Analysis of chaotic methods for compression and encryption processes in data communication

Data compression and encryption are critical issues for efficiency and security requirements of information transmission. In order to improve the performance and the flexibility of multimedia applications, it is worthwhile to perform compression and encryption in a single process. Recently Hermassi et al. proposed a method for joint compression and encryption using chaotically mutated Huffman trees. The proposed method based on multiple Huffman tables simultaneously performs encryption and compression by a key-controlled swapping of the left and right branches of the Huffman tree. However, security problems were found. In this study describes the security weakness of the proposed method. By applying chosen-plaintext attacks, we show that secret key can be revealed.