Breaking a novel image encryption scheme based on improved hyperchaotic sequences

TL;DR

This paper critically analyzes a recent hyperchaotic image encryption scheme, demonstrating its vulnerability to known-plaintext attacks and highlighting security flaws related to key and plaintext sensitivity.

Contribution

It reveals that the proposed encryption scheme is insecure against known-plaintext attacks with minimal data and identifies key and plaintext sensitivity issues.

Findings

Can be broken with only one known plain-image

Performance improves with two known plain-images

Security defects in key and plaintext sensitivity

Abstract

Recently, a novel image encryption scheme based on improved hyperchaotic sequences was proposed. A pseudo-random number sequence, generated by a hyper-chaos system, is used to determine two involved encryption functions, bitwise exclusive or (XOR) operation and modulo addition. It was reported that the scheme can be broken with some pairs of chosen plain-images and the corresponding cipherimages. This paper re-evaluates the security of the encryption scheme and finds that the encryption scheme can be broken with only one known plain-image. The performance of the known-plaintext attack, in terms of success probability and computation load, become even much better when two known plain-images are available. In addition, security defects on insensitivity of the encryption result with respect to changes of secret key and plain-image are also reported.