How would you like to design a bitcoin banknote?

[Rudd-O]

How do the Load and Verify QR codes work?  What prevents someone from just filching value from the bill?

[odolvlobo]

How do the Load and Verify QR codes work?  What prevents someone from just filching value from the bill?

"Load and Verify" shows the address that holds the BTC. You use it to verify that the address actually has the expected amount of BTC.

The private key is displayed on the note, so nothing except careful handling prevents someone from stealing the coins from the note. It is designed for one-time use, and is not suitable to be used as currency.

[ercolinux]

A minor update to my generator:

https://github.com/salfter/btcnotes/

The back pattern has been rotated 90 degrees so the URLs show up better on the finished notes.  Next update will more than likely add more denominations (at least BTC0.1 and BTC0.2, and maybe some bigger notes) in more colors.

Here's an example of the output of this version:

https://dl.dropbox.com/u/57535575/job3860.pdf

Nice job. If you reduce a little the images you can print 6 on a page, that's even better

[salfter]

How do the Load and Verify QR codes work?  What prevents someone from just filching value from the bill?

The intent is that before they enter circulation, you would apply some sort of tamper-evident seal over the private key.  This seal would only be removed if you intended to take the note out of circulation.  

The public key is left uncovered so you can verify that the note contains the indicated value.

[salfter]

https://dl.dropbox.com/u/57535575/job3860.pdf

Nice job. If you reduce a little the images you can print 6 on a page, that's even better

Hmm...I hadn't considered that. About the only size consideration I made was to make them about the same height as a dollar bill so they'd fit in most wallets.

[ercolinux]

https://dl.dropbox.com/u/57535575/job3860.pdf

Nice job. If you reduce a little the images you can print 6 on a page, that's even better

Hmm...I hadn't considered that. About the only size consideration I made was to make them about the same height as a dollar bill so they'd fit in most wallets.

Actually in Europe € bills are of different size for every value and in most case smaller: €10 are 12.7x6.7cm, €5 are 12x6cm, €20 are 13.2x7.1cm
If you take the €10 size they're small enough to fit almost all wallets size, plus you can put a grid of 3x2bills on both A4 (21x29.7cm) with enough space for the small stamps, and letter (21.6x27.9) with still a small margin. Even better if you print in the €5 size.

[salfter]

https://dl.dropbox.com/u/57535575/job3860.pdf

Nice job. If you reduce a little the images you can print 6 on a page, that's even better

Hmm...I hadn't considered that. About the only size consideration I made was to make them about the same height as a dollar bill so they'd fit in most wallets.

Actually in Europe € bills are of different size for every value and in most case smaller: €10 are 12.7x6.7cm, €5 are 12x6cm, €20 are 13.2x7.1cm
If you take the €10 size they're small enough to fit almost all wallets size, plus you can put a grid of 3x2bills on both A4 (21x29.7cm) with enough space for the small stamps, and letter (21.6x27.9) with still a small margin. Even better if you print in the €5 size.

Sounds like usage of different sizes would be a major annoyance both to produce (if you're allowing for a mixed batch, as my script does) and to use.

That said, having just compared a dollar bill, one of my notes, and some boxes I printed in the dimensions you gave, it looks like I missed the mark a bit and made my bills a bit taller than intended.  The €10 bill looks to be just a smidge taller (maybe 1/16") than a dollar bill, while my notes look to be about 3/16" taller.

I was just about to post a new version, too...it's already up on GitHub, but I think I might hold off announcing it until I get the 3x2 layout sorted.  Getting 50% more notes out of a box of paper would be nice, especially given what 100% cotton paper costs.

[Richy_T]

Sounds like usage of different sizes would be a major annoyance [...] to use.

Not for the blind. But there's no significant issue in usage for the sighted and the different colors are helpful too. The dollar really is a horrendously designed banknote.

[pc]

Is there a mac version of the note-printer utility? thanks!

There's a web version available at bitaddress.org.

My understanding is it can be compiled for Mono (probably only if you're into compiling stuff yourself, this won't be point-and-click).  And it certainly runs under Windows using Parallels, Bootcamp, or any solution allowing Windows itself to run on a Mac.

Actually, you can download the .exe and just run Mono on it. (Download Mono, unzip the files, go to a terminal and run "mono BtcAddress.exe".)

I tried printing a note, and the QR codes showed up on the paper, but the background didn't. I haven't tried figuring out what's gone wrong with it yet, though.

[casascius]

Actually, you can download the .exe and just run Mono on it. (Download Mono, unzip the files, go to a terminal and run "mono BtcAddress.exe".)

I tried printing a note, and the QR codes showed up on the paper, but the background didn't. I haven't tried figuring out what's gone wrong with it yet, though.

I bet I know what's wrong, the case sensitivity in the filename is breaking it.  Try renaming the png's to consider, for example, that the string below will probably result in "note-Yellow.png" instead of how it is capitalized now.

                        printer.ImageFilename = "note-" + cboArtworkStyle.SelectedItem.ToString() + ".png";

[salfter]

...and now v0.4 is up:

https://github.com/salfter/btcnotes

The unannounced v0.3 added BTC0.1, BTC0.2, BTC20, BTC50, and BTC100 denominations.  v0.4 shrinks the notes a little bit so six of them will print on a page.  Given the roughly order-of-magnitude difference in value between the dollar and the bitcoin right now, that's like having $1 to $1000 denominations available.  The BTC0.1 note is mostly gray with some spot color, to make it a little more economical to print.  QR codes are printed in the same size as before; a 1-1/8" tamper-evident sticker (such as these, from the same supplier PrintCoins uses) is still needed to cover the private key.

Examples:

https://dl.dropbox.com/u/57535575/0.1-0.2-0.5-1-2-5.pdf
https://dl.dropbox.com/u/57535575/2-5-10-20-50-100.pdf

[K1773R]

I was toying with the idea of using fractal backgrounds, for their scalability and as an allusion to Bitcoin's mathematical nature.



The design isn't finished, but if you like it I can work on it some more and produce a few templates of different sizes. Resolution isn't a problem but I'm wondering what else I can put on it and whether to add some fine print.

And here's a variation with a prominent mathematician:



Although it would be pretty hard to relate Khayyam to Bitcoin, I like how this illustration worked with the rest of the design. If there is interest, we might even commission an artist to draw us a Gavin that watches over the QR-code.

awesome, i definately want one of these

[gsan]

awesome, i definately want one of these

Yeah, I know I promised to generate vectorized versions of those, I really didn't have time to get back to it yet. In fact I had reduced the fully vector SVG sizes to less than 1M at the time, maybe I can deliver them in a compatible format. I'll have a look at the new program when I have time.

[ercolinux]

...and now v0.4 is up:

https://github.com/salfter/btcnotes

The unannounced v0.3 added BTC0.1, BTC0.2, BTC20, BTC50, and BTC100 denominations.  v0.4 shrinks the notes a little bit so six of them will print on a page.  Given the roughly order-of-magnitude difference in value between the dollar and the bitcoin right now, that's like having $1 to $1000 denominations available.  The BTC0.1 note is mostly gray with some spot color, to make it a little more economical to print.  QR codes are printed in the same size as before; a 1-1/8" tamper-evident sticker (such as these, from the same supplier PrintCoins uses) is still needed to cover the private key.

Examples:

https://dl.dropbox.com/u/57535575/0.1-0.2-0.5-1-2-5.pdf
https://dl.dropbox.com/u/57535575/2-5-10-20-50-100.pdf

Really nice! Well done

[casascius]

awesome, i definately want one of these

Yeah, I know I promised to generate vectorized versions of those, I really didn't have time to get back to it yet. In fact I had reduced the fully vector SVG sizes to less than 1M at the time, maybe I can deliver them in a compatible format. I'll have a look at the new program when I have time.

A high resolution non-vector image of the blue and grey fractal banknote will look just as good. No need to worry about the vector requirement of my original contest - that original need has been met.

[salfter]

...and now v0.4 is up:

https://github.com/salfter/btcnotes

Make that v0.4.1 now, which uses shred instead of rm to get rid of temporary files more securely.

[Michael_S]

Hi all,

What an awesome thread this is. I have done something related to this thread:

I have tried to combine something of the best that I found in various respects:

* The designs of casascius (who built upon those of PSY and others as I understand) and salfter (10 nice colours, high resolution...)
* The idea of printcoin.com (but requires setting up webserver for secure offline operations)
* The method of salfter (which I think is the most advanced now in terms of design and realization)
* The idea and code base and approach of bitaddress.org (one single html file of ca. 400 kB does it all, works offline=secure, fully HTML and javascript based...)

So I incorporated the great designs of casascius and salfter into the html code of bitaddress.org, and I came up with a solution how everybody can easily generate HiRes bitcoin notes with great design and w/o IT expert knowledge. The only thing that is (probably) required is a Firefox browser.

The result is announced here: "https://bitcointalk.org/index.php?topic=43496.msg1383041#msg1383041" - just look at the screenshot alone and you'll have a first idea already.

[franky1]

not sure if this has already been posted but......

http://donttreadonmeme.com/what-is-a-bitcoin-bank-note/

websites already starting to sell them.. i guess this idea is catching on

[salfter]

The seals arrived in the mail today, so I've now finished my first batch of BTC1 notes:




I printed them on 100% cotton paper, so they should be nice and durable.  Time to try putting some of them into circulation...

[casascius]

Many of you have seen me around the forums canvassing for the acceptance of BIP 38, my password protected / two factor private keys proposal.  Many of these note designs I see are beautiful!  One of the motivators for BIP 38 is it would enable secure third-party printing of these notes.  As pretty as the notes are, their potential buyers have every reason to be concerned that someone else has their private key, and won't want to use them for more than pocket change.

My note generator implements my BIP 38, which allows a buyer to pick a passphrase, and a seller to print a whole heap of notes that require that passphrase in order to be redeemed, without ever knowing what the passphrase was.  The only flip side is, at least so far, my utility is the only thing that can decrypt them back into an unencrypted private key.

I would really like it if when someone went to MtGox or BlockChain.info and entered one of these encrypted private keys, the website would detect the encryption, say "enter passphrase" and offer to decrypt it on the spot.  Then, giving out beautiful password-protected notes would be a no-brainer: just buy a batch of notes from the person who produces them, and then upon receipt, simply write or overprint the password onto the note.  Redeeming them would be exactly the same as redeeming the current unprotected ones, with nothing more than an extra step of entering a password.

Those of you who have implemented your own note generators or redeemers, if you would like to implement BIP 38 and need any help, I'm more than happy to offer it.  My generator (written in C#) works as a starting point; you need access to an implementation of scrypt, sha256, and aes256 in order to do it.