Multi-rounds masking method against DPA attacks

Information incorporated into LSI, and an internal confidential key of a cryptograph is protected against illegally reading. It has been sufficiently proven that encryption standard algorithms used in cryptographic circuits cannot be decrypted computationally. However, several studies have been advanced on various physical analysis attacks that steal internal information. In particular, differential power analysis (DPA) has become a serious problem in recent years because it cracks security codes by statistically processing the difference in electricity power consumption during LSI operation. This study proposes a new method that is effective for two kinds of DPA attacks; hamming weight DPA and hamming distance DPA. Experimental results prove the validity of the proposed method.