An encryption circuit includes a pipelined encryption core having a plurality of round cores therein. The pipelined encryption core is configured to perform a real round operation on each of a plurality of pieces of input data received therein and generate encryption data from the input data using an encryption operation comprising the real round operation. An encryption controller is provided, which is coupled to the pipelined encryption core. The encryption controller is configured to control the pipelined encryption core so that at least one of the plurality of round cores performs a virtual round operation as part of the encryption operation. The pipelined encryption core is configured to perform a virtual encryption operation using at least one of: (i) dummy data, and (ii) a dummy encryption key.