On the Application of Isomorphic Composite Fields for AES against Differential Power Analysis

• Main Authors: Sue-Jing Huang, 黃淑菁
• Other Authors: Ming-Der Shieh
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/11403239385108916427

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 95 === Since Paul Kocher proved that side-channel attack (SCA) efficiently break Data Encryption Standard (DES) in 1996, many cryptosystem designers have not only focused on the mathematic security but also concerned about its hardware implementation security of cryptography. In 2001, National Institute of Standard and Technology (NIST) announced the new generation Advanced Encryption Standard (AES) which is also threatened under side-channel attack. Differential power analysis (DPA) involves the leaked power information to deduce the secret key during the execution of the algorithm. When the power consumption depends on processed data which covers a part of the secret key, the correlation exists between Hamming weight of the intermediate values and power consumption. In contrast to the countermeasures on a microprocessor, our thesis focuses on AES architecture against DPA for ASIC implementation view point. During encryption, the attacker observes the power consumption of the register to predict the intermediate values, so we propose a countermeasure against DPA by randomly generating a composite field to compute S-box. Assume that attacker does not know which the composite field is used, and then the useful information can not be obtained from power. Hence, we achieve the purpose of randomizing intermediate values. In other words, while we reduce the correlation between power consumption and intermediate values, the security of cryptosystem is increased.