This document discusses separable reversible data hiding using matrix addition for color images. It proposes a scheme where the content owner encrypts the original image, then a data hider embeds additional data using a data hiding key. The receiver can extract the hidden data and recover the original image by separately providing the encryption key and data hiding key. Lossy and lossless compression techniques for images are also discussed. Reversible data hiding allows exact recovery of the original image and extraction of hidden data without errors when the amount of additional data is large.