Scalable asymmetric image encryption based on phase-truncation in cylindrical diffraction domain

摘要

In this paper, a scalable asymmetric image compression and encryption method is proposed based on discrete wavelet transform (DWT) and nonlinear operations in the cylindrical diffraction domain. In this scheme, the grayscale image is processed by a DWT, and four component images are obtained. Then single amplitude ciphertext is obtained by nonlinear operation of phase truncation after cylindrical diffraction. Since the reconstruction from the four component images of DWT is scalable, the proposed method also has scalability. Moreover, the proposed method has high security because it can resist the phase-retrieval attack and prevent information disclosure. Numerical simulations have demonstrated the security and effectiveness of the proposed method.