Bip39 Golang One example of manually generating entropy can be flipping a coin. But when an attacker provides you with a coin that's weighted a little in favor of heads, your First supply of entropy should have been corrupted. They don't retail outlet instantly personalized details, but are according to https://bookmarksknot.com/story20296701/bip39-passphrase-github-little-known-facts-about-seed-phrase-generator