WO2005116993A1 - 磁気記録媒体の認証方法、磁気記録媒体の認証システム、および認証可能な磁気記録媒体 - Google Patents
磁気記録媒体の認証方法、磁気記録媒体の認証システム、および認証可能な磁気記録媒体 Download PDFInfo
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- WO2005116993A1 WO2005116993A1 PCT/JP2005/009869 JP2005009869W WO2005116993A1 WO 2005116993 A1 WO2005116993 A1 WO 2005116993A1 JP 2005009869 W JP2005009869 W JP 2005009869W WO 2005116993 A1 WO2005116993 A1 WO 2005116993A1
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- Prior art keywords
- recording medium
- authentication
- authentication information
- magnetic
- magnetic recording
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
- G11B20/1215—Formatting, e.g. arrangement of data block or words on the record carriers on cards
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K1/00—Methods or arrangements for marking the record carrier in digital fashion
- G06K1/12—Methods or arrangements for marking the record carrier in digital fashion otherwise than by punching
- G06K1/125—Methods or arrangements for marking the record carrier in digital fashion otherwise than by punching by magnetic means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/06187—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code with magnetically detectable marking
- G06K19/06196—Constructional details
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K5/00—Methods or arrangements for verifying the correctness of markings on a record carrier; Column detection devices
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
- G11B20/00166—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
- G11B20/00173—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software wherein the origin of the content is checked, e.g. determining whether the content has originally been retrieved from a legal disc copy or another trusted source
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/008—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires
- G11B5/00804—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires magnetic sheets
- G11B5/00808—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires magnetic sheets magnetic cards
Definitions
- the present invention is applicable to a magnetic card for rewriting magnetic information as well as a read-only magnetic card that does not rewrite magnetic information, a magnetic recording medium authentication method, a magnetic recording medium authentication system, and an authentication. It relates to a possible magnetic recording medium.
- the present inventor can immediately detect the unauthorized use or unauthorized rewriting of the recorded contents, etc., when the unauthorized use has already been performed by another person, and the force is compatible with the conventional magnetic card.
- a magnetic card authentication method and authentication system that can maintain a certain level of security, and a magnetic card that can be authenticated by such a method.
- WO03Z102925 A1 such a technique proposed by the present inventor superimposes noise on magnetic card data and writes the data, and normalizes waveform disturbance due to motor wobble during reading. To extract the signal component, analyze the noise component, and convert it to data. It is.
- a write signal is generated with an accurate clock force. Generally, two signals of If and 2f are generated.
- the read waveform has characteristics of individual heads at the time of writing, Due to variations in the drive system, etc., the length will not be exactly 1 to 2. Each time it is written, it is slightly different and can be a unique feature of magnetic data.
- Various techniques have been proposed to use this to prevent forgery of magnetic cards.
- Japanese Patent Application Laid-Open No. H10-149417 discloses a technology for achieving a forgery prevention effect by encrypting jitter of a magnetic signal recorded on a magnetic card and recording the encrypted jitter on the magnetic card. ing.
- Patent Document 1 International Publication No. WO03Z102925 A1
- Patent Document 2 JP-A-10-149417
- the frequency of the noise component is overwhelmingly higher than that of the data waveform, it is higher than that of the conventional reader and writer. There is a problem that a device that can handle the frequency is required. In addition, there is a problem that the reliability of the noise component is lower than the reliability of the data due to the deterioration of the read conditions such as dirt, dirt, breakage, and bending attached to the read head and the card.
- an object of the present invention is to solve the above-mentioned problems of the conventional technology, to secure the same or higher reliability as the data itself, and to decrypt the data by a third party. It is an object of the present invention to provide a magnetic recording medium authentication method, a magnetic recording medium authentication system, and a magnetic recording medium that can be authenticated, which makes it extremely difficult.
- an authentication method for a magnetic recording medium for authenticating a magnetic recording medium in which basic information is magnetically recorded in a recording area the basic information is provided in the recording area.
- a magnetic recording medium authentication system for authenticating a magnetic recording medium in which basic information is magnetically recorded in a recording area
- the information is provided in the recording area.
- Basic information writing means for writing basic information using a write signal to at least one magnetic track, and a write signal in which the write signal is shifted by an arbitrary amount to at least one other magnetic track provided in the recording area.
- the authentication information is written by using the authentication information writing means and a read signal from the other magnetic track based on a read signal from the other magnetic track or a read signal from the other magnetic track based on the read signal from the other magnetic track.
- Authentication information generating means for generating authentication information based on the shift amount, and authentication means for executing authentication of the recording medium based on the authentication information.
- An authentication system for a magnetic recording medium comprising:
- the arbitrary shift amount is an amount related to a period of a write signal.
- the arbitrary shift amount is an amount related to the amplitude of the write signal.
- the arbitrary shift amount is an amount related to a cycle and an amplitude of a write signal.
- the authentication information generated by the authentication information generating step or means is recorded on a management server different from the magnetic recording medium.
- the authentication information generating step or means The authentication information generated by the above is recorded on the magnetic recording medium.
- the basic information writing step when the basic information of the magnetic recording medium is rewritten properly, the basic information writing step, the authentication information writing step, and the authentication information generating step By executing again, new authentication information is generated.
- the basic information writing means, the authentication information writing means, and the authentication information generation means Generate new authentication information by operating again.
- a magnetic recording medium authentication information generating apparatus for generating authentication information for authenticating a magnetic recording medium in which basic information is magnetically recorded in a recording area
- a basic information writing means for writing basic information using a write signal on at least one magnetic track provided in the recording area; and a write signal on at least one other magnetic track provided in the recording area.
- Authentication information writing means for writing authentication information using a write signal shifted by an arbitrary amount from the other magnetic track, or based on a read signal from the other magnetic track, or based on the one magnetic track force read signal and the other magnetic track
- Authentication information generating means for generating authentication information based on the shift amount by comparing the read signal with a force reading signal.
- An authentication information generation device for a magnetic recording medium is provided.
- the authentication information generating means includes a normalizing device for normalizing the read signal, and a waveform determining device for comparing the normalized read signal. including.
- the authentication information generating means generates the read signal power interpolation curve and calculates the peak shift amount
- the peak shift specifying device generates the interpolated curve.
- a waveform normalizer for normalizing the read signal with the interpolated interpolation curve, and the read signal normalized by the waveform normalizer based on the peak shift amount obtained by the peak shift specifying device.
- a peak shift correction device that corrects a peak shift, and the read signal that has been normalized and peak shifted corrected.
- a waveform judging device for comparing
- a write signal is used for an authentication apparatus for a magnetic recording medium for authenticating a magnetic recording medium in which basic information is magnetically recorded in a recording area.
- Basic information reading means for reading at least one magnetic track provided in the recording area on which the basic information has been written to generate a basic information read signal relating to the basic information, and shifting the write signal by an arbitrary amount.
- Authentication information reading means for reading at least one other magnetic track in the recording area using a write signal to generate an authentication information reading signal relating to authentication information; and an authentication information reading signal generated by the authentication information reading means. Or the basic information reading signal generated by the basic information reading means and the authentication information generated by the authentication information reading means.
- a read authentication information generating means for generating read authentication information by comparing the read information with an information read signal, and authentic authentication information separately recorded from the read authentication information read by the read authentication information generating means.
- Authentication means for performing authentication of the magnetic recording medium by comparing the magnetic recording medium with each other.
- the read authentication information generating means includes a normalizing device for normalizing the read signal, and a waveform determining device for comparing the normalized read signal. including.
- the read authentication information generating means generates an interpolation curve from the read signal and determines a peak shift amount by using a peak shift specifying device and a peak shift specifying device.
- a waveform normalizing device for normalizing the read signal using the created interpolation curve, and the read signal normalized by the waveform normalizing device, based on the peak shift amount obtained by the peak shift specifying device.
- a peak shift correction device that corrects the peak shift, and a waveform determination device that compares the normalized peak shift corrected read signal.
- the basic information is written on at least one magnetic track provided in the recording area using a write signal.
- Is written, and at least one other magnetic track provided in the recording area is authenticated using a write signal obtained by shifting the write signal by an arbitrary amount.
- Information is written and the authentication information is based on the shift amount based on the read signal from the other magnetic track or by comparing the read signal of the one magnetic track with the read signal from the other magnetic track. Is generated, and authentication of the magnetic recording medium can be executed based on the authentication information.
- the magnetic recording medium is configured such that the content of the generated authentication information is recorded on the magnetic recording medium! / Puru.
- a so-called magnetic card will be described as an example, and an authentication information writing device and an authentication information reading device described later will be described as being specialized for a magnetic card.
- the magnetic recording medium to which the present invention can be applied is not limited to a so-called magnetic card, but is intended to include all magnetic recording media for magnetically recording information, which require any kind of authentication.
- FIG. 1 shows a magnetic recording area 12 formed on a general magnetic card 10, and information is written to and read from the magnetic recording area 12.
- FIG. 4 is a schematic perspective view showing a relationship with a magnetic head 18 for performing the following.
- the magnetic recording area 12 is formed of a magnetic material directly applied to the substrate surface of the magnetic card 10 or a film applied with a magnetic material layer attached to the substrate surface of the magnetic card 10 as shown in FIG.
- three magnetic tracks 12a, 12b, and 12c are formed in the magnetic recording area 12.
- On the magnetic tracks 12a, 12b and 12c basic information for performing the original function of the magnetic card is recorded.
- This basic information may be read-only or rewritable. If the magnetic card is used for a bank cash card or a credit card of a credit company, it is read-only and the basic information such as the owner's name, account number, tail card number, date of issue, etc. Is recorded in advance. On the other hand, if the application of the magnetic card is a prepaid card, the usage amount and the usage frequency are recorded as basic information. This basic information can be rewritten after the card is distributed.
- FIG. 2 is a block diagram showing the overall configuration of an authentication system in which the magnetic recording medium authentication method according to the present invention can be applied to the magnetic card described with reference to FIG.
- the authentication system of this embodiment mainly includes an external interface unit 21, a first magnetic head 18a, a second magnetic head 18b, and a card reader main control unit. 22, a write signal generator 23, a waveform deformer 24, a random number generator 25, a first driver 26, a second driver 27, a first amplifier 28, and a second amplifier 29. , A waveform normalizing device 30, a waveform determining device 31, and a signal reader 32.
- the first magnetic head 18a is for writing and reading a signal to and from a track A such as the magnetic track 12a of the magnetic card 10, and the second magnetic head 18b is for This is for writing and reading signals to and from track B such as magnetic track 12b.
- the first driver 26 is for writing and reading signals to and from the first magnetic head 18a
- the second driver 27 is for writing and reading signals to and from the second magnetic head 18b. It is for doing.
- the first amplifier 28 is for amplifying the signal read by the first magnetic head 18a
- the second amplifier 29 is for amplifying the signal read by the second magnetic head 18b. Things.
- the external interface unit 21 is for enabling the system to be connected to a server computer or the like, for example.
- the driver 27 forms an authentication information writing unit of the authentication system, and includes a first magnetic head 18a, a second magnetic head 18b, a first amplifier 28, a second amplifier 29, and a waveform normalizing device 3.
- the waveform determination device 31 and the signal reader 32 constitute an authentication information reading unit of the present authentication system.
- FIG. 3 is a diagram exemplifying a write signal when data as basic information is written on a track of a magnetic card by the width of a waveform.
- the two types of waveforms which have a waveform width of 1 and a waveform width that is twice that, convert the 1 and 0 into binary numbers and perform data conversion.
- FIG. 3A illustrates a waveform of a write signal written to track A of the magnetic card 10 by the first magnetic head 18a via the first driver 26, and the track A is written in accordance with the write signal waveform.
- the magnetization patterns formed on the magnetic material of FIG. Similarly, FIG.
- FIG. 3B illustrates a waveform of a write signal written to track B of the magnetic card 10 by the second magnetic head 18b via the second driver 27, and according to this write signal waveform.
- FIG. 3C illustrates a waveform of a reference clock for controlling such a write operation.
- a write signal to the track B illustrated in FIG. 3B is generated by the write signal generator 23, and is directly transmitted through the second driver 27 and the second magnetic head 18b.
- the write signal to the track A illustrated in FIG. 3A is the same write signal generated by the write signal generator 23 in accordance with the present invention.
- the data is written to the track A via the first driver 26 and the first magnetic head 18a. That is, the waveform deforming device 24 converts the write signal generated by the write signal generator 23 based on the random number arbitrarily generated by the random number generator 25 into a temporal signal as shown by a reference symbol T in FIG. It is deformed to a waveform that is shifted to.
- (A) of FIG. 4 shows an example of a voltage waveform for simultaneously writing to track A and track B.
- the amplitude may be shifted.
- the waveform of the write signal to the track A may be temporally shifted with respect to the signal waveform to be written to the track B, and the amplitude may be shifted.
- waveform deformation is performed based on random numbers arbitrarily generated from the random number generator 25.
- the present invention is not limited to waveform deformation using such random numbers. Any waveform deforming device can be used as long as it can generate innumerable deformed signals.
- Fig. 4 (B) shows the signal read from the data written to track A and track B at the same time. The displacement of the initial position is corrected and is shown as an example. Due to fluctuations in the speed of the drive system (motor, etc.) of the Z writer during writing and reading, data whose data height or data width has expanded or contracted are read as read signals.
- the force is simple if the speed of the magnetic card changes linearly. Actually, the speed fluctuates between fast and slow, including the servo system of the motor. Therefore, the speed change curve can be approximated by a cubic curve. Not surprisingly, this curve changes each time you read the data. Hereinafter, this curve is called an interpolation curve. Interpolation is 1 Needless to say, the width and the width are divided according to the data. The interpolation curve performs both data width interpolation and data height interpolation. In this way, the resulting data waveform will also extract the desired secret key.
- FIG. 5 shows an example of a waveform reproduced by a card reader, an example of a waveform in which the amplitude of the reproduced waveform is normalized, and an example of a waveform in which the period is further normalized.
- a conversion function of the amplitude axis is first obtained by using cubic spline interpolation.
- FIG. 6 is a diagram for explaining the normalization of the period. As shown in FIG. 6, the peak array peakX [] on the time axis is not usually equally spaced. If peakX [] is plotted on the horizontal axis and its index is plotted on the vertical axis, the plot will follow a slightly meandering trajectory rising to the right. Gm (x) is the plot of this plot connected to the cubic spline interpolation curve with the vertical axis as the X axis. Naturally, the indexes on the vertical axis are equally spaced.
- the time on the peakX mouth corresponding to any resolution can be obtained by G m (x), and the force can also obtain the amplitude of the waveform Wnl (X).
- the waveform W n2 (X) normalized to the period 2 can be obtained.
- the track A and B forces of the magnetic card on which the write signal illustrated in FIG. FIG. 4B illustrates read signals read by the second magnetic head 18b and amplified by the first amplifier 28 and the second amplifier 29, respectively.
- the waveform normalizing device 30 performs normalization of the waveform as described above, and FIG. 7 shows each track whose data width (period) has been normalized by the waveform normalizing device 30.
- FIG. 7 shows an example of a waveform of a read signal from a track B, as shown in FIG. A cubic spline curve is used to make the data width uniform, and the track curve data width is also interpolated using the curve.
- This deviation can be used as a signal or a secret key, that is, as authentication information.
- the deviation of the amplitude is interpolated by the interpolation curve of track A by the interpolation curve of track B. Can be taken out.
- This shift can also be used as an encryption or secret key, that is, as authentication information.
- FIG. 9 is a diagram for explaining an example of detecting an amplitude shift
- FIG. 10 is a diagram for explaining an example of detecting a time-direction shift.
- the waveform determination device 31 sets a predetermined threshold value for the amplitude and detects when the threshold value is exceeded, thereby reading from the track A. From the obtained and normalized signal waveform, a detection signal having a shift waveform corresponding to the shift in the amplitude is generated. In the example of detecting a time lag shown in FIG. 10, in the time lag of each corresponding vertex between the normalized signal waveform read from the track A and the signal waveform read from the track B, A detection signal having a corresponding shift waveform is generated.
- Such a shift waveform of the detection signal is converted into a write signal to track A by the above-described waveform deforming device 24 of the authentication information writing unit, which is deformed based on a random number arbitrarily generated from the random number generator 25. Of the write signal to the track B. Therefore, these deviations are different for each magnetic card due to the difference in the random number generated from the random number generator 25 when writing the data.
- such deviation can be used as authentication information indicating that each magnetic card is genuine.
- the deviation generated by each magnetic card is separately recorded or stored for each magnetic card, so that the deviation caused by the detection signal by the waveform determination device 31 and the recorded or stored
- the magnetic card can be authenticated as being genuine, and if the deviations do not match, the magnetic card can be authenticated. That is not the case.
- Such a shift as the authentication information may be obtained by recording or storing the shift of the width or the height as a numerical value in addition to the description with reference to FIG. 9 and FIG. It may be recorded or stored as a rough numerical value, or may be recorded or stored as a binary numerical value. That is, a signal detected by the method described with reference to FIGS. 9 and 10 is digitized and used as a key for authenticity determination. There are numerous methods of digitizing existing methods alone. For example, binarization based on the presence or absence of a detected signal, measuring the width of the signal itself and the time interval between detection signals and the next detection signal, and using that time as a numerical value, and the magnitude of signal deviation Various methods such as binarization are conceivable.
- Such a shift as the authentication information may be recorded or stored in a memory or the like of the card reader main control unit 22, or may be recorded or recorded in an arbitrary part of the magnetic card itself. May be. Furthermore, such authentication information may be recorded or stored in a server computer that manages a card reader Z writer used in a bank or various stores.
- the signal reader 32 receives the data signal of the track B, which has not been subjected to waveform deformation, and sends the data signal to the card reader main controller 22 as data of basic information.
- FIG. 11 is a block diagram showing the overall configuration of an authentication system that performs a magnetic recording medium authentication method as another embodiment of the present invention. It is.
- the bit interval of a reproduced pulse waveform in a magnetic recording system becomes smaller than a certain value, the waveform suddenly interferes (delay in magnetic change), causing a decrease in the peak value and displacement of the pulse. This is called a peak shift.
- the shift between the read signal of track A and the read signal of track B was detected assuming that there was no influence of the peak shift in the read signal. Therefore, the accuracy of the authentication information cannot be improved without considering the effect of this peak shift.
- the embodiment shown in FIG. 11 allows for more accurate reading of authentication information in consideration of the influence of such a peak shift.
- the system configuration of the embodiment of FIG. 11 is different from the system configuration of the embodiment of FIG. 2 in that the peak shift specifying device is provided between the first amplifier 28 and the second amplifier 29 and the waveform normalizing device 30.
- the configuration is substantially the same as that of the embodiment of FIG. 2 except that a peak shift correcting device 34 is disposed between the waveform normalizing device 30 and the waveform determining device 31. Therefore, in FIG. 11, the corresponding components are denoted by the same reference numerals as those used in FIG. 2, and the detailed configuration and operation thereof will not be described repeatedly. Only the different components and operations will be described.
- the first magnetic head 18a, the second magnetic head 18b, the write signal generator 23, the waveform deforming device 24, a random number generator 25, a first driver 26, and a second driver 27 constitute an authentication information writing unit of the authentication system, and include a first magnetic head 18a, a second magnetic head 18b, and a first magnetic head 18b.
- the amplifier 28, the second amplifier 29, the peak shift identifying device 33, the waveform normalizing device 30, the peak shift correcting unit 34, the waveform judging device 31, and the signal reader 32 constitute the authentication information reading unit of the authentication system. Make up.
- the operation of the authentication information writing unit of the present authentication system is substantially the same as the operation of the authentication information writing unit of the embodiment in Fig. 2 and will not be described again here. Only the operation of the authentication information reading unit will be described in detail.
- data is recorded as basic information on tracks A and B of the magnetic card 10 by write signals as illustrated in FIG. It is assumed that That is, as described in the above-described embodiment, the data on the track A is intentionally made longer or shorter than the data on the track B.
- the write signal of track B is a waveform having a reference width
- the write signal of track A is a waveform in which the width of track B is also shifted.
- the signal recorded on the track A of the magnetic card 10 is read by the first magnetic head 18a, and the signal recorded on the track B is read by the second magnetic head 18b. And are amplified by the second amplifier 29, respectively.
- FIG. 12B shows these read signals.
- the points to be noted here are the same as those described in the description of the embodiment in FIG.
- due to the peak shift that occurs at the time of reading deviation in the amplitude direction actually occurs due to only the deviation in the width direction.
- FIG. The read signal illustrated in FIG. 3 is a signal read from tracks A and B of the magnetic card 10 at the same time through the magnetic heads 18a and 18b without any deviation in the amplitude direction.
- the peak shift specifying device 33 uses “0” ⁇ “1”, “ The point of change from “1” to “0” is specified as the part where the peak shift occurs!
- the peak shift specifying device 33 creates an interpolation curve from the read signal of the track B to determine the peak shift amount.
- FIG. 14 is a diagram for explaining the procedure for this.
- the peak shift specifying device 33 detects the peak shift (indicated by a triangle in FIG. 14) in the waveform of the track B as illustrated in FIG. , Interpolation song Create a line IC.
- the peak shift specifying device 33 calculates the interpolation curve IC and the portion of the waveform of the track B illustrated in FIG. 13 which is determined to have a peak shift (indicated by the X in FIG. 14). From the deviation, the approximate value of the peak shift amount (in this example, the values of the six points PS-Bl, PS-B2, PS-B3, PS-B4, PS-B5, and PS-B6 as shown in FIG. 14) ).
- the waveform normalizing device 30 normalizes the waveform of the read signal of the track B using the interpolation curve IC obtained by the peak shift specifying device 33 as described above. Further, the peak shift correcting device 34 converts the waveform normalized by the waveform normalizing device 30 into an approximate value of the peak shift amount obtained as described above by the peak shift specifying device 33 (PS in this embodiment). — The peak position is corrected using B1 to PS—B6 (6 points). Fig. 15 is a diagram for explaining this peak position correction.By shifting the peak position in the direction indicated by the arrow in Fig. 15, it is possible to reproduce the ideal read signal for the original write signal. it can.
- the waveform normalizing device 30 normalizes the waveform of the read signal of the track A using the interpolation curve IC obtained by the peak shift specifying device 33 as described above.
- FIG. 16 shows a read signal of the track A thus normalized.
- the peak shift correction device 34 corrects the peak shift occurrence portion of the waveform of the read signal of the track A that has been normalized by the waveform normalization device 30 by the value estimated by the track B force. That is, as shown in FIG.
- the power of correcting the peak shift as described above , Redundant 00, or 11 are also contemplated.
- the present embodiment is an example of a method for correcting a peak shift of a read signal, and the present invention is not limited to this.
- the write signal must be transformed in advance into a waveform that allows for peak shift. Thus, it is possible to cause a peak shift to appear apparently.
- FIG. 18 shows side-by-side waveforms of track A and track B that have undergone normalization and peak shift correction as described above. In the same way as above, the period shift between the waveform of track A and the waveform of track B in FIG. 18 is detected. The subsequent operation of the system is the same as that described with reference to the embodiment of FIG. 2 and will not be described again.
- the basic information indicates that the card is used by the user, but if the authentication information does not match, it is determined that the use of the card is an illegal use.
- This may be the case, for example, when the basic information is read from a magnetic card and the basic information is copied to another magnetic card and forged.
- Such a magnetic card has the same basic information as the original, but no signal is written so as to generate a signal deviation between tracks of the magnetic card as authentication information as described above. Because. Therefore, in such a case, its use is immediately refused.
- a malicious user illegally obtains the basic information of another person's magnetic card, and if the forged magnetic card is used by impersonating the person, the unauthorized use can be reliably prevented.
- the authentication information is recorded at a different position from the basic information of the magnetic card. It is also conceivable that it is included in the basic information. Even if a malicious user illegally obtains basic information and authentication information recorded on a magnetic card and forges the magnetic card based on this, the signal waveform obtained from the forged magnetic card The deviation is different from the original magnetic card. Therefore, the authentication information extracted from the forged magnetic card is compared with the authentication information of the original card recorded on the magnetic card, and if they do not match, it can be immediately determined that the card has been used illegally.
- the reading device accesses each server and computer. This can omit the procedure of performing communication, and can reduce communication cost and communication time.
- the deviation of the detected waveform as the authentication information changes every time the basic information is rewritten. Therefore, the authentication information based on the deviation of the detected waveform also changes each time the basic information is rewritten.
- the detected waveform shifts and authentication information based on this is generated, and this is used as new authentication information each time, and is different from the basic information. If it is recorded in a magnetic card, it can be handled in the same manner as a read-only magnetic card.
- the magnetic card of the present embodiment has a feature that compatibility with a conventional magnetic card reader Z writer can be ensured.
- writing of authentication information to a magnetic card in the present authentication system is possible only by adding a waveform deformer 24, a random number generator 25, etc. to a conventional card reader Z writer. . Therefore, the contents of the basic information can be read from the magnetic force of the present embodiment using a conventional reading device. Therefore, the conventional device can be continued to be used as a connection until the device is replaced with a device capable of reading and writing the authentication information according to the present embodiment.
- a conventional magnetic card can be read and written in a conventional manner using a magnetic card reader Z writer corresponding to the authentication information of this embodiment.
- the magnetic recording medium authentication method, magnetic recording medium authentication system, and authenticateable magnetic recording medium according to the present invention include a read-only magnetic card such as a credit card and a rewritable magnetic card such as a pre-read card. It can be used in the manufacture, distribution, sale, etc. of all recording media that magnetically record information that require so-called authentication.
- FIG. 1 is a schematic perspective view showing a relationship between a magnetic card and a magnetic head.
- FIG. 2 is a block diagram showing the overall configuration of an authentication system that performs a magnetic recording medium authentication method according to the present invention.
- FIG. 3 is a diagram exemplifying a write signal in a case where data as basic information is written on a track of a magnetic card by a width of a waveform.
- FIG. 4 is a diagram illustrating a write signal and a read signal.
- FIG. 5 is a diagram showing an example of a waveform reproduced by a card reader, an example of a waveform in which the amplitude of the reproduced waveform is normalized, and an example of a waveform in which the period is further normalized.
- FIG. 6 is a diagram for explaining the regularity of the period.
- FIG. 7 is a diagram exemplifying a read signal waveform from each track whose data width has been normalized by the waveform normalizing device.
- FIG. 8 is a diagram exemplifying a read signal waveform of each track force whose data height has been normalized by the waveform normalizing device.
- FIG. 9 is a diagram for explaining an example of detecting a deviation in amplitude.
- FIG. 10 is a diagram for describing an example of detecting a time-direction shift.
- FIG. 11 is a block diagram showing an overall configuration of an authentication system that performs a magnetic recording medium authentication method as another embodiment of the present invention.
- FIG. 12 is a diagram illustrating a write signal and a read signal in the embodiment of FIG. 11;
- FIG. 13 is a diagram specifically showing a peak shift portion in the read signal illustrated in FIG.
- FIG. 14 is a diagram for explaining a procedure for creating an interpolation curve for the read signal strength of the track B illustrated in FIG. 12 and obtaining the peak shift amount of the track B.
- FIG. 15 is a diagram for explaining normalization and peak shift correction of a read signal of track B illustrated in FIG. 12.
- FIG. 16 is a diagram for explaining normalization of a read signal of a track A illustrated in FIG. 12;
- FIG. 17 is a diagram for explaining a peak shift correction of a read signal of track A illustrated in FIG. 12;
- FIG. 18 is a diagram for explaining detection of a shift portion of the period of the read signal of the track A and the track B illustrated in FIG. 12 which has been subjected to the normal shift and the peak shift correction.
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- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Multimedia (AREA)
- Signal Processing For Digital Recording And Reproducing (AREA)
- Recording Or Reproducing By Magnetic Means (AREA)
- Digital Magnetic Recording (AREA)
Abstract
Description
Claims
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JP2006513985A JPWO2005116993A1 (ja) | 2004-05-31 | 2005-05-30 | 磁気記録媒体の認証方法、磁気記録媒体の認証システム、および認証可能な磁気記録媒体 |
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JP2004-307030 | 2004-10-21 |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0822675A (ja) * | 1994-06-30 | 1996-01-23 | Oki Electric Ind Co Ltd | 磁気記録データ読取方法 |
JPH10326333A (ja) * | 1997-05-23 | 1998-12-08 | Nisetsuto Kk | プリペイドカードおよびその偽造識別装置 |
JPH11250190A (ja) * | 1998-02-27 | 1999-09-17 | Anritsu Corp | カード識別方法およびカード識別装置 |
JP2001282746A (ja) * | 2000-03-30 | 2001-10-12 | Hitachi Seibu Software Ltd | ユーザ認証システム |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH10149417A (ja) * | 1996-11-20 | 1998-06-02 | Nisetsuto Kk | 磁気カードの書込装置、読取装置および磁気カード |
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2005
- 2005-05-30 JP JP2006513985A patent/JPWO2005116993A1/ja active Pending
- 2005-05-30 WO PCT/JP2005/009869 patent/WO2005116993A1/ja active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0822675A (ja) * | 1994-06-30 | 1996-01-23 | Oki Electric Ind Co Ltd | 磁気記録データ読取方法 |
JPH10326333A (ja) * | 1997-05-23 | 1998-12-08 | Nisetsuto Kk | プリペイドカードおよびその偽造識別装置 |
JPH11250190A (ja) * | 1998-02-27 | 1999-09-17 | Anritsu Corp | カード識別方法およびカード識別装置 |
JP2001282746A (ja) * | 2000-03-30 | 2001-10-12 | Hitachi Seibu Software Ltd | ユーザ認証システム |
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