Cryptanalysis of an Image Encryption Scheme Based on a Compound Chaotic Sequence

TL;DR

This paper critically analyzes a recent image encryption scheme based on compound chaotic sequences, revealing vulnerabilities such as susceptibility to differential attacks, weak keys, and poor randomness, thereby questioning its security effectiveness.

Contribution

The paper provides a detailed cryptanalysis of the scheme, identifying specific security flaws and demonstrating its weaknesses against various attack methods.

Findings

Differential chosen-plaintext attack can break the scheme with three images

Existence of weak and equivalent keys reduces security

The scheme lacks sensitivity to plaintext changes

Abstract

Recently, an image encryption scheme based on a compound chaotic sequence was proposed. In this paper, the security of the scheme is studied and the following problems are found: (1) a differential chosen-plaintext attack can break the scheme with only three chosen plain-images; (2) there is a number of weak keys and some equivalent keys for encryption; (3) the scheme is not sensitive to the changes of plain-images; and (4) the compound chaotic sequence does not work as a good random number resource.