code: @Override
      @Deprecated
      public ApkSignStatus verifyApk() throws IOException {
          ZipEntry entry = zf.getEntry("META-INF/MANIFEST.MF");
          if (entry == null) {
              // apk is not signed;
              return ApkSignStatus.notSigned;
          }
  
          try (JarFile jarFile = new JarFile(this.apkFile)) {
              Enumeration<JarEntry> entries = jarFile.entries();
              byte[] buffer = new byte[8192];
  
              while (entries.hasMoreElements()) {
                  JarEntry e = entries.nextElement();
                  if (e.isDirectory()) {
                      continue;
                  }
                  try (InputStream in = jarFile.getInputStream(e)) {
                      // Read in each jar entry. A security exception will be thrown if a signature/digest check fails.
                      int count;
                      while ((count = in.read(buffer, 0, buffer.length)) != -1) {
                          // Don't care
                      }
                  } catch (SecurityException se) {
                      return ApkSignStatus.incorrect;
                  }
              }
          }
          return ApkSignStatus.signed;
      }
docs: {@inheritDoc}
  
  @deprecated using google official ApkVerifier of apksig lib instead.