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Brainwallets Get An Upgrade With WarpWallet

Bitcoin brainwallets allow you to keep access to your bitcoins in your memory alone, but generating them has often been too confusing for most people. WarpWallet is a tiny app that is here to fix that, and offers higher security than ever before.

Brainwallets are essentially long, but memorable passwords for a bitcoin wallet. The idea is that the passphrase is not recorded anywhere else, except inside your mind. They were made this way because humans don’t remember random strings of numbers and letters very well. So rather than remembering a 51-digit private key that looks like:


You can instead make up your own passphrase and use a brainwallet generator to turn it into the corresponding 51-digit, 256-bit private key that bitcoin wallets can use.

In this way you are creating your own Bitcoin address by personally choosing your private key, which is the most secure method to generate a bitcoin address. Of course if you aren’t careful with the generation process you could make a mistake and have an insecure key, so picking the safest generator is of utmost important.

There a range of choices for software that can generate a private key from your passphrase, and the same exact passphrase will indeed generate the same exact private key in different programs.

The hardest step while making a brainwallet is choosing a really great passphrase.

A good passphrase has to be one that is as long as possible, but at the same time easy for you to remember. It could be something such as the last thing your favorite teacher said to you, your favorite quote, or your favorite line from a song. To increase the security of the phrase swap some letters for numbers, such as turning o’s to 0’s or i’s to 1’s. By mixing it up enough, future computers attempting to brute force attack the phrase, by entering every lyric to every song and every line from every book, would never stumble upon your wallet.

Complicated instructions have often discouraged bitcoin beginners from getting a brainwallet. Searching online for a brainwallet generator will usually result in some advanced user instructions, thick with cryptography terms such as ECDSA, compression, and SHA256. However, the process doesn’t need to be complex and there are some great tools out there to do the geeky work for us.

The first two user-friendly generator services were Bitaddress and Both work well but can be overly convoluted, with confusing extra options that can scare away less experienced users.

Although both websites claim to run open-source code, that you can read on Github, it is understandable that people who are not coders themselves could be afraid that these services might be trying to gather their private keys.

Although none of the wallet generators have been compromised, nor have there been any claims of theft from either service, new users are unlikely to complete any due diligence, and the instructions to download the code and run it yourself in an offline environment are more than likely too complicated for inexperienced users to follow.

In an effort to solve these problems and make a superior brainwallet generator, WarpWallet – a simple-looking but powerful tool written by the co-founders of OkCupid and Keybase – was released in late 2013. Not only is their ‘download and run locally’ option extremely easy to do, as described in the walk-through process below, but they’ve upgraded the security for the whole brainwallet generation process.

WarpWallet adds two major security improvements that the other generators do not offer.

WarpWallet uses a more secure hashing algorithm for this task, called Scrypt. This algorithm  makes address generation require both extensive memory and time. People trying to guess your passphrase will find it too resource intensive for their computer to process the same amount of information that other generators make much easier.

Secondly, you have the option of "salting" your passphrase with your email address. The attacker will therefore need to know which email address you used on top of all of the computational work he is doing. Any attacker of a WarpWallet address would have to target you individually, rather than coming across your passphrase in a generic sweep. Since you already remember your own email address, this extra level of security requires very little extra effort.

Together these security additions make for an extremely secure brainwallet.

To demonstrate the security of their site and process, WarpWallet’s developers have run several hacker challenges, as you can see on the website. The first four challenges were extremely easy, and were intended as a warm up to get hackers interested in the larger challenge.

The fifth challenge remains unclaimed, and it seems relatively easy. Gain access to a wallet holding some Bitcoins. The private key was generated using a passphrase that is only 8 characters long and all alphanumerics, for example b234FEzz. There was no salt on this passphrase either, just an 8 character brainwallet made of numbers and letters. Over a year later, no one has been able to break the code and retrieve the 20 bitcoin reward.

If hackers can’t break those 8 characters for a 20 bitcoin prize, then your salted passphrase using far more characters is orders of magnitude safer.

WarpWallet is so simple to use that we decided to walk you through it here. You can start out by going to their website and saving the application locally, which is surprisingly simple. Just right-click anywhere on the page and ‘save as’ to your local machine.

After that point you can yank the network cable out of your computer if you want, that one HTML page file is all you need to generate a brainwallet.

Even offline the page will open up in your web browser, and for those that still might not trust the developers you can easily open up the file in any code editor or notepad to look through it.

To generate your brainwallet place your pass-phrase, and a favorite old email address that you won’t ever forget, into the blanks then click “Generate.” In about 18 to 20 seconds you’ll see a page like this:

The public bitcoin address it makes for you is perfectly ok for you to write down, it can only be used to send bitcoins to your brainwallet. Keep it backed up in as many places as you like. Copy it’s QR code too, for easy loading.

However, the private key is something you might not want to copy down at all. If you have a great place to hide a paper copy or hardware wallet, such as a very sturdy safe, then you could use this private key in its raw form. It certainly can be scary to put a large amount of money in a place that is easily forgettable, so some users may want to back it up.

If you are confident in your pass-phrase memorizing ability however, the idea is not to make any copies at all, because your passphrase can re-generate this exact private key in the future. No need to leave copies lying around where thieves can physically steal them.

Since you will likely need to use this application again one day, make sure you copy the html page file you downloaded to a couple of different locations. Throw it on a thumb drive and into your safe, or just leave it installed on your computer. You’ll need it again to access the funds you’ve saved in your brainwallet, unless of course you’ve saved the private key separately.

That’s it; you now have a means to carry around any amount of undetectable funds to any place on Earth.

Now that brainwallet generators like WarpWallet can make more secure wallets, and make them easier than ever before, more people will be able to move large amounts of money around with ease. As former Bitcoin Foundation director John Matonis once said: “it sure beats lugging around 17 kilos of gold bullion.”


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