code: public KSIBuilder setPublicationsFilePkiTrustStore(File file, String password) throws KSIException {
          if (file == null) {
              throw new KSIException("Invalid input parameter. Trust store file is null");
          }
          FileInputStream input = null;
          try {
              this.trustStore = KeyStore.getInstance("JKS");
              char[] passwordCharArray = password == null ? null : password.toCharArray();
              input = new FileInputStream(file);
              trustStore.load(input, passwordCharArray);
          } catch (GeneralSecurityException | IOException e) {
              throw new KSIException("Loading java key store with path " + file + " failed", e);
          } finally {
              Util.closeQuietly(input);
          }
          return this;
      }
docs: Loads the {@link KeyStore} from the file system and sets the {@link KeyStore} to be used as a truststore to verify
  the certificate that was used to sign the publications file.
  
  @param file
  keystore file on disk, not null.
  @param password
  password of the keystore, null if keystore isn't protected by password.
  @return Instance of {@link KSIBuilder}.
  @throws KSIException
  when any error occurs.