Efficient image scrambling using polyphase filter banks

Proposes a modification to the classic time-frequency permutation method of signal scrambling which reduces its complexity and memory requirements without decreasing its performance. This new approach is applicable to any filter bank or transform and requires only that the decomposition in question be implemented in a polyphase form. To minimize the computational complexity, modulated polyphase filter banks like the cosine-modulated and allpass filter banks can be selected. Using a two dimensional extension to the basic algorithm, the authors consider the problem of image scrambling and include simulation results