Add Paper Wallet Generation in Bitcoin Core #5058

Ported by @andymeows and @whitj00 from @andymeows' dogecoin implementation.

Tested on Mac, Windows, and Linux with qt4 and qt5

Includes warning if computer is connected to Internet.

While not optimal, it is better than using a website like brainwallet.org and anything that makes cold storage easier for the average user is good IMO.

This is likely controversial and I am open to discussion on how to improve this.

I'll fix the missing image

NACK, when/if we add this, it should be a real paper wallet, not a single ECDSA private key. It would also be good to have paper wallet support merged before we start making them, too...

I'm assuming you mean deterministic paper wallets?

On Oct 7, 2014, at 12:46 PM, Luke-Jr notifications@github.com wrote:

NACK, when/if we add this, it should be a real paper wallet, not a single ECDSA private key. It would also be good to have paper wallet support merged before we start making them, too...

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@whitj00 I'm not aware of any other way to make actual paper wallets. A single key/address is not a wallet.

@luke-jr ok, makes sense. I think I did see HD paper wallets before, but thats useless in bitcoin core until we implement it.

What is the objection to including it? I understand that there are more optimal ways to do it, but until those are practical, wouldn't any feature that makes it easier to secure their coins be beneficial.

Users are not supposed to ever work with individual keys, and there is no safe way for them to do so. Even if one foolishly ignores the many issues with address reuse, micromanaging individual keys requires a strong understanding of the Bitcoin system. For example, I wouldn't even trust myself to properly/safely manage individual keys.

I do like the concept.

But in any case, due to its insistence on being synced to the network, Bitcoin Core is not a good online/offline wallet. Its utility for something like paper wallets is very limited, as any paper wallet you create will already be potentially 'spoiled' by being connected to the internet.

Have you looked at armory?

Maybe we should turn this into a separate key generation + printing utility? An external utility that you can run on a non-internet-connected PC. This idea has been brought up before, but now that we have an implementation this is easier to do.

An external one exists, bitaddress, and breainwallet. The current main issue with paper wallets in my opinion is that they're to complicated to do safely for the average user. They end up using an online service, that has ma vulnerabilities.

This is why it should be built into core, and not armory, which is aimed at advanced users.

This WArns you that you should disconnect from the internet, and this works (and is preferred) on a offline PC

Don't forget that Bitcoin Core is also aimed at advanced users. Average users would better use multibit, or electrum.

paper wallet may require BIP or a standard to discussed, such as format, storage, etc., as there are many parties take care of this standard.

@imharrywu Already exists, see https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki

@luke-jr, the issue is that bitcoin core doesn't support mnemonics. A similar feature like this would be great in electrum, but until bitcoin core does, it doesn't make sense to use bip-39

@laanwj agreed, but bitcoin core is not exclusively used by advanced users.

Many merchants I've spent BTC at use bitcoin core, because of issues with multi bit or another spv wallet, or because they need a full chain for whatever reason.

I've never seen a merchant using armory (i'm sure theres a few though)

Would it be preferable to make this feature only accessible offline?

@whitj00 Yes, that was my original point: it doesn't make sense to have this in any form in Bitcoin Core right now.

@whitj00 But it doesn't really make sense to use Bitcoin Core offline. It's a full node, it needs to be online. You'd never run it on a computer that is not connected to the internet. That's why I suggested a separate tool. It could still be packaged and released as part of Bitcoin Core, but it would be a separate executable that has no network connectivity at all.

@laanwj it would be interesting to see what percentage of people use bitcoinpaperwallet online.

I also think this should not go into bitcoin-core. A standalone paper wallet generation app would def. make much more sense. It makes no sense to generate a offline paper wallet within a app that serves/acts as a full node.

Should be closed IMO.

I also think this should not go into bitcoin-core. A standalone paper wallet generation app would def. make much more sense. It makes no sense to generate a offline paper wallet within a app that serves/acts as a full node.

Exactly. It's useful functionality, but just doesn't fit in the goal of this software.