Intrusion detection using a conductive material

Tampering with an assembly that includes an integrated circuit is detected by measuring a change in at least one property of a conductive molding formed over at least a portion of the integrated circuit. For example, the conductive molding can be a mixture of resin with conductive powder and/or fibers. The molding can be formed as a continuous region or as strips of conductive material. Conductive contacts are positioned to provide and receive current through portions of the conductive material. For example, the property of the molding can be an impedance of a portion of the conductive molding. A significant change in the impedance measured through one or more conductive contacts indicates tampering with the assembly.