A method and apparatus for concealing data. Frequency information is identified for a number of data object types of a set of data objects in the data using a frequency map. A set of pixel values is assigned to the set of data objects based on the frequency information for use in encrypting the set of data objects to form encrypted data. An image is generated that includes a set of pixels that represents the encrypted data. Each pixel in the set of pixels has a pixel value from the set of pixel values that is assigned to a corresponding data object of the set of data objects.