Bip39 Library One particular example of manually generating entropy will be flipping a coin. However, if an attacker offers you a coin that may be weighted slightly in favor of heads, your Original source of entropy will have been corrupted. It is possible to see the complete source code in https://my-social-box.com/story4080826/bip39-word-list-with-numbers-seed-phrase-generator-no-further-a-mystery