A Brain wallet uses your own brain to construct and remember a very special sequence of words. The words can be very similar to the Seed phase that we described for HD wallets. Unlike an HD Seed, a Brain phrase requires that you chose all the words in the phrase and its length. We will call this Brain wallet phrase your Brain phrase. The longer the Brain phrase, the less likely you Brain wallet coins will be stolen – but it will be harder for you to remember.
You need to be sure you can remember your phrase for as long as you plan to hold coins in your Brain wallet. This may be for just one hour until you cross some dangerous border and can get to the other side to change wallets. Or this could be for 50 years if you choose. Not to be morbid, but if you die with your Brain wallet then your heirs can’t recover your funds.
To create the wallet you will enter your Brain phrase into a client-side Brain wallet generator, (you can use the same one described above as a Paper wallet generator That generator will create a public/private key pair and a receive address. You will want to write down your receive address so that funds can be sent to your Brain wallet. You don’t need to record your public/private keys since they will only be needed when you want to spend your Brain funds and those keys can be regenerated based on your Brain phrase as at any time in the future.
After you have recorded your receive address, and you are SURE that you have memorized your Brain phrase then, for extra security, you should clear your browser cache and close the browser window to eliminate all traces of this wallet. After doing so I hope you will never forget your Brain phrase since it no longer exists anywhere except in your gray matter.
This type of wallets can be very risky for two reasons: 1) Obviously you can simply forget your phrase and then your money is gone forever, and 2) you need to understand what makes a good or bad phrase and you must very carefully choose your phrase. For example, ANY published phrase from today, or from the past 500 years, in any language, (songs, poems, newspaper sentence, speeches, …) is a BAD choice. Hackers will run every known phrase in the universe through a brain wallet generator and then check the address for coins. If they find them then they will steal them. Picking a phrase and then substituting keyboard symbols and numbers for some of the letters will improve your security. For this reason, a good Brain phrase won’t be anything that will be super easy for you to remember. If you forget your phrase then there is absolutely no recover and you have lost your funds forever. If you choose to write it down then your Brain wallet just becomes a Paper wallet (and not a Brain wallet any longer).
What do you think about this explanation? Is there more you would have wanted to know? If so then comment before and we will respond.