Baptista-type chaotic cryptosystems: Problems and countermeasures

TL;DR

This paper analyzes the security issues of Baptista-type chaotic cryptosystems, discusses a defect causing decryption errors, and proposes countermeasures to address these problems to improve cryptosystem robustness.

Contribution

It identifies a critical defect in an enhanced Baptista-type cryptosystem and introduces solutions to rectify this, along with addressing other existing vulnerabilities.

Findings

The enhanced cryptosystem has a nonzero probability of decryption errors.

Identified a defect causing error propagation in the cryptosystem.

Proposed countermeasures to fix vulnerabilities in Baptista-type cryptosystems.

Abstract

In 1998, M. S. Baptista proposed a chaotic cryptosystem, which has attracted much attention from the chaotic cryptography community: some of its modifications and also attacks have been reported in recent years. In [Phys. Lett. A 307 (2003) 22], we suggested a method to enhance the security of Baptista-type cryptosystem, which can successfully resist all proposed attacks. However, the enhanced Baptista-type cryptosystem has a nontrivial defect, which produces errors in the decrypted data with a generally small but nonzero probability, and the consequent error propagation exists. In this Letter, we analyze this defect and discuss how to rectify it. In addition, we point out some newly-found problems existing in all Baptista-type cryptosystems and consequently propose corresponding countermeasures.