Patent ID: 8707056

Claim:
Apparatus for processing data comprising: processing circuitry configured to operate in a selectable one of a secure domain and a non-secure domain; a memory coupled to said processing circuitry and configured to store secure data within a secure region of said memory and to store non-secure data within a non-secure region of said memory, said secure data being accessible to said processing circuitry when operating in said secure domain and being non-accessible to said processing circuitry when operating in said non-secure domain, and said non-secure data being accessible to said processing circuitry when operating in said secure domain and being accessible to said processing circuitry when operating in said non-secure domain; a user input device coupled to said processing circuitry and configured to receive user input data; and a display coupled to said processing circuitry and configured to display a display image in dependence upon a frame of image data read from a frame buffer stored within said non-secure region; wherein said processing circuitry is configured to operate in said secure domain to store a subject image comprising at least a portion of said frame of image data within a validated display area of said frame buffer and to store within said secure region validation data dependent upon said subject image; and said processing circuitry is configured to operate in said secure domain to receive a user input from said user input device and, upon receipt of said user input, to read displayed data stored within said validated display area and to compare check data dependent upon said displayed data with said validation data to confirm said displayed data matches said subject image.