The paper introduced Differential Power Analysis （DPA） attack of the decrypt encrypted circuits with SMS4, it is one particularly powerful type of Side Channel Attacks （SCA）. All its theories are based upon the physical characters, power consumption models and data-dependent power consumption of CMOS logic gates which form the integrated circuits （ICs）. The paper introduced the design and realization of DPA attacks of SMS4. Correct secret key of encryption algorithm is cracked successfully with experiments. It comes gradually and closely ...
