Method of storing wallet on paper

[Nightshader]

In respect of opening up my account here I like to share some things learned over the last few days.

EDIT:

This advice must be regarded with RED warning tape!

Got some Bitcoins in my wallet, how to cold store them on paper?

I already made some backups of the wallet.dat the bitcoin-qt (original) client uses to store my wallet. But that didn't feel good knowing that this one file could be brute-forced to open the pass-phrase. So after some research the conclusion was: Just knowing the uncompressed private key of the wallet is the only thing needed to store securely on paper ( given the private key only, one can calculate the public Bitcoin address and the blockchain knows the number of btc on this address and stores it forever ).

What I practically did:

• Extracted the real uncompressed private key so I'am independent of the clients backup format
• Using Bitcoin-qt go the Help menu and Enable the Debug window
• Use the command: walletpassphrase "yourpassword" 600
• Now your locked/encrypted wallet has been opened for private commands
• Use the command:dumpprivkey yourbitcoinaddress
• Now you see something like 91b24bf9f5288532960ac687abb035127b1d28a5
• Offline created QRcodes containing the private key and the Bitcoin address using http://sourceforge.net/projects/qrcodegenerator/files/code/
• Without storing on media directly print two copies of the QRcodes and in plaintext to avoid any QRcode reading problems in the future - who knows

Using two wallets: "cold storage" and "active use"

Now knowing about the cold storage being safe on paper in two separate vaults, it was time to reduce the risk and switch wallets.

Steps:

• Downloaded the Bitcoin address generator on https://www.bitaddress.org for off-line use
• Generated new Bitcoin address and stored this cold like above.
• Send some of the bitcoins to this "active use" wallet
• Waited for many confirmations and closed the client, deleted the wallet from Bitcoin-qt since this is long term cold storage
• Added the "active use" wallet by using the command: importprivkey <bitcoinprivkey> ActiveUse rescan=true
• Now the switch is complete and the risk has been reduced to just the "active use" coins on my computer

So without installing another client, wallet manager or giving my details to some online website the wallet has been stored on paper and switched. Your coins are always recoverable without knowing any password when you have the private key available in plaintext - after many years this is easily accessible and independence is good - specifically when it's our private wallet you should not depend on 3th-party tools,websites or some kind of vendor lock.

BTC tips are welcome: 1JqZaexSV45MFDYzKbV4sak3QevkJdMJsj

[deepceleron]

In respect of opening up my account here I like to share some things learned over the last few days.

Got some Bitcoins in my wallet, how to cold store them on paper?

I already made some backups of the wallet.dat the bitcoin-qt (original) client uses to store my wallet. But that didn't feel good knowing that this one file could be brute-forced to open the pass-phrase. So after some research the conclusion was: Just knowing the uncompressed private key of the wallet is the only thing needed to store securely on paper ( given the private key only, one can calculate the public Bitcoin address and the blockchain knows the number of btc on this address and stores it forever ).

What I practically did:

• Extracted the real uncompressed private key so I'am independent of the clients backup format
• Using Bitcoin-qt go the Help menu and Enable the Debug window
• Use the command: walletpassphrase "yourpassword" 600
• Now your locked/encrypted wallet has been opened for private commands
• Use the command:dumpprivkey yourbitcoinaddress
• Now you see something like 91b24bf9f5288532960ac687abb035127b1d28a5
• Offline created QRcodes containing the private key and the Bitcoin address using http://sourceforge.net/projects/qrcodegenerator/files/code/
• Without storing on media directly print two copies of the QRcodes and in plaintext to avoid any QRcode reading problems in the future - who knows

This is bad advice that is a good way to lose Bitcoins. If you are advocating this for:

• backing up your wallet: The balance of your bitcoins may not be in the address you see, and the entire contents of one address may be emptied by just one small transfer.
• paper wallet: The whole point is to generate a can't-be-hacked wallet. You've made one on your computer in the way everyone expects you have, leaving data behind on that machine or a log of your activity if you've been hacked and have a key and screen recording trojan horse.

If you are attempting to make a backup of a wallet, there is a backup wallet option in the menu of Bitcoin-Qt.

[Nightshader]

• backing up your wallet: The balance of your bitcoins may not be in the address you see, and the entire contents of one address may be emptied by just one small transfer.

Most paper wallets if have seen only store both the public and private keys. How does Armory do this?

• paper wallet: The whole point is to generate a can't-be-hacked wallet. You've made one on your computer in the way everyone expects you have, leaving data behind on that machine or a log of your activity if you've been hacked and have a key and screen recording trojan horse.

My bad, should be done using a live-cd and take it off-line just to be sure it's totally secure.

So this advice must be regarded with RED warning tape!

it's the noob section after all

[deepceleron]

• backing up your wallet: The balance of your bitcoins may not be in the address you see, and the entire contents of one address may be emptied by just one small transfer.

Most paper wallets if have seen only store both the public and private keys. How does Armory do this?

A paper wallet is fine for creating one address and sending bitcoins there for long-term storage. However, copying a single address from a working wallet is not effective; if you are using the wallet, then your balance may quickly move to other addresses; Bitcoin creates 100 other addresses for future use by default, due to change.

Armory allows you to create a deterministic wallet. This is a wallet where all the other addresses that will ever exist are based on an initial secret seed, so it is sufficient to create a backup of only this seed.

[bimblebob]

• backing up your wallet: The balance of your bitcoins may not be in the address you see, and the entire contents of one address may be emptied by just one small transfer.

Most paper wallets if have seen only store both the public and private keys. How does Armory do this?

A paper wallet is fine for creating one address and sending bitcoins there for long-term storage. However, copying a single address from a working wallet is not effective; if you are using the wallet, then your balance may quickly move to other addresses; Bitcoin creates 100 other addresses for future use by default, due to change.

Armory allows you to create a deterministic wallet. This is a wallet where all the other addresses that will ever exist are based on an initial secret seed, so it is sufficient to create a backup of only this seed.

Thanks, +1

[Nightshader]

Armory allows you to create a deterministic wallet. This is a wallet where all the other addresses that will ever exist are based on an initial secret seed, so it is sufficient to create a backup of only this seed.

+1 Thanks for explaining. Seems like I need to convert and start depending on one of the deterministic types but doesn't this always require some additional software or supplier when thinking about long-term storage? For example if Armory doesn't exist anymore in 2023 who is going to recover/recreate my wallet?

This would leave the option to use single "receiving one transaction only" paper wallets? My only concern is staying future-proof and independent as possible. Not disregarding the various tools but there are no guarantees to stay around for years to come.

[dwdoc]

I posted a video showing how to create a secure paper wallet using a windows PC and a single CD. No usb drive necessary.

http://youtu.be/azZYO4FuBCs