Topic: Printing bitcoins, an implementation - page 3. (Read 17683 times)
As I said, I think the bitbill is using an ASN.1/DER encoded form of the key which is inefficient and unnecessary.
Something doesn't seem quite right with this challenege,
looking at the other thread with basically the same premise and goal, Hal provided his private key
"C85AFBACCF3E1EE40BDCD721A9AD1341344775D51840EFC0511E0182AE92F78E
My new attempt to base58 encode this is:
EV71KQfoePBeWT79sV1VE7fWRgv1KNUxTNapH6ZbaRfB"
The base58 encoded block on the bitbill is much much longer than Hal's example base58 encoded private key. Am I missing something?
looking at the other thread with basically the same premise and goal, Hal provided his private key
"C85AFBACCF3E1EE40BDCD721A9AD1341344775D51840EFC0511E0182AE92F78E
My new attempt to base58 encode this is:
EV71KQfoePBeWT79sV1VE7fWRgv1KNUxTNapH6ZbaRfB"
The base58 encoded block on the bitbill is much much longer than Hal's example base58 encoded private key. Am I missing something?
How long does it take to verify the contents of a mybitcoin account?
Or how much money is on your walmart gift card?
It's a very simple matter, only takes a second.
Or how much money is on your walmart gift card?
It's a very simple matter, only takes a second.
Wouldn't it be possible to have a QR code of the associated public key on the note, so that someone could scan the bill and say 'yep this bill has X bitcoins assigned to it'?
I haven't read the entire thread so forgive me if this is repetitive.
I haven't read the entire thread so forgive me if this is repetitive.
How long would it take to verify the note? 10min?
Wouldn't it be possible to have a QR code of the associated public key on the note, so that someone could scan the bill and say 'yep this bill has X bitcoins assigned to it'?
I haven't read the entire thread so forgive me if this is repetitive.
I haven't read the entire thread so forgive me if this is repetitive.
Perhaps invisible ink can satisfy that requirement.
Boy, you are married to that invisible ink idea, aren't ya?
I think the difference here is in our ideas of the use case. I see it as a replacement for giftcards, being secure enough to get to the grandkids intact.
You see it as a replacement for FRNs, needing to stand up to the abuse and attacks that they do. Certainly, you're welcome to print access codes to digital money on a note that would then be subjected to getting "folded, crumpled, washed, used as narcotic paraphernalia, and manipulated by moist genitalia."
If you can keep the cost of such a note low enough, while maintaining security, go for it. I'd still say that digital, via debit cards, smart-phone apps, and the like, will replace FRNs for daily use, though. Why give up all the advantages that digital currency has over printed?
There's two issues that I see in this. The first one is that there's nothing protecting the image and anyone that sees the image can take the currency. In addition, there's nothing on the note that guarantees that the note is even worth anything. The only way to verify that the note is worth something is to scan the note. It's also a huge waste of paper since once the note is used it's worthless. What I would suggest is using a digital note on e-ink technology. The printed bitcoin could then be used over again. In addition there should be something added to the note that can be sensed through touch, sight or sound to tell if the note is lineament or not and then finally there needs to be some key such as a password, biometric print or fob that can be used to lock and unlock the note.
I don't recall seeing scratch-off layers on anything except for relatively stiff card stock or plastic. Paper money gets folded, crumpled, washed, used as narcotic paraphernalia, and manipulated by moist genitalia. Could a bitcoin note utilizing a scratch-off layer stand up to such abuse? I doubt it. In fact, I have a used scratch-off game right here. After folding it a few times, I see cracks in the remaining paint. We'd do well to look into other more durable methods. Perhaps invisible ink can satisfy that requirement.
here in Italy, 100% of the cards for buying phone prepaid credit are scratch cards, instant lottery tickets are scratch cards, etc... I've never heard of someone buying a card that was used and re-printed with the metal layer.
OFC I must say usually you don't buy them from other people but from "commercial entities". Still, if one can quickly check if the money is in the process of being double-spent, this is still way more safer then cheques.
OFC I must say usually you don't buy them from other people but from "commercial entities". Still, if one can quickly check if the money is in the process of being double-spent, this is still way more safer then cheques.
Or... He could cover the sensitive data with metallic paint. Works fine for the lottery.
Global community note: in the US, scratch cards such as ptmhd suggested are used extensively, in raffles of all kinds, but mostly in state-run lottery schemes. They are priced at 1-5 dollars per scratch cards, and have prizes in excess of $1000, depending on the state and card. It's a proven technology, and fairly secure.
That said, I don't see why BOTH technologies couldn't co-exist, though I do lean towards scratch cards being more economically viable. (code + paint vs code (special ink) + UV layer (special ink) + IR layer (Special ink) + solvent to redeem)
But one only has a small probability that cheating a scratch-off game will earn a reward. Assuming an honest issuer, freshly issued notes carry a probability of 1 that they represent bitcoins.Global community note: in the US, scratch cards such as ptmhd suggested are used extensively, in raffles of all kinds, but mostly in state-run lottery schemes. They are priced at 1-5 dollars per scratch cards, and have prizes in excess of $1000, depending on the state and card. It's a proven technology, and fairly secure.
That said, I don't see why BOTH technologies couldn't co-exist, though I do lean towards scratch cards being more economically viable. (code + paint vs code (special ink) + UV layer (special ink) + IR layer (Special ink) + solvent to redeem)
Scratch-offs would only work if the issuer printed a difficult to replicate but easily verifiable image on top of the scratch area. That requires three layers of printing, versus one or two for invisible ink. Therefore, scratch-off bitcoin notes are more expensive and must represent more bitcoins to offset their production cost. Subsequently, they are a nicer target than invisible ink notes.
If the notes are cheap to produce then the issuer can afford to periodically recall notes and issue new ones. This way, the issuer can keep up with technology, preserve the value of his notes and reclaim the bitcoins associated with lost or destroyed notes. Holders who can't bring their notes back to the issuer to receive new ones can just reveal the invisible ink and redeem the bitcoins themselves before the end of the recall period.
Here's how I think a one bitcoin note might look. I'm happy to share the .idw file if anyone would like.
scratch card ... fairly secure.
It's secure for the issuer, because there's also a checksum printed on the card. But it's not so secure for the layperson, who depends for security upon buying the scratchcard from a trusted vendor. As these scratchcards are not widely used as money, that's good enough.
Or... He could cover the sensitive data with metallic paint. Works fine for the lottery.
Global community note: in the US, scratch cards such as ptmhd suggested are used extensively, in raffles of all kinds, but mostly in state-run lottery schemes. They are priced at 1-5 dollars per scratch cards, and have prizes in excess of $1000, depending on the state and card. It's a proven technology, and fairly secure.
That said, I don't see why BOTH technologies couldn't co-exist, though I do lean towards scratch cards being more economically viable. (code + paint vs code (special ink) + UV layer (special ink) + IR layer (Special ink) + solvent to redeem)
Global community note: in the US, scratch cards such as ptmhd suggested are used extensively, in raffles of all kinds, but mostly in state-run lottery schemes. They are priced at 1-5 dollars per scratch cards, and have prizes in excess of $1000, depending on the state and card. It's a proven technology, and fairly secure.
That said, I don't see why BOTH technologies couldn't co-exist, though I do lean towards scratch cards being more economically viable. (code + paint vs code (special ink) + UV layer (special ink) + IR layer (Special ink) + solvent to redeem)
It's invisible to every specrtum of light, or just the human-visible ones?
Let's say you have ink that is invisible to human eyes, but it is visible in IR. You could just print it on top of ink or paper that is as visible in IR. You can do the same with UV too. Beyond the UV to IR spectrum though, the cost of trying to read this invisible ink gets high. The issuer can avoid this problem by not letting the note represent too many bitcoins. Better idea, Scan the note, digitally process it to bring out the private key (using filters, perhaps?), transfer the money out, then spend the original, now worthless, paper.
But the ink is invisible. There's nothing to filter.Better idea, Scan the note, digitally process it to bring out the private key (using filters, perhaps?), transfer the money out, then spend the original, now worthless, paper.
But the ink is invisible. There's nothing to filter.we'll be doing the scratch card method prints
QR code of the funded address is visible
QR code of the private key is under a layer of metallic paint
see DIY howto here http://artmind-etcetera.blogspot.com/2009/05/how-to-make-scratch-off-lottery-tickets.html
that way no need for invisible ink and co, just print all data and cover the sensitive parts
What's to stop someone from painting another scratch-off layer?QR code of the funded address is visible
QR code of the private key is under a layer of metallic paint
see DIY howto here http://artmind-etcetera.blogspot.com/2009/05/how-to-make-scratch-off-lottery-tickets.html
that way no need for invisible ink and co, just print all data and cover the sensitive parts
Quote
also no need for standardization. printouts will remain a marginal form of btc circulation, more or less as gift cards
+a way to build reputation in community (issuing printed btc requires audience that trusts that they will not be spent by issuer)
It'd be nice though to just use a code without having to figure out which standard it followed. +a way to build reputation in community (issuing printed btc requires audience that trusts that they will not be spent by issuer)
Interesting concept of a "bitcoin note". I also like the design you suggested.
However, such a note is different from usual bank notes, since it has value only during a limited period of time. Basically until someone redeem the bitcoin on the address and transfer it to an other address.
That's why I think there should be a note saying what exactly this is.
Something like:
<< This is a private key of a bitcoin address which was holding 1 BTC at block number NNNN. >>
However, such a note is different from usual bank notes, since it has value only during a limited period of time. Basically until someone redeem the bitcoin on the address and transfer it to an other address.
That's why I think there should be a note saying what exactly this is.
Something like:
<< This is a private key of a bitcoin address which was holding 1 BTC at block number NNNN. >>
that way no need for invisible ink and co, just print all data and cover the sensitive parts
also no need for standardization. printouts will remain a marginal form of btc circulation, more or less as gift cards
+a way to build reputation in community (issuing printed btc requires audience that trusts that they will not be spent by issuer)
also no need for standardization. printouts will remain a marginal form of btc circulation, more or less as gift cards
+a way to build reputation in community (issuing printed btc requires audience that trusts that they will not be spent by issuer)
This. Scratch cards are the way to go, if you're going to print the things...
And yeah, I can see grandmas sending scratch card bitcoins to kids every christmas. Heck, they might even make cards with the BTC already printed on them.
I can also see the news story when a whole bunch of them get to their recipients already spent because some unscrupulous employee snagged the Private keys off the cards before they got their protective coating of scratchy-paint. (Possible, but very difficult... involves a hi-speed digital camera and the willingness to place pieces of yourself close to machinery that's moving very very fast.) Remember, parents, verify before you buy!
Is there really no way to read the invisible ink without leaving obvious signs the ink has been seen already?
we'll be doing the scratch card method prints
QR code of the funded address is visible
QR code of the private key is under a layer of metallic paint
see DIY howto here http://artmind-etcetera.blogspot.com/2009/05/how-to-make-scratch-off-lottery-tickets.html
that way no need for invisible ink and co, just print all data and cover the sensitive parts
also no need for standardization. printouts will remain a marginal form of btc circulation, more or less as gift cards
+a way to build reputation in community (issuing printed btc requires audience that trusts that they will not be spent by issuer)
Photocopy the invisible ink bitcoin bill, and spend it. When the new owner tries to redeem it, they discover that the invisible ink is a lie.
This is not directly defrauding the issuer of the bills, but it would bring the system into disrepute.
The issuer can employ watermarks that show up on photocopies, as banks already do with checks.This is not directly defrauding the issuer of the bills, but it would bring the system into disrepute.
Better idea, Scan the note, digitally process it to bring out the private key (using filters, perhaps?), transfer the money out, then spend the original, now worthless, paper.
Seriously, though... When even the dude in the mud hut in Zimbabwe has a smart-phone, Do we really need paper money anymore?
I'd think phones would be much more convenient, if implemented well. Buying beers is always a slow process with cash because of fiddling with change. With an NFC smartphone it could just be take phone out of pocket, unlock screen, tap on the bar ... done.
Emphasis on "implemented well". Some smart phones stink ("hold on, I have to run app-kill") and the prospect of getting drunks and technology to play nice doesn't sit well with me. An electronic system would have to work easier than a paper/plastic one. For example, the bartender would tell me the price, I touch the screen no more than once after unlocking my phone, wave it, and get beer. Having to aim the phone at a QR code or coordinate precisely with the bartender won't work.Photocopy the invisible ink bitcoin bill, and spend it. When the new owner tries to redeem it, they discover that the invisible ink is a lie.
This is not directly defrauding the issuer of the bills, but it would bring the system into disrepute.
The issuer can employ watermarks that show up on photocopies, as banks already do with checks. This is not directly defrauding the issuer of the bills, but it would bring the system into disrepute.
Jump to: