PROJECT TITLE:

Lossless and Reversible Data Hiding in Encrypted Images withPublic Key Cryptography - 2016

ABSTRACT:

This project proposes lossless, reversible, and combined information hiding schemes for ciphertext images encrypted by public-key cryptosystems with probabilistic and homomorphic properties. In the lossless theme, the ciphertext pixels are replaced with new values to embed the extra information into many least significant bit planes of ciphertext pixels by multilayer wet project coding. Then, the embedded data can be directly extracted from the encrypted domain, and the information-embedding operation will not have an effect on the decryption of original plaintext image. Within the reversible scheme, a preprocessing is employed to shrink the image histogram before image encryption, therefore that the modification on encrypted pictures for knowledge embedding will not cause any pixel oversaturation in plaintext domain. Although a small distortion is introduced, the embedded information will be extracted and the first image can be recovered from the directly decrypted image. Because of the compatibility between the lossless and reversible schemes, the info-embedding operations within the two manners can be simultaneously performed in an encrypted image. With the combined technique, a receiver could extract a part of embedded data before decryption, and extract another part of embedded information and recover the initial plaintext image once decryption.