Bitcoin Forum

I know that most laser printed stuff fades away quite fast. I assume Mike used an ink printer. But even then, it's not for an eternity.

Does anyone have anymore information on this one?

Regards

I've asked this before on the forum but never really got any answers.
I have done my own research however, and there are quite a few factors involved.

•Firstly, the rate of deterioration depends on the ink and paper used.
Using ink to print the keys would detiriorate faster than if the keys were printed using a laser printer. Lasers are fairly accurate and are less prone to smudging if they get wet. (The paper itself could break down if the water gets absorbed and would damage the keys even if they were printed user laser ink jets).
•Secondly, normal paper erodes faster than acid free paper. I can't remember the figures offhand but normal paper erodes quite slowly (20-30 years) whereas acid-free paper can last 100+. I can't remember the figures offhand and the sources I found but I'll look them up when I have time.
•Paper thickness - this is another factor to take into consideration. The kind of gsm paper used will affect the rate of deterioration.

There were quite a few more points that I'd researched but can't remember them for the time being. If I do I'll be sure to add them to the list.

I don't know, depends on the quality of the paper and ink and the enviroment the coin is in.

Best condition for a coin and the paper under hologram should be in vacuum I guess. For really long term holding/saving you best should vacuum seal the coin in a plastic bag.

I basically just want to know if I can store them until I can give them to my grandchildren, so 50-100 years.

@AT101ET & @wttbs maybe the hologram seal helps? I don't think any air can reach the paper.

I collected paper money for many years including Confederate notes. Confederate notes were made on very cheap thin paper and ink was of lesser quality than today. The notes are still around and legible after 150 years. Temperature ( extreme heat or direct sun light for weeks on end ) would cause some fading but most retain ink even under tough conditions. Ink on paper can and does last for hundreds of years.

Engraving directly onto metal seems to work pretty good under any condition.

IF you're looking them to store for so long, go with Keyois Capsules (https://bitcointalk.org/index.php?topic=1659001.0) or Hardware secure wallets. Doesn't matter how good paper is , it can always get wet or burn

Those look great, I might get a couple of them just for the art of it. I keep currencies/valuables in a fireproof safe plus have them insured so kind of takes the worries out of it. The only real worry I have is blockchain broken by hack 

Likewise.   I have Deutsche Marks from the very early 1900's that have not been protected in any way.  The paper is still in good shape and ink 100% legible. 

You just have to make sure that the engraved keys are not visible under X-Ray or some other technologie I didn't think of though.

I did not see anyone here mention receipt paper, because I have had several receipts' ink fade away to nothing in less than 2 years. I dunno what ink is used, but the paper is pretty thin.

usually only thermo print... that does not last long time.

There are much cheaper ways to compromise the key on a physical Bitcoin.  Tamper-evident holograms only keep honest people honest.

http://www.coindesk.com/defcon-hackers-crack-physical-bitcoin-casascius-coins/

That is the worst thing i have heard/read so far. So it should be like either buy from original maker or otherwise dont peel them , just keep'em circulating :-\

I have done a little research into what ways of printing tends to last the longest.  Laser printers are effective for longer term archival purposes because it is essentially baking a layer of plastic (toner) onto the paper, which is why the paper is warm when it comes out. As a result, laser ink would does not easily deteriorate or fade.  An inkjet printer, on the other hand, sprays tiny droplets of liquid ink onto paper. Inkjet ink would be less resistant to moisture because it could bleed or run if the ink doesn't stay dry.  However, higher quality ink and paper can help reduce that risk.

There are also thermal printers which uses heat-sensitive paper and selectively transfers an image to the sheet.  One example of a thermal printer used for bitcoin is the Piper wallet, which is essentially a Raspberry Pi hooked up to a thermal printer.  According to their FAQ, the image will last 20 years when stored in typical office filing conditions (In a cool, dry environment with no exposure to light).
http://cryptographi.com/pages/piper-faq
 (http://cryptographi.com/pages/piper-faq) . We probably have all observed receipts fading to the point of being nearly unreadable within a year or so.  Piper wallet uses a higher quality thermal paper so it's different than what you would get as a receipt from a store, but would still not be ideal for long term storage given the other options.

As with all things, whether you use Laser, Inkjet, or Thermal, the quality of the ink and paper matter greatly, as well as the conditions in which the paper is kept.  Given that a private key on a physical bitcoin is going to be printed on a laser or inkjet printer, sealed under a hologram, and the coin stored in a plastic airtite case, flip, or slab, it would be reasonable to expect that any coin that does not get exposed to high level of moisture or temperature extremes would, at a minimum, last 80-100 years.  If the maker uses high quality paper and ink/toner, then it should last much longer. 

Huh. Really makes you think, why would I want another possible way to get my bitcoins hacked? A physical hack would be a lot cheaper and could go undetected for a while. Let's say I bought a 25BTC coin, opened it up with their method and recirculated it by selling it. After a few years and a few different owners I could sweep the address and no one would know for sure who did it. That's just terrifying!!

Back on topic though, you'd have to find out exactly what make/model of printer he used to print the private keys. From their you could find out from the manufacturers website or google how long they would actually last.

That's why you should ways check the address on the coin via uberbills or the blockchain. Unless they replace the publickey with another existing 25btc key, which will get unnoticed until the original owner of the coin with that specific public key finds out.

If I were a smart enough criminal to used the solvent described in that article I'd have to assume that criminal would be smart enough not to take the money right away. That way everyone would know it was you rather than there being a 1/2 or 1/10 chance it was you. The only proof would be the only people who owned the coins in the past or future's (up until you steal them) word. This could happen with any physical bitcoin in a few years. Someone's going to be left holding the beg and the person to blame will be the coin maker.

I still have several mistake v1's and the paper disc is still readable.

Store it correctly and you shouldnt have a problem, good question though.

Good question, as others have said, store them well and I'm sure they'll last a long time.

Someone send me one of those 1000BTC coins and I'll watch until I can't read it anymore ;). Sound good? I guess I could try it with a 10BTC coin too... But that would be much less erm.. Scientific shall we say? I'm MUCH more curious about the 1000BTC coins :)

I have a couple of redeemed Casascius coins, complete with peeled holo + paper with private key.
I have inspected the private keys with a magnifier, no signs of deterioration or any other damage at this point.

Is there a consensus on which paper is the best to print a private key with?  

I noticed AT101ET mentioned "acid free paper" which may be better than the standard laser office paper.  I've made a couple DIY coins and wouldn't mind picking up some better paper for my laser printer for keys under holograms.

How many coins do you have with receipt paper that was used in them?

thanks!

Most retail receipt are printed on thermal paper, the printer is an array of small heat emitters which the paper pass through, when thermal paper is subjected to heat then will it turn black. It is a commonly known that the print will not last much more than a year. Perfect for retail as it is cheap and reliable, and any warranty proff would be more or less gone after a year. Totally nogo for private keys.

I would imagine that if left untouched and out of direct sunlight the private key on the back would be legible for decades, no?

I had the same impression but others on here may know more.

Has Mike himself made a statement on the subject? So far all that's been discussed on the topic has been hearsay, correct?

Its an almost unanswerable question. We wont know how long they will last until they are no longer lasting ...

Need to understand paper and ink used by Mike, then draw parallels from the nearest equivalents

Interesting to know if the holos provide an air tight enclosure (and even if they block light)

Clearly having in an airtite or ANACS slab would assist, and keeping them in a slab case that blocks the light

I agree decades should be achievable, if not longer, given some old notes / maps ages

Not a direct answer to your question but I made a list of problems I had with other often-used cold storage methods: https://bitcointalk.org/index.php?topic=1634293.0


I would assume it will break down over time but keeping it sealed and out of light and heat should make it last a lot longer.