[Noisebridge-discuss] RFID Access System

Thu Feb 4 07:24:59 UTC 2010

I've seen the RFID passport walled demonstrated at Defcon last year. It appears to work fairly well.

As for grounding Faraday cages, it seems to me that for this type of application you don't need to ground the cage. I believe that you only need to ground the cage when you are dealing with extremely high electromagnetic fields that would generate a current. 

According to that page : 

"The metal layers are grounded to dissipate any electric currents generated from the external electromagnetic fields and thus block a large amount of the electromagnetic interference"
(My emphasis)

For what its worth, tinfoil does a pretty good job at the higher frequency RFID, not so much for the lower.  

http://www.rfid-handbook.de/rfid/frequencies.html

73, de K6EF

On Feb 3, 2010, at 11:14 PM, Christie Dudley wrote:

> One of the things Chris mentioned at his workshop is that the little shields that they issue with passports/North American travel cards do not work.  You may as well just wrap your stuff in plastic.  What he did demonstrate, however, is that a little tinfoil in your wallet goes a long ways to blocking the signal.  
> 
> Christie
> _______
> "The road of excess leads to the palace of wisdom." -- W. Blake.
> 
> 
> On Wed, Feb 3, 2010 at 1:56 PM, David Stainton <dstainton415 at gmail.com> wrote:
> Yeah nevermind... There's nothing to block here.
> If people want to play with RFID that's cool.
> I may even help... but let's not misuse it.
> 
> I have also been issued credit/debit/atm cards with RFID.
> After the first RFID workshop; as per Chris Paget's suggestion, I
> promptly microwaved them in
> the Noisebridge microwave for about 2 seconds.
> There was a satisfying and noticeable rectangular shape that appeared
> on the card...
> Also a well aimed smashing with a hammer may work as well.
> I have since gotten rid of all RFIDs that I used to carry before I was informed.
> 
> As for the passport issue; I don't have a solution and I'm not real
> enthused about the shielding wallets.
> It would be interesting to perform experiments to see just how well these
> RFID shielding passport wallets actually work. These wallets do not
> completely encase
> the RFID chip... so the RFID chip could still be some exposured to radiation.
> 
> I was thinking to make my own passport RFID shielding wallet out of
> sheet metal so that the passport
> could be shielded from all directions.
> But really the best shielding would be a faraday cage
> (http://en.wikipedia.org/wiki/Faraday_cage);
> and it that case the metal would be grounded. Not really possible to
> have a portable faraday cage in that case.
> 
> 
> ~david415
> 
> On Wed, Feb 3, 2010 at 9:40 AM, Ian Atha <thatha at thatha.org> wrote:
> > + Changing Subject--Door Bell != RFID Access System.
> >
> > David,
> >
> > I find your concerns valid and I sympathize with them, to a certain extend.
> >
> > I was wondering if you would be willing to describe to us what
> > measures you are currently taking to protect yourself from such
> > surveillance.
> >
> > I have been issued credit and debit cards with mandatory RFID tags, my
> > work badge is using some sort of RFID technology, and I've often found
> > RFID tags in products I have purchased. All these, assuming the emit a
> > constant value when read, could be used to track an individual.
> >
> > How do you currently protect yourself?
> >
> > Out of curiosity, would you be concerned if someone implemented a
> > smart-card based system? I presume that someone motivated enough could
> > target the electromagnetic noise emitted by a reader reading your
> > smartcard--the attacker wouldn't be able to track you around the
> > globe, but they'd know your Noisebridge visiting patterns.
> >
> > Lastly, what do you mean by "block the [...] motion". Although a
> > Noisebridge newbie, my understanding was that if someone is willing to
> > do something, they may do so. If the group decides an RFID tagging
> > system is unwelcome, there would have to be consensus on "ban RFID
> > systems from Noisebridge", no? What am I missing?
> >
> > Thank you,
> >
> > -ian.
> >
> >
> > On Wed, Feb 3, 2010 at 02:02, David Stainton <dstainton415 at gmail.com> wrote:
> >> Greetings Blaine,
> >>
> >> I've got to say that while I appreciate your enthusiasm in getting
> >> this doorbell problem solved I think
> >> RFID is a horrible technology for that purpose...
> >>
> >> I know a thing or two about RFID from hanging out with Chris Paget who
> >> graciously taught a couple
> >> of RFID workshops at Noisebridge...
> >>
> >> There is just now way I'm going to walk around with an RFID tag and I
> >> don't recommend anyone else do it either.
> >> The presence of an RFID tag can be detected from across the street or
> >> perhaps even farther away.
> >> RFID sensors could in fact be placed around the city to track the
> >> movements of Noisebridgers.
> >> Or how about a public-garbage-can that explodes when a certain number
> >> of Noisebridges congregate near it?
> >> Sound crazy? I'm sure that similar devices are being developed for
> >> sucka fool US passports with the new RFID tag...
> >>
> >> I will block the RFID access control motion. I will explain to all my
> >> Noisebridge friends my view on this matter.
> >> I won't be the only one to enthusiastically disagree.
> >>
> >> Please give it some thought before responding.
> >> BTW this seems to be your first post to the noisebridge-discuss list
> >> and you are suggesting this. Wow.
> >>
> >> Cheers
> >>
> >> ~david415
> >>
> >>
> >>
> >> On Tue, Feb 2, 2010 at 10:31 PM, Blaine Forbort <b.forbort at gmail.com> wrote:
> >>> I had a hell of a time getting in on Sunday.  There where a ton of people
> >>> near the buzzer, so I found it very odd that no one let me in.  Then a few
> >>> hours later someone reported that they had been buzzing for 10+ minutes, and
> >>> even though I was sitting near the buzzer, I only heard the buzzer go off
> >>> once and answered it immediately.
> >>>
> >>> I also spoke to another individual about the idea of an RFID system for the
> >>> gate.  The concept was very simple: a pool of RFID tags would be left at
> >>> Noisebridge.  You grab an RFID tag on your way out, and it would grant you
> >>> automatic reentry on your return.  The hardware for such a system would be
> >>> VERY simple; something like this:
> >>> http://www.makershed.com/ProductDetails.asp?ProductCode=MKPX2 with a
> >>> microcontroller and a relay.
> >>>
> >>> The question is, would Noisebridge cover the cost of the RFID tags?  They
> >>> run from $1.50 to $5 each depending on what kind of chip they use (Hitag
> >>> would be nice so it would work with my implant).  If so, I'd be very happy
> >>> to help with the project.
> >>>
> >>> Blaine
> >
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Mark Cohen
markc at binaryfaith.com

Science is a way of skeptically interrogating the universe with a fine understanding of human fallibility.
-Carl Sagan, 1996

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