Second Order DPA Against Fixed Masking

In recent years, power analysis attacks have caused increasingly serious security threats on cryptographicalgorithm, to solve this problem different researcher has put forward many solutions, and among them the fixed value masking technology is one of the mostly used due to its lower cost and faster speed. Both theoretical and practical results have shown that the masking method has a good resistance to differential power analysis (DPA) attack. So based on the in-depth study of fixed masking technology, this paper proposed a second order DPA attack (SODPA) with the help of a pre-processing treatment. In the end, we implemented this attack on a fixed value masked AES encryption algorithm running in Mega16. The experimental result shows that, if the mask value is unknown, ordinary DPA cannot recover the right key, while the second order DPA only needs about 500 power curves to get the correct key. In the meantime, the differences between right and wrong keys are very obvious, which strongly proved the validity and practicability of our method.