Research And Design Of Reversible Steganography Algorithm In Encrypted Domain

Due to the security risks in the current network environment,the security protection and management of sensitive data in the third-party platforms have received extensive attention.The security mechanism used mainly uses encryption to transform data into incomprehensible cipher text,which has a certain protective effect,but limits the effective management of data by the platform.Reversible steganography in encrypted domain is proposed to embed data into the encrypted cover and also allow the authorized users to perform reversible data extraction and lossless cover recovery,which is suitable for sensitive fields such as cloud platforms,military communications,and medical systems.However,the algorithms in this field are often difficult to balance security and embedding capacity.In this paper,we focus on the high performance and security of reversible data hiding algorithm in encrypted domain.The main research work and results are listed as follows:(1)A reversible data hiding algorithm based on additive homomorphism and histogram shifting is proposed.Firstly,a ciphertext reversible steganography framework with high security but without ciphertext expansion is designed by means of modulo addition.Then multi-predictors are used to highly concentrated data correlation under the framework,and a new histogram bidirectional shifting strategy is given for reversible embedding.Experimental results show that the algorithm has good security and reversibility without data expansion.Compared with similar algorithms,the performance of directly decrypting images under the same embedding rate is highly improved.(2)A reversible data hiding algorithm based on image camouflage and bit-plane compression is proposed.By using the "plain-plain" encryption,the cover information and the encryption behavior can be hided at the same time,and an edge optimization method based on prediction algorithm is designed to improve the encryption quality.The redundancy of the bit plane is improved by Gray coding.The reversible data hiding then can be perfonned through a bit-plane level compression.The experimental results also show the superior performance of the method in terms of security and steganography.