Cryptanalysis of Image Encryption Based on Permutation-Substitution Using Chaotic Map and Latin Square Image Cipher

Recently Panduranga et al. suggested an image encryption algorithm based on permutation-substitution architecture using chaotic map and Latin square. According to the proposal, the pixels of plain-image are firstly scrambled according to permutation vector, extracted from chaotic sequence, in permutation phase. In substitution phase, the permuted image is substituted by XOR operation with key image generated from a keyed Latin square. The algorithm has the ability to adapt and encrypt any plain-image with unequal width and height. Moreover, it also exhibits the features of high entropy, low pixels correlation, large key space, high key sensitivity, etc. However, a careful analysis of Panduranga et al. algorithm unveils few security flaws which make it susceptible to cryptographic attack. In this paper, we analyze its security and proposed a chosen plaintext-attack to break the algorithm completely. It is shown that the plain-image can be successfully recovered without knowing the secret key. The simulation of proposed attack demonstrates that Panduranga et al. algorithm is not at all secure for practical encryption of sensitive digital images.