(pics) Physical Bitcoin Bills - For Real World Transactions - Printcoins.com

[Daily Anarchist]

Whoops, I spoke to soon. Your 50 BTC note is still 3 BTC over spot. If you can make a single 1 BTC note and profitably sell it at 1.30 BTC, then you should be able to make a single 50 BTC note and profitably sell it at 50.30 BTC.

I would imagine the pricing system looks something like this:

                              Purchasing 1 Note       Purchasing 5 Notes      Purchasing 20 Notes      Purchasing 100 Notes      Purchasing 1,000 Notes

1 BTC Note              1.30 BTC                    6.25 BTC                    24 BTC                        115 BTC                       1,100 BTC

5 BTC Note              5.30 BTC                    26.25 BTC                   104 BTC                       515 BTC                       5100 BTC  

10 BTC Note            10.30 BTC                   51.25 BTC                   204 BTC                       1015 BTC                     10,100 BTC  

20 BTC Note            20.30 BTC                   101.25 BTC                  404 BTC                       2015 BTC                     20,100 BTC

50 BTC Note            50.30 BTC                    251.25 BTC                 1004 BTC                      5015 BTC                     50,100 BTC


Make sense?

[1715162734]

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[1715162734]

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[1715162734]

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[casascius]

The downside: this will cost more in labor, shipping and materials.

The upside is that people who don't want to screw around with software will have a reliable way to get a very secure savings wallet, possibly the most secure wallet available to a non-technical person.  If we're jamming three or four holograms on this thing, the material costs are already somewhat expensive anyway.

[Daily Anarchist]

Whoops, I spoke to soon. Your 50 BTC note is still 3 BTC over spot. If you can make a single 1 BTC note and profitably sell it at 1.30 BTC, then you should be able to make a single 50 BTC note and profitably sell it at 50.30 BTC.

I would imagine the pricing system looks something like this:

                              Purchasing 1 Note       Purchasing 5 Notes      Purchasing 20 Notes      Purchasing 100 Notes      Purchasing 1,000 Notes

1 BTC Note              1.30 BTC                    6.25 BTC                    24 BTC                        115 BTC                       1,100 BTC

5 BTC Note              5.30 BTC                    26.25 BTC                   104 BTC                       515 BTC                       5100 BTC  

10 BTC Note            10.30 BTC                   51.25 BTC                   204 BTC                       1015 BTC                     10,100 BTC  

20 BTC Note            20.30 BTC                   101.25 BTC                  404 BTC                       2015 BTC                     20,100 BTC

50 BTC Note            50.30 BTC                    251.25 BTC                 1004 BTC                      5015 BTC                     50,100 BTC


Make sense?

The question you have to ask yourself is, even at very large orders, what is the absolute CHEAPEST I can sell 1 note worth. If the absolute cheapest amount you can sell a note for is 30 Bit cents over spot, then you'll have to make THAT your target goal for the bulk pricing. Notice above how I made it so that at 1000 notes ordered, the cost per note is 10 Bit cents over spot. Simply adjust that to be 30 Bit cents over spot, and re-adjust the rest to be slightly higher. In that case if somebody one orders, say, 1 note all by itself the cost might be 55 Bit cents above spot. Make sense?

[PrintCoins]

Whoops, I spoke to soon. Your 50 BTC note is still 3 BTC over spot. If you can make a single 1 BTC note and profitably sell it at 1.30 BTC, then you should be able to make a single 50 BTC note and profitably sell it at 50.30 BTC.

I would imagine the pricing system looks something like this:

                              Purchasing 1 Note       Purchasing 5 Notes      Purchasing 20 Notes      Purchasing 100 Notes      Purchasing 1,000 Notes

1 BTC Note              1.30 BTC                    6.25 BTC                    24 BTC                        115 BTC                       1,100 BTC

5 BTC Note              5.30 BTC                    26.25 BTC                   104 BTC                       515 BTC                       5100 BTC  

10 BTC Note            10.30 BTC                   51.25 BTC                   204 BTC                       1015 BTC                     10,100 BTC  

20 BTC Note            20.30 BTC                   101.25 BTC                  404 BTC                       2015 BTC                     20,100 BTC

50 BTC Note            50.30 BTC                    251.25 BTC                 1004 BTC                      5015 BTC                     50,100 BTC


Make sense?

I brought the price down significantly for the 50 BTC bill, but I do still include a percentage in my markup. I consider it a handling fee for the risk of managing $250 worth of cash. You may think that is no big deal as a transaction is a transaction, but I get a little nervous when I have to handle that much for someone. If someone ordered a hundred 50BTC bills, I would probably need to take the day off from work just to make sure I was ultra careful with each one being loaded.

If the markup is a big deal, just buy the open denomination bill, which is the cheapest one available. You can load it with whatever you like, and I don't have to handle your money for you.

Also, note that I just added "a stack of 100 1BTC bills" to the shopping system. There is a nice discount there, and coincidentally it is priced about the same as what you expected in your chart.

[Daily Anarchist]

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

[casascius]

I brought the price down significantly for the 50 BTC bill, but I do still include a percentage in my markup. I consider it a handling fee for the risk of managing $250 worth of cash. You may think that is no big deal as a transaction is a transaction, but I get a little nervous when I have to handle that much for someone. If someone ordered a hundred 50BTC bills, I would probably need to take the day off from work just to make sure I was ultra careful with each one being loaded.

Maybe we should share some notes on how to efficiently fund bills.

For me, loading BTC on coins gives me virtually no anxiety, even if I'm doing 2000+ BTC in a single run.  I have a rock solid way to track and load them.  I am using a database to track their loading status, and everything is crosschecked against the master list of bitcoin addresses so I don't load the wrong thing.  Also since I keep my BTC on paper wallets, I only unpaperize the BTC I am about to load right then and there - so there's no risk that I send all my BTC to the wrong place by fat fingering an amount.

[DeathAndTaxes]

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely? 

As far as 0.06 BTC markup.  You are aware there is no central bank which can subsidize printing costs.  Things like material, labor, custom holograms, etc do time take and resources.   Your expectations may be a little unrealistic.

[PrintCoins]

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely?  

As far as 0.06 BTC markup.  You are aware there is no central bank which can subsidize printing costs.  Things like material, labor, custom holograms, etc do time take and resources.   Your expectations may be a little unrealistic.

D&T -  Thank you, you are now my official spokesperson for all pricing issues.

Also, anyone is welcome to undercut me if I charge too much. You could probably charge much less and still make a profit if you have access to cheap labor.

[Daily Anarchist]

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely? 

As far as 0.06 BTC markup.  You are aware there is no central bank which can subsidize printing costs.  Things like material, labor, custom holograms, etc do time take and resources.   Your expectations may be a little unrealistic.

Well, obviously there is going to be markup. But 3 BTC markup on a 50 BTC note is too steep for me. So is 17 BTC on 100 1 BTC notes.

I'm sure, eventually, there will be competition in the Bit bill market, driving prices down.

[PrintCoins]

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely? 

As far as 0.06 BTC markup.  You are aware there is no central bank which can subsidize printing costs.  Things like material, labor, custom holograms, etc do time take and resources.   Your expectations may be a little unrealistic.

Well, obviously there is going to be markup. But 3 BTC markup on a 50 BTC note is too steep for me. So is 17 BTC on 100 1 BTC notes.

I'm sure, eventually, there will be competition in the Bit bill market, driving prices down.

I am just giving room for a competitor to step in and eat my lunch. If I charged too little, than what would be the incentive for anyone else to break into the market.

[Daily Anarchist]

That's really cool! I suppose as you get more confident with what you're doing the markup fee will drop, or disappear altogether. Also, as demand increases, including for larger amounts, there will be bulk pricing for larger notes. But as it's not too likely that somebody is going to order 100 50 BTC notes right now, it's not really that important. I'm glad you have bulk pricing for the 1 BTC notes. It's still a little too high for me right now. But if you can get your prices down to, say, 106 BTC for 100 1 BTC notes, I'd throw down for that.

You're creating a very important product and I'm glad you're putting a lot of thought into it. This can be something that is truly badass and puts Bitcoin on the map for a much larger segment of society.

Why would markup disappear completely? 

As far as 0.06 BTC markup.  You are aware there is no central bank which can subsidize printing costs.  Things like material, labor, custom holograms, etc do time take and resources.   Your expectations may be a little unrealistic.

Well, obviously there is going to be markup. But 3 BTC markup on a 50 BTC note is too steep for me. So is 17 BTC on 100 1 BTC notes.

I'm sure, eventually, there will be competition in the Bit bill market, driving prices down.

I am just giving room for a competitor to step in and eat my lunch. If I charged too little, than what would be the incentive for anyone else to break into the market.

Fair enough.

[pointbiz]

Is this the proposal?  Should work.

Person 1:
  Create a random private key (a)
  From the random private key calculate the standard public key (A = a*G)
  Send the public key (A) to person 2

Person 2:
  Create a random private key (b)
  From the random private key calculate the standard public key (B = b*G)
  Send the public key (B) to person 1

Person 1:
  From the random private key (a) and the public key created by person 2 (B) calculate the final public key (F = a*B)
    [Note a*B = a*b*G which makes the final private key a*b]
  Calculate the final public key address of the final public key (F)

Person 2:  
  From the random private key (b) and the public key created by person 1 (A) calculate the final public key (F = b*A)
    [Note b*A = b*a*G which makes the final private key b*a]
  Print the private key (b) on the bill - and cover it with a sticker to hide it
  Calculate the public key address of public key F and print it on the bill
  Send the bill to person 1

Person 1
  Finally print the private key (a) on the bill
  Can match the public key address calcluated above with the public key address on the bill

Burt you are a great source of clarity. Thanks for the above post!

[BurtW]

Thanks.  I really like this elliptical curve crypto - it is a lot more fun than RSA.

[DeathAndTaxes]

Thanks.  I really like this elliptical curve crypto - it is a lot more fun than RSA.

Maybe we should take this to another thread but can you explain this

(F = b*A)

since both keys are 256 bit numbers are we just doing simple multiplication here.

i.e.
5 * 8 = 40 (but obviously much larger numbers).   How are we handling 256 bit overflow.

Or maybe I am complete off.  Can you provide an example of (F = b*A) using real numbers.

[BurtW]

Quickly,

First, private keys are just very large numbers but public keys are actually a pair of two very large numbers representing the x, y coordinates of a point on an elliptical curve.

I use lower case letters to represent elements of the selected finite field and capital letters to represent points in the selected elliptical curve group.

So:  a = b*c represents simple modulo multiplication for the selected finite field, short for a = ((b*c) mod p)

And: A = B + C would represent the defined point addition operation on the selected elliptical curve group.  This is not simple addition, it is the way we define the addition of two points on the elliptical curve.

Then A = a*G is just G+G+G+G+...+G, a times.  And in this case the * represents the defined scalar multiplication operation for the selected finite field over the selected elliptical curve group - so no this is not simple multiplication it is a pretty involved function and can be a bit time consuming.

Clear as mud?

[PrintCoins]

Update: 0.5 BTC denomination bills now available.

If this price rally keeps up I might even get to roll out my 0.25 bills.

Here is a complete list of all intended colors (going down to 0.01 BTC - which would require bitcoins to be around $100 a piece to make sense):

http://printcoins.com/colors

[casascius]

Thanks.  I really like this elliptical curve crypto - it is a lot more fun than RSA.

Maybe we should take this to another thread but can you explain this

(F = b*A)

since both keys are 256 bit numbers are we just doing simple multiplication here.

i.e.
5 * 8 = 40 (but obviously much larger numbers).   How are we handling 256 bit overflow.

Or maybe I am complete off.  Can you provide an example of (F = b*A) using real numbers.

In this case, A is not a 256-bit number.  In programming terms, it is an object, a structure with two 256-bit numbers known as X and Y.  The definition of "multiplication" has been redefined - in C++ terms, the "multiplication operator" has been overridden with a far more complex definition.  So, F = b * A means "Perform the elliptic curve multiplication operation on point object A, using the 256-bit integer b as a parameter"... this operation returns another point object, not a number.

And 256 bit overflow is not a concern once you understand what "finite field" is.  Yes, there is overflow, and the overflow is thrown away - but you must critically understand that the overflow doesn't happen at 2^256, it happens at another number known as N, which is a 256-bit number, but smaller than 2^256.  So when you do scalar multiplication and the answer exceeds N, you handle the overflow by dividing by N and keeping the remainder (not dividing by 2^256 and keeping the remainder, as "handling 256 bit overflow" strictly means).

N is a constant you can find on the bitcoin wiki, search for "secp256k1".

[BurtW]

The number mike calls N is the same number I call p (for "prime") is the prime number:

p = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F

All the other parameters for the Bitcoin elliptical curve system can be found here: 

https://bitcointalk.org/index.php?topic=53177.msg635050#msg635050

and most of the thread at https://bitcointalk.org/index.php?topic=53177.0 is interesting and informative.

[casascius]

The number mike calls N is the same number I call p (for "prime") is the prime number:

p = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F

All the other parameters for the Bitcoin elliptical curve system can be found here:  

https://bitcointalk.org/index.php?topic=53177.msg635050#msg635050

and most of the thread at https://bitcointalk.org/index.php?topic=53177.0 is interesting and informative.

Between the two of us, one of us has it wrong, because I think the number that needs to be divided by and mod taken is

FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141.

This is the number I'm calling N.  The number above you have called p is the number I would call p as well, but I don't think that's the right number for this purpose.

THe person who has it wrong could very well be me, becuase chances are I implemented it, saw it worked, and forgot about it further.  I could have had a brainfart and used the other number instead, but this is the number I always thought i used.

[BurtW]

Ok we both agree:

Code:

p = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F

n = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141

According to the docs p is the prime number specifying the finite field used and n is the prime number specifying the order of G.

So I think the number p should be used for all the finite field math operations, for example a = b*c mod p

And n has something to do with G (the base point of the system).

So, I believe that I am correct in that the "overflow" in the finite field math is at p.

I am trying to remember exactly what n means and how it is used.  I remember reading it and understanding it at one point but I forget now exactly what it means.

If I find the reference again I will post it here.

We need to nail this down because it affects the all important calculation of the final private key f = a*b mod ?

So you could easily experimentally determine which one it is.  Calculate the final private key using each number and let us know which one calculates the correct final private key.