Encrypting touch-sensitive display

摘要

A hardware encryption device (18) comprises: a touch panel controller (60); and a cryptographic engine (62) in communication with the touch panel controller (60). The touch panel controller (60) receives co-ordinates from the cryptographic engine (62) corresponding to an area on a touch panel (24) selected by a user. The cryptographic engine (62) is operable to discriminate between a selection in a secure area (82) on a screen (80) and a selection in a non-secure area (72 or 92) on a screen (70 or 90), and to action the selection differently depending on whether the selection is in a secure area (80) or a non-secure area (70 or 90).