An arrangement for protecting data saved in a memory, in which arrangement at least one memory element and at least one data processing element are combined by means of required interfaces into a data processing entity. The arrangement comprises at least one scrambler (300, 410, 600) connected to the data processing entity, which scrambler (300, 410, 600) scrambles the form in which the data to be saved in the memory element is represented and/or descrambles data saved in the memory element into plain text when data is taken from the memory element for the use of the data processing elements.