JP2000020656A - Method for discriminating authenticity of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic recording medium authenticity discriminating method, having high safety and capable of reducing cost by collating digital data with collation data of recorded in a data recording part, and at detecting of consistency between both the data, determining the trueness of a magnetic recording medium. SOLUTION: Respectively different digital magnetic data D1, D2 are recorded in respective magnetic data recording tracks T1, T2 of a magnetic recording medium 1 by the use of a writing magnetic head. These data D1, D2 are converted into corresponding digital data D3 through a prescribed algorithm. The converted digital data D3 are recorded in a collation data recording track T3 in the medium 1 by a writing magnetic head HW3 as collation data. Namely an interference wafeform obtained by reading out the data D1, D2 from the tracks T1, T2 is used as analog data, the analog data are converted into corresponding digital data, based on the prescribed algorithm and the digital data are used as collation data D3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a credit card,
The present invention relates to a method for determining the authenticity of a magnetic recording medium such as a prepaid card.

[0002]

2. Description of the Related Art Conventionally, for example, a credit card,
Cards such as prepaid cards write digital data at a high recording density on the magnetic layer to prevent counterfeiting, so that the recorded information cannot be easily read from the outside.

However, since the recorded magnetic data can be freely rewritten and erased due to the characteristics of the magnetic layer and digital data, forgery and falsification are possible. In recent years, it has been highlighted as a major social problem. In particular, since it is now easy to obtain magnetic stripes, it is possible to manufacture similar cards, and also to read magnetic data from the magnetic layer exposed on the surface of the information recording medium, and to use magnetic transfer technology. Therefore, there is also a problem that magnetic data can be easily transferred to another magnetic layer.

A system has been developed in which analog data is intentionally used instead of digital data as described above as magnetic data to be recorded on a magnetic recording medium (Japanese Patent Laid-Open No. 8-315355).

[0005]

In order to prevent the falsification of the magnetic recording medium due to the falsification of the digital data as described above, the digital data read from the magnetic layer is
A method has been developed in which the authenticity is determined by collating with collation data recorded in advance. That is, the digital data once read from the magnetic layer is converted into another digital data by a specific algorithm, and the data for collation is stored in another place (another track of the same magnetic recording medium or a recording device of a host computer). Record as The authenticity determination is performed by converting the digital data read from the magnetic recording medium into another digital data by the above-described algorithm, and comparing the converted digital data with the above-described digital data for comparison.

[0006] However, the above-mentioned authenticity determination method has a problem that the algorithm itself is easily deciphered and the magnetic recording medium can be altered. In general, digital data converted by an algorithm is usually recorded on another track of the same magnetic recording medium, rather than being recorded on a recording device of a host computer using a communication line that is expensive. . In this case, since the digital data before and after the conversion can be known from the magnetic recording medium, an environment in which algorithm analysis can be easily performed is provided. Therefore, decoding of the algorithm itself greatly reduces the security of the magnetic recording medium and the authenticity determination method.

On the other hand, the above-described system using analog data is a special system that handles analog data obtained from magnetic fibers randomly dispersed in a magnetic recording medium as primary data. However, this system has a problem that if the magnetic recording medium is analyzed, it becomes clear that the above system is used, and it is essential that this system uses a dedicated magnetic recording medium, There is a problem that it is not compatible with other systems.
The present invention has been made in view of such circumstances, and has as its object to provide a method for determining the authenticity of a magnetic recording medium that is highly secure and that can reduce costs.

[0008]

In order to achieve the above object, a method for determining the authenticity of a magnetic recording medium according to the present invention comprises recording different digital magnetic data on a plurality of magnetic data recording tracks of the magnetic recording medium. Reading digital magnetic data of two magnetic data recording tracks to obtain analog data with a unique interference waveform; converting the analog data into corresponding digital data by a predetermined algorithm; Recording the data as collation data in a data recording unit, comprising: an encoding process for producing a magnetic recording medium capable of determining authenticity; and digital magnetic data on two magnetic data recording tracks of the magnetic recording medium after the encoding is completed. To obtain analog data with a unique interference waveform A step of converting the analog data into corresponding digital data by the algorithm; collating the digital data with collation data recorded in the data recording unit; And a terminal reading verification process including a verification step of determining that the recording medium is authentic.

Further, in the method for judging the authenticity of a magnetic recording medium according to the present invention, the terminal reading and collating process may determine that the magnetic recording medium is authentic in the collating step, and then determine a plurality of magnetic data on the magnetic recording medium. Updating digital magnetic data in at least one of the recording tracks, and reading digital magnetic data of two magnetic data recording tracks including the updated magnetic data recording track to obtain analog data with a unique interference waveform. A step of converting the analog data into corresponding digital data by the algorithm; and a step of recording the digital data as collation data in a data recording unit.

[0010] Further, in the method of judging the authenticity of a magnetic recording medium according to the present invention, the data recording section for recording collation data is a collation data recording track capable of rewriting / erasing the magnetic recording medium. .

Further, the method for judging the authenticity of a magnetic recording medium according to the present invention is configured such that at least one of magnetic data recording tracks of the magnetic recording medium can rewrite and erase magnetic data.

In the present invention as described above, an interference waveform obtained by reading digital magnetic data on two magnetic data recording tracks is used as analog data, and this analog data is converted into corresponding digital data by a predetermined algorithm. Since the data is used as collation data (data for authenticity determination), only digital data is recorded on the magnetic recording medium, and it is impossible to detect analog data and analyze the above algorithm. In addition, even if the forger writes the same data to the digital magnetic data of the magnetic data recording track, the same magnetic output cannot be obtained, and the analog data to be detected is different and is fake. Can be reliably determined.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

First, a description will be given of an example of a magnetic recording medium which is a target of the method for judging the authenticity of a magnetic recording medium of the present invention.

FIG. 1 is a perspective view of a card-shaped magnetic recording medium. In FIG. 1, a magnetic recording medium 1 includes a substrate 2 and a magnetic layer 3 formed over one surface of the substrate 2. In the magnetic layer 3, two magnetic data recording tracks T1, T2 and a collation data recording track T3 are set in parallel with the long side direction of the magnetic recording medium 1.

The substrate 2 constituting the magnetic recording medium 1 is made of nylon, cellulose diacetate, cellulose triacetate, vinyl chloride, polystyrene, polyethylene, polypropylene, polyester in consideration of heat resistance, strength, rigidity and the like required for the substrate. It can be composed of a composite material alone or in combination of materials appropriately selected from materials such as resins such as polyimide, polycarbonate, biodegradable resins, metals such as copper and aluminum, paper, and impregnated paper. The thickness of such a substrate 2 is 0.005 mm to
It can be about 5 mm.

The magnetic layer 3 constituting the magnetic recording medium 1
Is usually obtained by dispersing a magnetic powder in a resin binder. As the magnetic powder, for example, γ-Fe ₂ O
₃ , Co-coated γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Fe, Fe
-Cr, Fe-Co, Co- Cr, Co-Ni, Ba ferrite, Sr ferrite, and a magnetic particle such as CrO _2. The resin binder (or ink vehicle) includes butyral resin, vinyl chloride / vinyl acetate copolymer resin, urethane resin, polyester resin,
Cellulose resin, acrylic resin, styrene / maleic acid copolymer resin and the like are used, and rubber-based resin such as nitrile rubber or urethane elastomer is added as needed. Considering heat resistance, the glass transition temperature (T.sub.T) of polyamide, polyimide, polyethersulfone, etc.
A resin having a high g) or a system in which Tg increases due to a curing reaction can be used. In a dispersion of magnetic particles dispersed in the resin or ink vehicle as described above, a surfactant, a silane coupling agent, if necessary,
A pigment such as a plasticizer, wax, silicone oil, or carbon may be added. The magnetic layer 3 can also be formed by using the above magnetic material itself by a vacuum deposition method, a sputtering method, a plating method, or the like. Authenticity determination method of the magnetic recording medium Next, the authenticity determination method of the magnetic recording medium of the present invention,
The above-described magnetic recording medium 1 will be described as an example with reference to FIGS.

The method for determining the authenticity of a magnetic recording medium according to the present invention comprises:
It comprises an encoding process for creating a magnetic recording medium that can be authenticated, and a terminal reading and collating process. (Encoding Process) FIG. 2 is a flowchart for explaining the encoding process. First, as shown in FIG. 3, different digital magnetic data D1, D2 are recorded on the magnetic data recording tracks T1, T2 of the magnetic recording medium 1 using the write magnetic heads HW1, HW2 (data recording step S1). ). In FIG. 3, the magnetic recording medium 1 is transported in the direction of arrow a, and the write magnetic head HW1 and the write magnetic head HW2 are integrally scanned in parallel with the scanning direction of the magnetic data recording track. In the illustrated example, the areas of the magnetic data recording tracks T1 and T2 where the digital magnetic data D1 and D2 are recorded are indicated by oblique lines.

Next, as shown in FIG. 4, the read magnetic heads HR1, HR2 are read from the magnetic data recording tracks T1, T2 of the magnetic recording medium 1 on which the digital magnetic data D1, D2 are recorded as described above. The data is read using the data (data reading step S2). In this case, the magnetic recording medium 1 is transported in the direction of arrow a. In the present invention, the read magnetic heads HR1 and HR2 are single track magnetic heads having the same characteristics. As shown in FIG. 5, the same magnetic poles of the coils of the magnetic heads are connected, and the remaining poles are positive and negative poles, respectively. And And the read magnetic head HR
1 and HR2 need to be integrally scanned in parallel in the scanning direction of the magnetic data recording track.

FIG. 6 shows such a read magnetic head H
It is a figure showing the magnetic output waveform read by R1 and HR2. In FIG. 6, (A) shows a read magnetic head HR.
1 shows a magnetic output waveform W1 of the digital magnetic data D1 of the magnetic data recording track T1 by No. 1. Also,
(B) shows the magnetic output waveform W2 of the digital magnetic data D2 on the magnetic data recording track T2 by the read magnetic head HR2. Thus, the digital magnetic data D1 and D2 read by the read magnetic heads HR1 and HR2 are different. And, as mentioned above,
Since the read magnetic heads HR1 and HR2 are connected to the same pole of the coil of each magnetic head, the amplified magnetic output signals obtained from the positive and negative poles of the integrated read magnetic heads HR1 and HR2 have a magnetic output waveform. A unique interference waveform (analog waveform A) as shown in FIG. 6C in which W1 and the magnetic output waveform W2 interfere with each other.

Next, the analog data A obtained as described above
Is converted into corresponding digital data D3 by a predetermined algorithm (conversion step S3). For example, FIG.
As shown in (C), the analog waveform A is divided by a clock having a predetermined timing (in the illustrated example, divided by 24 lines), and the output of each divided portion is +4 to -4 (except for 0, the + side is excluded). Is rounded up and the negative side is rounded down.)
Specify in stages. Then, each output level can be converted into 3-bit digital data by quantizing as follows. FIG. 7 is a diagram showing a waveform W3 for the first four data of the digital data D3 thus converted.

Output level → digital data + 4 → 111 + 3 → 110 + 2 → 101 + 1 → 100-1 → 011-2 → 010-3 → 001-4 → 000 Then, the digital data is converted by the predetermined algorithm as described above. The data D3 is used as the collation data as shown in FIG.
3 (data recording unit) using the write magnetic head HW3 (recording data recording step S4). In the example shown,
The area of the collation data recording track T3 where the magnetic recording medium 1 is conveyed in the direction of arrow a and the collation data is recorded is indicated by oblique lines.

The magnetic recording medium 1 is brought into a state in which it can be determined whether the magnetic recording medium 1 is true or false by the encoding process including steps S1 to S4.

As described above, in the present invention, the digital magnetic data D of the two magnetic data recording tracks T1 and T2 are recorded.
1 and D2 are used as analog data A, and the analog data A is converted into corresponding digital data by a predetermined algorithm to obtain collation data D3 (data for authenticity determination). Since only digital data is recorded on the recording medium 1, even if the magnetic recording medium is analyzed, it is possible to know the reading method of the present invention using the unique analog data A in the middle.
And it is impossible to analyze the algorithm. (Terminal reading collation process) FIG. 9 is a flowchart for explaining the terminal reading collation process. First, as shown in FIG. 10, digital magnetic data D1 and D2 recorded on magnetic data recording tracks T1 and T2 of the magnetic recording medium 1 are read by a read magnetic head HR1.
1 and HR12, and at the same time, digital magnetic data D3 recorded on the collation data recording track T3 is read using the read magnetic head HR13 (data reading step S11). In FIG. 10, the magnetic recording medium 1 is transported in the direction of arrow a. The read magnetic heads HR11 and HR12 are single track magnetic heads having the same characteristics.
Similarly to 2, the same pole of the coil of each magnetic head is connected, and the remaining poles are used as a positive pole and a negative pole, respectively. The read magnetic heads HR11 and HR12 need to be integrally scanned in parallel with the scanning direction of the magnetic data recording track.

The magnetic output waveform read by such read magnetic heads HR11 and HR12 becomes a unique interference waveform (analog waveform A '). This analog waveform A
'Indicates that after the completion of the encoding process, if the digital magnetic data D1 and D2 recorded on the magnetic data recording tracks T1 and T2 have not been tampered with, etc.,
The waveform is the same as the unique interference waveform (analog waveform A) shown in FIG. On the other hand, the read magnetic head H
The magnetic output waveform read by R13 becomes a magnetic output waveform W3 shown in FIG.

Next, the analog data A 'is converted into the corresponding digital data D3' by the same algorithm as the encoding process described above (conversion step S12). Next, the digital data D3 'is collated with the digital magnetic data (reference data) D3 read from the collation data recording track T3 by the read magnetic head HR13 as described above (collation step S1).
3). In the collation step S13, when the two data have coincidence, it is determined that the magnetic recording medium is genuine, and when it is determined that there is no coincidence, a command signal such as transaction stop is issued as a fake medium. The determination of the coincidence of both data can be performed by various comparison methods.For example, a correlation index is formed using a statistical method for both data, and if the correlation index is equal to or greater than a predetermined threshold value, there is concordance. It is determined that the medium is a counterfeit medium if it is less than a predetermined threshold.

For the purpose of changing a used magnetic recording medium to an unused state, a falsifier may place digital magnetic data D on magnetic data recording tracks T1 and T2 of the magnetic recording medium.
Even if the same digital magnetic data is written as D1, D2,
Exactly the same magnetic output cannot be obtained. This is because the transport speed of the magnetic recording medium or the magnetic head always fluctuates. That is, once the contents of the digital magnetic data are changed, it is not possible to completely restore the contents of the digital magnetic data before the change, and the analog data obtained from the magnetic data recording tracks T1 and T2 becomes different. Since the digital data after the algorithm conversion is different, such a magnetic recording medium can be reliably determined to be a fake.

If it is determined in the verification step S13 that the data is authentic, the contents of the digital magnetic data on the magnetic data recording tracks T1 and T2 of the magnetic recording medium 1 can be updated to desired contents (data update). Step S
14). That is, as shown in FIG. 11, different desired digital magnetic data D1 'and D2' are recorded on the magnetic data recording tracks T1 and T2 of the magnetic recording medium 1 using the write magnetic heads HW11 and HW12. In FIG. 11, the magnetic recording medium 1 is transported in the direction of arrow a. Also,
The write magnetic head HW11 and the write magnetic head HW12
Scanning is performed integrally and in parallel with the scanning direction of the magnetic data recording track. In the illustrated example, the areas of the magnetic data recording tracks T1 and T2 on which the digital magnetic data D1 'and D2' are recorded are indicated by dotted oblique lines. By updating the digital magnetic data of the magnetic data recording tracks T1 and T2, information on the use of the magnetic recording medium 1 (residual frequency) can be recorded as needed.

Next, as shown in FIG. 12, the above-described data reading is performed on the magnetic data recording tracks T1 and T2 of the magnetic recording medium 1 on which the digital magnetic data D1 'and D2' are recorded as described above. As in step S11, reading is performed using the reading magnetic heads HR11 and HR12 (data reading step S15). The magnetic output waveform read by such read magnetic heads HR11 and HR12 becomes a unique interference waveform (analog waveform A ″).

Next, the analog data A "is converted into the corresponding digital data D3" by the same algorithm as the encoding process described above (conversion step S16). Next, the converted digital data D3 ″
As the collation data as shown in FIG.
The write magnetic head HW1 on the collation data recording track T3 of FIG.
3 (verification data update step S1
7). In the illustrated example, the magnetic recording medium 1 is transported in the direction of arrow a, and the area of the collation data recording track T3 on which the collation data D3 ″ is recorded is indicated by hatching.

By the above steps S14 to S17, the magnetic recording medium 1 is in a state where new magnetic data is recorded and the authenticity can be determined. Thereafter, by performing the above-described authenticity determination and performing necessary data updating when the authenticity determination result is determined to be authentic, it is possible to safely operate the magnetic recording medium while arbitrarily changing recording information.

In the above-described method for determining the authenticity of a magnetic recording medium of the present invention, the read magnetic head H in the encoding process is used.
The positional relationship between R1 and the read magnetic head HR2, and between the read magnetic head HR11 and the read magnetic head HR12 in the terminal read collation process, are parallel to the scanning direction of the magnetic data recording track. And 2
The same digital magnetic data is recorded on the magnetic data recording tracks T1 and T2 (or a single digital magnetic data is recorded with a width including both tracks), and the read magnetic heads HR1 and HR2 use Alternatively, when reading is performed by the read magnetic heads HR11 and HR12, the electromotive force generated from the coil of each magnetic head has an opposite phase relationship to each other. Therefore, the read magnetic heads HR1 and HR are located at positions where the obtained magnetic output is the lowest.
2 or read magnetic heads HR11, HR1
By fixing 2, azimuth adjustment can be easily performed.

In the above-described method for determining the authenticity of a magnetic recording medium according to the present invention, the collation data recording track T3 of the magnetic recording medium is used as the data recording unit for recording the collation data D3. Other than a magnetic recording medium, such as a storage device, may be used.

In the above example, the magnetic data of the two magnetic data recording tracks T1 and T2 of the magnetic recording medium determined to be authentic in the terminal read / verify process are updated. The magnetic data may be updated. In this case, the update of the magnetic data
Duplicate recording, erasing, etc. for a certain part of the track may be performed.

In the method for determining the authenticity of a magnetic recording medium according to the present invention, a magnetic head for both reading and writing can be used as the magnetic head. In this case, the write magnetic head HW1 (HW11) and the read magnetic head HR1
(HR11), a read / write magnetic head H1 (H11) is used, and a write magnetic head HW2 (HW
Instead of the magnetic head 12) and the read magnetic head HR2 (HR12), a read / write magnetic head H2 (H12) is used. Also in this case, the magnetic heads H1 and H2 (the magnetic heads H11 and H12) are single track magnetic heads having the same read characteristics, connect the same pole of the coil of each magnetic head, and connect the remaining poles to the positive pole and the negative pole, respectively. And

The two magnetic data recording tracks T
1 and T2, two magnetic heads HR1, HR2 (HR11, HR2) as described above.
Instead of arranging 12) in parallel, a multi-track magnetic head having two tracks with the same read gap in a single magnetic head may be used. In this case, the same poles of the coils mounted on the magnetic cores forming the respective gaps are connected, and the remaining poles are defined as a positive pole and a negative pole, respectively.

Further, it goes without saying that scanning may be performed by fixing the magnetic recording medium 1 and transporting each magnetic head.

In addition to the magnetic recording medium 1 in which the magnetic layer 3 is provided over the entire area as described above, the magnetic recording medium includes three magnetic data recording tracks T1, T2 and a collation data recording track T3. It may have a stripe-shaped magnetic layer.

In the magnetic recording medium, any one of the magnetic data recording tracks T1 and T2 is used for rewriting magnetic data.
Those that cannot be erased may be used. The magnetic data recording track on which magnetic data cannot be rewritten / erased may be a magnetic barcode provided at a predetermined position on a magnetic recording medium. Magnetic barcodes are printed in a desired pattern shape by screen printing or the like using a magnetic paint containing magnetic particles and a resin binder, and the magnetic layer is irradiated with laser light, electron beam, discharge breakdown, routing (engraving). ), Etc., and a concave portion may be formed. When one of the magnetic data recording tracks is formed from such a magnetic barcode, a magnetic head in which two coils are wound is usually used as a read magnetic head, and a constant current is applied to one of the coils of the magnetic head. Then, an induced current or voltage induced when the magnetic head scans over a magnetic data recording track (magnetic bar code) is detected by the other coil. Then, one of the coils is connected to the same pole of the coil of the ordinary read magnetic head as described above.

Further, the magnetic recording medium may be provided with a concealing layer for making it difficult to recognize the magnetic layer and the magnetic barcode, or for enhancing the effect of protecting and decorating the magnetic recording medium. This masking layer is made of ethyl cellulose,
Cellulose nitrate, ethyl hydroxyethyl cellulose,
Cellulose derivatives such as cellulose acetate propionate and cellulose acetate; styrene resins such as polystyrene and poly-α-methylstyrene; or styrene copolymer resins; polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polyacrylic acid Acrylic resin such as butyl or methacrylic resin alone or copolymerized resin; rosin, rosin modified maleic resin, rosin modified phenol resin, rosin ester resin such as polymerized rosin; polyvinyl acetate resin, cumarone resin, vinyl toluene resin, vinyl chloride Various pigments are added to binders such as resins, polyester resins, polyurethane resins and butyral resins according to the color to be colored, and further, if necessary, plasticizers, stabilizers, waxes, greases, drying agents, drying aids Agent, curing agent, After adding the dispersing agent and the dispersing agent, using a coloring paint or ink which is sufficiently kneaded with a solvent or a diluent, by a coating method such as a normal gravure method, a roll method, a knife edge method, an offset method or a printing method. Can be formed.

[0041]

As described in detail above, according to the present invention,
The interference waveform obtained by reading the digital magnetic data on the magnetic data recording track of this book is used as analog data, and the analog data is converted into corresponding digital data by a predetermined algorithm, and is used as collation data (data for authenticity determination). Therefore, only digital data is recorded on the magnetic recording medium, and even if the magnetic recording medium is analyzed, it is necessary to know the reading method of the present invention using intermediate analog data and analyze the algorithm. It is impossible for a forger to change data on the magnetic recording medium to, for example, an unused state. Also, even if the same digital magnetic data data is written to the magnetic data recording track, the same magnetic output cannot be obtained, and the obtained analog data is different. If it is changed, it is impossible to make the digital data after the algorithm conversion the same as that before the change, and even if the forger alters the data on the magnetic recording medium, such a magnetic recording medium is surely regarded as a fake. Can be determined. Further, when the same digital magnetic data is recorded on two magnetic data recording tracks and read by the magnetic head section, the electromotive force generated from the coil of each magnetic head (each read gap) has a phase opposite to that of each other. The azimuth adjustment can be easily performed by fixing each magnetic head (multi-track magnetic head) at a position where the obtained magnetic output is minimized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a magnetic recording medium which is a target of a method for determining the authenticity of a magnetic recording medium according to the present invention.

FIG. 2 is a flowchart for explaining an encoding process constituting the present invention.

FIG. 3 is a diagram showing a state in which digital magnetic data is recorded on a magnetic recording medium in an encoding process.

FIG. 4 is a diagram showing a state in which digital magnetic data of a magnetic recording medium is read in an encoding process.

FIG. 5 is a diagram showing a connection state of a read magnetic head used in the present invention.

6A and 6B are diagrams showing magnetic output waveforms read by a read magnetic head, wherein FIGS. 6A and 6B are magnetic output waveforms of digital magnetic data of each magnetic data recording track by each read magnetic head, and FIG. () Shows a unique interference waveform (analog waveform) in which the magnetic output waveforms of (A) and (B) interfere with each other.

FIG. 7 is a waveform showing a part of digital data obtained by converting analog data by a predetermined algorithm.

FIG. 8 is a diagram showing a state in which digital magnetic data for collation is recorded on a magnetic recording medium in an encoding process.

FIG. 9 is a flowchart for explaining a terminal reading collation process constituting the present invention.

FIG. 10 is a diagram showing a state in which digital magnetic data of a magnetic recording medium is read in a terminal read / verify process.

FIG. 11 is a diagram showing a state in which digital magnetic data is recorded on a magnetic recording medium in a terminal read / verify process.

FIG. 12 is a diagram showing a state in which digital magnetic data of a magnetic recording medium is read in a terminal read / verify process.

FIG. 13 is a diagram showing a state in which digital magnetic data for collation is recorded on a magnetic recording medium in a terminal read collation process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording medium 2 ... Substrate 3 ... Magnetic layer T1, T2 ... Magnetic data recording track T3 ... Verification data recording track (data recording part) HW1, HW2, HW3, HW11, HW12, HW1
3. Write magnetic head HR1, HR2, HR3, HR11, HR12, HR1
3. Read magnetic head D1, D2, D1 ', D2', D1 ", D2" ... Digital magnetic data D3, D3 "... Digital magnetic data for verification A, A ', A" ... Analog data W1, W2 ... Digital magnetic Data reading waveform S1 to S17: Step ← a: Transport direction of magnetic recording medium

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06K 19/10 G06K 19/00 B // G01B 7/00 R

Claims (4)

[Claims] 1. A step of recording different digital magnetic data on a plurality of magnetic data recording tracks of a magnetic recording medium, and reading digital magnetic data of two magnetic data recording tracks to obtain analog data with a unique interference waveform. Creating a magnetic recording medium capable of judging the authenticity, comprising the steps of: converting the analog data into corresponding digital data by a predetermined algorithm; and recording the digital data as collation data in a data recording unit. An encoding process; reading digital magnetic data on two magnetic data recording tracks of the magnetic recording medium after the encoding is completed to obtain analog data with a unique interference waveform; and converting the analog data to digital data corresponding to the algorithm. Convert A terminal reading collation step comprising: comparing the digital data with collation data recorded in the data recording section, and judging that the magnetic recording medium is genuine when the two data have coincidence. And a process for determining the authenticity of a magnetic recording medium. 2. The terminal read collation process updates digital magnetic data in at least one of a plurality of magnetic data recording tracks of the magnetic recording medium after determining that the magnetic recording medium is authentic in the collation step. Reading digital magnetic data of two magnetic data recording tracks including a magnetic data recording track with updated magnetic data to obtain analog data with a unique interference waveform, and converting the analog data to a digital signal corresponding to the algorithm. 2. The method according to claim 1, further comprising a step of converting the digital data into data and a step of recording the digital data as collation data in a data recording unit. 3. The magnetic recording medium according to claim 1, wherein the data recording section for recording collation data is a collation data recording track on / from which a magnetic recording medium can be rewritten and erased. True / false judgment method. 4. The magnetic recording medium according to claim 1, wherein at least one of the magnetic data recording tracks of the magnetic recording medium is capable of rewriting / erasing magnetic data. True / false judgment method.