Miyaji Laboratory

Abstract

A key recovery attack using differential analysis is known to be the most effective attack against Salsa20/ChaCha. The difference correlation is used for the difference analysis, but the number of searches for the correlation of multiple input differences is enormous and research has not progressed. The security of stream ciphers is based on the mixing property, and Sobti et al. proposed the Diffusion analysis method from the viewpoint of mixing property. In this study, we improved the Diffusion analysis of Sobti et al. to search for correlations of multiple input differences, proposed a new Diffusion analysis that can limit the search range of correlations of multiple input differences from the viewpoint of agitation, and proposed the Diffusion analysis To identify the correlation of multiple input differences.