Bitcoin Wiki - User contributions [en]

User:Jrwr

2011-06-25T03:41:30Z

Jrwr:

== Welcome to JRWR's Talk Page of DOOM! ==

I'm engaged in several projects related to Bitcoin and Reddit - /r/Gaming

==== Tip Jar ====
[http://blockexplorer.com/q/getreceivedbyaddress/17ZCvqZH2suk4SoczhcjK7HPi9NjJqPs9R 17ZCvqZH2suk4SoczhcjK7HPi9NjJqPs9R]
=== Articles Created or Edited/Improved ===
[[WalletPaperbackup|WalletPaperBackup]]

=== Projects Worked On ===
[http://jrwr.co.cc/bitcoind/ Bitcoin Block Chain mirror, Updated every 6 hours]

[http://valvearg.com/wiki/Valve_ARG_Wiki Portal 2 ARG Wiki]

[http://jrwr.co.cc/black-knights/ The Black Knights - AstroEmpires guild forums]

[http://jrwr.co.cc/logicwiki/index.php?title=Main_Page LogicWiki - The LOGIC Guild Wiki]

[http://zombie.halibah.com Survivor Zero - A Zombie RPG-FPS Made by Reddit Users] -- Current Project

=== About Me ===
Forrest F. 
21 Year old programmer, mostly in PHP. I'm in the Dept of Labor Job Corps Program Training to work as a Rail Road Clerk, Stuck on a Lenovo s10e Netbook with a Atom 1.60Ghz and a Cricket Wireless Card (Yay 7.5GB a month!)

User:Jrwr

2011-06-24T03:50:57Z

Jrwr: /* Projects Worked On */

== Welcome to JRWR's Talk Page of DOOM! ==

I'm engaged in several projects related to Bitcoin and Reddit - /r/Gaming

==== Tip Jar ====
1BsVCbS5ikd8zLwaFSzm41PbbwzE5fDJYQ

=== Articles Created or Edited/Improved ===
[[WalletPaperbackup|WalletPaperBackup]]

=== Projects Worked On ===
[http://jrwr.co.cc/bitcoind/ Bitcoin Block Chain mirror, Updated every 6 hours]

[http://valvearg.com/wiki/Valve_ARG_Wiki Portal 2 ARG Wiki]

[http://jrwr.co.cc/black-knights/ The Black Knights - AstroEmpires guild forums]

[http://jrwr.co.cc/logicwiki/index.php?title=Main_Page LogicWiki - The LOGIC Guild Wiki]

[http://zombie.halibah.com Survivor Zero - A Zombie RPG-FPS Made by Reddit Users] -- Current Project

=== About Me ===
Forrest F. 
21 Year old programmer, mostly in PHP. I'm in the Dept of Labor Job Corps Program Training to work as a Rail Road Clerk, Stuck on a Lenovo s10e Netbook with a Atom 1.60Ghz and a Cricket Wireless Card (Yay 7.5GB a month!)

User:Jrwr

2011-06-24T03:46:18Z

Jrwr:

== Welcome to JRWR's Talk Page of DOOM! ==

I'm engaged in several projects related to Bitcoin and Reddit - /r/Gaming

==== Tip Jar ====
1BsVCbS5ikd8zLwaFSzm41PbbwzE5fDJYQ

=== Articles Created or Edited/Improved ===
[[WalletPaperbackup|WalletPaperBackup]]

=== Projects Worked On ===
[http://jrwr.co.cc/bitcoind/ Bitcoin Block Chain mirror, Updated every 6 hours]

[http://jrwr.co.cc/black-knights/ The Black Knights - AstroEmpires guild forums]

[http://jrwr.co.cc/logicwiki/index.php?title=Main_Page LogicWiki - The LOGIC Guild Wiki]

[http://zombie.halibah.com Survivor Zero - A Zombie RPG-FPS Made by Reddit Users] -- Current Project

=== About Me ===
Forrest F. 
21 Year old programmer, mostly in PHP. I'm in the Dept of Labor Job Corps Program Training to work as a Rail Road Clerk, Stuck on a Lenovo s10e Netbook with a Atom 1.60Ghz and a Cricket Wireless Card (Yay 7.5GB a month!)

WalletPaperbackup

2011-06-24T02:15:34Z

Jrwr: /* Example */

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ «2»] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file
 
''«It should be noted this guide is for Windows Only, A Linux based guide is coming soon»
''
=== How to use with your Wallet ===
#Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
##File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://i.imgur.com/8b7nz.png Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://i.imgur.com/XT4Uc.png Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://i.imgur.com/OEj6G.png Screen Shot]

[http://i.imgur.com/yxoBZ.jpg Example of printed output]

Guide By: [[User:Jrwr|Jrwr]] 01:44, 24 June 2011 (GMT)

WalletPaperbackup

2011-06-24T02:12:16Z

Jrwr: /* Example */

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ «2»] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file
 
''«It should be noted this guide is for Windows Only, A Linux based guide is coming soon»
''
=== How to use with your Wallet ===
#Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
##File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]

[http://i.imgur.com/yxoBZ.jpg Example of printed output]

Guide By: [[User:Jrwr|Jrwr]] 01:44, 24 June 2011 (GMT)

Talk:Securing your wallet

2011-06-24T02:02:31Z

Jrwr:

The five paragraphs in Technical Background all say the same thing. --[[User:Mcandre|Mcandre]]

Note: the backupwallet.sh script in the linux section doesn't actually work.
I suspect it is caused by the wiki changing the formatting.
I wrote my own version that uses much more standard shell syntax.

[[User:Wscott|Wscott]] 11:28, 11 February 2011 (GMT)

I fixed the backupwallet.sh script. It just needed a nowiki tag around a conditional statement. -- [[User:Mweather|Mweather]] 23:48, 20 May 2011 (GMT)

The approach for "Making a secure workspace" seems to differ greatly for linux and mac. Why? It seems like if you are going to make firefox secure, which is basically all the linux section recommends, you would want to do that on a mac too. And the recommendation in the mac section to keep the wallet in an encrypted volume with a symlink in the expected system location should be done on a linux box too, shouldn't it, like using truecrypt or something... Am I wrong??? Can someone with advanced knowledge please advise...? Also, if you want bitcoin to run all the time in the background on linux, but you have it set up in a separate user from your main user account, well, you are out of luck? Can justifications and explanations be added to the recommendations, and also I guess some alternatives with pros and cons be offered, for people with different needs and computing situations. Thanks! --[[User:GusGustavo|GusGustavo]] 13:33, 26 May 2011 (GMT)

== Time Sensitivity ==

Is it possible to still send money to my wallet, even if it's backed up and offline? Do bitcoins ever expire if they're not spent, or is there anything bad that can happen by not using my bitcoin client in a long time? [[User:Daniel.benoy|Daniel.benoy]] 23:18, 8 June 2011 (GMT)

== Creating a New Wallet ==

This section isn't helpful; it tells you when to create a new wallet, but not how. I'm a new user, and the wallet was created when I installed the BitCoin program. I will find out how to create a new wallet, and then edit this section so that it actually explains the task that it sets out to explain. :-) [[User:ErgoOne|ErgoOne]] 15:19, 9 June 2011 (GMT)

== Making a secure workspace ==

For me space needed in ~/Library/Application Support/Bitcoin (Mac) is more than 400MB (!) after having loaded all blocks from bitcoin app. So 100MB is much too small (may be sufficient for just wallet.dat, but then the steps to do had to be changed). [[User:Hartrock|Hartrock]] 18:48, 12 June 2011 (GMT)

I updated the wiki steps to just backup wallet.dat --[[User:ChocoboLee|ChocoboLee]] 19:18, 15 June 2011 (GMT)

== Flaws with argument regarding encryption ==

Can someone please explain to me how encrypting your wallet will actually protect against a trojan stealing it. Because once you mount the encrypted file, and decrypt it not only can bitcoin see it but the trojan can as well. This strategy seems to work only in the following circumstances:
1. The wallet that has the majority of your cash you never decrypt when you have an open internet connection.
2. Assumes that a trojan only operates when an internet connection is present and it can transmit the wallet data file.

Even if you were paranoid and never were connected to the internet when the wallet file with the bulk of your funds was decrypted this still would not solve the problem. In the event that a trojan seeks to copy your wallet file to another location on your computer it could wait for an open internet connection to transmit this data. So even if you reencrypt the wallet file before connecting to the internet this type of trojan has already made a copy of the decrypted file and can transmit it as soon as an internet connection becomes available.

Also how in the world could you ever use this wallet to transfer cash to another user if you are offline? Maybe I don't understand how bitcoin works but don't you need to be online in order to transfer bitcoins? Basically the bottom line is that bitcoin cannot read an encrypted wallet file which means that in order to use the wallet you need to decrypt it which means its vulnerable to trojans who can steal it the moment you want to use it.

This seems to be a fundamental flaw in this discussion "securing your wallet" Why doesn't bitcoin just address this in the software allowing for the wallet to always be encrypted and require a password upon startup. If you want bitcoin to go mainstream I don't understand why you can't address this fundamental flaw that would be solved by an always encrypted wallet file that the software can read and write to.

====Added a new entry to backup methods====
[[WalletPaperbackup]] Is a great way to get your wallet out of the digital world and onto paper
--[[User:Jrwr|Jrwr]] 02:02, 24 June 2011 (GMT)

Talk:WalletPaperbackup

2011-06-24T01:52:28Z

Jrwr:

You can find the Post that started it all [http://forum.bitcoin.org/index.php?topic=21043.0 Here] --[[User:Jrwr|Jrwr]] 01:52, 24 June 2011 (GMT)

Talk:WalletPaperbackup

2011-06-24T01:52:05Z

Jrwr: Created page with "You can find the Post that started it all [http://forum.bitcoin.org/index.php?topic=21043.0 Here] ~~~~"

You can find the Post that started it all [http://forum.bitcoin.org/index.php?topic=21043.0 Here] [[User:Jrwr|Jrwr]] 01:52, 24 June 2011 (GMT)

Securing your wallet

2011-06-24T01:50:47Z

Jrwr: /* General Solutions */

==Introduction==

Wallet security can be broken down into two independent goals:
# Protecting your wallet against loss.
# Protecting your wallet against theft.

In the case that your current wallet hasn't been protected adequately (e.g. put online with a weaker password):
# Making a new secure wallet, using appropriate long-term protection.

==Technical Background==

Bitcoin transactions send Bitcoins to a specific public key. A Bitcoin address is an encoded hash of a public key. In order to use received Bitcoins, you need to have the private key matching the public key you received with. This is sort of like a super long password associated with an account (public key). Your Bitcoin wallet contains all of the private keys necessary for spending your received transactions. If you delete your wallet without a backup, then you no longer have the authorization information necessary to claim your coins, and the coins associated with those keys are lost forever.

The wallet contains a pool of queued keys. By default there are 100 keys in the [[key pool]]. The size of the pool is configurable using the "-keypool" command line argument. When you need an address for whatever reason (send, “new address”, generation, etc.), the key is not actually generated freshly, but taken from this pool. A brand new address is generated to fill the pool back to 100. So when a backup is first created, it has all of your old keys plus 100 unused keys. After sending a transaction, it has 99 unused keys. After a total of 100 new-key actions, you will start using keys that are not in your backup. Since the backup does not have the private keys necessary for authorizing spends of these coins, restoring from the old backup will cause you to lose Bitcoins.

Creating a new address generates a new pair of public and private keys, which are added to your wallet. Each keypair is mostly random numbers, so they cannot be known prior to generation. If you backup your wallet and then create more than 100 new addresses, the keypair associated with the newest addresses will not be in the old wallet because the new keypairs are only known after creating them. Any coins received at these addresses will be lost if you restore from the backup.

The situation is made somewhat more confusing because the receiving addresses shown in the UI are not the only keys in your wallet. Each Bitcoin generation is given a new public key, and, more importantly, each sent transaction also sends some number of Bitcoins back to yourself at a new key. When sending Bitcoins to anyone, you generate a new keypair for yourself and simultaneously send Bitcoins to your new public key and the actual recipient's public key. This is an anonymity feature – it makes tracking Bitcoin transactions much more difficult.

So if you create a backup, do more than 100 things that cause a new key to be used, and then restore from the backup, some Bitcoins will be lost. Bitcoin has not deleted any keys (keys are never deleted) – it has created a new key that is not in your old backup and then sent Bitcoins to it.

== Making a new wallet ==

In the case that a wallet has been distributed, or stored, in a (real or potential) compromised state, it is wise to create a new wallet and transfer the full balance of Bitcoins to an address contained only in the newly created wallet.

For example, this will be necessary if one created a wallet with a password of 12 characters, as suggested. However a few years have passed and the wallet is now more easily compromised. Just re-encrypting isn't secure. One needs to make a new wallet and make the old wallet worthless (spending the funds to the new wallet).

==Making a secure workspace==

===Linux===

The first step is to make a [http://www.howtogeek.com/howto/ubuntu/add-a-user-on-ubuntu-server/ new user,] so run:

<code>adduser new_user_name</code>

as root. When you get to the prompt 'Enter the new value, or press ENTER for the default', just keep hitting ENTER.

Then switch user to the new user. To get to the new user you can use the switch user icon for your system, which on Ubuntu is in the 'System/Quit' screen, or if there is no switch icon on your system you can log out and log back in as the new user. Then click on a folder in the new user to display the file browser, then keep going up folders until you see the new user home directory, then right click to bring up the Properties dialog, then click on the Permissions tab, then in the Others section, set the folder access to None.

For secure browsing, open Firefox, and then go into the Edit menu and click Preferences. Starting from the left, click on the General tab, and in the 'Startup/When Firefox starts' pop up menu, choose 'Show a Blank Page'. Then click on the Content tab, and deselect 'Load images automatically' and deselect 'Enable Javascript'. Then click on the Privacy tab, and in the 'History/Firefox will' pop up menu, choose 'Never remember history'. Then click on the Security tab, and in the Passwords section, deselect 'Remember passwords for sites' and deselect 'Use a master password'. Then click on the Advanced tab, then click on the Update tab, and then in the 'Automatically check for updates to' section, deselect 'Add-ons' and 'Search Engines'.

When javascript is disabled, the [http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.3.23/bitcoin-0.3.23-linux.tar.gz/download linux download page] will not download automatically, so you'll have to click on the 'direct link' part of the "Problems with the download? Please use this 'direct link' or try another mirror." line.

After you've made your secure new user, to maintain security you should use it only for bitcoin.

It's also a good idea to encrypt the Home directory of whatever user you run Bitcoin under using ecryptfs-utils. To do this:
# If the Home directory is not empty you should back it up first, by just copying the data to an external drive or something.
# install ecryptfs-utils (on Ubuntu: sudo apt-get install ecryptfs-utils)
# log out of X (graphical system) and press Ctrl+Alt+F1 to login to the command shell (you must be logged out or some files will be open and the tool won't be able to encrypt your data)
# change directory to something that's not in your home folder (ex: cd / )
# run the migration tool (on Ubuntu: sudo ecryptfs-migrate-home -u username)
# if it's successful, you can now press ALT+F8 to go back to the GUI and login
# run 'ecryptfs-unwrap-passphrase' and '''WRITE DOWN OR SAVE THE CODE IT RETURNS''' because you will need it if you ever have to pull your data off while the OS is not working. (You can run it again later if you need to, but run it now so that you can get your data if your Linux install gets botched.)
# run 'ecryptfs-setup-swap' to encrypt your swap partition (the encrypted folder data is not encrypted while it's in memory, and so if it's ever sent to the swap partition it can be stolen from there unless that too is encrypted - be aware that this will mean you cannot use Hibernate anymore, as the bootloader won't be able to restore the hibernation data)
(instructions from [http://bodhizazen.net/Tutorials/Ecryptfs/#Migrate])

===Mac===

=====Backup all data (500MB)=====
Follow these instructions to backup all the bitcoin data (wallet and block chains) to an encrypted disk image.
# Open Disk Utility
# Click New Image and choose 500MB, 128-bit or 256-bit (faster or more secure) encryption and single partition.
# Save it somewhere you won't lose it (like your Wuala, Dropbox, Strongspace or whatever)
# Choose a safe and strong password
# Move everything from ~/Library/Application Support/Bitcoin/ to the image
# Symlink it back so the app would be able to use it
:::ln -s /Volumes/Bitcoin ~/Library/Application Support/Bitcoin

Don't forget to mount your image before using Bitcoin and unmount after quitting it.

=====Backup just wallet.dat (40MB)=====
Follow these instructions to backup just the wallet.dat file. This results in a smaller disk image, but it's more complicated to do.
# Open Disk Utility
# Click New Image and choose 40MB, 128-bit or 256-bit (faster or more secure) encryption and single partition.
# Save it somewhere you won't lose it (like your Wuala, Dropbox, Strongspace or whatever)
# Choose a safe and strong password
# Move your wallet.dat file to the image
# Symlink it back so the app would be able to use it
:::ln -s /Volumes/Bitcoin/wallet.dat ~/Library/Application Support/Bitcoin/wallet.dat

[[File:MountWalletAndLauchnBitcoin_OSX_Automator.png|thumbnail|150px|Mount Wallet and launch Bitcoin]]
Don't forget to mount your image before using Bitcoin and unmount after quitting it.

'''Note''': If you start the Bitcoin application without having the image mounted, the application will overwrite your symlink with a new wallet. If that happens, don't panic. Just delete the new wallet.dat, mount the image, and recreate the symlink like above.

'''Automation''': You can create a small application using [http://en.wikipedia.org/wiki/Automator_%28software%29 Automator] (included in OS X) to automatically mount the wallet and then launch Bitcoin App. See the Screenshot on how to do this.

===Windows===

If you are using Windows XP or Windows 7, you can keep your wallet on an encrypted disk image created by third-party software, such as [http://www.truecrypt.org/ TrueCrypt] (open source) or [http://www.jetico.com/encryption-bestcrypt/ Jetico BestCrypt] (commercial). You can probably do the same with Windows Vista (but why would you use that?) or Windows 2000.

'''NOTE:''' You should configure BitCoin in this manner only on computers where you use BitCoin, but do not use that computer to mine. For example, this is a good configuration for a notebook or tablet computer.

Assuming that you have installed the Windows BitCoin client and run it at least once, the process is described below.

To mount the BitCoin data directory on an encrypted drive
<ol start=1 type=1>
<li>Use the third-party disk image encryption program of your choice to create and mount an encrypted disk image of at least 100 MB in size.</li>
<li>Locate the BitCoin data directory, and copy the directory with all contents to the encrypted drive.
For help finding this directory, see [[Securing_your_wallet#Locating_BitCoin_s_data_directory|Locating BitCoin's Data Directory]].</li>
<li>Create a Windows shortcut that starts BitCoin with the <code>-datadir</code> parameter and specifies the encrypted drive and directory.
For example, if you installed Bitcoin in the default directory, mounted your BitCoin encrypted drive as <code>E:\</code>, and stored your BitCoin data directory on it as <code>Bitcoin</code>, you would type the following command as the shortcut Target:
<blockquote><code>C:\Program Files\Bitcoin\bitcoin.exe -datadir=E:\Bitcoin</code></blockquote></li>
<li>Open BitCoin's settings and configure it NOT to start automatically when you start Windows.
This is to allow you to mount the BitCoin encrypted disk image before starting BitCoin.</li>
<li>Shut down BitCoin, and then restart it from the new shortcut.</li>
</ol>

After doing this, any time you want to use BitCoin, you must first mount the BitCoin encrypted disk image using the same drive designation, and then run BitCoin from the shortcut that you created, so that it can find its data and your wallet. :-)

== Locating BitCoin's data directory ==

The [[data directory]] is the location where Bitcoin's data files are stored, including the wallet data file.

=== Windows ===

Go to Start -> Run (or press WinKey+R) and run this:

explorer %APPDATA%\BitCoin

BitCoin's data folder will open. For most users, this is the following locations:

C:\Documents and Settings\YourUserName\Application data\BitCoin (XP)

C:\Users\YourUserName\Appdata\Roaming\BitCoin (Vista and 7)

"AppData" and "Application data" are hidden by default.

=== Linux ===

By default BitCoin will put its data here:

~/.bitcoin/

You need to do a "ls -a" to see directories that start with a dot.

If that's not it, you can do a search like this:

find / -name wallet.dat -print 2>/dev/null

=== Mac ===

By default BitCoin will put its data here:

~/Library/Application Support/Bitcoin/

==Backup==

'''Note''': I would strongly recommend against using Dropbox to back up your Bitcoin data due to [http://en.wikipedia.org/wiki/Dropbox_(service)#Criticism security concerns] such as:
# the fact that they store your encryption key (meaning that a disgruntled Dropbox employee or an attacker who gained access to the system could decrypt your Dropbox data and steal your Bitcoins)
# the fact that the Dropbox client only needs a password for the first login. After it authenticates once, the server assigns it a token which it uses to show that, at one time, its user knew the password rather than sending the actual password (meaning that if you ever use the Dropbox client on another PC, that PC's users can access your Dropbox - even if you change your password - and can steal your Bitcoins or get a virus that will steal your Bitcoins).

For these reasons, I personally prefer to use Wuala, which does not store your encryption key and requires a password each time (the client can be set to remember your password, but the server will check each time to make sure that the client is sending the correct password). Like Dropbox, the basic, lowest-storage-space account with Wuala is free of charge, and coincidentally, Wuala [http://www.wuala.com/en/bitcoin is experimenting with allowing users to pay for "upgraded" plans using Bitcoin.]

In fact, whether you use Dropbox as your backup or not, use what Steve Gibson calls "pre-Internet encryption" (which he actually [http://itknowledgeexchange.techtarget.com/security-corner/cloud-security-and-privacy-do-they-exist/ discussed in the context of Dropbox's security concerns]) and use some form of encryption on the files before you back them up, just in case someone other than yourself ever gains access to that backup. Make sure to pick a password that's memorable but secure.

The only file you need to back up is "wallet.dat". Ensure that BitCoin is closed, copy this file somewhere else, encrypt it, and put it somewhere safe. Ideally, you would put this file in two places: one nearby, and one 100+ miles away.

You can use the [[api|backupwallet]] JSON-RPC command to back up without shutting down Bitcoin.

=== General Solutions ===

Your wallet.dat file is not encrypted by BitCoin. Anyone who can access it can easily steal all of your coins. Use one of these encryption programs if there is any chance someone might stumble upon your wallet.
* [http://www.7-zip.org/ 7-zip] - Supports strongly-encrypted archives.
* [http://www.axantum.com/axcrypt/ AxCrypt]
* [http://lrzip.kolivas.org lrzip] - Compression software for Linux and OSX that supports very high grade password protected encryption
* [http://www.truecrypt.org/ TrueCrypt] - Volume-based on-the-fly encryption (for advanced users)
* [http://www.rarlab.com/ WinRar] - Commonly used archive software that supports verification records and encryption.

There is also a list of [[OpenSourceEncryptionSoftware|open source encryption software.]]

There is also a method to Print out and encrypt your Wallet.dat as a special barcode. See details here: [[WalletPaperbackup]]

==== Password Strength ====
Brute-force password cracking has come a long distance, a previously thought secure password of random [a-Z] [0-9] [!-~] of 8 characters long can be trivially solved now (using appropriate hardware)... The recommended length is '''at least''' 12 characters long. You can also use a multi-word password. [http://www.baekdal.com/tips/password-security-usability The Usability of Passwords]

However, simply using dictionary words is also insecure as it opens you up to a dictionary attack. If you use dictionary words, be sure to throw random symbols and numbers in the mix as well.

A good way to create secure but easy-to-remember passwords is to pick a password (ex: d0g) and pad it with a good number of repeated characters afterward (such as 10 $ signs - so d0g becomes d0g$$$$$$$$$$) - this is just as cryptographically secure as a random password of equal length so long as the attacker does not know which symbol you are following your "word" with and how many times it is repeated. ([https://www.grc.com/haystack.htm source])

If you use keyfiles in addition to a password, it is unlikely that your encrypted file can ever be cracked using brute force methods, even 10 years from now when even a 12 character password might be too short.

Assume that any encrypted files you store online (eg. gmail, Dropbox) will be stored somewhere forever and can never be erased.

==== Storage of Archive ====
One of the most simple methods for storing a appropriately '''encrypted''' archive of your wallet.dat file is to send the archive as an email attachment to your own e-mail address. Services like gmail.com use very comprehensive distributed networks that make the loss of data very unlikely. One can even obfuscate the name of the files within the archive, and name the archive something less inviting, such as: 'personal notes' or 'car insurance'.

Another solution is to use a file storage service like [http://www.wuala.com/bitcoin Wuala] ( encrypted, [http://www.bitcoin.org/smf/index.php?topic=5817.0 instructions]), [http://www.dropbox.com Dropbox] and [http://en.wikipedia.org/wiki/Comparison_of_online_backup_services others], including the more secure [http://www.spideroak.com SpiderOak].

=== Linux solution ===

Linux users can setup cron by running 'crontab -e' and adding this line:

01 */1 * * * /usr/local/bin/backupwallet.sh

This cron line runs backupwallet.sh at the 01 minute of every hour. Remember to add a newline after the last line of the crontab file, or else the last line won't run.

backupwallet.sh:

#!/bin/bash

TS=$(date "+%Y%m%d-%H-%M")
WALLET=/tmp/wallet${TS}
WALLET_E=/tmp/wallet${TS}.crypt

if
echo -n making backup...
bitcoind backupwallet $WALLET
<nowiki>[[ ! -s "$WALLET" ]]</nowiki>
then echo failed
elif
echo done
echo -n encrypting....
! gpg -r myusername --output $WALLET_E --encrypt $WALLET
then echo failed
elif
echo done
echo -n copying to distant server...
! scp $WALLET_E user@myserver.org:~/wallets/
then echo failed
else echo done
fi

rm -f $WALLET $WALLET_E

The shell script:

* Calls bitcoind backupwallet to create a time/date-stamped wallet.
* GPG encrypts the wallet with your public key.
* Copies the result to a backup location.

[[Category:Technical]]

==Restore==

Assuming your backup is recent enough that you haven't used up all of your key pool... restoring a wallet to a new (or old) location and rescanning the block chain should leave you with all your coins. Just follow these steps:
* Quit bitcoin(d).
* Copy your backed up wallet.dat into your bitcoin profile directory.
* If copying into existing profile, delete file ''blkindex.dat'' and ''blk0001.dat'' to make the client re-scan the block chain.
And you'll be good as new.

==Erasing Plain Text Wallets==

A good practice is to keep at least two wallets, one as a "current account" for everyday transactions and one as a "savings account" where you store the majority of your Bitcoins.

The "savings account" wallet should be backed up in encrypted form only and all plaintext copies of this wallet should be erased. In case someone gains unauthorised access to your computer (either by physically stealing it or by exploiting a system vulnerability via the internet), they will only be able to spend the coins in your "current account" wallet.

In most operating systems, including Windows, Linux, and Mac OS X, simply deleting a wallet.dat file will ''not'' generally destroy it. It is likely that advanced tools can still be used to recover the wallet.dat file, even after it has been deleted.

The Linux '''shred''' command can be used to overwrite the wallet file with random data prior to deleting; this particular copy of the file will then be practically impossible to recover. Using shred (and similar tools on Windows) however does not guarantee that still other copies don't exist somewhere hidden on your HD. That will depend on your system configuration and what packages you have installed. Some system restore and backup tools, for instance, create periodic snapshots of your filesystem, duplicating your wallet.dat.

In Mac OS, clicking "Secure Empty Trash" in the Finder menu will shred the contents of the trash can. As with any OS this doesn't guarantee that there are not other copies elsewhere on your system.

For Windows, the built-in command ''cipher /W'' will shred all previously-deleted files. [http://www.cylog.org/utilities/cybershredder.jsp CyberShredder] can securely deleted individual files.

==eWallet==

Storing bitcoins with an [[eWallet]] provider incurs risks as well. Basically you grant the third party, in this case eWallet, full access to your wallet.

==See Also==

* [[Data directory]]

[[de:Sichere deine Geldbörse]]
[[zh-cn:保护你的钱包]]

Securing your wallet

2011-06-24T01:49:57Z

Jrwr: /* General Solutions */

==Introduction==

Wallet security can be broken down into two independent goals:
# Protecting your wallet against loss.
# Protecting your wallet against theft.

In the case that your current wallet hasn't been protected adequately (e.g. put online with a weaker password):
# Making a new secure wallet, using appropriate long-term protection.

==Technical Background==

Bitcoin transactions send Bitcoins to a specific public key. A Bitcoin address is an encoded hash of a public key. In order to use received Bitcoins, you need to have the private key matching the public key you received with. This is sort of like a super long password associated with an account (public key). Your Bitcoin wallet contains all of the private keys necessary for spending your received transactions. If you delete your wallet without a backup, then you no longer have the authorization information necessary to claim your coins, and the coins associated with those keys are lost forever.

The wallet contains a pool of queued keys. By default there are 100 keys in the [[key pool]]. The size of the pool is configurable using the "-keypool" command line argument. When you need an address for whatever reason (send, “new address”, generation, etc.), the key is not actually generated freshly, but taken from this pool. A brand new address is generated to fill the pool back to 100. So when a backup is first created, it has all of your old keys plus 100 unused keys. After sending a transaction, it has 99 unused keys. After a total of 100 new-key actions, you will start using keys that are not in your backup. Since the backup does not have the private keys necessary for authorizing spends of these coins, restoring from the old backup will cause you to lose Bitcoins.

Creating a new address generates a new pair of public and private keys, which are added to your wallet. Each keypair is mostly random numbers, so they cannot be known prior to generation. If you backup your wallet and then create more than 100 new addresses, the keypair associated with the newest addresses will not be in the old wallet because the new keypairs are only known after creating them. Any coins received at these addresses will be lost if you restore from the backup.

The situation is made somewhat more confusing because the receiving addresses shown in the UI are not the only keys in your wallet. Each Bitcoin generation is given a new public key, and, more importantly, each sent transaction also sends some number of Bitcoins back to yourself at a new key. When sending Bitcoins to anyone, you generate a new keypair for yourself and simultaneously send Bitcoins to your new public key and the actual recipient's public key. This is an anonymity feature – it makes tracking Bitcoin transactions much more difficult.

So if you create a backup, do more than 100 things that cause a new key to be used, and then restore from the backup, some Bitcoins will be lost. Bitcoin has not deleted any keys (keys are never deleted) – it has created a new key that is not in your old backup and then sent Bitcoins to it.

== Making a new wallet ==

In the case that a wallet has been distributed, or stored, in a (real or potential) compromised state, it is wise to create a new wallet and transfer the full balance of Bitcoins to an address contained only in the newly created wallet.

For example, this will be necessary if one created a wallet with a password of 12 characters, as suggested. However a few years have passed and the wallet is now more easily compromised. Just re-encrypting isn't secure. One needs to make a new wallet and make the old wallet worthless (spending the funds to the new wallet).

==Making a secure workspace==

===Linux===

The first step is to make a [http://www.howtogeek.com/howto/ubuntu/add-a-user-on-ubuntu-server/ new user,] so run:

<code>adduser new_user_name</code>

as root. When you get to the prompt 'Enter the new value, or press ENTER for the default', just keep hitting ENTER.

Then switch user to the new user. To get to the new user you can use the switch user icon for your system, which on Ubuntu is in the 'System/Quit' screen, or if there is no switch icon on your system you can log out and log back in as the new user. Then click on a folder in the new user to display the file browser, then keep going up folders until you see the new user home directory, then right click to bring up the Properties dialog, then click on the Permissions tab, then in the Others section, set the folder access to None.

For secure browsing, open Firefox, and then go into the Edit menu and click Preferences. Starting from the left, click on the General tab, and in the 'Startup/When Firefox starts' pop up menu, choose 'Show a Blank Page'. Then click on the Content tab, and deselect 'Load images automatically' and deselect 'Enable Javascript'. Then click on the Privacy tab, and in the 'History/Firefox will' pop up menu, choose 'Never remember history'. Then click on the Security tab, and in the Passwords section, deselect 'Remember passwords for sites' and deselect 'Use a master password'. Then click on the Advanced tab, then click on the Update tab, and then in the 'Automatically check for updates to' section, deselect 'Add-ons' and 'Search Engines'.

When javascript is disabled, the [http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.3.23/bitcoin-0.3.23-linux.tar.gz/download linux download page] will not download automatically, so you'll have to click on the 'direct link' part of the "Problems with the download? Please use this 'direct link' or try another mirror." line.

After you've made your secure new user, to maintain security you should use it only for bitcoin.

It's also a good idea to encrypt the Home directory of whatever user you run Bitcoin under using ecryptfs-utils. To do this:
# If the Home directory is not empty you should back it up first, by just copying the data to an external drive or something.
# install ecryptfs-utils (on Ubuntu: sudo apt-get install ecryptfs-utils)
# log out of X (graphical system) and press Ctrl+Alt+F1 to login to the command shell (you must be logged out or some files will be open and the tool won't be able to encrypt your data)
# change directory to something that's not in your home folder (ex: cd / )
# run the migration tool (on Ubuntu: sudo ecryptfs-migrate-home -u username)
# if it's successful, you can now press ALT+F8 to go back to the GUI and login
# run 'ecryptfs-unwrap-passphrase' and '''WRITE DOWN OR SAVE THE CODE IT RETURNS''' because you will need it if you ever have to pull your data off while the OS is not working. (You can run it again later if you need to, but run it now so that you can get your data if your Linux install gets botched.)
# run 'ecryptfs-setup-swap' to encrypt your swap partition (the encrypted folder data is not encrypted while it's in memory, and so if it's ever sent to the swap partition it can be stolen from there unless that too is encrypted - be aware that this will mean you cannot use Hibernate anymore, as the bootloader won't be able to restore the hibernation data)
(instructions from [http://bodhizazen.net/Tutorials/Ecryptfs/#Migrate])

===Mac===

=====Backup all data (500MB)=====
Follow these instructions to backup all the bitcoin data (wallet and block chains) to an encrypted disk image.
# Open Disk Utility
# Click New Image and choose 500MB, 128-bit or 256-bit (faster or more secure) encryption and single partition.
# Save it somewhere you won't lose it (like your Wuala, Dropbox, Strongspace or whatever)
# Choose a safe and strong password
# Move everything from ~/Library/Application Support/Bitcoin/ to the image
# Symlink it back so the app would be able to use it
:::ln -s /Volumes/Bitcoin ~/Library/Application Support/Bitcoin

Don't forget to mount your image before using Bitcoin and unmount after quitting it.

=====Backup just wallet.dat (40MB)=====
Follow these instructions to backup just the wallet.dat file. This results in a smaller disk image, but it's more complicated to do.
# Open Disk Utility
# Click New Image and choose 40MB, 128-bit or 256-bit (faster or more secure) encryption and single partition.
# Save it somewhere you won't lose it (like your Wuala, Dropbox, Strongspace or whatever)
# Choose a safe and strong password
# Move your wallet.dat file to the image
# Symlink it back so the app would be able to use it
:::ln -s /Volumes/Bitcoin/wallet.dat ~/Library/Application Support/Bitcoin/wallet.dat

[[File:MountWalletAndLauchnBitcoin_OSX_Automator.png|thumbnail|150px|Mount Wallet and launch Bitcoin]]
Don't forget to mount your image before using Bitcoin and unmount after quitting it.

'''Note''': If you start the Bitcoin application without having the image mounted, the application will overwrite your symlink with a new wallet. If that happens, don't panic. Just delete the new wallet.dat, mount the image, and recreate the symlink like above.

'''Automation''': You can create a small application using [http://en.wikipedia.org/wiki/Automator_%28software%29 Automator] (included in OS X) to automatically mount the wallet and then launch Bitcoin App. See the Screenshot on how to do this.

===Windows===

If you are using Windows XP or Windows 7, you can keep your wallet on an encrypted disk image created by third-party software, such as [http://www.truecrypt.org/ TrueCrypt] (open source) or [http://www.jetico.com/encryption-bestcrypt/ Jetico BestCrypt] (commercial). You can probably do the same with Windows Vista (but why would you use that?) or Windows 2000.

'''NOTE:''' You should configure BitCoin in this manner only on computers where you use BitCoin, but do not use that computer to mine. For example, this is a good configuration for a notebook or tablet computer.

Assuming that you have installed the Windows BitCoin client and run it at least once, the process is described below.

To mount the BitCoin data directory on an encrypted drive
<ol start=1 type=1>
<li>Use the third-party disk image encryption program of your choice to create and mount an encrypted disk image of at least 100 MB in size.</li>
<li>Locate the BitCoin data directory, and copy the directory with all contents to the encrypted drive.
For help finding this directory, see [[Securing_your_wallet#Locating_BitCoin_s_data_directory|Locating BitCoin's Data Directory]].</li>
<li>Create a Windows shortcut that starts BitCoin with the <code>-datadir</code> parameter and specifies the encrypted drive and directory.
For example, if you installed Bitcoin in the default directory, mounted your BitCoin encrypted drive as <code>E:\</code>, and stored your BitCoin data directory on it as <code>Bitcoin</code>, you would type the following command as the shortcut Target:
<blockquote><code>C:\Program Files\Bitcoin\bitcoin.exe -datadir=E:\Bitcoin</code></blockquote></li>
<li>Open BitCoin's settings and configure it NOT to start automatically when you start Windows.
This is to allow you to mount the BitCoin encrypted disk image before starting BitCoin.</li>
<li>Shut down BitCoin, and then restart it from the new shortcut.</li>
</ol>

After doing this, any time you want to use BitCoin, you must first mount the BitCoin encrypted disk image using the same drive designation, and then run BitCoin from the shortcut that you created, so that it can find its data and your wallet. :-)

== Locating BitCoin's data directory ==

The [[data directory]] is the location where Bitcoin's data files are stored, including the wallet data file.

=== Windows ===

Go to Start -> Run (or press WinKey+R) and run this:

explorer %APPDATA%\BitCoin

BitCoin's data folder will open. For most users, this is the following locations:

C:\Documents and Settings\YourUserName\Application data\BitCoin (XP)

C:\Users\YourUserName\Appdata\Roaming\BitCoin (Vista and 7)

"AppData" and "Application data" are hidden by default.

=== Linux ===

By default BitCoin will put its data here:

~/.bitcoin/

You need to do a "ls -a" to see directories that start with a dot.

If that's not it, you can do a search like this:

find / -name wallet.dat -print 2>/dev/null

=== Mac ===

By default BitCoin will put its data here:

~/Library/Application Support/Bitcoin/

==Backup==

'''Note''': I would strongly recommend against using Dropbox to back up your Bitcoin data due to [http://en.wikipedia.org/wiki/Dropbox_(service)#Criticism security concerns] such as:
# the fact that they store your encryption key (meaning that a disgruntled Dropbox employee or an attacker who gained access to the system could decrypt your Dropbox data and steal your Bitcoins)
# the fact that the Dropbox client only needs a password for the first login. After it authenticates once, the server assigns it a token which it uses to show that, at one time, its user knew the password rather than sending the actual password (meaning that if you ever use the Dropbox client on another PC, that PC's users can access your Dropbox - even if you change your password - and can steal your Bitcoins or get a virus that will steal your Bitcoins).

For these reasons, I personally prefer to use Wuala, which does not store your encryption key and requires a password each time (the client can be set to remember your password, but the server will check each time to make sure that the client is sending the correct password). Like Dropbox, the basic, lowest-storage-space account with Wuala is free of charge, and coincidentally, Wuala [http://www.wuala.com/en/bitcoin is experimenting with allowing users to pay for "upgraded" plans using Bitcoin.]

In fact, whether you use Dropbox as your backup or not, use what Steve Gibson calls "pre-Internet encryption" (which he actually [http://itknowledgeexchange.techtarget.com/security-corner/cloud-security-and-privacy-do-they-exist/ discussed in the context of Dropbox's security concerns]) and use some form of encryption on the files before you back them up, just in case someone other than yourself ever gains access to that backup. Make sure to pick a password that's memorable but secure.

The only file you need to back up is "wallet.dat". Ensure that BitCoin is closed, copy this file somewhere else, encrypt it, and put it somewhere safe. Ideally, you would put this file in two places: one nearby, and one 100+ miles away.

You can use the [[api|backupwallet]] JSON-RPC command to back up without shutting down Bitcoin.

=== General Solutions ===

Your wallet.dat file is not encrypted by BitCoin. Anyone who can access it can easily steal all of your coins. Use one of these encryption programs if there is any chance someone might stumble upon your wallet.
* [http://www.7-zip.org/ 7-zip] - Supports strongly-encrypted archives.
* [http://www.axantum.com/axcrypt/ AxCrypt]
* [http://lrzip.kolivas.org lrzip] - Compression software for Linux and OSX that supports very high grade password protected encryption
* [http://www.truecrypt.org/ TrueCrypt] - Volume-based on-the-fly encryption (for advanced users)
* [http://www.rarlab.com/ WinRar] - Commonly used archive software that supports verification records and encryption.

There is also a list of [[OpenSourceEncryptionSoftware|open source encryption software.]]

There is also a method to Print out your Wallet.Dat as a special Barcode, See Details here: [[WalletPaperbackup]]

==== Password Strength ====
Brute-force password cracking has come a long distance, a previously thought secure password of random [a-Z] [0-9] [!-~] of 8 characters long can be trivially solved now (using appropriate hardware)... The recommended length is '''at least''' 12 characters long. You can also use a multi-word password. [http://www.baekdal.com/tips/password-security-usability The Usability of Passwords]

However, simply using dictionary words is also insecure as it opens you up to a dictionary attack. If you use dictionary words, be sure to throw random symbols and numbers in the mix as well.

A good way to create secure but easy-to-remember passwords is to pick a password (ex: d0g) and pad it with a good number of repeated characters afterward (such as 10 $ signs - so d0g becomes d0g$$$$$$$$$$) - this is just as cryptographically secure as a random password of equal length so long as the attacker does not know which symbol you are following your "word" with and how many times it is repeated. ([https://www.grc.com/haystack.htm source])

If you use keyfiles in addition to a password, it is unlikely that your encrypted file can ever be cracked using brute force methods, even 10 years from now when even a 12 character password might be too short.

Assume that any encrypted files you store online (eg. gmail, Dropbox) will be stored somewhere forever and can never be erased.

==== Storage of Archive ====
One of the most simple methods for storing a appropriately '''encrypted''' archive of your wallet.dat file is to send the archive as an email attachment to your own e-mail address. Services like gmail.com use very comprehensive distributed networks that make the loss of data very unlikely. One can even obfuscate the name of the files within the archive, and name the archive something less inviting, such as: 'personal notes' or 'car insurance'.

Another solution is to use a file storage service like [http://www.wuala.com/bitcoin Wuala] ( encrypted, [http://www.bitcoin.org/smf/index.php?topic=5817.0 instructions]), [http://www.dropbox.com Dropbox] and [http://en.wikipedia.org/wiki/Comparison_of_online_backup_services others], including the more secure [http://www.spideroak.com SpiderOak].

=== Linux solution ===

Linux users can setup cron by running 'crontab -e' and adding this line:

01 */1 * * * /usr/local/bin/backupwallet.sh

This cron line runs backupwallet.sh at the 01 minute of every hour. Remember to add a newline after the last line of the crontab file, or else the last line won't run.

backupwallet.sh:

#!/bin/bash

TS=$(date "+%Y%m%d-%H-%M")
WALLET=/tmp/wallet${TS}
WALLET_E=/tmp/wallet${TS}.crypt

if
echo -n making backup...
bitcoind backupwallet $WALLET
<nowiki>[[ ! -s "$WALLET" ]]</nowiki>
then echo failed
elif
echo done
echo -n encrypting....
! gpg -r myusername --output $WALLET_E --encrypt $WALLET
then echo failed
elif
echo done
echo -n copying to distant server...
! scp $WALLET_E user@myserver.org:~/wallets/
then echo failed
else echo done
fi

rm -f $WALLET $WALLET_E

The shell script:

* Calls bitcoind backupwallet to create a time/date-stamped wallet.
* GPG encrypts the wallet with your public key.
* Copies the result to a backup location.

[[Category:Technical]]

==Restore==

Assuming your backup is recent enough that you haven't used up all of your key pool... restoring a wallet to a new (or old) location and rescanning the block chain should leave you with all your coins. Just follow these steps:
* Quit bitcoin(d).
* Copy your backed up wallet.dat into your bitcoin profile directory.
* If copying into existing profile, delete file ''blkindex.dat'' and ''blk0001.dat'' to make the client re-scan the block chain.
And you'll be good as new.

==Erasing Plain Text Wallets==

A good practice is to keep at least two wallets, one as a "current account" for everyday transactions and one as a "savings account" where you store the majority of your Bitcoins.

The "savings account" wallet should be backed up in encrypted form only and all plaintext copies of this wallet should be erased. In case someone gains unauthorised access to your computer (either by physically stealing it or by exploiting a system vulnerability via the internet), they will only be able to spend the coins in your "current account" wallet.

In most operating systems, including Windows, Linux, and Mac OS X, simply deleting a wallet.dat file will ''not'' generally destroy it. It is likely that advanced tools can still be used to recover the wallet.dat file, even after it has been deleted.

The Linux '''shred''' command can be used to overwrite the wallet file with random data prior to deleting; this particular copy of the file will then be practically impossible to recover. Using shred (and similar tools on Windows) however does not guarantee that still other copies don't exist somewhere hidden on your HD. That will depend on your system configuration and what packages you have installed. Some system restore and backup tools, for instance, create periodic snapshots of your filesystem, duplicating your wallet.dat.

In Mac OS, clicking "Secure Empty Trash" in the Finder menu will shred the contents of the trash can. As with any OS this doesn't guarantee that there are not other copies elsewhere on your system.

For Windows, the built-in command ''cipher /W'' will shred all previously-deleted files. [http://www.cylog.org/utilities/cybershredder.jsp CyberShredder] can securely deleted individual files.

==eWallet==

Storing bitcoins with an [[eWallet]] provider incurs risks as well. Basically you grant the third party, in this case eWallet, full access to your wallet.

==See Also==

* [[Data directory]]

[[de:Sichere deine Geldbörse]]
[[zh-cn:保护你的钱包]]

Securing your wallet

2011-06-24T01:48:55Z

Jrwr: Adding WalletPaperbackup To the list of backup methods

==Introduction==

Wallet security can be broken down into two independent goals:
# Protecting your wallet against loss.
# Protecting your wallet against theft.

In the case that your current wallet hasn't been protected adequately (e.g. put online with a weaker password):
# Making a new secure wallet, using appropriate long-term protection.

==Technical Background==

Bitcoin transactions send Bitcoins to a specific public key. A Bitcoin address is an encoded hash of a public key. In order to use received Bitcoins, you need to have the private key matching the public key you received with. This is sort of like a super long password associated with an account (public key). Your Bitcoin wallet contains all of the private keys necessary for spending your received transactions. If you delete your wallet without a backup, then you no longer have the authorization information necessary to claim your coins, and the coins associated with those keys are lost forever.

The wallet contains a pool of queued keys. By default there are 100 keys in the [[key pool]]. The size of the pool is configurable using the "-keypool" command line argument. When you need an address for whatever reason (send, “new address”, generation, etc.), the key is not actually generated freshly, but taken from this pool. A brand new address is generated to fill the pool back to 100. So when a backup is first created, it has all of your old keys plus 100 unused keys. After sending a transaction, it has 99 unused keys. After a total of 100 new-key actions, you will start using keys that are not in your backup. Since the backup does not have the private keys necessary for authorizing spends of these coins, restoring from the old backup will cause you to lose Bitcoins.

Creating a new address generates a new pair of public and private keys, which are added to your wallet. Each keypair is mostly random numbers, so they cannot be known prior to generation. If you backup your wallet and then create more than 100 new addresses, the keypair associated with the newest addresses will not be in the old wallet because the new keypairs are only known after creating them. Any coins received at these addresses will be lost if you restore from the backup.

The situation is made somewhat more confusing because the receiving addresses shown in the UI are not the only keys in your wallet. Each Bitcoin generation is given a new public key, and, more importantly, each sent transaction also sends some number of Bitcoins back to yourself at a new key. When sending Bitcoins to anyone, you generate a new keypair for yourself and simultaneously send Bitcoins to your new public key and the actual recipient's public key. This is an anonymity feature – it makes tracking Bitcoin transactions much more difficult.

So if you create a backup, do more than 100 things that cause a new key to be used, and then restore from the backup, some Bitcoins will be lost. Bitcoin has not deleted any keys (keys are never deleted) – it has created a new key that is not in your old backup and then sent Bitcoins to it.

== Making a new wallet ==

In the case that a wallet has been distributed, or stored, in a (real or potential) compromised state, it is wise to create a new wallet and transfer the full balance of Bitcoins to an address contained only in the newly created wallet.

For example, this will be necessary if one created a wallet with a password of 12 characters, as suggested. However a few years have passed and the wallet is now more easily compromised. Just re-encrypting isn't secure. One needs to make a new wallet and make the old wallet worthless (spending the funds to the new wallet).

==Making a secure workspace==

===Linux===

The first step is to make a [http://www.howtogeek.com/howto/ubuntu/add-a-user-on-ubuntu-server/ new user,] so run:

<code>adduser new_user_name</code>

as root. When you get to the prompt 'Enter the new value, or press ENTER for the default', just keep hitting ENTER.

Then switch user to the new user. To get to the new user you can use the switch user icon for your system, which on Ubuntu is in the 'System/Quit' screen, or if there is no switch icon on your system you can log out and log back in as the new user. Then click on a folder in the new user to display the file browser, then keep going up folders until you see the new user home directory, then right click to bring up the Properties dialog, then click on the Permissions tab, then in the Others section, set the folder access to None.

For secure browsing, open Firefox, and then go into the Edit menu and click Preferences. Starting from the left, click on the General tab, and in the 'Startup/When Firefox starts' pop up menu, choose 'Show a Blank Page'. Then click on the Content tab, and deselect 'Load images automatically' and deselect 'Enable Javascript'. Then click on the Privacy tab, and in the 'History/Firefox will' pop up menu, choose 'Never remember history'. Then click on the Security tab, and in the Passwords section, deselect 'Remember passwords for sites' and deselect 'Use a master password'. Then click on the Advanced tab, then click on the Update tab, and then in the 'Automatically check for updates to' section, deselect 'Add-ons' and 'Search Engines'.

When javascript is disabled, the [http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.3.23/bitcoin-0.3.23-linux.tar.gz/download linux download page] will not download automatically, so you'll have to click on the 'direct link' part of the "Problems with the download? Please use this 'direct link' or try another mirror." line.

After you've made your secure new user, to maintain security you should use it only for bitcoin.

It's also a good idea to encrypt the Home directory of whatever user you run Bitcoin under using ecryptfs-utils. To do this:
# If the Home directory is not empty you should back it up first, by just copying the data to an external drive or something.
# install ecryptfs-utils (on Ubuntu: sudo apt-get install ecryptfs-utils)
# log out of X (graphical system) and press Ctrl+Alt+F1 to login to the command shell (you must be logged out or some files will be open and the tool won't be able to encrypt your data)
# change directory to something that's not in your home folder (ex: cd / )
# run the migration tool (on Ubuntu: sudo ecryptfs-migrate-home -u username)
# if it's successful, you can now press ALT+F8 to go back to the GUI and login
# run 'ecryptfs-unwrap-passphrase' and '''WRITE DOWN OR SAVE THE CODE IT RETURNS''' because you will need it if you ever have to pull your data off while the OS is not working. (You can run it again later if you need to, but run it now so that you can get your data if your Linux install gets botched.)
# run 'ecryptfs-setup-swap' to encrypt your swap partition (the encrypted folder data is not encrypted while it's in memory, and so if it's ever sent to the swap partition it can be stolen from there unless that too is encrypted - be aware that this will mean you cannot use Hibernate anymore, as the bootloader won't be able to restore the hibernation data)
(instructions from [http://bodhizazen.net/Tutorials/Ecryptfs/#Migrate])

===Mac===

=====Backup all data (500MB)=====
Follow these instructions to backup all the bitcoin data (wallet and block chains) to an encrypted disk image.
# Open Disk Utility
# Click New Image and choose 500MB, 128-bit or 256-bit (faster or more secure) encryption and single partition.
# Save it somewhere you won't lose it (like your Wuala, Dropbox, Strongspace or whatever)
# Choose a safe and strong password
# Move everything from ~/Library/Application Support/Bitcoin/ to the image
# Symlink it back so the app would be able to use it
:::ln -s /Volumes/Bitcoin ~/Library/Application Support/Bitcoin

Don't forget to mount your image before using Bitcoin and unmount after quitting it.

=====Backup just wallet.dat (40MB)=====
Follow these instructions to backup just the wallet.dat file. This results in a smaller disk image, but it's more complicated to do.
# Open Disk Utility
# Click New Image and choose 40MB, 128-bit or 256-bit (faster or more secure) encryption and single partition.
# Save it somewhere you won't lose it (like your Wuala, Dropbox, Strongspace or whatever)
# Choose a safe and strong password
# Move your wallet.dat file to the image
# Symlink it back so the app would be able to use it
:::ln -s /Volumes/Bitcoin/wallet.dat ~/Library/Application Support/Bitcoin/wallet.dat

[[File:MountWalletAndLauchnBitcoin_OSX_Automator.png|thumbnail|150px|Mount Wallet and launch Bitcoin]]
Don't forget to mount your image before using Bitcoin and unmount after quitting it.

'''Note''': If you start the Bitcoin application without having the image mounted, the application will overwrite your symlink with a new wallet. If that happens, don't panic. Just delete the new wallet.dat, mount the image, and recreate the symlink like above.

'''Automation''': You can create a small application using [http://en.wikipedia.org/wiki/Automator_%28software%29 Automator] (included in OS X) to automatically mount the wallet and then launch Bitcoin App. See the Screenshot on how to do this.

===Windows===

If you are using Windows XP or Windows 7, you can keep your wallet on an encrypted disk image created by third-party software, such as [http://www.truecrypt.org/ TrueCrypt] (open source) or [http://www.jetico.com/encryption-bestcrypt/ Jetico BestCrypt] (commercial). You can probably do the same with Windows Vista (but why would you use that?) or Windows 2000.

'''NOTE:''' You should configure BitCoin in this manner only on computers where you use BitCoin, but do not use that computer to mine. For example, this is a good configuration for a notebook or tablet computer.

Assuming that you have installed the Windows BitCoin client and run it at least once, the process is described below.

To mount the BitCoin data directory on an encrypted drive
<ol start=1 type=1>
<li>Use the third-party disk image encryption program of your choice to create and mount an encrypted disk image of at least 100 MB in size.</li>
<li>Locate the BitCoin data directory, and copy the directory with all contents to the encrypted drive.
For help finding this directory, see [[Securing_your_wallet#Locating_BitCoin_s_data_directory|Locating BitCoin's Data Directory]].</li>
<li>Create a Windows shortcut that starts BitCoin with the <code>-datadir</code> parameter and specifies the encrypted drive and directory.
For example, if you installed Bitcoin in the default directory, mounted your BitCoin encrypted drive as <code>E:\</code>, and stored your BitCoin data directory on it as <code>Bitcoin</code>, you would type the following command as the shortcut Target:
<blockquote><code>C:\Program Files\Bitcoin\bitcoin.exe -datadir=E:\Bitcoin</code></blockquote></li>
<li>Open BitCoin's settings and configure it NOT to start automatically when you start Windows.
This is to allow you to mount the BitCoin encrypted disk image before starting BitCoin.</li>
<li>Shut down BitCoin, and then restart it from the new shortcut.</li>
</ol>

After doing this, any time you want to use BitCoin, you must first mount the BitCoin encrypted disk image using the same drive designation, and then run BitCoin from the shortcut that you created, so that it can find its data and your wallet. :-)

== Locating BitCoin's data directory ==

The [[data directory]] is the location where Bitcoin's data files are stored, including the wallet data file.

=== Windows ===

Go to Start -> Run (or press WinKey+R) and run this:

explorer %APPDATA%\BitCoin

BitCoin's data folder will open. For most users, this is the following locations:

C:\Documents and Settings\YourUserName\Application data\BitCoin (XP)

C:\Users\YourUserName\Appdata\Roaming\BitCoin (Vista and 7)

"AppData" and "Application data" are hidden by default.

=== Linux ===

By default BitCoin will put its data here:

~/.bitcoin/

You need to do a "ls -a" to see directories that start with a dot.

If that's not it, you can do a search like this:

find / -name wallet.dat -print 2>/dev/null

=== Mac ===

By default BitCoin will put its data here:

~/Library/Application Support/Bitcoin/

==Backup==

'''Note''': I would strongly recommend against using Dropbox to back up your Bitcoin data due to [http://en.wikipedia.org/wiki/Dropbox_(service)#Criticism security concerns] such as:
# the fact that they store your encryption key (meaning that a disgruntled Dropbox employee or an attacker who gained access to the system could decrypt your Dropbox data and steal your Bitcoins)
# the fact that the Dropbox client only needs a password for the first login. After it authenticates once, the server assigns it a token which it uses to show that, at one time, its user knew the password rather than sending the actual password (meaning that if you ever use the Dropbox client on another PC, that PC's users can access your Dropbox - even if you change your password - and can steal your Bitcoins or get a virus that will steal your Bitcoins).

For these reasons, I personally prefer to use Wuala, which does not store your encryption key and requires a password each time (the client can be set to remember your password, but the server will check each time to make sure that the client is sending the correct password). Like Dropbox, the basic, lowest-storage-space account with Wuala is free of charge, and coincidentally, Wuala [http://www.wuala.com/en/bitcoin is experimenting with allowing users to pay for "upgraded" plans using Bitcoin.]

In fact, whether you use Dropbox as your backup or not, use what Steve Gibson calls "pre-Internet encryption" (which he actually [http://itknowledgeexchange.techtarget.com/security-corner/cloud-security-and-privacy-do-they-exist/ discussed in the context of Dropbox's security concerns]) and use some form of encryption on the files before you back them up, just in case someone other than yourself ever gains access to that backup. Make sure to pick a password that's memorable but secure.

The only file you need to back up is "wallet.dat". Ensure that BitCoin is closed, copy this file somewhere else, encrypt it, and put it somewhere safe. Ideally, you would put this file in two places: one nearby, and one 100+ miles away.

You can use the [[api|backupwallet]] JSON-RPC command to back up without shutting down Bitcoin.

=== General Solutions ===

Your wallet.dat file is not encrypted by BitCoin. Anyone who can access it can easily steal all of your coins. Use one of these encryption programs if there is any chance someone might stumble upon your wallet.
* [http://www.7-zip.org/ 7-zip] - Supports strongly-encrypted archives.
* [http://www.axantum.com/axcrypt/ AxCrypt]
* [http://lrzip.kolivas.org lrzip] - Compression software for Linux and OSX that supports very high grade password protected encryption
* [http://www.truecrypt.org/ TrueCrypt] - Volume-based on-the-fly encryption (for advanced users)
* [http://www.rarlab.com/ WinRar] - Commonly used archive software that supports verification records and encryption.

There is also a list of [[OpenSourceEncryptionSoftware|open source encryption software.]]

There is also a method to Print out your Wallet.Dat as a special Barcode, See Details here: [WalletPaperbackup]

==== Password Strength ====
Brute-force password cracking has come a long distance, a previously thought secure password of random [a-Z] [0-9] [!-~] of 8 characters long can be trivially solved now (using appropriate hardware)... The recommended length is '''at least''' 12 characters long. You can also use a multi-word password. [http://www.baekdal.com/tips/password-security-usability The Usability of Passwords]

However, simply using dictionary words is also insecure as it opens you up to a dictionary attack. If you use dictionary words, be sure to throw random symbols and numbers in the mix as well.

A good way to create secure but easy-to-remember passwords is to pick a password (ex: d0g) and pad it with a good number of repeated characters afterward (such as 10 $ signs - so d0g becomes d0g$$$$$$$$$$) - this is just as cryptographically secure as a random password of equal length so long as the attacker does not know which symbol you are following your "word" with and how many times it is repeated. ([https://www.grc.com/haystack.htm source])

If you use keyfiles in addition to a password, it is unlikely that your encrypted file can ever be cracked using brute force methods, even 10 years from now when even a 12 character password might be too short.

Assume that any encrypted files you store online (eg. gmail, Dropbox) will be stored somewhere forever and can never be erased.

==== Storage of Archive ====
One of the most simple methods for storing a appropriately '''encrypted''' archive of your wallet.dat file is to send the archive as an email attachment to your own e-mail address. Services like gmail.com use very comprehensive distributed networks that make the loss of data very unlikely. One can even obfuscate the name of the files within the archive, and name the archive something less inviting, such as: 'personal notes' or 'car insurance'.

Another solution is to use a file storage service like [http://www.wuala.com/bitcoin Wuala] ( encrypted, [http://www.bitcoin.org/smf/index.php?topic=5817.0 instructions]), [http://www.dropbox.com Dropbox] and [http://en.wikipedia.org/wiki/Comparison_of_online_backup_services others], including the more secure [http://www.spideroak.com SpiderOak].

=== Linux solution ===

Linux users can setup cron by running 'crontab -e' and adding this line:

01 */1 * * * /usr/local/bin/backupwallet.sh

This cron line runs backupwallet.sh at the 01 minute of every hour. Remember to add a newline after the last line of the crontab file, or else the last line won't run.

backupwallet.sh:

#!/bin/bash

TS=$(date "+%Y%m%d-%H-%M")
WALLET=/tmp/wallet${TS}
WALLET_E=/tmp/wallet${TS}.crypt

if
echo -n making backup...
bitcoind backupwallet $WALLET
<nowiki>[[ ! -s "$WALLET" ]]</nowiki>
then echo failed
elif
echo done
echo -n encrypting....
! gpg -r myusername --output $WALLET_E --encrypt $WALLET
then echo failed
elif
echo done
echo -n copying to distant server...
! scp $WALLET_E user@myserver.org:~/wallets/
then echo failed
else echo done
fi

rm -f $WALLET $WALLET_E

The shell script:

* Calls bitcoind backupwallet to create a time/date-stamped wallet.
* GPG encrypts the wallet with your public key.
* Copies the result to a backup location.

[[Category:Technical]]

==Restore==

Assuming your backup is recent enough that you haven't used up all of your key pool... restoring a wallet to a new (or old) location and rescanning the block chain should leave you with all your coins. Just follow these steps:
* Quit bitcoin(d).
* Copy your backed up wallet.dat into your bitcoin profile directory.
* If copying into existing profile, delete file ''blkindex.dat'' and ''blk0001.dat'' to make the client re-scan the block chain.
And you'll be good as new.

==Erasing Plain Text Wallets==

A good practice is to keep at least two wallets, one as a "current account" for everyday transactions and one as a "savings account" where you store the majority of your Bitcoins.

The "savings account" wallet should be backed up in encrypted form only and all plaintext copies of this wallet should be erased. In case someone gains unauthorised access to your computer (either by physically stealing it or by exploiting a system vulnerability via the internet), they will only be able to spend the coins in your "current account" wallet.

In most operating systems, including Windows, Linux, and Mac OS X, simply deleting a wallet.dat file will ''not'' generally destroy it. It is likely that advanced tools can still be used to recover the wallet.dat file, even after it has been deleted.

The Linux '''shred''' command can be used to overwrite the wallet file with random data prior to deleting; this particular copy of the file will then be practically impossible to recover. Using shred (and similar tools on Windows) however does not guarantee that still other copies don't exist somewhere hidden on your HD. That will depend on your system configuration and what packages you have installed. Some system restore and backup tools, for instance, create periodic snapshots of your filesystem, duplicating your wallet.dat.

In Mac OS, clicking "Secure Empty Trash" in the Finder menu will shred the contents of the trash can. As with any OS this doesn't guarantee that there are not other copies elsewhere on your system.

For Windows, the built-in command ''cipher /W'' will shred all previously-deleted files. [http://www.cylog.org/utilities/cybershredder.jsp CyberShredder] can securely deleted individual files.

==eWallet==

Storing bitcoins with an [[eWallet]] provider incurs risks as well. Basically you grant the third party, in this case eWallet, full access to your wallet.

==See Also==

* [[Data directory]]

[[de:Sichere deine Geldbörse]]
[[zh-cn:保护你的钱包]]

User:Jrwr

2011-06-24T01:45:30Z

Jrwr: Created page with "== Welcome to JRWR's Talk Page of DOOM! == I'm engaged in several projects related to Bitcoin and Reddit - /r/Gaming ==== Tip Jar ==== 1BsVCbS5ikd8zLwaFSzm41PbbwzE5fDJYQ === A..."

WalletPaperbackup

2011-06-24T01:44:54Z

Jrwr:

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ «2»] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file
 
''«It should be noted this guide is for Windows Only, A Linux based guide is coming soon»
''
=== How to use with your Wallet ===
#Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
##File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]

Guide By: [[User:Jrwr|Jrwr]] 01:44, 24 June 2011 (GMT)

WalletPaperbackup

2011-06-24T01:29:44Z

Jrwr:

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ «2»] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file
 
''«It should be noted this guide is for Windows Only, A Linux based guide is coming soon»
''
=== How to use with your Wallet ===
#Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
#:File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]

WalletPaperbackup

2011-06-24T01:23:41Z

Jrwr: /* How to use with you Wallet */

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ «2»] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file

=== How to use with you Wallet ===
«It should be noted this guide is for Windows Only, A Linux based guide is coming soon»
 
#Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
#:File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]

WalletPaperbackup

2011-06-24T01:22:23Z

Jrwr:

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ «2»] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file

=== How to use with you Wallet ===
# Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
#:File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]

WalletPaperbackup

2011-06-24T01:21:22Z

Jrwr:

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack][http://jrwr.co.cc/bitcoin/paperback/ [2]] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file

=== How to use with you Wallet ===
# Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
#:File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]

WalletPaperbackup

2011-06-24T00:55:26Z

Jrwr: Created page with "== PaperBack Encrypted Paper Backup of your Wallet == === Basics === A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack] allows a user to encrypt and print a..."

== PaperBack Encrypted Paper Backup of your Wallet ==

=== Basics ===
A program called [http://www.ollydbg.de/Paperbak/index.html PaperBack] allows a user to encrypt and print a paper copy of a file, to restore the file you scan or provide a image of the printed paper and it decodes the file

=== How to use with you Wallet ===
# Download PaperBack from the location provided before
#Open PaperBack
#Open Options and select the options you wish to have (For more info, read the page provided above)
#Drag and drop the file (wallet.dat) into the window for printing
#:File -> Save to bitmap, It will ask you what file to encode, and then where to save the bitmap

=== Restoring your Wallet ===
#Scan or provide the bitmap of the backup
#Wait for processing
#Save wallet.dat

=== Example ===
Here is the first Image: [http://imgur.com/8b7nz Encoded Image] 
Its a empty wallet.dat with Encryption on (AES-256), standard options past that 
Here is the damaged copy, Opened in GIMP saved as a JPEG at 4% Compression, then converted back into a Bitmap: [http://imgur.com/8b7nz Damaged Re-Encoded Image]
 
ECC had to correct 56bytes of bad data.. once decoded the md5 hashes where the same!
 
Here is a screenshot asking for the password (The password is "bitcoin")
[http://imgur.com/OEj6G Screen Shot]