Reversible data hiding in encrypted images with private-key homomorphism and public-key homomorphism

摘要

This paper proposes two reversible data hiding schemes in encrypted images that provide lossless recovery of directly decrypted images. The modified homomorphic encryption is introduced to encrypt the original image so that the private-key homomorphism and public-key homomorphism are both available. To embed secret message into encrypted image, a part of encrypted pixels are replaced with new ciphertexts by homomorphic property. Finally, the original image and embedded secret message can be restored by direct decryption. Optimal visual quality is obtained by the proposed schemes, since the directly decrypted pixel value is equal to the original pixel value. And the embedding rate is further improved. In addition, the proposed schemes are suitable for compressed multimedia, which extends the application scenarios. Experimental results are presented to demonstrate the effectiveness and superiority of the proposed schemes. (C) 2018 Elsevier Inc. All rights reserved.