SM4密码算法的阶梯式相关能量分析

Stepwise correlation power analysis of SM4 cryptographic algorithm

针对相关能量分析(CPA)易受噪声干扰、分析效率低的问题,提出了一种阶梯式CPA方案。首先,通过构造一种新的阶梯式方案提高CPA中信息的利用率;其次,通过引入confidence指标提升每一次分析的正确率,解决前几次分析正确率得不到保证的问题;最后,基于SM4密码算法结构给出了一个阶梯式CPA方案。模拟实验结果表明,在达到90%分析成功率的前提下,阶梯式CPA比传统CPA减少了25%能量迹条数的需求。现场可编程门阵列(FPGA)上的实验表明,阶梯式CPA恢复完整轮密钥的能力已经非常接近将搜索空间扩展到最大时的极限。阶梯式CPA能以足够小的计算量减少噪声的干扰、提高分析的效率。

Focused on the low analysis efficiency of Correlation Power Analysis(CPA)interfered by noise,a stepwise CPA scheme was proposed.Firstly,the utilization of information in CPA was improved by constructing a new stepwise scheme.Secondly,the problem that the accuracies of previous analyses were not guaranteed was solved by introducing the confidence index to improve the accuracy of each analysis.Finally,a stepwise CPA scheme was proposed based on the structure of SM4 cryptographic algorithm.The results of simulation experiments show that,on the premise of the success rate up to 90%,stepwise CPA reduces the demand of power traces by 25%compared to classic CPA.Field Programmable Gate Array(FPGA)based experiments indicate that the ability of stepwise CPA to recover the whole round key is very close to the limit of expanding the search space to the maximum.Stepwise CPA can reduce the interference of noise and improve the efficiency of analysis with a small amount of calculation.