DWT-based color image encryption using multi-chaotic maps

This paper introduces a discrete wavelet transform (DWT)-based color images encryption method by multi-chaotic maps. Three improved one-dimensional (1D) chaotic maps are utilized to produce the keystreams, where the original image and the external secret key are employed to update the initial conditions and parameters of the chaotic systems. The image sub-bands obtained via DWT decomposition are firstly encrypted. In what follows, the image after inverse discrete wavelet transform (IDWT) reconstruction is further diffused in the spatial domain by the keystreams to strengthen the security of the cryptosystem. Experimental results and security analysis show the feasibility, validity and security of the proposed scheme.