buildIV function
Implementation
IV buildIV(String masterPassword) {
  final mp = md5.convert(utf8.encode(masterPassword)).bytes;
  final mp16 = mp.sublist(0, 16);
  final b64 = base64.encode(mp16);
  return encrypt.IV.fromBase64(b64);
}IV buildIV(String masterPassword) {
  final mp = md5.convert(utf8.encode(masterPassword)).bytes;
  final mp16 = mp.sublist(0, 16);
  final b64 = base64.encode(mp16);
  return encrypt.IV.fromBase64(b64);
}