The smallest ARIA module with 16-bit architecture This paper presented the smallest hardware architecture of the ARIA block cipher algorithm. A 128-bit data block was divided into eight 16-bit blocks to reduce the hardware size. The 16-bit architecture allowed two S-Boxes and 16-bit diffusion operation. We proposed a design for the substitution layer and the memory block. The proposed round key generator processed a 16-bit block of a 128-bit round key for three cycles. The proposed ARIA module with a 128-bit key comprised 6,076 equivalent gates using a $0.18-\mu $m CMOS standard cell library. It took 88 clock cycles to generate four initial values for a round key and 400 clock cycles to en/decrypt 128-bit block data. The power consumption of 16-bit ARIA was only $5.02 \mu $W at 100 kHz 1.8V.