Coming Very Soon, a real Bitcoin you can hold! (and is worth 1 BTC)

[casascius]

Because Bitcoin is projected to deflate in the future, I don't know how well any of these "tangible" Bitcoin projects will do. What happens when Bitcoins are worth "thousands", how are you going to get change back for that coin? A deflationary system would only have a chance to work in the digital world, since a deflationary system will always require you to break off from what you already have.

Easy, just make new denominations when the time comes.  Although each coin costs the same to make, at the same time Bitcoin value rises, I am sure that eventually someone will be able to do it on a massive scale for cheaper.

For the visible public key, you should just use the address' firstbits.

I am showing the first 8 characters, this way it's highly improbable that someone else will generate and use an address with the same firstbits before I issue the coin.  I had to generate all the addresses in advance in order to get unique holograms with pre-printed addresses.  And having 8 characters also makes it far less likely that I will accidentally deposit the 1 BTC to somebody else's address.

Personally, I would have marked the private key as a QR code instead of or in addition to an alphanumeric form. In any case, I am interested in seeing how this new coin turns out.

You'll probably find that the effort of tearing into the coin will probably be much more than typing 22 characters on a keyboard, there is a hard protective layer on top of the hologram.  That said, I am still at the point where I could put them in as QR codes, since I have yet to put them in the coins (a process I am doing solely by myself).

...I suspect casascius might know the best ways, as he has had the paper wallets for a long time now.

I just simply use a copy of bitcoind with the import/export patch applied.  To use it, I generally just delete wallet.dat (yes), then start it up with an empty wallet and let the block chain catch up, then import keys, then spend the entire balance to some more permanent address so the wallet.dat is worth 0 again, and then shut down.  It's convenient - I never have to worry about the wallet going out of sync with the block chain, because I'm literally deleting the wallet every time I use it.

[1715329953]

1715329953

[Blackout]

Is pywallet windows 7 friendly or is this a linux thing?

I am fairly a geek and I still find bitcoin difficult sometimes... I can only imagine the ordinary person.  This is why bitcoins are going for $25 on ebay.  No one wants to sign up with weird exchanges and transfer money to 3rd world countries through middle men and install a thing that they don't understand that is not safe or encrypted and have to transfer between so many places.
This is what holds bitcoins back.  It needs to be easy to the common person.

[jackjack]

Is pywallet windows 7 friendly or is this a linux thing?

I am fairly a geek and I still find bitcoin difficult sometimes... I can only imagine the ordinary person.  This is why bitcoins are going for $25 on ebay.  No one wants to sign up with weird exchanges and transfer money to 3rd world countries through middle men and install a thing that they don't understand that is not safe or encrypted and have to transfer between so many places.
This is what holds bitcoins back.  It needs to be easy to the common person.

W7 friendly
Two ways to use it:
 If you aren't afraid by the CLI you only need to install python 2.7
 Otherwise you will need to install two more packages (twisted and zope.interface, just read the readme)

[joulesbeef]

jackajck, a user called sukrim packaged our hopper into a nice *.exe for people that werent that technical. we use the same dependencies and it seemed to work very well for the windows noobs masses... not that it is all that complex.. You'd be surprised the many ways someone can screw it up. Might want to think about releasing something like that.

your app and his paper wallets and things go hand in hand(yeah i see tearing into the coins might be a problem).. it would help if it was a tiny bit grandma friendly.

[FlipPro]

Because Bitcoin is projected to deflate in the future, I don't know how well any of these "tangible" Bitcoin projects will do. What happens when Bitcoins are worth "thousands", how are you going to get change back for that coin? A deflationary system would only have a chance to work in the digital world, since a deflationary system will always require you to break off from what you already have.

Easy, just make new denominations when the time comes.  Although each coin costs the same to make, at the same time Bitcoin value rises, I am sure that eventually someone will be able to do it on a massive scale for cheaper.

Makes sense. So a good business plan for a private company to do would be to get into the Bitcoin minting sector, and introduce this "tangible currency" to troubled third world nations who want to get rid of their dictators and want a free source of money. That would be one of the biggest goals people should be working on right now, is getting underdeveloped nations to accept this. It would be so easy to sell, but would obviously require money!

[joeyjoe]

can you make pound coins with this?

[Stephen Gornick]

They would have to destructively tear off the hologram to read the key.

Would there be any relatively common scanning technologies (such as those used at a forensic lab or for medical purposes?) that could read this code without tampering with the sticker?

[casascius]

They would have to destructively tear off the hologram to read the key.

Would there be any relatively common scanning technologies (such as those used at a forensic lab or for medical purposes?) that could read this code without tampering with the sticker?

I did think of it... which is why I went with regular inkjet on paper for the printing.  And the printing is relatively light, and combined with other printed marks I have made on the private key sheets that help me ensure they have been placed with the right pre-printed hologram sticker.

During the decision making process, I asked myself this same question.  I felt that if I used laser printing, that the fused toner could be detectable through ultrasound or that it might reflect some sort of radiation or have magnetic properties that could be detected.  So I completely steered clear.  And if I had done anything engraved, it almost certainly would be detectable in reflections of radiation.

So... I suppose I would be interested if someone finds a way.  I suspect these coins are going to be collected more than circulated, and a major objective I had in producing the coins is simply to seed the concept that Bitcoins can be tangible and can be a backing and they don't have to exist purely in cyberspace.

If someone finds a way to compromise my coins, their utility will be reduced somewhat - people just won't be able to circulate them amongst strangers.  I take comfort in suspecting that's not happening a whole lot, as compared to people giving away the coins as gifts or to people who they know.  (Example: I gave a family member bitcoins for babysitting...they would have done it for free but the circumstances dictated that paying them something was appropriate...and that something was bitcoins.)

[Troll Toll]

I like how casascius completely ignored the entire "wrong translation" situation...

[bg002h]

I like how casascius completely ignored the entire "wrong translation" situation...

...honestly, who cares?  Simple crap can be fixed simply...putting together a production process is step 1 to making a streamlined, cheap way to produce long term physical representations of BTC...the last thing we want are central bit coin banks to issue their own coins with no private key (only the promise to redeem them for one on demand)...the start of fractional reserve bit coin banking I think could end up being a very bad thing...

[casascius]

You will like this even worse: I am in the process of making even more elaborate coins with the same wrong translation in all its glory.

I just don't care.

Worrying about the translation is inconsistent with my goals in producing the coin.

[nmat]

You will like this even worse: I am in the process of making even more elaborate coins with the same wrong translation in all its glory.

I just don't care.

Worrying about the translation is inconsistent with my goals in producing the coin.

So what are your goals? I also support correct Latin translations

[casascius]

The problem is everybody seems to have a different idea of what the correct translation should be.

Vires in numeris is the only one where once upon a time there was consensus, even if it was incorrect or ill-founded.

And I believe Bitcoin has a long future ahead of it.  Me doing physical bitcoins is just to say "hey world, guess what, tangible bitcoins are possible, they're not just imaginary".  I will have simply pioneered the physical bitcoin (with all due respect to BitBills).  Someone else will do a leaner, meaner, badder, cheaper, more secure physical bitcoin...and they'll get the Latin right as well.

[newguy05]

The whole point of this exercise is to have physical bitcoin similar to gold coins that can be easily traded in person.  Each physical bitcoin should worth exactly 1 BTC and can be given/received just like a gold coin or any real currency.

To enforce this system, the construction of the coin have to be in such a way that if opened to obtain the private key of the 1BTC then the coin itself would be completely destroyed or at least easily identified as "used up".  I think the OP is using some sort of seal to ensure this.

Either way the whole system depends on not able to easily "fake", duplicate, or temper with the physical bitcoin construction. If people can duplicate the coin, or easily extract the private key of the BTC within the physical coin while leaving the structure interact, then this whole system collapses, as noone knows if the coin is 1) fake or 2)already used up.   

This is not an easy problem to solve.  OP is on the right track, but it takes a whole army of people to create regular coins...and what we are talking about here is far more complex than your regular pennies and quarters construction.  Nonetheless, thumbs up for thinking ahead of the herd.

[BkkCoins]

@Casascius

I just saw these hollow coins for storing microSD cards inside.
I don't know if you could make these with a Bitcoin  design but that would be pretty cool and probably sell too.

http://www.ebay.com/itm/NEW-Hollow-Spy-Coin-Micro-SD-Card-Covert-US-Half-Dollar-/230435475593?pt=LH_DefaultDomain_0&hash=item35a7065089

[BurtW]

For anyone interested it is possible to crack open one of these beauties and imported the Bitcoin into your wallet.dat.  It was not easy but it is possible.  Hopefully there will be a more user friendly way to do this soon.  Personally I think the best idea would be a web site which downloads a Javascript with two input windows:  1) A place to enter the mini private key from inside the coin and 2) a place to enter your destination public Bitcoin address.  The script would transfer the Bitcoin off the (now destroyed) physical Bitcoin and send it to the desired destination address.  Not having that, this is how I did it.  Ugly I admit:

• Bought a physical coins from https://www.casascius.com/
• Found the full Bitcoin address by entering the address on the outside of the coin (12ho33tJ) here:  http://firstbits.com/
• Verified it contained one Bitcoin in value at: http://blockexplorer.com/address/12ho33tJq5o4uQUnyEemErAgeTfS7YoXDc
• Installed pywallet from: https://github.com/downloads/jackjack-jj/pywallet/PWI_0.0.3.exe
• Before trying to decode my mini private key I used the private key published at https://en.bitcoin.it/wiki/Mini_private_key_format in order to test the decode process.  The mini private key I used was: S4b3N3oGqDqR5jNuxEvDwf
• I then made a file named “short” containing exactly these 22 characters.  This is not as easy as it sounds because most editors add CR/LF and EOF characters to a file.  I used hexedit to make a file of exactly these characters.
• Then I used openssl like so:   bash-4.1# openssl dgst -sha256 < short
• I got the following result and verified it with the result on the wiki page: 0c28fca386c7a227600b2fe50b7cae11ec86d3bf1fbe471be89827e19d72aa1d
• Then I killed my precious unicorn (peeled off the sticker) and read the private key from the sticker.
• I then made a file named “mine” containing exactly these 22 characters.
• Then I used openssl like so:   bash-4.1# openssl dgst -sha256 < mine
• Turned off my Windows Bitcoin client so I could run the pywallet browser
• I used pywallet to import the key in to my wallet.dat.  When it imported the private key into my wallet.dat file the Bitcoin address matched the address on the coin (12ho33tJq5o4uQUnyEemErAgeTfS7YoXDc) so I knew I had the correct private key.
• Finally, I fired up the Windows Bitcoin client with a –rescan and I got 1 more Bitcoin in my wallet!

I really like my coins and do not plan on destroying any more of them any time soon.  They are beautiful and collectable and I just ordered another batch.

[casascius]

• I then made a file named “short” containing exactly these 22 characters.  This is not as easy as it sounds because most editors add CR/LF and EOF characters to a file.  I used hexedit to make a file of exactly these characters.
• Then I used openssl like so:   bash-4.1# openssl dgst -sha256 < short
• I got the following result and verified it with the result on the wiki page: 0c28fca386c7a227600b2fe50b7cae11ec86d3bf1fbe471be89827e19d72aa1d

Glad to see you got it working!

In Linux the three steps above can be replaced by the following single command:

 echo -n CodeGoesHere | sha256sum

[BurtW]

I am using Cygwin.  I can try that and see if it works on Cygwin.

Thanks, that does save a step (I only know enough Cygwin/Linux to be slightly dangerous - and learn something new every day).  Either of these will also work and will save the step of creating the file:

bash-4.1# echo -n S4b3N3oGqDqR5jNuxEvDwf | openssl dgst -sha256
0c28fca386c7a227600b2fe50b7cae11ec86d3bf1fbe471be89827e19d72aa1d

bash-4.1# echo -n S4b3N3oGqDqR5jNuxEvDwf | sha256sum
0c28fca386c7a227600b2fe50b7cae11ec86d3bf1fbe471be89827e19d72aa1d

[GlenBot]

Received my coins yesterday.  VERY IMPRESSIVE.  Very cool.  Great job, casascius!  Thanks!

 

[zhoutong]

A good idea, but there's one vulnerability of any physical Bitcoin that exists today - possibility of duplication. The public keys displayed can ensure that the money itself is backed by some Bitcoins, but before redemption, no one really knows whether there are the second piece of money that has the same public key.

Although holograms are hard to make, but it's not entirely impossible to duplicate. For fiat money, government controls most of the technologies to manufacture paper money, and to some extent, this control is quite effective.

One thing about crypto currency is that it can be easily duplicated and spent twice, and Bitcoin solved the problem perfectly, through P2P networks.

I wonder if there's any potential for a physical form of Bitcoin that can utilize the P2P network effectively by itself? Or other ways that can effectively reduce or eliminate the problem of double spending attacks on physical Bitcoins?