Research On Reversible Data Hiding Method In Digital Image Ciphertext Domain

Information hiding is an important branch of information security technology and has been widely used in the fields of secure communication,intellectual property protection and content authentication.Reversible information hiding is a special information hiding technology that embeds secret information in an image in a reversible manner.After extracting embedded information,it can recover the original image without distortion.Reversible information hiding has a wide range of application values in areas sensitive to content such as military communication,medical care and legal argumentation,etc.With the rapid development of cloud computing technology,the related information security needs to be improved.In order to ensure the security of cloud image content,encryption technology can be used for encryption.Cloud administrators often need to embed specific information in the encrypted image.In this application scenario,the reversible information hiding technology of the encryption domain emerges as the times require.The research of the subject has important theoretical significance and practical application value.(1)A reversible information hiding method for image encryption domain based on contrast mapping is proposed.In this paper,a new framework for reversible information hiding of encrypted images using generalized reversible contrast mapping is presented.The content owner can embed the secret data and vacate the embedded space before the image is encrypted.After encrypting and uploading the cloud,the administrator can embed the data into the encrypted image.This method ensures reversibility,the data embedded by the content owner and the cloud manager can be correctly extracted and the original image is restored without distortion.The experimental results show the effectiveness of the method,which not only ensures the data embedded by the cloud manager,but also satisfies the data needs of the content owner.The directly decrypted confidential image has good rate distortion performance.(2)A reversible information hiding method for image encryption domain based on prediction difference is proposed.In this paper,the image pixels are divided into sampled pixels and non-sampling pixels.The prediction difference is predicted by interpolation technique.The error map of the embedded domain data is extracted by the prediction difference decision.The error map is embedded into the sampled pixels by integer transform technology.After the processed image is encrypted,the data can be embedded by simple operation,and the position map can be decrypted and extracted to accurately extract the embedded information without distortion to restore the original image.The experimental results show that the algorithm can extract the information without error and restore the original image without distortion,and improve the data embedding capacity,and achieve good results.