一個基於混沌映射且採用明文關聯置換與擴散之影像加密系統的分析與改進

Abstract

去年七月，Huang 等人提出了一個基於混沌映射且採用明文關聯置換與擴散之影像加密系統(CIES-UBPRPD)。在CIES-UBPRPD 中，置換與擴散都是與明文產生關連的操作。儘管Huang 等人宣稱CIESUBPRPD有著高度的明文敏感性，我們依然發現其設計上的缺陷使得它無法抵抗選擇明文攻擊。本篇論文分析了CIES-UBPRPD 中的安全缺陷，且提出一種選擇明文攻擊破解它。我們也提供了一種改進過後的加密演算法，克服了CIES-UBPRPD 原先的缺陷。

Recently, a simple chaotic map-based image encryption system using both plaintext related permutation and diffusion (CIES-UBPRPD) has been proposed by Huang et al. In CIES-UBPRPD, both the permutation operation and the diffusion operation are related to plain images. Despite the claim that CIES-UBPRPD has high plaintext sensitivity, we have found that it still vulnerable to chosen-plaintext attack. In this thesis, we analyze the security flaws of CIES-UBPRPD and propose a chosen-plaintext attack to break it. Furthermore, we present an improved encryption algorithm to remedy those flaws of CIES-UBPRPD.