Abstract: A secure personal identification document and a system for obfuscating the document in order to prevent the unauthorized use of the document, the document including at least one person identifier arranged to be viewed by another person and the system including the personal identification document and a remote controller. The personal identification document also contains circuitry arranged to respond to an input signal from the remote controller, a signal receiving means, a memory device having at least one stored code, a comparator for comparing the input signal with the code; and an obfuscating means, such that the remote controller is arranged to provide the input signal over the air to the signal receiving means, and such that the comparator is arranged for comparing the input signal to the stored code and for causing the obfuscating means to obfuscate the person identifier if the input signal matches the code.