Quote from: DannyHamilton on April 10, 2014, 01:22:21 AM

Quote from: chriswilmer on April 10, 2014, 12:13:54 AM

OK fine, but I just want to point out that you kind of stress me out a little when you say "any brainwallet you can memorize can be cracked" because it makes me doubt my understanding of cryptography (because it implies that the 12 word randomly generated mnemonics in wide use are not strong enough).

Those 12 words are generally meant to be written down.

There are very few people in the world who can memorize a completely random set of 12 unrelated words and recall them all in exact order a decade or two later if they haven't used the set for anything in the meantime.

If you are capable of that, then you can use a passphrase generator that generates properly random sets of enough words, and then memorize it if you like.

The vast majority of people who are trying to create brainwallets, are trying to come up with something out of their own head that they have enough of a connection to that they believe that they will remember it after a significant amount of time has passed. This is a VERY BAD idea.

*sigh* I'm not disputing that it's a bad idea. I just think it's possible to say "brainwallets are a bad idea for reasons X, Y, and Z, and here are examples of passphrases that would get cracked immediately and others that are considered safe (i.e., 12 randomly generated words following the electrum method)." I think most people have at least some intuition about what they are capable of memorizing, but very poor intuition for what makes a good, unfeasible to guess, private key.