Breaking a modified substitution-diffusion image cipher based on chaotic standard and logistic maps

TL;DR

This paper analyzes a chaotic map-based image encryption scheme, revealing that both the original and modified versions are vulnerable to known-plaintext attacks and contain security flaws.

Contribution

It demonstrates that the modified scheme remains insecure and identifies additional security weaknesses in both schemes.

Findings

Both original and modified schemes are vulnerable to known-plaintext attacks.

Security flaws exist in both versions of the encryption scheme.

The modifications did not eliminate the original scheme's vulnerabilities.

Abstract

Recently, an image encryption scheme based on chaotic standard and logistic maps was proposed by Patidar et al. It was later reported by Rhouma et al. that an equivalent secret key can be reconstructed with only one known/chosen-plaintext and the corresponding ciphertext. Patidar et al. soon modified the original scheme and claimed that the modified scheme is secure against Rhouma et al.'s attack. In this paper, we point out that the modified scheme is still insecure against the same known/chosen-plaintext attack. In addition, some other security defects existing in both the original and the modified schemes are also reported.