Abstract: To validate the resistibility to power analysis attacks for different countermeasures,this paper presented the method which can find the feasible power analysis attacks in various implementations of cryptographic algorithms.The presented method includes three parts,the basic theory for identifying the feasible attacks,the enhanced data dependence graph which used to describe the implementation of a cryptographic algorithm,and the algorithm for identifying different kinds of power analysis attacks.A typical countermeasure of AES based on random masking is used to illustrate how to identify the feasible attacks.By Combining with the quantitative analysis of the resistibility to power analysis attacks for a cryptographic device,the design flow of power analysis attacks resistant cryptographic device can be established.