Vector instructions for performing ZUC stream cipher operations are received and executed by the execution circuitry of a processor. The execution circuitry receives a first vector instruction to perform an update to a liner feedback shift register (LFSR), and receives a second vector instruction to perform an update to a state of a finite state machine (FSM), where the FSM receives inputs from re-ordered bits of the LFSR. The execution circuitry executes the first vector instruction and the second vector instruction in a single-instruction multiple data (SIMD) pipeline.