Is it possible to read a private key under a hologram using an X-ray?

[BTCOVERFIATS]

Hey fam,

Been wondering this for awhile and finally had to ask. Lets say you went to pick up a Casascius coin in person and you had to fly back with it in your carry-on luggage.

Is it possible that when the Casascius coin went through the airport x-ray machine they would be able to see the private key underneath the hologram?

Maybe it isn't possible with the x-ray technology at the airport, but how about just any x-ray in general? Has this every been tested?

Best,
BTCOVERFIATS

[1714234930]

1714234930

[1714234930]

1714234930

[1714234930]

1714234930

[1714234930]

1714234930

[1714234930]

1714234930

[Bullion-n-BTC]

Negative. Well it’s not if you use any kind of paper media to print the private keys on… be it stone paper, card stock, etc etc it doesn’t work. Maybe if for some reason you punched the private key into a metal square or something before applying the holo you MAY be able to but not paper. I’ve tried that among many other things doing some testing a while back. X-Rays were a no go

[OgNasty]

This was something I took into account when engraving private keys into metal under a hologram. In order to combat against this, early coins I made using this technique were covered by an insulating piece to keep from metals reacting over time, then a thin piece of metal to make it so X-rays wouldn’t be able to determine the hidden private key. Eventually I phased this addition out because of time and additional cost, but the ultimate deciding factor was that it isn’t very difficult to remove and reattach holograms without damaging them as has been demonstrated repeatedly over time, so it’s good to remember that holograms are like door locks. They keep honest people honest.

[stackinsats777]

This was something I took into account when engraving private keys into metal under a hologram. In order to combat against this, early coins I made using this technique were covered by an insulating piece to keep from metals reacting over time, then a thin piece of metal to make it so X-rays wouldn’t be able to determine the hidden private key. Eventually I phased this addition out because of time and additional cost, but the ultimate deciding factor was that it isn’t very difficult to remove and reattach holograms without damaging them as has been demonstrated repeatedly over time, so it’s good to remember that holograms are like door locks. They keep honest people honest.

Any threads about removing holograms being not so difficult? Every peeled coin I’ve seen has been blatantly obvious. And any discussions I’ve seen have said they’re quite secure. Would love to read up on it if you have any info! Always good to know how to detect fakes

[FatFork]

I think it depends on the specific type of printing involved. For example, good X-ray scanners used in airports can identify money within bags by detecting even minuscule traces of metal present in the ink used on banknotes. Metal has a higher density than paper.

However, most commercial x-ray devices (even medical ones) have very poor resolution. And since Casascius coins are already made of metal anyway, all the detector will detect are the coins themselves, not the information printed on them. I suppose it is theoretically possible with some sophisticated high-tech laboratory equipment. But for that to happen, someone would need prolonged physical access to your coins. In that case, there are simpler methods of physical tampering, such as using solvents to remove the holographic sticker without leaving any visible damage.

Any threads about removing holograms being not so difficult? Every peeled coin I’ve seen has been blatantly obvious. And any discussions I’ve seen have said they’re quite secure. Would love to read up on it if you have any info! Always good to know how to detect fakes

Defcon hackers crack physical bitcoin Casascius coins

[rsincognito]

Yes I always wondered that if you could travel through TSA Xray with a backup seed phrase on a metal plate and risk exposer of your private key, glad im not the only one thinking these thoughts lol

[minerjones]

This was something I took into account when engraving private keys into metal under a hologram. In order to combat against this, early coins I made using this technique were covered by an insulating piece to keep from metals reacting over time, then a thin piece of metal to make it so X-rays wouldn’t be able to determine the hidden private key. Eventually I phased this addition out because of time and additional cost, but the ultimate deciding factor was that it isn’t very difficult to remove and reattach holograms without damaging them as has been demonstrated repeatedly over time, so it’s good to remember that holograms are like door locks. They keep honest people honest.

Any threads about removing holograms being not so difficult? Every peeled coin I’ve seen has been blatantly obvious. And any discussions I’ve seen have said they’re quite secure. Would love to read up on it if you have any info! Always good to know how to detect fakes

How about this coin from 2015?
I redeemed it this morning... hologram came off clean, zero residue or marks

And the mirror finish reacted with the ink/paper (plastic) that the QR private key was printed on.
Left a semi-readable part.... 

It all comes down to how you store your coins and the quality of holograms the maker used.
Seemingly they last a lot longer on coins not polished like Cas brass.

[krogothmanhattan]

This was something I took into account when engraving private keys into metal under a hologram. In order to combat against this, early coins I made using this technique were covered by an insulating piece to keep from metals reacting over time, then a thin piece of metal to make it so X-rays wouldn’t be able to determine the hidden private key. Eventually I phased this addition out because of time and additional cost, but the ultimate deciding factor was that it isn’t very difficult to remove and reattach holograms without damaging them as has been demonstrated repeatedly over time, so it’s good to remember that holograms are like door locks. They keep honest people honest.

Any threads about removing holograms being not so difficult? Every peeled coin I’ve seen has been blatantly obvious. And any discussions I’ve seen have said they’re quite secure. Would love to read up on it if you have any info! Always good to know how to detect fakes

How about this coin from 2015?
I redeemed it this morning... hologram came off clean, zero residue or marks

And the mirror finish reacted with the ink/paper (plastic) that the QR private key was printed on.
Left a semi-readable part.... 

It all comes down to how you store your coins and the quality of holograms the maker used.
Seemingly they last a lot longer on coins not polished like Cas brass.

   Interesting indeed....I hope the waterproof paper I have been using will last a long time and I am sure it will in the long run.

   I also printed the private key in QR and alphanumeric format so in case any issues with the qr code happen, it will still be able to be swept using the other and vice versa.

[BTCOVERFIATS]

Thanks for all of your responses so far guys. I really appreciate it!

If anyone has any other input I would love to hear it!

The more the merrier!

I love this forum!

Cheers,
BTCOVERFIATS

[polymerbit]

Our tests have also shown that no, X-rays will not be able to help with the deciphering of a private key under a hologram or scratch off.

Metal will reflect xrays. It shows up as a black square or circle.

[polymerbit]

I think it depends on the specific type of printing involved. For example, good X-ray scanners used in airports can identify money within bags by detecting even minuscule traces of metal present in the ink used on banknotes. Metal has a higher density than paper.

This is correct, furthermore.... each security thread has a specific signature.

If you ever wondered how a cop knows which cars to pull over for civil asset forfeiture... well there you go.

Almost all banknotes contain both metal fibres within the substrate, and metallic pigments within the intaglio ink (the part of the design that feels raised to the touch).

This is rather similar to MICR toner found on cheques.

These include but are not limited to: Magnetic ink (containing ferromagnetic components), IR-metameric Inks (can be seen under certain IR light).

[DaveF]

Just a small just a small point; on metal it would be just about impossible to detect and read what has been printed through an X-ray.

And in general when printing on paper and then securing under hologram it is just about impossible.

However and this is a big important however there have been some cheap ass cut rate refilled toner cartridges out there that have a lot and I need a lot of metal in the toner.

There were discussions about this on tech support forums 20+ ago since these toners utterly destroy parts of the printer as the toner dust goes everywhere.

To the extent that in the early 2000s, might have even have been earlier, one of the laser printer manufacturers did a demo where they actually could read what was printed on a piece of paper with an X-Ray using the cheap aftermarket toner even when it was covered with a piece of cardboard.

I don't know if any of these toners still exist, and they weren't even doing it to discuss the security implications, but more to prove the point of do you want a whole bunch of conductive metal dust blowing around the inside of your laser printer? And if you do then kiss your warranty goodby.

I thought it was just marketing crap, but I saw myself the damage one of these cartridges did on a LaserJet 4 and those printers were just about indestructible.

So is it possible, yes in theory, but not reality.

Someone would need to have access to your non metallic collectable, that had a hologram that had almost no metallic content covering the private key, and the person who printed the private key would have had to use the cheapest aftermarket toner they could find. And then they would need to take said collectable and put it on a flat surface and hit it straight on with an x-ray. So....not worth even thinking about.

If they had that kind of access, they might as well just peel it and take your BTC

-Dave

[krogothmanhattan]

Just a small just a small point; on metal it would be just about impossible to detect and read what has been printed through an X-ray.

And in general when printing on paper and then securing under hologram it is just about impossible.

However and this is a big important however there have been some cheap ass cut rate refilled toner cartridges out there that have a lot and I need a lot of metal in the toner.

There were discussions about this on tech support forums 20+ ago since these toners utterly destroy parts of the printer as the toner dust goes everywhere.

To the extent that in the early 2000s, might have even have been earlier, one of the laser printer manufacturers did a demo where they actually could read what was printed on a piece of paper with an X-Ray using the cheap aftermarket toner even when it was covered with a piece of cardboard.

I don't know if any of these toners still exist, and they weren't even doing it to discuss the security implications, but more to prove the point of do you want a whole bunch of conductive metal dust blowing around the inside of your laser printer? And if you do then kiss your warranty goodby.

I thought it was just marketing crap, but I saw myself the damage one of these cartridges did on a LaserJet 4 and those printers were just about indestructible.

So is it possible, yes in theory, but not reality.

Someone would need to have access to your non metallic collectable, that had a hologram that had almost no metallic content covering the private key, and the person who printed the private key would have had to use the cheapest aftermarket toner they could find. And then they would need to take said collectable and put it on a flat surface and hit it straight on with an x-ray. So....not worth even thinking about.

If they had that kind of access, they might as well just peel it and take your BTC

-Dave

    Great points all around. Any Cipher Bond or Cypher Bills that I made I placed two thin pieces of aluminum foil on each side of the private keys.

    Also since I printed two private key formats, it would also obfuscate the qr code in a way as well.

     Another way is to print out the same qr code and place over each other in the opposite direction so if the can be read they would be unsweepable.

[polymerbit]

However and this is a big important however there have been some cheap ass cut rate refilled toner cartridges out there that have a lot and I need a lot of metal in the toner.

There were discussions about this on tech support forums 20+ ago since these toners utterly destroy parts of the printer as the toner dust goes everywhere.

So is it possible, yes in theory, but not reality.

Someone would need to have access to your non metallic collectable, that had a hologram that had almost no metallic content covering the private key, and the person who printed the private key would have had to use the cheapest aftermarket toner they could find. And then they would need to take said collectable and put it on a flat surface and hit it straight on with an x-ray. So....not worth even thinking about.

-Dave

Fortunately most modern aftermarket toners sold today do not have this issue.

There are companies that can test the toner to find the particle size, chemical makeup, and foreign particulate (such as metal).

It's possible to buy security toners that would emit such signatures, such as MICR toner.

But no would make that mistake, since those toners cost about 5x a normal aftermarket cartridge.

[Kryptowerk]

[...]

Defcon hackers crack physical bitcoin Casascius coins

Scary. I think if you put enough (criminal) energy in cracking most of these physical security features, you can possibly find ways.

Regarding the X-ray question: I remember discussing this a while ago with some folks that are quite tech savy and their estimate was with a modern and rightly callibrated x-ray-machine you would probably be able to read an engraved private key.
Haven't heard of anyone putting this to the test so far, though.

Also I am certain there is current technology (if not just an x-ray machine) that would be able to do this. Most of this tech is probably still extremely expensive and only in the hands of a few researchers and scientists in fields that don't really care about stealing a few BTC from crypto collectibles.