code: public void close() {
  		if (defaultContext != null) {
  			defaultContext.close();
  			defaultContext = null;
  		}
  		if (defaultContextControl != null) {
  			defaultContextControl.close();
  			defaultContextControl = null;
  		}
  	}
docs: Close the transformer engine.
  
  The close functions closes all stored default crypto contexts. This
  deletes key data and forces a cleanup of the crypto contexts.