Abstract: An article such as a plastic credit card contains concealed identifying information. The information is in the form of a series of binary information bits and it is stored in an electronic serial memory. The memory is on an integrated circuit chip imbedded in the credit card with electrical connections to two terminals on opposite surfaces of the card. The stored information bits are read out from the credit card by an apparatus which supplies current to the terminals to energize readout from the serial memory. The information bits read out are in the form of sequential variations in the current flowing to the credit card which are detected and accumulated in a shift register for utilization by a display device or a computer.