针对密码芯片的自适应选择明文旁路模板分析

Adaptive chosen plaintext template analysis against cipher chips

为了提高旁路模板分析密钥恢复攻击的效率,提出一种自适应选择明文旁路模板分析方法.该方法选择密码算法中密钥参与的异或操作为攻击点,以两个操作数的汉明距离构建旁路信号模板,从二进制位为全'1'的明文开始,按选择明文与密钥的汉明距离不断减小的方向每次改变选择明文得到一个比特位,将选择明文逐步逼近并最终恢复密钥.针对微控制器AT89C52)上实现的高级加密标准密码算法攻击实验表明该方法可在不增加攻击所需样本的条件下提高攻击效率.

To improve the efficiency of side channel template based key recover attack, an adaptive chosen plaintext template analysis method is presented. This method takes the exclusive or （XOR） operation between plaintext and secret key in cipher as attacking target, builds side channel templates for the Hamming distance between two operands. From a chosen plaintext whose binary bits are all ＂1＂, the binary bits in the chosen plaintext are changed bit by bit to reduce the Hamming distance between the plaintext and the key. Till the Hamming distance between the chose plaintext and the key is reduced to zero, the secret key should be equal to the plaintext. Attack experiment against advanced encryption standard （AES） encryption executed in an AT89C52 microcontroller shows that the attack efficiency is improved while the number of side channel samples holds in the level in traditional method.