针对标准相关性能量分析(CPA)在旁路攻击中存在的运算时间长、搜索空间大等问题,在分析了功耗泄露信息与数据相关性的基础上,结合标准相关性分析方法,提出一种基于密钥差异位的改进相关性分析方法.该方法利用加密密钥同猜测密钥差异位与猜测密钥同实际能量消耗间的相关系数反比映射这一特征,在给定一个密钥假设的情况下,通过逐位改变0、1取值进行相关性计算获取正确密钥;在搭建实验平台上,针对AES首轮首字节加密实现对改进前后的相关性分析方法分别进行攻击实验.对比表明新方法在破解密钥的基础上成功将密钥搜索空间由原来28成功降至9.%Traditional correlation power analysis(CPA) had the problems of long analysis time and complexity computation.Combining the CPA,this paper proposed a method of correlation analysis based on difference variability,which used the difference between encryption key and hypothetical key.This method used the reciprocal relation between different bits and correlation relation.On the basis of given hypothesis key,it changed the value of every bit to obtain the correct key,which only needed 9 calculations to capture the 8 hit sub-key.Advanced encryption standard (AES) is cracked respectively in traditional CPA experiment and improved experiment.The result shows that the new method improves the efficiency on the basis of cracking the key successfully.
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