Andrew Gumbrell March 12, 2010 7:10 AM

From the comments:

‘Now the TSA has a reason to confiscate all of our coins, “just in case.”‘

BF Skinner March 12, 2010 7:25 AM

I give these out as party favors. Has anyone ever run them through an x-ray to see if the sd is visible?

Winter March 12, 2010 7:48 AM

I need more room than a mere nickel or pound.

I wait for the higher value banknotes. But I would prefer wire transfers when they become available.


kevinm March 12, 2010 8:12 AM

A microSD card in a phone is common nowadays and data could be hidden amongst (or within) the MP3s but if you get searched and they find a hollow nickel then you won’t be able to explain that away.

remarkable March 12, 2010 8:18 AM

“…if you get searched and they find a hollow nickel then you won’t be able to explain that away.”

How about this explanation: “please cite the statute that makes this your business.”

Tim March 12, 2010 8:23 AM

Imagine the chaos you could cause with these.

Fill a bunch of these with various explosive residue.

Go to the airport and use them to purchase items at newsstand to place them in circulation just outside the security entrance to the gates. People will receive them as change for buying a news paper.

See how many of them are detected by security. If they can not detect them maybe the TSA should outlaw change? If you had enough you could carry a few pounds of c4 onto a flight.

konrads March 12, 2010 8:24 AM

@remarkable: countries have the right to turn you away at the border. Do you want to risk your business trip / vacatiom because you want to make a fuss with TSA / local country border guard? Sure, you would win the trial, but is it worth it?

jgreco March 12, 2010 8:29 AM

@remarkable at

Exactly, and even if you feel like cooperating (I don’t know why you would though) all you have to say is the truth: “I bought it off the internet because it is cool”. Really, it’s not the hollow coin you’ll have to explain. It’s whatever illegal material you placed inside of it.

Anyways, the article doesn’t really explain it that I see, but it does show some sort of keyring device. will these coins snap together by themself, or do they need to be held together?

jgreco March 12, 2010 8:34 AM


I’d hate to see how many pounds of hollow change you’d need to smuggle several pounds of C4. I think the wheel–barrels of change might tip some people off to funny-business 😉

Does anyone know the weight limit for carryon luggage? I bet you’d exceed it pretty quick. Change can be pretty heavy and it looks like there is still a significant mass of metal in these.

Tim March 12, 2010 9:11 AM

@ jgreco

🙂 Yeah, I lot of coins.

The TSA is scared of 4oz of water. images a few grams of anything that might really burn…. they will freak out.

paul March 12, 2010 9:11 AM

I see this as more of a problem for corporate security. Vending machines are now incredibly effective dead drops for essentially unlimited amounts of data.

ZR March 12, 2010 9:26 AM


These things have been out there for eons. Performers use them for close-up coin magic.

According to the U.S. Treasury F.A.Q., the answer is- No. It is only illegal to alter a US coin with the intention of spending it as if it were a coin of a different value.
From the website: “Section 331 of Title 18 of the United States code provides criminal penalties for anyone who ‘fraudulently alters, defaces, mutilates impairs, diminishes, falsifies, scales, or lightens any of the coins coined at the Mints of the United States.’ This statute means that you may be violating the law if you change the appearance of the coin and fraudulently represent it [in a monetary transaction in trade for goods or services] to be other than the altered coin that it is. As a matter of policy, the U.S. Mint does not promote coloring, plating or altering U.S. coinage: however, there are no sanctions against such activity absent fraudulent intent.”

Anthony March 12, 2010 9:32 AM

I’d quite like one of these and my 11 year old brother would love it, though it seems as though the site is being DDOS’d by Bruce’s readers at the moment.

Artle March 12, 2010 9:55 AM

This wouldn’t last a week. I’d put it in my pocket, forget about it, and spend it at a Starbucks. There goes the data card…;(

Marco Romeny March 12, 2010 10:01 AM

Hey, if you are in SoHo, New York, we have been selling the half-dollar for some time at KIOSK – the half-dollar is slightly suspect, we know, and it probably isn’t the cheapest place to get the coins (hey, we have rent to pay!) but it’s a fun place to check out!

In exchange for the higher price, you get a nice description and a pretty giftable packing… (yeah, like you need that…)

Anyway, here is my shameless plug:

A Secure Magician March 12, 2010 10:02 AM

I have several hollow coins. Normally the nickle ones do not lock together. The more expensive half dollar and silver dollor coins may or may not lock. Some of the locking ones can be opened with pressure in the proper area. Others use a special tool called a bang ring to unlock them.

All of the coins I own do not sound normal when dropped on a hard surface. Instead of a ringing sound, you hear a dull thump.

So no high tech device is needed to detect them. Just an ear.
Besides, you can hide a micro SD card anywhere – under a band-aid, in a pack of gum, etc. I’d carry it between my fingers, perhaps in a gum wrapper, and drop it if I need to ditch it. A gum wrapper is much less suspicious than a hollow coin.

HJohn March 12, 2010 10:04 AM

@Trichinosis USA: Change you can believe in! ;-7

Now that is the best analysis I’ve heard yet!

Happy Friday

BF Skinner March 12, 2010 10:41 AM

@jgreco @Tim

Actually you don’t need the nickles (which cost WAY more than a nickel) for this attack to work.
Any currency would do and as the amount of cocain on the American dollar show, bills are absorbant. but since
bills given to vendors end up in the bank…I’d try the ATMs. have something dab traces on to the money as
it comes out of the delivery shute.

@Artle “wouldn’t last a week”
My grandmother used to mark her lucky bingo counters (coins) with nail polish

David March 12, 2010 10:43 AM

@Anthony: This also appeared on Slashdot (they often pick up on articles in this blog). I’m not sure there’s enough readers here to Slashdot a site.

Sara March 12, 2010 11:13 AM

Magicians have been using similar gimmicks for generations, such as those made by Tango:

The coin photos of the Spy coins and lack of text, suggest they may be of poor quality…

Nick Lancaster March 12, 2010 11:14 AM


The gimmicked coins I am familiar with from magic tricks require a ‘bang ring’ (as Secure Magician mentioned) to separate the two parts.


I could see a ‘folding quarter’ being a real coin, but the usual magic trick half-dollar would require you to destroy a minimum of two coins to create. It would likely be easier to make a mold of an actual coin and then have your way with casts that aren’t and never will be legal tender.

Joseph March 12, 2010 11:52 AM

–How about this explanation: “please cite the statute that makes this your business.”

And their response: “We can hold you for several days without even bringing charges. You just bought yourself a weekend in a jail cell, smartass.”

Ungle Bulgaria March 12, 2010 1:04 PM


You might win, after spending months in jail. Good luck with that. Even if you’re not guilty of carrying a concealed secure electronic intellectual property transportation device, they will make your life hell. When you don’t show up for work, you’ll lose your job. Then, you’ll miss your rent/mortgage payments, lose your house. Your girlfriend/wife will leave you. Finally, your dog will die. After all this, they’ll search your abode while it’s on the street for eviction, and find enough violations to toss you in prison for a dozen other charges.

A Telco Security Dweeb March 12, 2010 1:55 PM

What if, before you go through security, you need a nickel to provide exact change to buy a package of chewing gum, while waiting for your flight, you reach into your pocket for some loose coins, and… hey, that’s great, I can pay the exact $1.35 that my “DoubleMint” gum costs!

“Thanks, gotta run now, they just announced boarding.”

As you head down the ramp to the airplane, you think, hey, wait a minute, wasn’t THAT nickel, THE nickel?

Oh sh**…


Clive Robinson March 12, 2010 5:21 PM

Perhaps a silly question for most of you,

Why use US currency?

There are plenty of other coins out there that are “trick”

There are rather nice Euro coins and UK 2pound coins made of two different metals as an innere disk and outer ring.

Get a smaler one and mount it on a ring or chain or whatever and call it your “lucky piece”

Put a phone card SIM in it if you must,

As for the SD card I said this the last time around wrap it in a bit of tin foil and put it in your wallet with all your CC’s and spare forign SIM’s for your Quad band phone.

If your wallet is anything like mine with a coin pouch etc you would be surprised what you can leave in there and get through airport screening.

The last time I went through airport screening I had a tin opener and a beer bottle opener in my wallet. Not deliberatly I’d just forgoton they where in there along with a small sewing kit, safety pins and one or two minor medical items.

I’ve yet to see a wallet being searched by any airport security staff.

I’m not saying they don’t but I don’t know anybody who has seen anybodies wallet get searched or even checked. And some of the people I know fly as many (if not more miles) than Bruce.

So if anybody has seen a wallet getting searched shout up and let me know where and when.

As for the chewing gum packet trick.

Remember take the sticks of gum out, drop the SD card in the bottom so it lies flat against the bottom then put all but a couple of the sticks back.

Then when you put your pocket stuff in the tray just make sure the bottom of the packet is resting up against your keys or other metal objects and a few lose coins on top or a metal clip bill fold etc.

The chances are if they do see something odd they will “hand search through and mis the SD card. If they do find it the fact that it’s in the packet but not otherwise hidden is a simple case of “Ah that’s where it got to”.

As for hiding SD cards under sticking plasters don’t most metal detector wands can pick them up.

You would do better to have jacket with a metal zip fastener and a small hole in your left side jacket pocket. Drop the SD card down into the lining and work it with your fingers across to the corner by the lump of zip fastener at the botom of the zip.

Get a thick leather belt with a solid buckle (similar to those used on leather tool belts) and slide the micro SD card down the fold in the leather where the buckle is fastend.

Or just get a divers style watch with an alarm, unscrew the back remove the piezo crystal transducer and you will have room for about four micro SD cards (remember to remove the little spring).

At a pinch you can just put the micro SD card under the watch body with a small piece of sticky tape. Provided you lay the watch flat face up in the tray the chances are no one will notice, afterall you do tend to find micro chips in watches…

Then if you know what you are doing why not hide the micro SD card in the case of either your USB flash drive or USB broadband modem, or lift the space bar on you laptop keyboard and tuck it under there with a bit of “sticky fluff” (made with pocket lint and a bit of boild sweet or choclate).

Belive me when I say you would not belive what gets under key caps on laptops, pins paper clips, bits of sweet wrapers, bits of blue tack, chads from 2/4 hole paper punches, even postage stamps, then there is food and dead flies and magots, and drinks resedue of all forms (coke is the worst that munches through any electrical contacts and tarnishes just about any metal you will find inside a laptop.

If you put your mind to it the list of hiding places is almost endless. The trouble is making them “plausable”.

For instance here’s one hiding place you have probably not thought of…

Your trouser fly… In the more expensive trousers the base of the zip is effectivly tucked away in what is a tiny pocket. Likewise if you look at your “blue jeans” with the copper rivet.

Providing you place the micro SD card carefully it is very unlikley to show up on any body scanners including those microwave back scatter systems and a pat down is not going to find it nor is a wave of a wand.

However no plausable explanation as to how it got there…

Matthew Carrick March 12, 2010 7:28 PM

The Canadian Twoonie has a diameter of 28mm and a Thickness of 1.8 mm so you have more (usable?) space to work with compared to a quarter.

aw March 13, 2010 4:36 AM

@Clive Robinson: ”However no plausable explanation as to how it got there…”

You are not hiding it from TSA – you are just afraid of loosing it if you were mugged by some hoodlum.

yt March 13, 2010 6:49 AM

@ Clive “As for hiding SD cards under sticking plasters don’t most metal detector wands can pick them up. You would do better to have jacket with a metal zip fastener and a small hole in your left side jacket pocket. Drop the SD card down into the lining and work it with your fingers across to the corner by the lump of zip fastener at the botom of the zip.”

Or if you happen to be female, hide it in your underwire bra. Some bras are even made with little pouches sewn into the cups so you can put in different-sized push-up inserts. That would place the SD card close enough to the metal underwires that they would be assumed to be what set off the metal detector. Even if they did a strip search, the chances of finding it would be pretty low unless they were specifically looking for an SD card, and practically took the bra apart.

Lucia March 13, 2010 10:36 AM

Why are you speaking of carrying a hollow coin with SD/MicroSD cards in them? Can’t you think of stupider things to do at the border?

Have you heard of rapidshare? It’s a cool new thing, you upload files to it, then you download them from some other place. Neat isn’t it. And, psst, you can even encrypt them before uploading, if you are a real spy, that is.

Tom Dickson-Hunt March 13, 2010 8:36 PM

Have you heard of rapidshare? It’s a cool new thing, you upload files to it, then you download them from some other place. Neat isn’t it. And, psst, you can even encrypt them before uploading, if you are a real spy, that is.

Yeah, but it’s not so easy to upload ~32g of data on short notice. A microSD is faster, in that instance.

But I really don’t get the point of hiding these things at all. Just put it in a digital camera, and if necessary duplicate the file system that the camera puts on. (This is fairly simple; just put a blank one in the camera, take a few pictures, and then put it in a computer-based SD reader to put your data on it. I’m not sure if the camera will interfere with your data if you take pictures with it, though.) Perfectly deniable and just about undetectable anyway.

Section9_Bateau March 14, 2010 3:37 PM

As someone who HAS been wanded at a checkpoint, while carrying a SD card (won’t say where), the wand did NOT detect the SD card, and I was wanded directly over where it was located (within 1-2″).

There was no other metal on my body (other then probably the zipper on my pants), the TSA just “likes” me. I did not set off the standing metal detector either.

Conundrum September 11, 2015 5:31 AM

200GB available, 500+GB if you really want to risk it getting damaged in the X-ray scanner.
For anyone wanting to doubt that they can indeed be damaged by X-rays, I nuked 3 32GBs on purpose to test this along with some 8GB and 16GB and a 2GB older card.
The 32’s all got affected with mere seconds of pulsed exposure from my test jig, but in common with biology X-rays under 10kev seem to do the most damage.
After wrapping another card in thin foil it did not get affected at all though at higher energies this foil may make things worse.

Bit of minor milling and these coins would reliably store a card with simple foil around it to absorb the shock of typical usage scenarios.
I came up with an undetectable RFID variant too which is immune to any conceivable EMP but still detectable with modified equipment, which is now patent pending.

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