Salsa20的差分故障分析

Differential Fault Analysis of Salsa20

Salsa20是eSTREAM计划最终获胜算法之一,其主要特征是利用模加、异或和循环移位三种运算的混合提供算法所需扩散性和混淆性。目前对该算法的分析主要集中在统计分析和差分分析两方面。本文研究Salsa20/256的差分故障分析,在基于随机字的故障诱导模型下,通过诱导96个错误,将以近似1的概率获得186比特的密钥信息,从而将恢复Salsa20/256全部密钥比特的时间复杂度降为270,这表明Salsa20/256对基于随机字的差分故障分析是脆弱的。

Salsa20 is one of the finalists of the eSTREAM project. Its main feature is using the ARX operations （i. e. addition, rotation, and xor on 32-bit words） to achieve good confusion and diffusion effects. At present, many cryptanalytic results on it are statistical cryptanalysis and differential crypta- nalysis. In this paper, we further investigate a differential fault analysis of Salsa20/256. By adopting a random fault word model, when inducing 96 faults,the 186 bit key can be recovered with a probability close to 1 ,accordingly the complexity of recovering the full key bits of Salsa20/256 can be reduced to 2^70 , which implies that Salsa20/256 is sensitive to the differential fault analasis.