Reversible Data Hiding in Encrypted Image Based on Flipping MSB Encryption Process

A novel reversible data hiding method based on vacating room for specific encryption process in encrypted image is proposed by Huang and Wang in 2020. In their method, they applied pixel value expansion approach to vacate a specific room for data concealing. However, we find out that the Huang and Wang's method will have a shortcoming of non-reversible encryption while the specific room is larger than 193. This paper proposes an improved method for overcoming the shortcoming of nonreversible encryption developed by Huang and Wang. In our embedding process, the prediction error (PE) is firstly computed, and then, the prediction error strategy is taken into consideration for secret data embedding. The prediction error strategy is applied to determine that the original pixel or flipping one MSB original pixel is suitable for performing message hiding. The experimental results show that the proposed method has superior performance in terms of embedding capacity and compression ratio than that of the other state-of-the-art methods.