. In this paper image cryptography and steganography performed in frequency domain using random phase mask encoding are presented. The use of random phase mask allows to deccorrelate initial image and makes it unrecognized. This property is used for proposed image encryption and for steganography to increase the security level of the encoded image and to make it less visible. Finally,twokeys are needed to decrypt the image. The e#ciency of the proposed approach is demonstrated by the computer modeling. 1. Introduction The growing possibilities of modern communications require the special means of con#dential and intellectual property protection against unauthorized access and use. Especially these problems are actual for computer networks, which make possible to exchange the large amount of video information, and for TV systems. The formulation and solution of two problems of image cryptography and steganography considered from the common position are presented in the paper. Image c..