So his internal calculation:

( value_of_heavily_used_forum_account < $200 )

This is a good reason to find out personal information on people you give loans to.

Note that printcoins.com does not. I have considered GoDaddy evil way before this SOPA thing, and this just hammers the point home.

This is so exciting. Will a fully anonymous person pay back nearly $200 in cash?

If you are not willing to spend 5 BTC you can't eat my toast.

Obviously you value your time much less than others. This isn't really for end users, but for people that want to sell their own bitcoin bills. They will end up paying more for their paper than they are paying me. They get the ease of just entering in quantity and selecting denomination, and not having to do anything in photoshop. 400 Bills sent to the printer at a push off a button.

Impossible to know. When you buy physical bitcoins off someone you are putting your trust into them.

The code to create the PDF will automatically generate the keypair and put the QR codes into the bill. It would take modifying the code to remove the private key. Though the printer could also scan the private key themselves to steal them (or also modify the code to make it record them).

That said, when the details of the algorithm are solid and can be translated into php or a bash script, I will be incorporating 3rd party private key addition to the bills (you would print a sheet, sticker it, send it to someone else to print over keypair two and they would sticker and cut it).

I am opening up physical bitcoin bill printing to others.

This will mean that you can easily create a dynamic pdf to generate these bills:



I will also provide help on the printing process. The cost will be 5 BTC and you will also need the following:

* A website (with a DNS registered to you)
* A color printer (I recommend Brother as their replacement ink is rather affordable - you go through a lot)
* 100% cotton paper 25lb or more in weight. Don't use wood pulp paper, it will fall apart in wallets.
http://www.amazon.com/s/?field-keywords=100%25+cotton+paper
* A good paper cutter:
http://www.amazon.com/Swingline-ClassicCut-Guillotine-Paper-Trimmer/dp/B00006IATF/ref=sr_1_5?ie=UTF8&qid=1324645320&sr=8-5
search for "paper stack cutter" to get something that cuts more than a few pages at a time (you will have to pay a lot more for that).
* 25mm (1 inch) square tamper evident holograms stickers. You can use much larger ones if you like. You will need one for each side of the bill. A package of 100 generics should be about $6, but Casascius is creating custom bitcoin ones that will be marked with your site name. They are preferable.
http://www.ebay.com/sch/i.html?_nkw=25mm+tamper+evident+hologram

Let's say you have about 1,000,000 bitcoins in your exchange, but 10,000 are lost due to operational mistakes. Your accounts still say they have 1,000,000 bitcoins. Who do you update for a loss? Do you update their losses? Do you subtract it from your profits? Do you just say, well it isn't like everyone is going to pull out 1,000,000 BTC in one day anyway. Lets just leave it float. No point in rocking the boat for a problem that isn't likely to ever get noticed.

What about if you lost 10% of the bitcoins in one day from a hack. Do you eat it, or just say... well no point in rocking the boat. Who will notice. It isn't like anyone is going to pull out 900K in btc in one day.

This isn't exactly scamming. This is not exactly stealing. The bitcoins in the DB still exist, they just don't happen to be backed by real bitcoins anymore, and we can make up the losses eventually.

And if you want to go to the dark side... (not saying they are)
---
Why not just take out a loan for 200K in btc, and upgrade all of the servers and support staff so the whole operation runs at top notch speed. They can just make back the money and then some from all the happy customers. With all this skilled talent, think of our savings in preventing mistakes. ...
---

The thing is, they could also be completely transparent and show that they are on the up and up. A full disclosure of all of their bitcoin addresses, along with a list of all balances in their accounts would help. The accounts could just display a code with the balance, and users could verify that the code in their account matches the db record and the same balance. It wouldn't be perfect, but it would at least make it an effort to cheat.

I suppose you are right. It is just one consideration people should have when dealing with an exchange.

I simply am listing the issues that have come up on the board, and note that if the errors outstrip their profits than their balance sheet will not line up, hence the possibility of a run.

@plogank was wondering how this could be spun negatively. If I saw my bank making mistakes that made it lose money, I would pull my money out, especially if it wasn't backed by something like FDIC protection.

I don't know if I would call this bad mouthing. I am just voicing a concern that I haven't seen mentioned anywhere else. Really I think that mtgox does quite well for itself with all of the volume, and most likely it's profits make for a balanced budget. But I also wouldn't be surprised if I was wrong in this assumption.

In other words: I reserve the right at some unknown (maybe non-existant) date to say "I told you so."

I have the benefit of never being able to be proved wrong

There is already a wiki page that does this:

https://en.bitcoin.it/wiki/In_Person_Traders

and people can put in whatever information they like.

Also, this is a list of physical merchants that accept bitcoin:

https://en.bitcoin.it/wiki/Real_world_shops

Personally I think the wiki model works best.

You see it as, hey great customer service. I see it as a system that is poorly automated, and fraught with human error. They make enough money that they don't sweat the small stuff, and that is cool and all, but I am always wondering if it will come to light that their errors mean that they do not actually have as much in the way of bitcoins or cash to meet the balances in their accounts.

Things I have seen
* The major hack which they "rolled back." How much they lost is unknown.
* Large pools of money they shift around between single addresses (suggesting to me a human activity rather than an automated bitcoin management system)
* The time they sent a large sum of bitcoins into oblivion (I forget how much)
* These errors where people are credited extra

Maybe they make enough profit per transactions that money slipping through the cracks is no big deal, but if they don't a run on the bank is a possibility.

Can anyone point to something that will just create a priv/pub pair.

I don't actually want to have the client running, I just want to buy some namecoins off someone, and have an address to store them at (in case some day in the future they are worth something).

Does namecoin work exactly the same way for priv/pub addresses. Can I use the same pair as a namecoin address and a bitcoin address. Can I use what is generated here:
https://www.bitaddress.org/
to create a namecoin address?

Also, is their a blockexplorer for namecoin? What about a nice friendly gui interface that will work on my mac for my wallet?

0.6 doesn't exist.

Strongcoin also allows for import, as well as pywallet.

I keep instructions here:
http://printcoins.com/redeem

It is what I print on my bills.

That would be another service to run on a webserver which is a bit heavy duty. Also, getting all the private keys out of it would require using pywallet to export them, and then reimport them into your desktop wallet.

I created a php library that uses "bitcoin-off-the-grid" (BOTG) (source: https://bitcointalk.org/index.php?topic=23081.20) which is a bash script.

Here is the library:
https://github.com/RobKohr/PHP-Bitcoin-Address-Creator

I trimmed out a bunch of stuff from BOTG to make it more script friendly, and wrapped a php exec call to it. It seems to work pretty well.

An exchange can't get around it as far as I can see. This is why you should only keep coins in the exchange for a limited time while doing an exchange. Get them back to the safety of your wallet once you are done.

Your wallet should be the safe place for coins, and an ewallet provider should not be trusted with plain text private keys. Ever. It would be the same as everyone in a city giving a homeless man their cash to hold onto in a cardboard box that he occasionally might walk away from (but his cat will watch it for him). If it disappears, either he made off with it, his cat made off with it, or someone got around his perfect security (duct tape). No one will ever know what happened.

I think reusing addresses is a bad idea and should be discouraged. Creating new addresses is free, and it makes it so their is no confusion as to who paid and who didn't. I basically use addresses as "order numbers" so that it is easy to relate an order to a payment.

I created a fork of pywallet which will import a text file of private keys into your wallet.
https://github.com/RobKohr/pywallet

The webserver could generate the pubs/privs and when you log in as an admin, you could download that private key list and import into your wallet. I would recommend that you delete the private keys on the webserver after you import them into your wallet.

I appreciate the red flag waving. It is important to alert developers to issues like that.

I currently have a pdf generator written in php to create bitcoin bills. I use a textarea to paste in addresses from bitaddress to generate the pdf (this is all done on localhost). I would like to just cut out that step and have php generate the addresses and then the pdf. This is so I can package the whole thing up nicely and release it open source.

I also want to create a simple ecommerce library that would create the private and public key on the server and keep the private keys encrypted (to be later downloaded by a site owner and decrypted).

Does anyone have an PHP code that can do what is done on this website:

https://www.bitaddress.org

Namely create private keys and associated public addresses?