sS md5(String text) ctex {
  if (text == null) ret "-";
  return bytesToHex(md5AsByteArray(toUtf8(text))); // maybe different than the way PHP does it...
}

sS md5(byte[] data) {
  if (data == null) ret "-";
  ret bytesToHex(md5AsByteArray(data));
}

sS md5(File file) {
  ret md5OfFile(file);
}