Abstract: A credit card having information stored thereon in the form of a matrix of apertures formed through the credit card in a predetermined order, and a verifier adapted to read the information matrix from the credit card and by comparison of the information encoded on the credit card with a comparison code manually entered by a user through a keyboard, determine whether the credit card use is authorized. The verifier generally comprises a processing unit operatively coupled to a random access memory into which the encoded information on the credit card is stored. The processing unit is pre-programmed with the matrix bit positions and the sequence of a scrambler code and the numerical value of the scrambler code is then determined. The processing unit is further pre-programmed to determine the matrix bit positions and the sequence of a user code from the information matrix as a function of the numerical value of the scrambler code so that the numerical value of the user code can be determined.