Bip39 Compliant Passphrase While it uses BIP32 method you are able to even now import BIP39 seeds into Electrum wallet. Also besides BIp32 There may be BIP44 Model which some wallet use for that era of seeds. It is possible to see the entire source code in standalone, offline html https://loanbookmark.com/story18738956/bip39-mnemonic-brute-force-not-known-facts-about-bip39-phrase