Topic: How would you like to design a bitcoin banknote? - page 8. (Read 94792 times)

I understand that it helps a bit with trust in some situations.  I was responding to franky saying that this would keep the bills in circulation longer. I don't agree since in that case you probably do not know who printed the bill.

If the person who manufactured the bill is someone you trust and is different from the person who wrote the passphrase, then you know the passphrase writer doesn't know the private key.  It's the same scenario if a reseller were to buy my two-factor bar and I provide the key under the hologram and he provides the passphrase, giving me only the intermediate code.  The trust footprint is reduced to just the possibility that we're colluding (or the possibility he knows of a way to read under my hologram undetected).

I only see a benefit for encrypted paper bills if I am the only one who knows the pass phrase. If someone writes their phrase on the bill and then pays me with it, I don't see any benefit over having an unencrypted private key.  In fact, making it harder to spend doesn't even sound like a good thing to me.

with the holograms themselves hiding the redeem part to allow for changing between mutliple hands. im now STARTING to consider this as a more secure way of transferring bitcoin without electronic devices needed between each party for daily exchange. as oppose to a one use item like a gift voucher or cheque.

i still see gaps in security where people can say "but im still typing my passphrase into some one elses website"

the only thing i can think to quash those thoughts is that people have their own offline program much like vanitygen or brain wallet which produces the addresses but adding to that it also encrypts the private key locally based on the passphrase they chose.
basically asking users to type in passphrase and how many addresses to produce and it produces a list of clear public addresses and bip38 codes. (no private key in sight) they copy and paste the list to you where you never know the passphrase to encrypt it and are not involved with the encryption process. all you do is just print the public address and bip38 QR Codes to the relevant load/redeem section.

and at redemption. the user then scans the redeem code into the local program(same program as last paragraph) it requests the passphrase and converts it into a usable private key to paste into blockchain.info/mtgox.

by making it slightly harder for people to redeem them in under 3 seconds will actually make people prefer to keep them in circulation for longer.. in theory anyway.. which adds more benefit to the whole reason of paper money, as oppose to cheques/gift voucher methods. meaning that people are not easily tempted to rip off the hologram as soon as they get their hands on a note.

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.

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...

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

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://bitcointalksearch.org/topic/m.1383041" - just look at the screenshot alone and you'll have a first idea already.

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

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.

Really nice! Well done

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.

awesome, i definately want one of these

...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

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";

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.

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.

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.

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.

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.