DES密码旁路立方体分析

Side Channel Cube Attacks on DES

将立方体分析和旁路攻击结合，基于8位汉明重泄露模型，首次对DES分组密码抗旁路立方体攻击安全性进行了评估．在黑盒攻击场景下，攻击者首先按照一定规则生成立方体和超多项式，然后利用不同选择明文，计算其在加密过程某比特的高阶差分，判断该立方体对应的超多项式是否合法．对DES加密输出第l轮输出不同字节进行了黑盒旁路立方体攻击实验，结果表明：未经防护的DES密码易遭黑盒旁路立方体攻击；如果攻击者能够精确获取加密第1轮输出某一字节的汉明重泄露，最好的攻击结果为2＾9.35个选择明文可将DES主密钥搜索空间降至2＾15．

In this paper ,we investigate the security of DES block cipher against side-channel cube attacks based on 8-bit Hamming weight leakage model. Under the black-attack scenario, the adversary firstly generates random cube and superpoly. Then the cube is used to generate chosen plaintexts. The adversary deduces one bit of the intermediate state from the side channel attack for each chosen plaintext and computes the high order differences of these one bit values to verify the relations between the cube and superpoly. Simulation experiments are launched on output of first round of DES. The results demonstrate that the unprotected implementation of DES is vulnerahle to side-channel cube attacks. If the adversary can accurately deduce the Hamming weight of the intermediate states from the side-channel leakages, many cubes and superpolys can be extracted and used for key recovery. The best experiment result is 2^9.35 chosen plaintexts, which can reduce the DES master keysearch space to 2^15.