Reversible Data Hiding In Encrypted Domain Based On Additive Homomorphism And Difference Histogram

With the rapid development of computer science and the popularization of information technology,image as a representative of information transmission occupies a place,but its information security issues such as copyright and privacy are also imminent in the transmission process.Encryption technology has become the first choice for information security protection,and has wide range of applications,but its drawback is that image encrypted ciphertext information can easily attract attention,attacked,damaged even cracked by an attacker,and the decrypted plaintext is unpredictable and control when it was copied and transmitted sybsequently,These security risks has existed.The technology of data hiding can protect the security of information rely on hiding the existence of the secret information.It is not vulnerable to attack.In practical applications,there are some special occasions such as medical and military aspects where information needs to be hidden but the original cover must be kept confidential,and the restored cover can not be distorted.That is reversible data hiding process on the basis of the encrypted image,which is a reversible data hiding technology in encrypted domain,a perfect combination of encryption technology and data hiding technology,this will hava an important practical significance.The work of this paper has the following aspects:Firstly,research on the related literatures of encryption technology and data hiding technology domestic and overseas.The emphasis is put on the details of the classical LSB algorithm,histogram shifting,scrambling encryption scheme and pseudo-random sequence encryption.The algorithm of the combination of the two literature has also been studied for the core algorithm has injected new ideas.Secondly,there mainly have the following problems in the existing algorithms.Aiming at the problem that the error of receiver side and can not guarantee the fully reversible.Based on the research of predecessors' scheme,an algorithm based on additive homomorphism encryption mechanism and difference histogram shifting mechanism is proposed,a reversible solution is achieved;Because of the receiver side can not satisfy the detachable characteristic of the existing scheme,the embedded data can not be extracted and the original image can not be recovered flexibly,In this paper,a solution of detachable at recevier side is designed;For the case of insufficient embedded capacity and low PSNR,In this paper,the original image is pre-processed to shrink the left and right four edge values of the image pixels,so as to avoid PSNR of the image caused by pixel overflow in the subsequent operation.By grouping and dividing the images,three differences occur for each group,establish the difference histogram for each image block,then shift the histogram to take the boundary value of the multi-level embedding in each of the difference histogram,so that embedded capacity has been greatly improved.At last,the embedded data can be successfully extracted and the original image can be perfectly recovered.The simulation results show that the proposed scheme achieves high capacity and high PSNR,and the receiver side satisfies the separable mechanism and ensures reversibility.Compared with other classical literature,the result is obviously improved.