if(localTargetFile.exists()) {
            localTargetFile.delete();
        }
        tempDownloadFile.renameTo(localTargetFile);
    }

    static String calculateSha256Sum(File file) throws Exception {
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        InputStream fis = new FileInputStream(file);
        try {
            int n = 0;