Cryptanalysis and Security Evaluation of a Fast Image Encryption Algorithm Based on the Modified Logistic Map

Ensuring the security of digital images is crucial in various domains, including medical imaging, secure communications, and military applications. Recently, a fast image encryption algorithm based on a substitution-permutation network and a modified logistic map has been proposed, claiming to offer enhanced security and computational efficiency. The encryption process follows three main phases: permutation, substitution, and XOR operation with a pseudo-random binary sequence. However, in this study, we conduct a rigorous cryptanalysis of the algorithm and demonstrate its susceptibility to chosen-plaintext attacks. By systematically reversing each encryption phase, we develop an efficient method capable of recovering the original image with a computational complexity of $O(N)$, where N represents the image size. The experimental results confirm the feasibility of our attack, revealing fundamental weaknesses in the algorithm’s security mechanisms. Our findings indicate that the encryption scheme fails to provide the necessary cryptographic robustness required for protecting sensitive image data. This study underscores the importance of comprehensive security evaluations in cryptographic algorithm design and highlights the need for more resilient encryption schemes to withstand modern attack vectors.