docs: public boolean saveEncryptionKeyData(KeyData data) {
          JSONObject objectToSave = new JSONObject();
          try {
              objectToSave.put(KEY_DPK, DPKEncryptionUtil.byteArrayToHexString(data
                      .getEncryptedDPK()));
              objectToSave.put(KEY_IV, DPKEncryptionUtil.byteArrayToHexString(data.getIv()));
              objectToSave.put(KEY_SALT, DPKEncryptionUtil.byteArrayToHexString(data.getSalt()));
              objectToSave.put(KEY_ITERATIONS, data.iterations);
              objectToSave.put(KEY_VERSION, data.version);
  
              String valueToSave = objectToSave.toString();
  
              SharedPreferences.Editor editor = this.prefs.edit();
              editor.putString(preferenceKey, valueToSave);
              editor.commit();
  
          } catch (JSONException e) {
              LOGGER.log(Level.SEVERE, e.getLocalizedMessage(), e);
              return false;
          }
  
          return true;
      }