docs: public synchronized String get() {
          ConfidentialStore cs = ConfidentialStore.get();
          if (secret == null || cs != lastCS) {
              lastCS = cs;
              try {
                  byte[] payload = load();
                  if (payload == null) {
                      payload = cs.randomBytes(length / 2);
                      store(payload);
                  }
                  secret = Util.toHexString(payload).substring(0, length);
              } catch (IOException e) {
                  throw new Error("Failed to load the key: " + getId(), e);
              }
          }
          return secret;
      }