Cryptanalysis and enhancements of image encryption based on three-dimensional bit matrix permutation

Recently, an image encryption based on three-dimensional bit matrix permutation (TDBMP) has been proposed by Zhang et al. The encryption scheme has combined Chen chaotic system with a 3D Cat map in the permutation stage, and defined a new mapping rule (double random position permutation) and utilized key-streams generated by Logistic map to confuse the permuted image. However, we have found that this scheme is vulnerable to chosen plaintext attack and is not applicable to secure communications. In this paper, the shortcomings of TDBMP have been analysed and a chosen plaintext attack has been proposed to break the scheme. After that, we propose an enhanced algorithm to overcome the presented shortcomings in the above original scheme. Experimental results also illustrate that the enhanced scheme not only maintains the merits of the original one, but also has better cryptographic performances in key space, plaintext sensitivity, statistical characteristics, robustness against cropping attack and execution speed, and can therefore effectively ensure a secure image communication.