Sequins defeat high-tech surveillance equipment

Sebastian points out new technology may make concealed carry more difficult.

What the people that develop these tools don’t tell the politicians that will buy them is they are easy to defeat. Just as a tank can be defeated with a Molotov Cocktail, if you know what you are doing very simple and readily available materials can defeat multi-million dollar surveillance equipment.

In this particular instance what the developers probably aren’t telling the potential buyers is that there is something called the Skin Effect. This is, in essence, a law of physics that says the higher the frequency of an electromagnetic wave the shallower the penetration of that wave through a conductor. It depends on the resistivity and magnetic permeability of the conductor but for copper a 1 Terahertz wave will have a skin depth of about 66 nm. The typical aluminum foil you buy at the grocery store has a thickness of 200 um which is over 3000 times thicker. I don’t have the skin depth numbers for aluminum but I can tell you that lining your jacket with aluminum foil will make your jacket completely opaque to such machines. Even aluminized mylar balloons or “space blankets” will be opaque. Hence, these machines will not be able to see anything on the other side of the metal lined clothing. I expect even sequined purses and dresses will be opaque.

10 thoughts on “Sequins defeat high-tech surveillance equipment

  1. One of my big fears is mandated rfid tags on firearms. Disabling them will be a crime. The innocent have nothing to fear 🙂

  2. So, the skin effect is why higher frequency communication equipment has difficulty penetrating buildings and such? (I think Faraday cages as well…)

  3. AM, the simple answer is yes. The higher the frequency the lower the penetration through a conductor. But higher frequencies also “leak” through holes easier if you don’t have a solid conductor covering the entire building it’s not simple to predict.

  4. A mylar-lined jacket would be pretty brutal in warm weather; any idea what the smallest mesh for a Faraday cage would have to be to work? Or, how tight would a Faraday cage mesh have to be to render such technology useless, or of minimal value, in the absence of complete opaqueness?

    This also raises an interesting Constitutional question: Would the wearing of such an opaque (or near opaque) garment justify a further, and more intrusive, search because the .gov’s fancy hardware couldn’t see past the garment and the assumption would be that the purpose of the garment was to defeat the technology for nefarious purposes?

    And, while the .gov must obey the Constitution (well, sort of, maybe, sometimes….) private sector firms are bound by no such requirement. What the local donut chasers can’t do, Best Buy could.

  5. The “mesh size” for THz frequencies is going to be much smaller than you can see through. But it may be so thin you can see through it. Something like the pink anti-static plastic bags you store/handle electronic parts in might work. Just put one of these in your big coat pocket with some old RAM sticks. If they want to search you plead innocent and scream bloody murder. If enough people do it in the winter time then the technology will be discredited and you won’t have to worry about it by the next summer.

  6. RFID tags are easily shielded. I worry more about RFID implants in humans than in guns and have put a fair amount of thought into them.

    I haven’t tested it but I suspect they are pretty easy to destroy without the owner even knowing it happened. If this is true then if enough people walking into crowded places and zapping them (without even knowing the owner) will cause the technology to be discredited. And beyond that they can be spoofed. Read the RFIDs of the guns of some cops in a distant city, shield or disable your guns RFID, and then cycle through your list of tags as needed should you want to have your gun appear to have a tag as you are carrying it. Or just “flash” your spoofed RFIDs as desired to cause false alarms. And since you are actively spoofing you can boost the power and with the proper antenna you could be a 100 yards away when you trigger the alarms. I don’t think it’s that big of a problem provided enough people want to “get in on the fun”. The “bad guys” (anti-gun governments and private businesses) will spend large amounts of money on the equipment which will overwhelm them with false alarms and the equipment will ultimately be ignored and thrown away.

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