process method
Implementation
Uint8List process(String mnemonic, {passphrase = ''}) {
final salt = Uint8List.fromList(utf8.encode(saltPrefix + passphrase));
derivator.reset();
derivator.init(Pbkdf2Parameters(salt, iterationCount, desiredKeyLength));
return derivator.process(Uint8List.fromList(mnemonic.codeUnits));
}