The proliferation of stream-based applications has led to the widespread use of Data Stream Management Systems (DSMSs), which can support the real-time requirements of these applications. DSMSs were developed to efficiently execute continuous queries (CQs) over incoming data. Multiple CQs can be optimized together to form a query network by sharing operators across CQs. DSMSs are also required to enforce access controls over operators according to data providers’ policies. In this paper, we propose the first solution to satisfy access control policies at run-time in shared-operator networks in an non-disruptive, efficient manner. Specifically, we propose a new set of low overhead streaming operators, coined as Privacy Switches (PrSs), which are strategically placed in the operator network to dynamically allow or deny the flow of data in certain branches of the network based upon the current state of access control permissions. Our experimental evaluation confirms that our approach introduces low overheads in the shared operator networks while achieving high savings in the overall network performance.