Reversible steganography in encrypted domain is widely used in medical

cloud services

military

commercial and other fields. Aiming at the problems of encrypted domain information hiding algorithm

such as incomplete guarantee of reversibility

low embedding rate and incomplete separation

this paper proposed a separable and reversible steganography in encrypted domain. Firstly

the conditions and construction methods for the ergodic matrix of image encryption are given. The carrier image owner sets the key1 to construct the ergodic matrix and encrypts the plaintext image

the information embedder sets the key2

in order to achieve the goal of expectation interpolation

the number of embedding bits is determined according to the size of interpolation interval

and then the final interpolation is determined by the difference correction factor and secret information together

so that the final interpolation is close to the expectation interpolation to the maximum extent

ensuring the high quality of the encrypted image. There is no additional information

no data overflow and reversibility is guaranteed in the whole process

the two permissions do not interfere with each other

and the algorithm is completely reversible and separable

and the average embedding rate can reach 3 bit/pixel. The experimental results show that the algorithm is better than the other eight excellent algorithms in terms of embedding capacity

reversibility and separability.