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PaperCoin - paper offline Bitcoin wallets

papercoin.org

41–50 of 51 posts

Re: PaperCoin - paper offline Bitcoin wallets

#42
post #37

Earlier quoted context omitted.

Given a public key you can look up the balance in the blockchain. Casascius has a cool system where the private key is hidden behind a tamper-evident hologram so you can be sure money hasn't been removed, but obviously that's not a DIY option.

Of course they can check at the point of sale, but times where paper money is most useful and times where you have immediate access to the blockchain do not exactly overlap. If they can check right then and there, might as well just do it electronically and skip the paper. My point is basically that paper money is a store of value while these "paper bitcoins" are a proxy for a store of value, which introduces problem…

Yeah, I don't think paper Bitcoins are useful for trade. I think they're more useful to keep private keys from getting stolen.

Re: PaperCoin - paper offline Bitcoin wallets

#43
post #7
post #6

Earlier quoted context omitted.

To be fair, at the bottom of the page he links to source and a zip that you can use to run internally if you so desire. If it concerns you, then run it on your own machine.

The generation could still be deterministic in some way. I haven't looked over the code yet, so I don't know. Even if it is securely created, there's nothing stopping the code being modified to some clients.

That's the point of distributing the source code.

Re: PaperCoin - paper offline Bitcoin wallets

#45
post #32
post #25

Earlier quoted context omitted.

So you are saying even hybrid wallets like blockchain.info are unsafe?

Look at how bitcoin.org handles it, see the [?] boxes there: http://bitcoin.org/en/choose-your-wallet

But some hybrid wallets like blockchain.info are so secure.

They do client side encryption, js verifier makes sure any server attacks don't affect the wallets directly, allows user to backup their wallets the way they want, has some redudant backup options, two-factor authentication, and so much more. I don't see a reason why not to trust such wallets.

I agree there have been past instances where the server was comproised and users lost their wallets, but with such hybrid wallets if you are taking regular backups of your wallets you are pretty safe.

Re: PaperCoin - paper offline Bitcoin wallets

#46
post #21
post #19

Am I the only person who can't follow the instructions? What is the finished product supposed to look like?

Where the instructions say fold - you fold 180 degrees, not 90. So the wallet stays always flat. I added the 180 degrees note to the instructions.

It's also worth noting that the direction of the fold is always away from the printed side. The black blocks are meant as a security layer which gets folded overtop the key info (so you can't see the keys through the paper) and the final fold followed by taping of the ends together seals everything in with only the QR code and the "Remarks" area showing on the outside.

Re: PaperCoin - paper offline Bitcoin wallets

#47
post #3

I hate dinging hobby projects, but then it's Bitcoin and people seem to be actually trusting hobby projects with non-trivial fractions of their (extremely notional) net worth, so I'll just point out that transferring a public/private key pair which allows people to spend money together over HTTP is not a security best practice.

>I hate dinging hobby projects

I don't think you should feel even a hint of remorse, crypto and money are both very serious things. A project with crypto and money at its center is in my mind basically exempt from any margin for error normally associated with a hobby project.

Re: PaperCoin - paper offline Bitcoin wallets

#48
post #45
post #32

Earlier quoted context omitted.

Look at how bitcoin.org handles it, see the [?] boxes there: http://bitcoin.org/en/choose-your-wallet

But some hybrid wallets like blockchain.info are so secure. They do client side encryption, js verifier makes sure any server attacks don't affect the wallets directly, allows user to backup their wallets the way they want, has some redudant backup options, two-factor authentication, and so much more. I don't see a reason why not to trust such wallets. I agree there have been past instances where the server was compr…

There have also been several bitcoin services where the owners ran away with the users' money.

Re: PaperCoin - paper offline Bitcoin wallets

#49
post #45
post #32

Earlier quoted context omitted.

Look at how bitcoin.org handles it, see the [?] boxes there: http://bitcoin.org/en/choose-your-wallet

But some hybrid wallets like blockchain.info are so secure. They do client side encryption, js verifier makes sure any server attacks don't affect the wallets directly, allows user to backup their wallets the way they want, has some redudant backup options, two-factor authentication, and so much more. I don't see a reason why not to trust such wallets. I agree there have been past instances where the server was compr…

I doubt any significant potion of the user base uses the client side verifier.

Re: PaperCoin - paper offline Bitcoin wallets

#50
post #15

There seems to be some confusion about this project, so I'll try to explain: PaperCoin creates paper Bitcoin gift cards. You put money on the address, then you give the private key to whoever, and now they own the wallet. (Correct me if I'm wrong, I'm not the author.) It all happens client-side using jsPDF, and you can run it locally by downloading the .zip in the footer. It's really not meant to replace any financia…

The site creator should probably add your instructions somewhere on the page. Thank you for explaining!
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