| 摘要 |
PROBLEM TO BE SOLVED: To realize a data recording method for a magnetic card, to which a not-easily-soluble counter measure is applied in preventing forgery and alternation, and also an authenticity discriminating method for a magnetic card. SOLUTION: In writing data in a recording layer in the depth layer of a magnetic card using the F2F method, a modulation pulse regulated by the cryptographic key of a cryptographic key generator 25 is outputted from a modulation pulse generator 26, and is recorded on a recording layer on the surface layer of the magnetic card. In reproduction, the modulation pulse is always reproduced synchronously with the reading of data and superposed on the F2F output of an F2F waveform generator 22. In addition, this modulation pulse is so constructed as to be a pulse of small energy so as to impart strain in an unnoticeable degree even if the F2F waveform is observed. |
