code: public boolean verifyTimestampImprint() throws NoSuchAlgorithmException {
          if (timeStampToken == null)
              return false;
          MessageImprint imprint = timeStampToken.getTimeStampInfo().toASN1Structure().getMessageImprint();
          byte[] md = MessageDigest.getInstance("SHA-1").digest(digest);
          byte[] imphashed = imprint.getHashedMessage();
          boolean res = Arrays.equals(md, imphashed);
          return res;
      }
docs: Checks if the timestamp refers to this document.
  @throws java.security.NoSuchAlgorithmException on error
  @return true if it checks false otherwise
  @since	2.1.6