A low-power and low-cost advanced encryption standard(AES) coprocessor is proposed for Zigbee system-on-a-chip(SoC) design.The cost and power consumption of the proposed AES coprocessor are reduced considerably by optimizing the architectures of SubBytes/InvSubBytes and MixColumns/InvMixColumns,integrating the encryption and decryption procedures together by the method of resource sharing,and using the hierarchical power management strategy based on finite state machine (FSM) and clock gating(CG) technologies.Based on SMIC 0.18μm complementary metal oxide semiconductor(CMOS) technology,the scale of the AES coprocessor is only about 10.5 kgate,the corresponding power consumption is 69.1μW/MHz, and the throughput is 32 Mb/s,which is reasonable and sufficient for Zigbee system.Compared with other designs,the proposed architecture consumes less power and fewer hardware resources,which is conducive to the Zigbee system and other portable devices. A low-power and low-cost advanced encryption standard (AES) coprocessor is proposed for Zigbee system-on-a-chip (SoC) design. The cost and power consumption of the proposed AES coprocessor are reduced by optimizing the architectures of SubBytes / InvSubBytes and MixColumns / InvMixColumns, integrating the encryption and decryption procedures together by the method of resource sharing, and using the hierarchical power management strategy based on finite state machine (FSM) and clock gating (CG) technologies. Based on SMIC 0.18 μιη complementary The corresponding power consumption is 69.1 μW / MHz, and the throughput is 32 Mb / s, which is reasonable and sufficient for Zigbee system. Compared with other designs, the proposed architecture consumes less power and fewer hardware resources, which is conducive to the Zigbee system and other portable devices.