JP2563464B2 - Anti-counterfeiting method of magnetic card by magnetic recording density swing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic card forgery prevention method by a magnetic recording density swing applied to a terminal for processing a magnetic card that requires high security.

[Prior Art] FIG. 4 shows a state of magnetic recording on a conventional magnetic card 10. Data is recorded on track 11. The recording state of the magnetic storage when the data magnetically recorded on the track 11 is viewed with a magnet viewer or the like is as shown by reference numeral 12. This recording status 12 is F / 2F encoded (10
1001) is recorded, and logical "1" is shown.
Is represented by two narrow intervals, and a logical "0" is represented by one wide interval. The ratio of the narrow width to the wide width is 1: 2, and the recording density is constant.

[Problems to be Solved by the Invention] As described above, the content of data magnetically recorded by using the conventional magnetic recording method can be easily read by looking through a magnet viewer or the like. Also, by using a magnetic card reader / writer that is widely used,
The magnetic recording contents written on the card can be easily read and written. Therefore, in a magnetic card that is required to have high security, it is required that it is difficult to read and write the written magnetic recording content in a device that is widely used.

Therefore, the present invention provides a magnetic card forgery prevention method by a magnetic recording density swing that can prevent the forgery of a magnetic card, and cannot read or write the magnetic recording contents in the card by a widely used device. The purpose is to do.

[Means for Solving the Problems] The present invention has taken the following means in order to solve the above problems and achieve the object. That is, by providing a data recording track and a timing clock recording track for decoding on the magnetic card, and synchronizing the data and the timing at the time of recording, and recording while changing the recording frequency, the magnetic on the magnetic card is recorded. When reading data whose recording density is changing, the data is decoded by the timing clock recorded on the magnetic card.

In addition, more specifically, the following is performed. When data is recorded, the set rate value of the rectangular wave rate generator is changed every moment by a program to change the basic clock of its output, and when the above basic clock is input, the output of the rectangular wave rate generator divided by 1/2 is encoded. A means for forming a clock, a means for using the output of a rate generator for inputting the basic clock and outputting a pulse for one clock once for every four clock inputs, the basic clock, the encode clock, and the timing By recording the data encoded by the clock and the timing clock on separate tracks of the magnetic card being carried, a means for recording the data whose recording density has changed and the timing clock for its decoding in synchronization with each other is provided. I was prepared.

[Action] By taking such a means, the following action is exhibited. That is, the magnetic recording on the magnetic card is recorded with the magnetic recording density changed without a single regulation.

[Embodiment] FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention. FIG. 2 is a diagram showing a recording state of magnetic information on a magnetic card. On the magnetic card 10, a data recording track 1 and a timing clock recording track 2 on which a timing clock for reading and decoding is recorded are provided. 3 and 4 are views showing the state of magnetic recording.

In FIG. 1, T1 is a programmable interval timer for changing the recording density, which is used as a rectangular wave rate generator, and at the time of magnetic recording, the set rate value is changed every moment to program the basic clock SB. For example, when the input frequency f ₀ is 1 MHz and the set rate value RT is 1000, the basic clock is 1 kHz, and until the set rate value RT is 500, the basic clock SB is 2 kHz. T2 inputs the basic clock SB and divides it by 1/2 to encode the encoded clock EC
Is a rectangular wave rate generator that outputs

T3 inputs the basic clock SB and 1 for 4 clock inputs
It is a rate generator that outputs a pulse for one clock at a rate of twice, and uses its output as a timing clock TM for reading and decoding.

FIG. 3 is a diagram showing the timing of writing / reading magnetic information. Therefore, the magnetic recording method in this system will be described below with reference to FIG. 3 as needed.

The shift clock SC for serially shifting the write data is input to the P / S converter. The shift clock SC is input to the P / S converter at a rate of one every two encode clocks EC. The serial data SD is shifted by the shift clock SC. For example, as shown in FIG. 3, the serial data SD becomes (10110). In the case of logic "1", the FM encoder switches the polarity at the timing of the encode clock EC next to the shift clock SC and outputs the signal SO. The direction of the coil current of the data write head DW1 is switched by the write amplifier according to the polarity of the signal SO, and data is magnetically recorded. At the same time, a current corresponding to the polarity of the timing clock TM is passed through the coil of the timing head DW2 to magnetically record the timing clock TM, and the recording shown in FIG. 2 is performed on the magnetic card. When this is read by the magnetic read heads DR1 and DR2 arranged at the same track interval as DW1 and DW2, the signals IN1 and IN2 are the third
These signals are read in as shown in the figure and the waveform of these signals is shaped into signals INA1 and INA2. The FM decoder can decode the serial data SDA (10110) depending on the polarity change of the signal INA1 corresponding to t1 of the signal INA2, input it to the P / S converter, and read the output as a byte image. I can.

The present invention is not limited to the embodiments described above, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

EFFECTS OF THE INVENTION According to the present invention, means for providing a data recording track and a timing clock recording track for decoding on a magnetic card, and recording while varying the recording frequency while synchronizing the data and the timing during recording. Means to do
Since the magnetic card has means for decoding the data by the timing clock recorded on the magnetic card in order to read the data while varying the magnetic recording density on the magnetic card, it is possible to prevent the forgery of the magnetic card, and It is possible to provide a magnetic card forgery prevention method by a magnetic recording density swing in which magnetic recording contents cannot be read from or written to a card with a generally popular apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 3 are views showing an embodiment of the present invention, FIG. 1 is a block diagram showing the constitution of the present invention, and FIG. 2 is a magnetic recording state of a card. FIG. 3 and FIG. 3 are state diagrams of signals generated in magnetic recording and reproduction. FIG. 4 is a diagram showing a conventional card magnetic recording state. 1,11 …… Data recording track, 2 …… Timing clock recording track, 3,4,12 …… Magnetic recording status, 10 …… Magnetic card, T1 …… Programmable interval timer, T2
...... Square wave rate generator, T3 …… Rate generator.

Claims (1)

(57) [Claims] 1. A data recording track and a timing clock recording track for decoding are provided on a magnetic card, and the data and the timing clock are synchronized during recording.
In addition, when the data is recorded while changing the recording frequency and the data in which the magnetic recording density on the magnetic card is changed is read, the data is decoded by the timing clock recorded on the magnetic card. A method for preventing forgery of a magnetic card by a magnetic recording density swing characterized by the above.