docs: public static String generateCharsSymbolsString(int lenght) {
          StringBuffer buf = new StringBuffer(lenght);
          SecureRandom rand = new SecureRandom();
          for (int i = 0; i < lenght; i++) {
              buf.append(charsSymbols[rand.nextInt(charsSymbols.length)]);
          }
          return buf.toString();
      }