I use 3 layer of aluminum foil in the outer bill pocket of my wallet.  Folded, it blocks all crds in the wallet from being scanned.

  • http://www.briangreen.net/ Brian Green

    Simple but effective. I’ve heard a lot of people using empty (and cleaned) foil crisp packets too. And for folks that don’t think this is an issue, check out the Red Team videos on YouTube to see how easily they cloned an RFID building access card that was in someone’s back pocket :-)

  • http://www.blogger.com/profile/18168765000988930390 talkorsing

    Would this type of thing work as a Faraday cage in case of an EMP? Or would it still need a ground wire?

  • Jeff

    JFF (Just for Fun)– here’s a link to a free ebook by Cory Doctorow about just that kind of thing using rfid,
    http://manybooks.net/titles/doctorowother08Little_Brother.html

  • Jeff

    JFF (Just for Fun)– here’s a link to a free ebook by Cory Doctorow about just that kind of thing using rfid,
    http://manybooks.net/titles/doctorowother08Little_Brother.html

  • http://twitter.com/escapethewolf clinton emerson

    Zero Trace will last years and can be washed! Check it out!
    http://www.escapethewolf.com/products

    • http://www.briangreen.net Brian Green

      I’d love to see a series of Zero Trace inserts that can be used with other/existing packs to provide the same functionality. If you make those I want a kickback for the idea ;)

  • http://twitter.com/escapethewolf clinton emerson

    Zero Trace will last years and can be washed! Check it out!
    http://www.escapethewolf.com/products

  • http://www.briangreen.net/ Brian Green

    I’d love to see a series of Zero Trace inserts that can be used with other/existing packs to provide the same functionality. If you make those I want a kickback for the idea ;)

  • Amy

    Brian, what about mylar balloons? I have a few of those floating around the house – leftovers from a recent b-day party. My little boy might object to me cutting them up, but if it’s in the name of increased security….

    • http://www.briangreen.net Brian Green

      Amy, the material I used has a mylar layer heat bonded on it and is exactly what you need. Mylar on its own is very flimsy and delicate, you might be able to make a mylar “pocket” and place it inside or between other more durable materials. Let me know if you come up with something. – Brian

  • gulliverian

    Easy to test passive RFID, just have someone with an RFID access card for doors at work test it.

    • http://www.briangreen.net Brian Green

      Yup! I realized that I have an RFID access card for a particular section I go in occasionally for work, I put it in this pouch and it kills the functionality immediately, even when almost touching the reader. Take it back out and it’s working just fine.

  • JDBinshadows

    Be warned by keeping your phone in a Faraday cage will start your phone on a hunt for a network, this in turn boosts it’s signal strength full bore open which in turn will drain your battery. If you use this concept, place your phone into airplane mode to preserve the battery.

  • Innocuus

    Just wondering if you could specify exactly what the fabric is you used, or at least what it’s intended use is (by the company that makes it). I clicked on the link and their website lists a couple of different fabrics with similar names. I guess since this article is a couple years old they’re probably changed the site or available fabric range.

    • http://www.briangreen.net Brian Green

      This particular piece of fabric that I used was a small sample square of Cuben Fiber. In fact it is a laminate of three layers; two sheets of Cuben Fiber with a layer of mylar (foil) film in between. For more than that I’ll have to check back to the site and find the exact product for you.

      • jessica

        I am also wondering exactly what kind of fabric you used. I have been searching all over the internet for this fabric and I just can’t figure out what yours is called or where to get some. The website linked doesn’t seem to sell to consumers, and it isn’t clear what kind of their fabric is metallic like yours. I would like to use a similar lightweight fabric to make a bag to protect my laptop and travel documents. Any advice?

        • http://www.briangreen.net Brian Green

          Jessica, I got this material as part of a request I made for small samples squares by emailing the contact at http://www.cubenfiber.com. They were kind enough to send me a bunch of samples of their available materials, but they do not have a webpage that lists the individual product they make — in fact the foil backed Cuben Fiber was a complete surprise.

  • PrivacyAdvisor

    Kuku, mobile phones are always under attack. In Australia (and I would say in most other countries also) local councils hack your bluetooth so they know who is in the area, where they are, how fast they are traveling and how long they are there for. If you walk into any court in Australia, check the screen of your phone as I bet it gets hot after a while. That is them accessing your bluetooth to check who you are. Happens all the time, now shops are also doing this to see where about in the store you are so they can send an sms to you to promote something. walk past a shop in the complex and some will send you a sms to say “hey come on in and get this deal”. Your phone is very open so this is a good idea. Also your cards and passport, people sit on top of bridges in peak hour traffic and scan all the cards and any device with a chip, you don’t have to be 3-4 feet away you just boost the antenna. If you don’t believe me watch the news, people are being busted in Australia and the USA all the time for this. Very easy to do.