On the Leakage between Arithmetic Components of DES Algorithm

Security of cryptographic embedded devices has become a prevalent concern, especially since the introduction of Differential Power Analysis (DPA) by Paul Kocher et al. In the past years, many efforts have been made to improve the resistance against Side Channel Attack (SCA) of cryptographic devices. Among the countermeasures, masking is a typical and efficient strategy. However, a number of effective attacks on masked cryptographic devices have been developed in recent years, and this paper continues this line of research. On theory, a DES with a masking scheme is secure under first order SCA, but we dig out a new leakage problem which makes it possible to attack a masked DES without using higher-order power analysis. Concretely, we perform a first-order correlation power analysis based on the leakage relationship between two different arithmetic components of DES. And the reason for this leakage is analyzed and verified by us through simulation and real card attacks. Keywords—Data Encryption Standard (DES); Differential Power Analysis (DPA); Side Channel Attack (SCA); Leakage between components; Masking; Smartcards.