Bip39. Entropy values must be sourced from a powerful source of randomness. This means flipping a good coin, rolling a good dice, sound measurements etcetera. Do NOT use phrases from books, lyrics from tunes, your birthday or steet deal with, keyboard mashing, or nearly anything you believe is random, because https://thedeepdirectory.com/listings13161533/bip39-mnemonic-code-converter-tool-https-linktr-ee-bip39-bip39-github-no-further-a-mystery