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Author Topic: Print your own bitcoin bills - print.printcoins.com  (Read 6001 times)
PrintCoins
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October 03, 2012, 04:07:15 AM
 #41

@robkohr - hey just a quick note to say I think this is a pretty darn great start, and it's very kind of you to make this an open source and apparently noncommercial project. I also appreciate that your webpage has end-to-end instructions, including where to buy security holograms which is a nice touch.

For those crying spam/fraud/etc. the only fault of robkohr is that he didn't specify up front that this code has the potential for air-tight security by being run on local servers, and/or converted to javascript and run over SSL, etc. On the other hand, anyone crying 'scam!' should be smart enough to know that the current online version is a proof of concept, a starting point us to try out some small conversions -- clearly not a clearinghouse where anyone should dump hordes of coin. I believe robkohr's intentions are pure, but it would be silly to trust large amounts of coin with an unencrypted website on a webhost which may or may not be compromised by hackers. (Dollars to donuts, I'll bet hackers are trying to compromise printcoins.com right now since it's probably easy pickings.)

Here's what I love about printcoins:

* converts bitcoins to a tangible exchange, which makes it possible to engage ordinary citizens in bitcoins not just übernerds. For example, some workers are in my backyard right now are building me a chicken coop. They don't know squat about bitcoin. But I could probably pay them in bitcoin if I had a nice looking bill in my hand and explained to the foreman, "hey, if you're a gambling man, I'll pay you 25% in this very weird currency which has increased in value a few hundred percent in just a few months. Just hold onto this bill and don't lose it, and here's how you use your cell phone to see what it's worth from time to time."

* (once run on a local server) doesn't require trusting anyone with your wallets/addresses. I've loved the idea of buying Casascius coins, but I just can't get over my paranoia stemming from the fact that criminals have a huge motivation to insert themselves into the minting process. I don't just mean hackers, I mean people physically breaking into the minting premises and causing mischief.

What printcoins represents is a huge step towards easy distributed "minting" which is really the key to using bitcoin without putting your bitcoins online where hackers are trying -- and succeeding -- to steal them.

Thank you for your praise caton, it is greatly appreciated. If anyone would like to support paying for a vps and a cert, I can make this more locked down for everyone. Of course, you still have to trust me. The best remidy to that is to run this yourself.

Bitmessage.org: BM-2cT3oFVj68gugBD5JFvP3qmoBHWXJQ6ZkT
BTC Addr:18AA1hq6DVHn5WuK1fQhr5CdkqeG5Mj2ZL <--did you like my post? Send some encouragement here.
Print bitcoin bills: http://print.printcoins.com/
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December 02, 2012, 12:38:55 PM
 #42

+1 for post #40 from canton for this good summary.

...and +1000 for robkohr's proof-of-concept printcoin web page and for providing the source code.

Of course having an EASY Java Script solution like bitaddress.org would be the nicest solution for the people who cannot easily set up a local web server but still want a save solution to print their own printcoins. --> Maybe I have an idea here...
The reason this is server side rather than js is that I have not found one decent pdf creation library written in javascript (just a couple half hearted attempts that were useless). pdf's are the simplest way to create something that will print to exact dimensions on the web.
--> ...concerning bitaddress.org (which is fully javascript based), I am able to generate proper PDFs extremely easily! I just use the "Print" button and print to my PDF-printer!!! (this is extremely easy under Linux (=my case), but free PDF printer drivers also exist for Windows and can be downloaded and installed at a click of a button).

So, robkohr (or any other programmer here), could you imagine considering offering a JS-based printcoin.com implementation?

I would use the JS-based bicoinaddress.org straight away, but it lacks two features for me (both of which printcoins.com offers):
- entering my OWN private keys (instead of having new random ones generated for the printed bills)
- the secret key QR code size is too large (unlike printcoin bills) to be covered by a 2.5 cm (1 inch) hologram.

Update: I have just requested here enhancement of the javascript code on bitaddress.org - maybe this is the more reasonable approach, since the codebase in javascript (a single html file) is already available.

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December 02, 2012, 05:27:51 PM
 #43

Business idea for you: With a desktop version or even a JS version you could rather sell cool bitcoin hologram stickers and paper with some suitable background artwork. The notes should also have space possible to customize besides the codes and amounts, for use as gifts.

With that and one extra QR code to be used to identify the issuer (by PGP signature of email address?), you will have set up anyone to start issuing their own bitcoin banknotes!

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December 03, 2012, 01:22:01 AM
 #44

Is it something like a legal tender?  Grin


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December 03, 2012, 02:31:49 AM
 #45

@robkhor
You can get a free certificate that is acceptable by almost all browsers at StartSSL.com. These are well known and used by many sites successfully. I've used them in the past without issues.

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December 03, 2012, 04:02:08 PM
 #46

So it gives the private key. Is there a web service for uploading the private key to use the BTC?

I am thinking about giving out some of these for Christmas.

Seeking Beta testers. PM me for more information.
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December 03, 2012, 06:17:03 PM
 #47

So it gives the private key. Is there a web service for uploading the private key to use the BTC?

I am thinking about giving out some of these for Christmas.

multiple ways:
http://printcoins.com/redeem
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December 03, 2012, 07:38:41 PM
 #48

I really think these can be a good idea and useful if they were produced by a reputable company at specific denominations.  After dealing with hurricane Sandy and not having power for a week, digital currency doesn't help if you can't get to it.  If a large company like MT Gox distributed them then I could see them taking off as far as trading goes, because you know what your getting. . . then again the other problem is making sure that the digital money wasn't used already which presents another problem . . . ugh.
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December 03, 2012, 11:49:38 PM
 #49

I really think these can be a good idea and useful if they were produced by a reputable company at specific denominations.  After dealing with hurricane Sandy and not having power for a week, digital currency doesn't help if you can't get to it.  If a large company like MT Gox distributed them then I could see them taking off as far as trading goes, because you know what your getting. . . then again the other problem is making sure that the digital money wasn't used already which presents another problem . . . ugh.
That's what tamper-proof hologram stickers placed over the private key QR is intended to solve, similarly to the ones used on Cass coins covering the key. It seems to me you would have to use sufficiently thick paper as well.

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December 05, 2012, 10:05:53 PM
 #50

When I locally install the source on a webserver

Well, I cant figure out why the denomination options arent showing up. Seems its pulling them from the php script. I dont know php well enough =( .. help?

Everything else works tho..

Was able to fix a syntax error in form.html .. the values now properly show up =)
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December 06, 2012, 12:05:34 AM
 #51

i personally dont know anyone who would accept one of these. how does this benefit the bitcoin user ?
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December 06, 2012, 01:57:50 AM
 #52

i personally dont know anyone who would accept one of these. how does this benefit the bitcoin user ?

one can use it as an offline wallet to stash their own coins if paranoid. It's only useful if you trust the person that printed them (who knows the private key since they printed it on the certificate to begin with).  They could be interesting gifts.
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December 06, 2012, 09:56:31 PM
 #53

+1 for post #40 from canton for this good summary.

...and +1000 for robkohr's proof-of-concept printcoin web page and for providing the source code.

Of course having an EASY Java Script solution like bitaddress.org would be the nicest solution for the people who cannot easily set up a local web server but still want a save solution to print their own printcoins. --> Maybe I have an idea here...
The reason this is server side rather than js is that I have not found one decent pdf creation library written in javascript (just a couple half hearted attempts that were useless). pdf's are the simplest way to create something that will print to exact dimensions on the web.
--> ...concerning bitaddress.org (which is fully javascript based), I am able to generate proper PDFs extremely easily! I just use the "Print" button and print to my PDF-printer!!! (this is extremely easy under Linux (=my case), but free PDF printer drivers also exist for Windows and can be downloaded and installed at a click of a button).

So, robkohr (or any other programmer here), could you imagine considering offering a JS-based printcoin.com implementation?

I would use the JS-based bicoinaddress.org straight away, but it lacks two features for me (both of which printcoins.com offers):
- entering my OWN private keys (instead of having new random ones generated for the printed bills)
- the secret key QR code size is too large (unlike printcoin bills) to be covered by a 2.5 cm (1 inch) hologram.

Update: I have just requested here enhancement of the javascript code on bitaddress.org - maybe this is the more reasonable approach, since the codebase in javascript (a single html file) is already available.

UPDATE: I think there is good news for the subject of this thread's title "print your own bitcoin bills", especially, if I add both "SECURELY" and "EASILY" at the same time. And in good quality of course.

Since today, a new solution exists:
* 100% offline
* Open Source < 500 kB (html/javascript)
* High Resolution images (printing in full 600 dpi), at least 10 different designs (=colors)
* No IT expert knowledge required:
  - No need to set up a web server
  - No need to work on the command line
* Works on Linux and Windows
* Only requires FIREFOX (may have problems with other browser, so consider Firefox not a browser but a bitcoin bill printing software)
* Configurable for certain individual aspects!

Now everybody can easily print High Quality bitcoin paper notes 100% securely.

So I think this fits perfectly to the subject of this thread, therefore I wanted to let you know about the news in this posting:
https://bitcointalk.org/index.php?topic=43496.msg1383041#msg1383041

Thanks for all the contributors to this topic.

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December 07, 2012, 06:25:03 PM
 #54

I'm still somewhat new to bitcoin, maybe that's why I see these as having very limited usefulness. On the one hand the geek in me wants to run out and get some holograms and roll my own, but otoh I see some drawbacks and I'd like others' feedback:

1. For tx where the sender is online, this adds needless complexity.

2. For offline transactions, the receiver has to trust that the buyer does not have a copy of the pk AND the bill does really have the stated btc on it. If that level of trust exists, the receiver might as well wait until the buyer gets online, no?

3. How would change work? meaning, I have a 10btc bill, and I'm buying something worth 1.37....? fall back to $/eur?

4. Use it for offline storage? The standard-no-art bitaddress.org paper wallet is just as good, and more low-key. I guess the hologram version has the advantage that it's not possible to get your pk qr accidentally scanned by a cctv camera, but that's about it. If someone else gets access to it, the tampered-with hologram is just there to tell you "don't bother checking, your bitcoins are gone".

Really, I only see this as a novelty item/gift card. That's ok, btw.

thoughts?

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December 07, 2012, 07:04:19 PM
 #55

I'm still somewhat new to bitcoin, maybe that's why I see these as having very limited usefulness. On the one hand the geek in me wants to run out and get some holograms and roll my own, but otoh I see some drawbacks and I'd like others' feedback:

1. For tx where the sender is online, this adds needless complexity.

2. For offline transactions, the receiver has to trust that the buyer does not have a copy of the pk AND the bill does really have the stated btc on it. If that level of trust exists, the receiver might as well wait until the buyer gets online, no?

3. How would change work? meaning, I have a 10btc bill, and I'm buying something worth 1.37....? fall back to $/eur?

4. Use it for offline storage? The standard-no-art bitaddress.org paper wallet is just as good, and more low-key. I guess the hologram version has the advantage that it's not possible to get your pk qr accidentally scanned by a cctv camera, but that's about it. If someone else gets access to it, the tampered-with hologram is just there to tell you "don't bother checking, your bitcoins are gone".

Really, I only see this as a novelty item/gift card. That's ok, btw.

thoughts?



1. Yes, notes are for local use. But when you haven´t got a local alpaca sock vendor there is the option to redeem your bitcoin notes and send them by an online tx.

2. No, the receiver only has to trust the _issuer_ of a properly designed, tamper-proof note.

3. A variety of large and small denominations, just like other forms of cash.

4. Yes, storage of a plain paper wallet is just like stashing cash.


 

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December 07, 2012, 08:45:16 PM
 #56

I'm still somewhat new to bitcoin, maybe that's why I see these as having very limited usefulness. On the one hand the geek in me wants to run out and get some holograms and roll my own, but otoh I see some drawbacks and I'd like others' feedback:

1. For tx where the sender is online, this adds needless complexity.

2. For offline transactions, the receiver has to trust that the buyer does not have a copy of the pk AND the bill does really have the stated btc on it. If that level of trust exists, the receiver might as well wait until the buyer gets online, no?

3. How would change work? meaning, I have a 10btc bill, and I'm buying something worth 1.37....? fall back to $/eur?

4. Use it for offline storage? The standard-no-art bitaddress.org paper wallet is just as good, and more low-key. I guess the hologram version has the advantage that it's not possible to get your pk qr accidentally scanned by a cctv camera, but that's about it. If someone else gets access to it, the tampered-with hologram is just there to tell you "don't bother checking, your bitcoins are gone".

Really, I only see this as a novelty item/gift card. That's ok, btw.

thoughts?



1. Yes, notes are for local use. But when you haven´t got a local alpaca sock vendor there is the option to redeem your bitcoin notes and send them by an online tx.

2. No, the receiver only has to trust the _issuer_ of a properly designed, tamper-proof note.

3. A variety of large and small denominations, just like other forms of cash.

4. Yes, storage of a plain paper wallet is just like stashing cash.


(printcoins operator here)

I have found that they have made great propaganda tools, and are great at getting people into bitcoins without having to set them up with the tech. I have bought silver, local eggs, and paid for people's services with them. Some go on to create digital wallets, and take part in the network, some use them again to buy stuff off of others, and some just sit on them hoping they will be worth a lot one day.

They are really great with bring people into bitcoin, but I think that between set up bitcoin users, mobile phone applications make better ways of transferring coins.

Bitmessage.org: BM-2cT3oFVj68gugBD5JFvP3qmoBHWXJQ6ZkT
BTC Addr:18AA1hq6DVHn5WuK1fQhr5CdkqeG5Mj2ZL <--did you like my post? Send some encouragement here.
Print bitcoin bills: http://print.printcoins.com/
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December 07, 2012, 10:44:25 PM
 #57

I agree that any experienced bitcoin user, both seller and buyer, will prefer mobile phone applications to bitcoin notes.

But my argument is to do the "granny" test on starting a small shop accepting bitcoin. Let´s say your granny is starting to sell alpaca socks in her shop, and all customers will be holders of both the kind of bitcoin notes I described - tamper-proof and with an easy way of identifying the issuer - and all will also have their mobile phone wallet applications.

Which method of payment would you recommend Granny to prefer?

The mobile application wallet route is the more technical one: She will at a minimum have to remember her password and back up her wallet. I don´t know the stats, but there is at least a large minority - if not majority - who will not give a single though to data security of their smartphones; many can´t even be bothered to do free security upgrades of their phone OS.

And then you have the notes, which builds nicely on her non-technical experience: If the issuer of the bitcoin note is someone from the local community she is on the top of her game in either accepting or rejecting the note. She will need no instruction in how to store the notes in her mechanical safe, and so on. The only technical part would be checking if the note is funded by scanning the QR code of the address, with no risk of divulging any private  keys to cell phone hackers. Or if we want to keep it completely offline as a principle: just an app to assist her in confirming the identity of the issuer (this could be done by a PGP email signature of the bitcoin address).

i think the latter approach will be a safer and softer way of introducing use of bitcoin to most people.

BTW: My compliments on your printcoins, they look both cool and serious.
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December 08, 2012, 11:07:32 AM
 #58

I've slept some more on this, and I think at least in the part of the adoption cycle we're in now, these are fantastic as gift cards, to get people to at least look up bitcoin. Great stuff.

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December 09, 2012, 03:42:55 AM
 #59




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December 09, 2012, 05:05:53 PM
 #60

I'm still somewhat new to bitcoin, maybe that's why I see these as having very limited usefulness. On the one hand the geek in me wants to run out and get some holograms and roll my own, but otoh I see some drawbacks and I'd like others' feedback:

1. For tx where the sender is online, this adds needless complexity.

2. For offline transactions, the receiver has to trust that the buyer does not have a copy of the pk AND the bill does really have the stated btc on it. If that level of trust exists, the receiver might as well wait until the buyer gets online, no?

3. How would change work? meaning, I have a 10btc bill, and I'm buying something worth 1.37....? fall back to $/eur?

4. Use it for offline storage? The standard-no-art bitaddress.org paper wallet is just as good, and more low-key. I guess the hologram version has the advantage that it's not possible to get your pk qr accidentally scanned by a cctv camera, but that's about it. If someone else gets access to it, the tampered-with hologram is just there to tell you "don't bother checking, your bitcoins are gone".

Really, I only see this as a novelty item/gift card. That's ok, btw.

thoughts?


Correct on all accounts. Here is a slightly more useful, but more complex version.

Any significantly advanced cryptocurrency is indistinguishable from Ponzi Tulips.
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