static String binaryUrlencode(byte[] data) {
  char[] chars = new char[data.length];
  for (int i = 0; i < data.length; i++)
    chars[i] = (char) (((int) data[i]) & 0xFF);
  try { return URLEncoder.encode(new String(chars), "UTF-8"); } catch (Exception e) { throw new RuntimeException(e); }
}