Bip39 Standard. Furthermore, BIP39 defines the passphrase solution, that provides a reasonable degree of additive security just in case your seed phrase is stolen or in any other case accidentally exposed. Even so, it also adds some risk, so it is usually recommended for more expert people. BIP32 and BIP44 https://britedirectory.com/listings13086764/bip39-generator-https-linktr-ee-bip39-getting-my-bip39-standalone-to-work