A copy protected recording medium (1) comprises a readable medium containing data encrypted according to at least one encryption method. A geometric box code (2) identifying the encryption method or methods used is associated with the readable medium by, for example, printing the geometric code onto the medium. The geometric code comprises at least one planer geometric figure formed by a plurality of lines, each of the lines encoding a bit of data by being either in an unbroken continuous state or in a broken discontinuous state, where each of the broken and the unbroken states correspond to one of the standard on/off digital states.