How would you like to design a bitcoin banknote?

[salfter]

Another possibly useful bit of code that creates QR codes in SVG format:

This depends on netpbm and qrencode.  Basically, what we do is create a QR code PNG, convert it to a PBM text file, and mangle that with an awk script (an admittedly naive script, but it should work for addresses and private keys) into an SVG file.

First, the awk script, which we will call pbmtosvg.awk:

Code:

#!/usr/bin/awk -f
BEGIN {getline; getline; w=$1; h=$2; y=0; print "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" width=\""w*3"\" height=\""h*3"\">"} 
{for (x=0; x<w; x++) if (substr($0, x+1, 1)=="1") printf("<rect width=\"3\" height=\"3\" x=\"%i\" y=\"%i\" />",x*3,y*3); else printf("<rect width=\"3\" height=\"3\" x=\"%i\" y=\"%i\" style=\"fill:#FFFFFF\" />",x*3,y*3); y++} 
END {print "</svg>"}

It reads the dimensions out of a PBM text file, then writes a grid of black and white rectangles into an SVG file.  To use it, try something like this:

Code:

for i in 1JzFx4iQqnpyBaQbjfZ9Tg2u4KzkSpTDzi 5HzQEdP55SGjBawGCw25A14FcjegFyPtbn3xhzb1rhpxX5dZcc4; do qrencode -s 1 -l M -o - $i | pngtopnm | pnmnoraw | ./pbmtosvg.awk >$i.svg; done

Some examples:


1JzFx4iQqnpyBaQbjfZ9Tg2u4KzkSpTDzi


5HzQEdP55SGjBawGCw25A14FcjegFyPtbn3xhzb1rhpxX5dZcc4

You can then merge these with one of the SVG note designs already given however you want. I'm thinking a little HTML file with some CSS positioning info should work to overlay QR codes (and, optionally, text) over a note.  By keeping all images in SVG format, your notes should print at whatever resolution your printer can deliver.

[1714021850]

1714021850

[1714021850]

1714021850

[1714021850]

1714021850

[casascius]

Next time I revisit this image, it needs to have some color bleeds so that minor variations in cutting don't result in white stripes along the edges.

If someone else beats me to it, please add bleeds.

[salfter]

I've put together an offline note generator:

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

Notes are rendered four to a page.  Five denominations (0.5,1, 2, 5, and 10 BTC) are currently supported, each of which prints in its own color.  Addresses and private keys are generated on-the-fly, rendered as both text and QR codes.  Page layout is done in PostScript with artwork that started out as SVG, so you get the highest print quality possible.  For convenience, final output is to PDF.  I considered using HTML and CSS to position SVG images directly, but print quality proved a bit hit-or-miss...Firefox was usually OK, but Chrome frequently rendered SVG elements at 72 dpi or so before printing.  Even with Firefox, I sometimes had some unexplained print failures.

For sample output, try this:

https://dl.dropbox.com/u/57535575/job2948.pdf

[teflone]

point me to a link that generates those with a unique private key... (wallet)

[Mushroomized]

I've put together an offline note generator:

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

Notes are rendered four to a page.  Five denominations (0.5,1, 2, 5, and 10 BTC) are currently supported, each of which prints in its own color.  Addresses and private keys are generated on-the-fly, rendered as both text and QR codes.  Page layout is done in PostScript with artwork that started out as SVG, so you get the highest print quality possible.  For convenience, final output is to PDF.  I considered using HTML and CSS to position SVG images directly, but print quality proved a bit hit-or-miss...Firefox was usually OK, but Chrome frequently rendered SVG elements at 72 dpi or so before printing.  Even with Firefox, I sometimes had some unexplained print failures.

For sample output, try this:

https://dl.dropbox.com/u/57535575/job2948.pdf

I think the notes should go from 1-256, each .01 raising the hue level a bit, that way it will give a cool effect, 

[salfter]

I've put together an offline note generator:

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

I think the notes should go from 1-256, each .01 raising the hue level a bit, that way it will give a cool effect, 

I was aiming for standard denominations that mirror existing paper currency. (At present value, I should probably do 0.1 and 0.2 BTC notes as well.)

[Mushroomized]

I've put together an offline note generator:

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

I think the notes should go from 1-256, each .01 raising the hue level a bit, that way it will give a cool effect, 

I was aiming for standard denominations that mirror existing paper currency. (At present value, I should probably do 0.1 and 0.2 BTC notes as well.)

But 1-256 is computery

[salfter]

point me to a link that generates those with a unique private key... (wallet)

If you're referring to my project, you need to clone it from the GitHub repo, make sure you have the software (including vanitygen) listed under Prerequisites in the README, and run the script. Each run generates new privkeys for each note. It's intended for offline use; it's not offered as a web service.

If you're referring to something else, never mind.

[kangasbros]

My take: https://github.com/kangasbros/skimpybtcnotes

I wanted something extremely simple & something that is cheap to print. So that they can use these in Africa

Banknotes:



Storage sheets:

[Mushroomized]

I wanted something extremely simple & something that is cheap to print. So that they can use these in Africa

[Mjbmonetarymetals]

Not sure if this has been mentioned on the thread -

http://www.youtube.com/watch?v=cLu5baef90g&feature=youtube_gdata_player

[salfter]

I've updated my generator:

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

It now produces 3/4" squares with human-readable privkeys that can be placed over the privkey QR codes before applying your tamper-evident labels.  Black boxes are also generated on the back opposite the privkey QR codes; if nothing else, they'll help you line up the label on the back.

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

https://dl.dropbox.com/u/57535575/job5456.pdf

[kangasbros]

Wrote a blog post about paper wallets: http://localbitcoins.blogspot.fi/2012/11/start-your-own-money-press.html

[dserrano5]

Wrote a blog post about paper wallets: http://localbitcoins.blogspot.fi/2012/11/start-your-own-money-press.html

What do you mean "Printer manufacturers are controlled by reptilians"? Is it actually insecure to print something sensitive, then connect the printer to an internet-connected machine? Even when power cycling it?

[Elxiliath]

Wow, this application is awesome!!!  I tried to do something like this myself, but it wasn't so easy.  Thanks so much for this Cas!

[Mushroomized]

So do you guys have any ideas how to use these for offline storage? I mean aside from genning the keys offline, printing them and storing them, do you guys do anything else to be super safe

[casascius]

My alpha version (source on github, binary+source at https://casascius.com/btcaddress-alpha.zip ) allows the creation of two-factor passphrase-protected notes.

If one computer is used to hash the passphrase, and you transfer the hashed version of it to another computer to produce the notes (via the "intermediate generator"), it would require a compromise of both machines for anyone to be able to decrypt the notes.

[fivemileshigh]

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

[casascius]

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.

[salfter]

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