Bip39 Seed To Private Key Or for pretty superior protection, you may "roll your individual" seed phrase with dice or a calculator as offline approaches. You may see the entire source code in standalone, offline html file. Alternatively it is possible to Look at the individual css and js documents https://health-lists.com/story19195456/bip39-light-the-smart-trick-of-bip39-phrase-that-nobody-is-discussing