Cryptanalyzing a chaos-based image encryption algorithm using alternate structure

TL;DR

This paper demonstrates that a chaos-based image encryption algorithm using an alternate structure is vulnerable to differential cryptanalysis, revealing security flaws and weaknesses in its key space and sensitivity to plaintext changes.

Contribution

It provides the first detailed differential cryptanalysis of IEAS, exposing its vulnerabilities and security defects, including insensitivity and limited key space.

Findings

IEAS can be broken with few known plaintexts using differential attack.

The attack applies to both low and high round versions of IEAS.

Security flaws include insensitivity to plaintext changes and small key space.

Abstract

Recently, a chaos-based image encryption algorithm using alternate structure (IEAS) was proposed. This paper focuses on differential cryptanalysis of the algorithm and finds that some properties of IEAS can support a differential attack to recover equivalent secret key with a little small number of known plain-images. Detailed approaches of the cryptanalysis for cryptanalyzing IEAS of the lower round number are presented and the breaking method can be extended to the case of higher round number. Both theoretical analysis and experiment results are provided to support vulnerability of IEAS against differential attack. In addition, some other security defects of IEAS, including insensitivity with respect to changes of plain-images and insufficient size of key space, are also reported.