How would you like to design a bitcoin banknote?

[casascius]

- Check the "Art?" checkbox on the Paper Wallet tab to see the SVG art wallet. It is a 4MB SVG external download via iframe.

4 megabytes? Ouch that's a big download.

I don't believe the art should actually be that large - and is only that large because it contains base64-encoded PNG graphics that ought to be vectorized.  Vector graphics ordinarily are pretty slim on space.

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[ErebusBat]

Practically speaking, even if the QR code is demolished beyond cooperation with a reader, if you can still read the human-readable private key with your own eyes, you're going to be able to recover the coins.

However the argument could be made that if the QR code is that damaged then the human readable key may be as well.

However these are not intended for long term carry around storage.

That being said I have been carrying some around in my wallet since early on... I will pull them and see how damaged they are.

[pointbiz]

4 megabytes? Ouch that's a big download. I might take a look at optimizing that SVG for web use, and see how hard it is to add in the Ubuntu font within it, since it's not a standard font for all OSes.

I don't have much experience with SVG any help making it smaller would be appreciated. We could look into what Casascius said about the base64 encoded PNGs.

I also updated my branch to use HTML Canvas elements for the complete banknote! This means no browser CSS issues or needing to use browser-specific transforms to get the address text to go vertical.

I'll take a look when I get some time.

I feel the public and private QR codes should be the same ratio... so at this moment the white boxes are not the correct size.

But the two addresses are different lengths; You've got more text to encode with a private key, so the QR code has more rows/columns. Forcing their outer dimensions to be the same means the private key's cells are smaller.

I meant that the white space reserved for the private key should be bigger. If you look in the code I posted I use the same multiplier to make the QR Code canvas bigger. That's what I meant by ratio.

I have not tried changing the error correction level maybe that alleviates the issue. Not sure of the pros/cons of reducing the error correction level other than what you've stated.

[casascius]

I made a couple minor revisions myself to the Bitcoin-note.svg file that I had.  It can be obtained at https://casascius.com/bitcoin-note.svg.zip, and is now 1128210 bytes (uncompressed).  Note that I might have a different revision than you, so some of the changes I made might not make sense relative to yours.

I did the following:

• REMOVED the embedded png's.  They are gone, nothing replaces them.  Oh well.  That's why the file is smaller.
• I uncovered the "Strength in Numbers" text, which was actually present in the file but covered over by solid objects that looked like scribbling.  The text is actually comprised of letter shapes, so there's no dependency on the Ubuntu font.
• I added labels "Load/Verify Balance" and "Spend (Private Key)", using letter shapes rather than a font.
• The white "bitcoinbitcoinbitcoinbitcoin" stripe wasn't present in this file, so I added it (also converted the letters to shapes, so it's not a font)

I'm not an artist by any means, but these manipulations were well within what I could do.

EDIT: fixed link

[midnightlightning]

How will the error correction from H=>M effect damage from being folded or perhaps water damage (ink jet)?

All right, so I did some tests for how well the error correction works. I printed out two notes using my code ("M" level error correction) onto 20# (standard) printer paper with an HP inkjet printer on "normal" quality setting). I used an iPod Touch rear camera to attempt to scan the QR codes under indoor lighting. I use an iPod touch for all the QR testing I do at work, since that rear camera is a fixed-focus 0.7 megapixel camera, which is probably the worst camera on a mobile device you'd attempt to scan a QR code with. It's bad not only because it's low megapixels, but also because the fixed focus of the lens is designed for taking pictures of other people, 3-6 feet away from you, not for macro scans of something right up close. So all macro shots are blurry on this camera, in addition to being low-res, so is a good worst-case camera.

I used the "QRreader" app, which has the feature that it can capture a photo the moment it recognizes a QR code in the live feed off the camera data. I targeted the private key QR code because (a) that's the more important of the two, and (b) it's the more dense QR code, so potentially harder to scan.


So here's what I got. I started very far away from the bitnote and slowly brought the camera closer to the note, and this was the first point that the QR code was recognized. Which is still pretty far away, but reads just fine. Also, at this far out, the rest of the note is visible to the camera/scanner, so this shot shows that the two-cell-width border around it is sufficient, as the scanner wasn't getting confused by the other artwork nearby.


I also tried starting almost flat with the paper (really foreshortened), and slowly coming up to a line of sight perpendicular to it. This was the first point that it was recognized, so this is about the limit of skew possible and still be recognized.


To address the fold question, I folded the bill neatly in half (what someone might do if it's too tall for their wallet). I slowly unfolded the bill, and this was the first point it was recognized. With where the QR codes are on the note, folding it in half tilts just the calibration blocks different from the rest of the glyph, so it does need to be pretty flat before it's recognized.


Taking folding to the extreme, I crumpled the note into a ball and then tried to unfold it and get it to scan. If the light is perpendicular to the node, there's no shadows from the folds, and it scans just fine. Here I'm holding the note at a little bit of an angle to the light so you can see the creases, and it still scans.


I then took the other (uncrumpled) note and started playing with water. Here I just dripped water onto it such that it discolored the white paper, but didn't really move the ink around. It scanned just fine. Then I started taking my wet finger and dabbing at the paper to coax the ink to bleed:


These two progressions still scanned just fine, even with large portions of the middle blacked out.


This one finally didn't scan (I took this picture with the phone's normal camera. Note this is a full 0.7 Megapixel image; the other snapshots that the QRreader app saves are slightly smaller images it grabs off the live sensor data). I had soaked the paper so thoroughly it had started to peel back layers of the paper in the middle of the glyph as I rubbed. You can also see the water stain itself has spread quite far as well, which may have contributed to it being unreadable.


Here's a shot of the back showing how much water has to bleed through before it's unreadable.

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

[adamstgBit]

Is there a web app to print these out?

[Stephen Gornick]

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

Waterproof paper might be desired:



 -  http://www.amazon.com/Rite-In-The-Rain-Copier/dp/B0016H1RYE

[paraipan]

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

Waterproof paper might be desired:

[img]https://i.imgur.com/GvAcY.jpg[img]

 -  http://www.amazon.com/Rite-In-The-Rain-Copier/dp/B0016H1RYE

Thanks Stephen, didn't know we could buy that kind of paper.



@adamstgBit yes, here you have it https://github.com/MidnightLightning/bitaddress.org

[FLHippy]

Is there a web app to print these out?

http://printcoins.com

[cbeast]

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

Waterproof paper might be desired:



 -  http://www.amazon.com/Rite-In-The-Rain-Copier/dp/B0016H1RYE

Looks good, but note that it's not for ink-jet printers. It might not matter so much what paper you use as ink. The artwork would probably be fine with ink-jet, but perhaps toner is better for the codes.

[FLHippy]

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

Waterproof paper might be desired:

I ran some notes printed on a Konica Minolta BizHub c360 color laser printer. Used 32lb 100% cotton paper with a tamper evident seal. I put it in my pants pocket and laundered the pants. The entire note was a little beat up especially on the edges but the ink didn't run at all. 100% readable.

put the note in the microwave and the seal got all sparkly and it left a little burn mark on the private key but it was still readable.

I'm looking for other ways people abuse money to see if the notes I printed will stand up to the abuse. I realize no one puts money in a microwave but I was feeling adventurous.

Also, I added the BitPay note to RobKohr's print coins project. I would have added all the notes from this contest but I could not locate layered project images for most of them. I also put aristus's turing note in the print coins project. It's easy to add a new note and the project is on github and I hope people ad more notes cause I love these things. http://printcoins.com

[midnightlightning]

Is there a web app to print these out?

Also, I added the BitPay note to RobKohr's print coins project. I would have added all the notes from this contest but I could not locate layered project images for most of them. I also put aristus's turing note in the print coins project. It's easy to add a new note and the project is on github and I hope people ad more notes cause I love these things. http://printcoins.com

You mean the "print your own" function of that site? Though that function needs you to use bitaddress.org in tandem with it for addresses. Bitaddress.org's developer added printing artwork to the next version of that site (post here, preview at https://www.bitaddress.org/bitaddress.org-v1.7-SHA1-.html) directly.

And, of course there's my branch which I've created at https://github.com/MidnightLightning/bitaddress.org (no web hosting; clone and open locally to use) which keeps it all to one file still. And it prints beautifully just hitting File > Print on your browser; two notes fit per letter page.

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

Waterproof paper might be desired:

It might not matter so much what paper you use as ink. The artwork would probably be fine with ink-jet, but perhaps toner is better for the codes.

By "bad paper" I was referring mainly to the thickness. 20# paper is pretty thin and flimsy (mine started peeling when it got really wet and I was trying to get the ink to bleed); high-quality printer paper is usually 24-36# (higher than that and it's usually considered "card stock"), and if you use cotton paper rather than wood pulp it's even more rip-resistant when wet, and dries out better. But to prevent the ink from bleeding, using laser toner rather than ink would be much preferred.

The paper's job should be to not dissolve/tear/break down. The ink's job should be to not bleed/rub off. Getting paper that tries to solve the ink bleeding issue seems like it's a bit of a kludge. cbeast's idea of doing the printing in two halves is interesting, but much more complex. If you only have access to black/white laser printing, that's a good option to be able to print color notes in inkjet, and black/white QR codes on top (gets back to the pre-printed check backgrounds idea) for a good mix of "pretty" and "durable".

[PrintCoins]

So even with a bad camera, bad paper, and bad ink, a moderate error correction level still stands up to a good deal of abuse before succumbing.

Waterproof paper might be desired:

I ran some notes printed on a Konica Minolta BizHub c360 color laser printer. Used 32lb 100% cotton paper with a tamper evident seal. I put it in my pants pocket and laundered the pants. The entire note was a little beat up especially on the edges but the ink didn't run at all. 100% readable.

put the note in the microwave and the seal got all sparkly and it left a little burn mark on the private key but it was still readable.

I'm looking for other ways people abuse money to see if the notes I printed will stand up to the abuse. I realize no one puts money in a microwave but I was feeling adventurous.

Also, I added the BitPay note to RobKohr's print coins project. I would have added all the notes from this contest but I could not locate layered project images for most of them. I also put aristus's turing note in the print coins project. It's easy to add a new note and the project is on github and I hope people ad more notes cause I love these things. http://printcoins.com

Note - the address for printing the bills is print.printcoins.com.


Thank you for adding the code for those bills!

[pointbiz]

v1.7 has been released with the artistic wallet:
https://www.bitaddress.org/bitaddress.org-v1.7-SHA1-46215e8a2f026b784f29ea86c00c866e634a22fa.html

I'm using an embedded PNG for this version. I wanted to keep the all-in-one aspect going.

I used this site to convert the SVG to 300 DPI PNG at 795x430 pixels:
http://image.online-convert.com/convert-to-png

I used this site to convert from the .png file to the base64 data:
http://www.dailycoding.com/Utils/Converter/ImageToBase64.aspx

Those links should be useful if you want to change the art work.


Regarding using SVG:
I still hope that at some point we can use an embedded SVG. The file really suffers from being software converted from PSD to SVG (think MS Word document to html document). There are still embedded PNGs within that SVG adding size and slowing rendering. Casascius has converted some of those PNGs and removed some others (which we might want back for the eye candy). I noticed there is some inefficient and/or useless SVG in there that isn't doing anything or using curves to make squares :S so getting the exact right SVG (and keeping it under 1MB) is gonna take some effort but in theory it's possible

[franky1]

the flaw with 'bank notes' is they are one use only.

where as FIAT bank notes can be passed back and forth with a guarantee and no worrys about if it has value (EG it privkey hasnt copied / wallet hasnt been emptied)

for bank notes to actually be useful for more then single trades. a 'bank' would need to be set up holding the private keys and the bank notes just have public keys. so that ur just trading an ownership of address 1XXXXXXXXX knowing the person before you, you or the person after you cant empty the wallet at any time while still handing the note about, by just copying the key onto a scrap of paper.

where its only redeemable when 'cashed in' at the earlier said bank.

just like FIAT bank notes.. they are technically backed IOU's

on english bank notes it clearly states bank of england promises to pay the bearer the sum of X on demand.

so whoever holds the note is guaranteed to cash out that sum, or they can trade it on, and on and on to other people.

but thats when things start to become centralised...

so what are the preventative methods that EG person one prints the note. but also hand writes the privkey and then hands the note on.. tells that person to balance check it while standing next to them.. and as soon as person 2 walks away, person 1 empties it.. making that note useless?

single use trades for small amounts (bank notes) wont work well without a 'centralised' party guaranteeing the individuals trading between each other wont steal.

but the bearer bonds thing where you give them as a gift/inheritance to trusted parties ... now thats a better idea..
id accept a bitcoin bearer bond off of a relative anyday, but never a bitcoin bank note that has changed hands and been looked at by a dozen different people.

[apetersson]

I used this site to convert the SVG to 300 DPI PNG at 795x430 pixels:
http://image.online-convert.com/convert-to-png

does that mean you send the private key over the net - unencrypted - to a third party just to create a qr code? or did i miss something?

[kangasbros]

I used this site to convert the SVG to 300 DPI PNG at 795x430 pixels:
http://image.online-convert.com/convert-to-png

does that mean you send the private key over the net - unencrypted - to a third party just to create a qr code? or did i miss something?

Probably only to preprocess the artwork...

[apetersson]

ok, sorry i mixed that up. the qr code is generated client-side in JS as it should. nothing to see here, move on.

[FLHippy]

v1.7 has been released with the artistic wallet:
https://www.bitaddress.org/bitaddress.org-v1.7-SHA1-46215e8a2f026b784f29ea86c00c866e634a22fa.html

Great job. I have some suggestions.

I think that the psy artwork appeals most to the folks not in the US. It's so radically different than the dead presidents we're used to. I like your site because the work is done on the client and not the server. That said, trust is hard to obtain when using websites. Running this locally makes some people feel safer. This is why I'm using RobKohr's print.printcoin.com project and I recommend it to other people. The problem is, the people who I have told about print.printcoins.com have a hard time getting it to run on a windows machine which is what most people use.

Do you have plans to add other note designs? Is your project on github? I could help add more notes.

I still wish all the participants had provided layered image files. All of the designs will appeal to someone. To those that entered the contest, if you can give me a layered PSD or gimp XCF (preferred) I will add the note to the print.printcoins.com project by RobKohr and perhaps we'll see it on the bitaddress site also.

I am also interested in the "bond style" design where it takes up a whole page and resembles a stock certificate.

[Raoul Duke]

Regarding the png's embedded on the SVG I have good news and bad news...

The good news first: I managed to convert those layers to SVG and I can get a revised file available to download as soon as I get on my laptop, probably by tomorrow.

The bad news: The SVG is 7MB...