A Search Method for Impossible Differential Paths of Related Keys in Block Ciphers

Abstract

The invention discloses a searching method for an impossible differential path of a related key of a block cipher. As an impossible differential attack method and a related key attack method are combined, the problems of automatic searching of the impossible differential path of the related key and searching of a longest analysis path in cryptanalysis are solved, and deeper and more thorough analysis for a cryptographic algorithm can be carried out. According to the searching method for the impossible differential path of the related key of the block cipher, the method for searching the impossible differential path of the related key is upgraded from the traditional manual analysis to computer automatic searching, the disadvantages that an existing manual analysis method is fussy and error-prone when being used for analyzing the cryptographic algorithm are avoided, the maximum length of the impossible differential path of the related key of the block cipher algorithm can be calculated rapidly and accurately, and the cryptanalysis efficiency is improved. The searching method for the impossible differential path of the related key of the block cipher realizes transformation of the cryptographic algorithm from a non-generalized Feistel structure to a generalized Feistel structure, can be widely applied to automatic search of the impossible differential paths of related keys of various cryptographic algorithms in different structures.

Description

technical field [0001] The invention belongs to the technical field of information security, and in particular relates to a search method for an impossible differential path of a block cipher-related key. Background technique [0002] With the continuous development of technology, the role of information security has become increasingly prominent, and people's lives are inseparable from information. Cryptography, as the basis of information security, has developed rapidly. Cryptography and cryptanalysis have co-evolved, so when cryptography developed, cryptanalysis also attracted attention. However, cryptanalysis has always been mainly based on manual analysis, although some people have proposed an impossible differential search method, with the help of computer-aided cryptanalysis. Both the manual analysis method and the proposed impossible differential search method have deficiencies: [0003] 1. The manual analysis method relies entirely on the manual understanding of t...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a search method for the impossible differential path of a block cipher related key, aiming to combine the related key differential search method and the impossible differential search method to solve the existing generalized Feistel structure or transformable The problem of computer automatic search for the maximum correlation key impossible differential path of block cipher algorithm with generalized Feistel structure, encryption and decryption matrix satisfying 1-property and round function satisfying bijection

The invention realizes the automatic search of the computer for the method of searching for the impossible differential path of the relevant key, does not need manual calculation to find the impossible differential path of the relevant key, and can traverse all paths, and overcomes incomplete manual analysis, error-prone, The disadvantage of low efficiency, and the ability to calculate the maximum length of the relevant key of the block cipher algorithm impossible differential path

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