A handheld data processing device includes stored data that is intended to be kept secure from unauthorized access. The handheld data processing device includes applications that store such secure data and which make use of plain text data corresponding to the secure data. An identifier is defined to be associated with defined plain text data. When the handheld data processing device is placed in a locked or secure state, code executable on the device is able to search for plain text identifiers. Code executable on the device is consequently able to display to the user whether plain text data is stored on the device or not.