Data protection by detection of intrusion into electronic assemblies

The present invention provides an intrusion barrier for protecting against mechanical or chemical intrusion into an electronic assembly, especially one containing volatile memory. It includes a screen material surrounding the electronic assembly which screen material has formed thereon fine conductive lines in close proximity to each other. The lines are formed of conductive particles of material dispersed in a solidified matrix of a material which looses its mechanical integrity when removed from the screen. An electrical supply and signal detection circuit is provided which generates an output signal responsive to a given change in resistance of the conductive lines, such that if the resistance changes are a result of a mechanical or chemical attack, a signal is generated which can cause the erasure of the volatile memory. Also, preferably radiation detection and temperature sensing circuits are provided to cause erasure of the volatile memory responsive to detection of a given intensity of radiation or a temperature below a given value.