Bip39. Entropy values have to be sourced from a robust supply of randomness. What this means is flipping a good coin, rolling a good dice, sound measurements etcetera. Don't use phrases from publications, lyrics from music, your birthday or steet tackle, keyboard mashing, or anything you think is random, for https://glowingdirectory.com/listings13107008/bip39-seed-generator-https-linktr-ee-bip39-bip39-words-an-overview