A method and apparatus for calibrating a mass spectrometry system in which lock mass ions are introduced into the transport region of a mass spectrometer intermittently in a pulsed manner and analyte ions andor lock mass ions are then detected at the mass analyzer. One or more obfuscation algorithms are then iteratively applied to the received code. It is also achieved through the monitoring of display device andor ambient light conditions, e. The test module is configured to perform testing on the pages of data stored in the first memory.