Make Your Bitcoin Addresses Safe with Paper Wallets

The biggest threat to your wallet isn’t a malicious WiFi packet-sniffing robot; it’s water. If you can, use a laser printer, as it melts waterproof plastic (toner) onto paper instead of using ink. If you must use an inkjet printer, consider storing your wallet in a zip-sealing plastic bag (like those sold on our site), printing on waterproof paper, or treating the paper with a clear coat spray such as Krylon “Preserve It”.

TL;DR: HANDLE YOUR PAPER WALLET LIKE CASH. IF YOU LOSE IT OR IT BECOMES UNREADABLE, YOUR COINS ARE GONE FOREVER.

The private key on this wallet is recorded in the common “Wallet Import Format” (WIF), a standard format for private keys that makes it easy to import your key into various Bitcoin wallet services. Many online platforms, such as blockchain.info and coinbase.com, allow you to import or “sweep” your paper wallet using this key. When you decide to access your funds, plan to transfer your entire balance in one go. This process involves moving all the Bitcoin stored on your paper wallet into a digital wallet, ensuring that all your funds are secure and accessible. After doing this, you should discontinue using the paper wallet, much like breaking open a piggy bank. Attempting to spend or withdraw only a portion of your funds can lead to the loss of the remaining balance, as the remaining funds might not be recoverable once partially accessed.

When you are ready to access your Bitcoin again, simply follow our How to import paper wallets guide to easily access your Bitcoin again.

TL;DR: YOU CAN ADD FUNDS TO YOUR WALLET AS FREQUENTLY AS YOU LIKE, BUT ALWAYS WITHDRAW THE ENTIRE BALANCE AT ONCE—OTHERWISE, YOU RISK LOSING THE REMAINING FUNDS FOREVER.

When generating your Bitcoin keys and printing them out, your wallet may be vulnerable to prying eyes. Although the wallet generator on this website is SSL-encrypted, it’s still possible for someone to be snooping on you. For instance, your computer might have malware that broadcasts your screen to a remote location without your knowledge. Such malware can capture sensitive information like your private keys, compromising the security of your wallet.

To mitigate this risk, the most important safety measure is to go offline and run the JavaScript wallet generator on your own computer instead of directly on the website. By downloading the website files and executing the generator offline, you eliminate the risk of online eavesdropping. This means your private keys are generated and stored in an environment disconnected from the internet, significantly reducing the chances of unauthorized access.

Additionally, ensure your computer is free from malware by running a comprehensive antivirus scan before generating your keys. It’s also advisable to use a clean, isolated environment such as a freshly installed operating system or a live bootable USB drive to further enhance security.

By following these precautions, you can create a secure Bitcoin paper wallet and protect your digital assets from potential threats.

TL;DR: DOWNLOAD THE WEBSITE FILES AND RUN THE WALLET GENERATOR WITH YOUR INTERNET CONNECTION TURNED OFF TO ENSURE MAXIMUM SECURITY.

Printing out secure documents, even on a computer that is 100% virus and trojan-free, presents a unique set of risks. Your printer driver and operating system may store copies of the documents you print in a “spool” or print queue. If a hacker or virus infiltrates your computer and knows to search for these cache files, they can potentially access your private keys and “sweep” your wallets. Therefore, it is crucial to securely delete your printer “spool” files after printing sensitive documents. Here are some tips on how to securely delete your printer cache files on different operating systems:

How to Delete Pesky Printer Cache Files

Macintosh:

1. Enable ‘FileVault’: Use FileVault to encrypt your entire filesystem. This prevents cache files from being ‘undeleted’ and accessed by unauthorized users.
2. Set Up a Symbolic Link: Create a symbolic link from /private/var/spool/cups/cache/ to a removable media volume such as an SD card. Disconnect the removable media when not in use to ensure that cache files are not accessible.

Windows:

1. Use an Encrypted Filesystem: Implement an encrypted filesystem to ensure that your cache files cannot be ‘undeleted’ and accessed by unauthorized users.
2. Change Cache File Destination: Refer to the FAQ on how to redirect the destination of your cache (spool) files to removable media. By doing this, you can remove the media after printing to keep your cache files secure.

Linux:

1. Use a Live-Boot CD: Instead of a regular hard drive OS installation, use a live-boot CD. This approach ensures that all cache files are deleted from memory when you reboot your computer, and no jobs are written to disk.

By following these steps, you can significantly reduce the risk of your private keys being compromised through printer cache files.

TL;DR: LEARN HOW TO DELETE YOUR PRINTER CACHE FILES AFTER PRINTING SECURE DOCUMENTS TO PROTECT YOUR PRIVATE KEYS.

If you have numerous applications on your computer or engage in potentially risky behavior—such as installing freeware or visiting websites that use Java or Flash—it is wise to dedicate a separate computer, or at least a bootable partition, thumb drive, or “live CD,” exclusively for paper wallet printing. This dedicated environment should never connect to the internet to minimize the risk of malware or hacking attempts.

Using a clean, isolated system for generating and printing your paper wallet significantly enhances security. Start by setting up a fresh installation of an operating system on a separate computer, partition, or bootable media. Ensure this environment remains offline at all times.

Transfer the wallet generator website files to this clean OS using a thumb drive or another non-networked method. Avoid using network connections or online downloads to reduce the risk of introducing malware. By isolating your wallet generation process from the internet, you ensure that your private keys remain secure and inaccessible to potential attackers.

Here are the steps to set up a dedicated offline environment:

1. Set Up a Dedicated Environment:

   • Use a separate computer, partition, thumb drive, or live CD.
   • Install a fresh operating system on this dedicated environment.

2. Transfer Wallet Generator Files:

   • Download the wallet generator website files on a different, secure computer.
   • Transfer these files to your dedicated offline environment using a non-networked method, such as a thumb drive.

3. Keep It Offline:

   • Never connect your dedicated environment to the internet.
   • Use this setup exclusively for generating and printing your paper wallet.

By following these precautions, you can create a secure paper wallet and protect your Bitcoin from online threats.

TL;DR: RUN THE WALLET GENERATOR ON A DEDICATED OFFLINE COMPUTER OR OPERATING SYSTEM TO ENSURE MAXIMUM SECURITY.

Some advanced printers come equipped with internal storage, such as hard drives, that can preserve copies of printouts. This feature poses a security risk if someone gains unauthorized access to your printer or if you dispose of your printer without securely wiping its storage. Additionally, sophisticated printers can potentially be hacked, exposing your private information.

This isn’t merely theoretical or a case of tinfoil-hat paranoia. There have been real-world instances where viruses have rewritten the firmware of non-computer devices that are indirectly connected to the internet. If your printer is connected to an internet-connected computer, it could be vulnerable to such attacks.

To mitigate these risks, avoid using advanced printers with internal storage for printing sensitive documents like paper wallets. Instead, use a simpler, “dumb” printer that lacks internal storage and sophisticated firmware. Ensure that your printer is never connected to the internet or to an internet-connected computer.

If you need to print sensitive documents, consider the following steps:

1. Choose a Simple Printer:

   • Use a basic printer without internal storage or sophisticated firmware that can be reprogrammed.

2. Isolate the Printer:

   • Ensure the printer is never connected to the internet.
   • Avoid connecting the printer to any computer that has internet access.

3. Secure Disposal:

   • If you must dispose of a printer, ensure all internal storage is securely wiped or destroyed to prevent data recovery.

By taking these precautions, you can significantly reduce the risk of your private information being compromised through your printer.

TL;DR: SMART PRINTERS SAVE COPIES OF WHAT THEY PRINT AND MAY BE VULNERABLE TO ADVANCED VIRUSES. USE A SIMPLE, OFFLINE PRINTER WHOSE FIRMWARE CAN’T BE REPROGRAMMED.