Cryptanalyzing an Image Encryption Scheme Using Synchronization of Memristor Chaotic Systems

This paper conducts a security analysis on an image encryption scheme that incorporates chaos synchronization and DNA encoding techniques. The scheme adheres to the typical Substitution–Permutation structure by introducing the DNA operation as a nonlinear component. Compared to the traditional chaotic ciphers, the designer claims that the scheme achieved better nonlinear properties through the DNA operation. However, the characteristics of the differential between some pairs of plaintexts and the corresponding ciphertexts can be exploited to break the permutation operation. Meanwhile, the substitution operation can also be cracked by checking the mapping between the intermediate variables inversely permuted from ciphertext and the corresponding plaintext. Given the weaknesses of the encryption scheme, we introduce effective strategies for the known-plaintext attack. Both rigorous theoretical analyses and detailed experimental results are provided to demonstrate the effectiveness of the attacks.