Bip39 Seed. In addition, BIP39 defines the passphrase choice, that adds a moderate number of additive defense just in case your seed phrase is stolen or otherwise accidentally uncovered. Nevertheless, Additionally, it adds some risk, so it is usually recommended for more skilled customers. BIP32 and BIP44 are similar standards https://adirectorysubmit.com/listings13171094/bip39-passphrase-https-linktr-ee-bip39-an-unbiased-view-of-bip39-passphrase