| abstract |
A semiconductor device is provided which effectively prevents forgery or alteration of IC cards or the like handling important information. Electrodes each having an unshaped irregular surface are provided, respectively, on the IC chip side and the substrate side. The electrodes are connected to each other, with the IC chip facing downward. Connection resistance is employed as a Key code by subjecting the capacitance between the electrodes to A/D conversion. This serves to prevent the duplication of IC cards or the like by employing the connection resistance having a random value as the key code of cryptograph. |