code: private String getDefaultIV() {
          return String.valueOf(hex(secret.substring(16, 32).getBytes(Charsets.UTF_8)));
      }
docs: Gets a segment of the application secret of 16 characters and encoded them in hexadecimal. The segment
  contains from the 16th to the 32th characters from the application secret (16 characters). The extracted
  segment is encoded in hexadecimal
  
  @return the default initialization vector.