i can understand the ability to make a brainwallet with electrum and iits remembering the 12 words seed but kinda sucks because words are made by the wallet and your self .
i see a lot of people speaking about brain wallet , basically if i want to make one how i will do that exactly ?? if i have wallets like bitcoin core , multibit etc ... ? pretty sure it's all about remembering the passphrase but those haven't unless you mean the password that helps you to send coins
Brain wallets are just a series of letters that is used as input for an SHA-256 hashing function. The hash is then used to generate the private key and bitcoin address.
Simplified: these words are used to control a bitcoin address.
Here is a simple code:
from bitcoin import *
priv = sha256('a brainwallet password from the bad guy')
pub = privtopub(priv)
addr = pubtoaddr(pub)
addr will then be your bitcoin address. The passphrase is used to generate the private key. Private keys control the bitcoins. If you choose a bad pass phrase, your bitcoins are gone.
You can generate brain wallet from command line, the web or a wallet.