This may be of use in Point-Of-Sale applications: Public address is pasted on counter, private key is kept in a safe and emptied out every night.

The ~10 minute delay for confirmations may be awkward though.

This is awesome!


I don't think you need to actually wait for any confirmations for transactions that don't involve large transfers of value. It's only for cases where you think the person has the computational means to pull off a double spend attack that you would need some confirmations to be sure the transaction won't be reversed.

You are notified that it has been broadcasted immediately, as the incoming transaction shows up on your client as unconfirmed. Your client then broadcasts to the rest of the network. The risk is that the stranger then immediately spends the same bitcoins again, and that subsequent spend becomes confirmed, while the ones you thought you received are not transferred to you. I believe that if the first transaction has a head start on the second one though, the chance that the second one will end up as the confirmed one is very low.

The engraver should be here tomorrow and I have 14 Gold metal USB drive business card I'm gonna test it on befire doing anything else, once i try one, i'll sell it to you with anything you want, whether it be a qr code, design, etc for 2btc. capactiy is 1gb

Awesome! I can't wait!

DEFINITELY count me in for one then!

Thanks!

Wait, gold? You mean it's colored gold, right? Not actual gold?

I love the idea and will definitely order a set BUT there is something I don't understand:

1) The intended use is for an off-the-internet life savings account, right?
2) But as you potentially have the keys for that I cannot trust it to hold my life savings (nothing against you, I think it's just a common sense precaution)

If I got that wrong and it's just for holding a few bucks, then it's more for showing off and probably don't need the private key card as you often use the account anyways..


Is there some safe way you could create those cards without you keeping the private key? Maybe provide you with an encrypted version you would then engrave?

Just wondering.. I want that set, but I also want it to have real practical use

i already have a secure key pair.

i suppose i could just order the public key half for my card?

Just a question: how easily can the QR codes be scanned if they are etched and appear white (instead of a high-contrast black and white)?

I tried to scan the QR on the photo of your prototype but the QR apps I usually use would not recognize it...