A new DWT-based lossless chaotic encryption scheme for color images

A new lossless color image encryption algorithm is proposed based on discrete wavelet transform (DWT)and the coupled map lattices (CML) in this paper. The plain-image is first transformed into the frequency domain by DWT. Then the image sub-bands are shuffled by using the key streams generated from CML and the plain-image. Finally, the image frequencies are transformed back to the spatial domain by using inverse DWT (IDWT). Thus the cipher-image is obtained. The experimental results show that the presented encryption algorithm has the advantages of large key space and high security, and fast encryption/decryption speed.