code: public static String createSecret() {
          Random random = new SecureRandom();
          StringBuilder buffer = new StringBuilder(BYTES_SECRET);
          for (int i = 0; i < BYTES_SECRET; i++) {
              int value = random.nextInt(MAX_CHARACTERS);
              if (value < ITERATIONS) {
                  buffer.append((char) ('A' + value));
              } else {
                  buffer.append((char) ('2' + (value - ITERATIONS)));
              }
          }
          
          return buffer.toString();
      }
docs: Generates a 64 byte (512 bit) secret
  
  @return A 64 characters random string based on SecureRandom