JP3720113B2 - Portable information storage medium, portable information storage medium system, and data access method for portable information storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a portable information storage medium that requires verification between applicant information for identifying a person who requests access and access conditions when accessing data. , Carrying The present invention relates to a bandable information storage medium system and a data access method for a portable information storage medium.
[0002]
[Prior art]
In recent years, so-called IC cards have attracted attention as portable information storage media of this type. In general, an IC card is a nonvolatile memo such as an EEPROM. With , Its non-volatile memo Li And a CPU for manipulating data. In the EEPROM, a plurality of files are provided, and data is stored in each file. Access to each file is done through the CPU. Ru Therefore, by setting an appropriate access condition in advance, it is possible to access a file only when the CPU determines that the access condition is satisfied.
[0003]
As an access condition, it is common to set whether or not collation is necessary for some keys. That is, a key is written in advance in the EEPROM, and this internal key is compared with a key that is given from the outside and temporarily stored in the RAM, and based on the result, it is determined whether or not the file can be accessed. .
[0004]
Keys set as access conditions include a key for authenticating a specific target person (for example, an IC card owner or an issuer) or a key for authenticating specific hardware (for example, a terminal device). There is. Among these keys, a key for authenticating a specific subject is unlocked by authenticating a password input via a transaction terminal device or the like.
Normally, as a condition for accessing a file, collation of a plurality of keys is set as a condition, and when collation is successful for all keys, access to the file is permitted.
[0005]
[Problems to be solved by the invention]
In the above-described conventional IC card, the IC card owner must input a password to the transaction terminal device every time the IC card is used, and prove that the card is a valid card owner. However, in the case of an IC card with excellent portability, the card owner always carries the card and the card is surely under its own control, so there is a case where there is very little possibility that others will illegally use the IC card. . In such cases, you will be asked to enter a password for each transaction to authenticate you. Ru This is problematic in that the handling of the IC card is unnecessarily complicated and lost for the convenience of the user. On the other hand, since a transaction terminal device that performs transactions with an IC card is generally public, any number of people can handle the device. For this reason, there is a risk that a third party may illegally obtain a password by eavesdropping on the communication line of the transaction terminal device, or by manufacturing and installing a fake transaction terminal device and using the device. There was also a problem that there was.
[0006]
Therefore, the object of the present invention is to solve the above-mentioned problem, and a portable information storage medium in which password input can be omitted as necessary and the password can be prevented from being stolen. , Carrying A portable information storage medium system and a data access method for a portable information storage medium.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that communication means (11, 12) capable of communicating with the outside, data, A data storage means for storing the password, an authentication means for acquiring the password input by the holder via the communication means, and authenticating the holder based on the password, and unlocking indicating whether the authentication means has been authenticated. Temporary storage means (14) for temporarily storing information; The unlocking information stored in the temporary storage means Based on the data stored in the data storage means Access Restrict In a portable information storage medium comprising data management means (12), Non-volatile storage means (15) for storing the unlocking information, wherein the data management means copies the unlocking information stored in the non-volatile storage means to the temporary storage means, and then the nonvolatile storage means The unlocking information stored in the sex storage means is erased, and the access is restricted based on the unlocking information stored in the temporary storage means It is characterized by that.
[0008]
The invention according to claim 2 is the portable information storage medium according to claim 1, wherein the data management means is In the non-volatile storage means Preserved Unlocking information Is rewritten based on a command from the outside.
[0009]
The invention according to claim 3 The portable information storage medium according to claim 1 or 2, a communication means (41, 42) capable of communicating with the portable information storage medium, a password input means (46) capable of inputting a password from a holder, A holder authentication command means (42) for sending a password input from the password input means to the portable information storage medium via the communication means and commanding authentication of the holder based on the password; And a portable password input device having a power source (45) for supplying power for its operation and power for application to the portable information storage medium via the communication means. In the storage medium system, the authentication unit of the portable information storage medium is configured to authenticate a holder in accordance with a command from a holder authentication command unit of the password input device. It was carried out, the data management unit of the portable information storage medium, and the unlocking state unlocking information stored in the nonvolatile storage means when the authentication by the authentication unit is successful It is characterized by doing.
[0010]
The invention according to claim 4 The portable information storage medium system according to claim 3, further comprising: a transaction apparatus (20) that exchanges data stored in a data storage means of the portable information storage medium with the portable information storage medium; The data management means of the portable information storage medium copies the unlocking information stored in the nonvolatile storage means from before the communication with the transaction device to the temporary storage means, and then the nonvolatile storage means The unlocking information stored in the transaction device is erased, and access from the transaction apparatus is restricted based on the unlocking information stored in the temporary storage means. It is characterized by that.
[0011]
The invention according to claim 5 Acquires a password input by the holder through communication with an external device, authenticates the owner based on the password, and stores data based on whether the authentication in the authentication step is successful. A data management method for restricting access to the portable information storage medium, wherein the unlocking information indicating whether the authentication is successful in the authentication step in communication with the first external device is nonvolatile In communication between the first storage step stored in the storage means and the external second device, the unlocking information stored in the nonvolatile storage means in the first storage step is copied and temporarily stored. A second storage step to be stored in the means, and after the second storage step, the unlocking information stored in the nonvolatile storage means is erased And a removing step that the data management step, limiting access the to the data from the second external device based on the unlocking information stored in the temporary storage means It is characterized by doing.
[0012]
The invention according to claim 6 6. The data access method for a portable information storage medium according to claim 5, further comprising a rewriting step of rewriting the unlocking information stored in the non-volatile storage means based on an external command. It is characterized by that.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment according to the present invention will be described in more detail with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the IC card 10 and the owner-specific verification device 40 according to the present invention and the connection relationship with the transaction terminal device 20.
[0016]
First, the configuration of the IC card 10 will be described with reference to FIG.
As shown in the figure, the IC card 10 includes an I / O interface 11, a CPU 12, a ROM 13, a RAM 14, and an EEPROM 15. The I / O interface 11 is an input / output circuit for transmitting and receiving data, and the CPU 12 communicates with the transaction terminal device 20 or the owner-specific verification device 40 via the I / O interface 11. A program to be executed by the CPU 12 is stored in the ROM 13, and the CPU 12 controls the IC card 10 in an integrated manner based on this program. The RAM 14 is a memory used as a work area when the CPU 12 performs such overall control. On the other hand, the EEPROM 15 is a memory for storing original data to be recorded on the IC card 10.
[0017]
The IC card 10 is supplied with power and a clock from the transaction terminal device 20 or the owner-specific verification device 40. Therefore, when the IC card 10 is disconnected from the transaction terminal device 20 or the like, the supply of power and clock to the IC card 10 is stopped. However, since the EEPROM 15 is a non-volatile memory, the recorded content is retained as it is even after the power supply is stopped. However, all the data in the RAM 14 is lost by stopping the power supply.
[0018]
All accesses to the memories 13, 14, and 15 in the IC card 10 are performed via the CPU 12, and these memories cannot be directly accessed from the outside. That is, when a predetermined “command” is given to the CPU 12 from the transaction terminal device 20 or the like, the CPU 12 interprets and executes the “command” and returns the result as a “response” to the transaction terminal device 20 or the like. It will be.
[0019]
For example, when writing to a predetermined file in the EEPROM 15, the data to be written is given to the CPU 12 together with the “write command”, and the write process is executed in the form of execution of the “write command” by the CPU 12. Will be done. Conversely, when reading data from a predetermined file in the EEPROM 15, a predetermined “read command” is given to the CPU 12, and the read process is performed in the form of execution of the “read command” by the CPU 12.
[0020]
As described above, when the execution of the “command” is completed in the IC card 10, a “response” for the executed “command” is returned to the outside. For example, when a “write command” is given, a “response” indicating whether or not the write process has been executed without any trouble is returned, and when a “read command” is given, it becomes a read target. Data will be returned in the form of responses. However, the access to the EEPROM 15 is not unconditionally performed, and it is assumed that an access condition described later is satisfied.
[0021]
FIG. 2 is a block diagram showing a hierarchical structure in the EEPROM 15 shown in FIG. The EEPROM of this embodiment is composed of four layers. That is, a first layer MF (Master File), a second layer DF (Dedicated File), a third layer EF (Elementary File), and a fourth layer record structure (not shown).
MF is a file of the entire data memory. The MF is a file for storing data common to each application (service). For example, information such as the name, address, and telephone number of the owner of the IC card 10 is recorded.
[0022]
The DF is a dedicated file, and the DF is set for each application.
The EF is a basic file, and there are two types: IEF for storing data to be interpreted and executed when the CPU manages and controls the IC card, and WEF for storing data used in the application.
[0023]
Each file described above is managed by a directory file. FIG. 3A is a diagram showing the structure of a directory file for managing the DF. The directory file 50 stores file attribute information such as a relative address 52 from the top of the file, a total allocated capacity 53, a remaining capacity 54, and a check code 56 for the entire data. Direct Li The file 50 is further provided with an unlocking information area 55 for storing unlocking information related to the handler key.
[0024]
FIG. 5 is a diagram illustrating the contents of unlocking information stored in the unlocking information area 55. The unlocking information is composed of eight handler keys. Each key is assigned to a different operator. For example, K8 is assigned to the IC card manufacturer and K7 is assigned to the issuer. When each key is “0”, it indicates that it is in an unlocked state, and when it is “1”, it indicates that it is in an unlocked state.
[0025]
FIG. 3B is a diagram showing the structure of a directory file that manages WEF. The WEF directory file 60 is provided with an access condition information area 65 for storing an access condition in addition to an area for storing a head address 62, a total capacity 63, and the like. Here, the access condition is a condition that must be satisfied when accessing the WEF, and defines the type of key that must be unlocked.
[0026]
FIG. 4 is a diagram illustrating access conditions stored in the access condition information area 65. The access condition is defined for each mode of access to the file, that is, for each of “reading”, “writing”, or “update” of data. Each access condition is composed of eight keys corresponding to the eight handler keys in the unlocking information described above. In each key, “1” indicates that the corresponding handler key needs to be unlocked, and “0” indicates that unlocking is not necessary. In the example of FIG. 4, for data “reading”, at least K1 is unlocked in the unlocking information, for “writing”, at least K1 and K4 are unlocked, and “update” ", At least K1 and K5 are unlocked about Is defined as a condition.
[0027]
Next, the configuration of the owner-specific verification device 40 will be described with reference to FIG.
The holder-specific verification device 40 is a portable password input-only device used for inputting the IC card holder's password into the IC card 10. The owner-specific collation device 40 mainly includes an I / O interface 41, a CPU 42, a ROM 43, a RAM 44, a battery 45, a pin pad 46, and a display 47.
[0028]
The I / O interface 41 is an input / output circuit for transmitting / receiving data to / from the IC card 10. When a password is input to the IC card 10 using the holder-specific verification device 40, the I / O interface 41 is connected to the I / O interface 11 of the IC card 10.
The ROM 43 is a memory in which a program to be executed by the CPU 42 is stored. Based on the program stored in the ROM 43, the CPU 42 performs overall control of the operation of the owner-specific verification device 40 and communicates with the IC card 10 via the I / O interface 41.
[0029]
The battery 45 is a power source that supplies power necessary for the operation of the owner-specific verification device 40. As described above, since the owner-specific verification device 40 also includes a power source, it can be carried with the IC card. Note that the power of the battery 45 is also supplied to the IC card 10 via the I / O interface 41 when the IC card 10 is connected to the owner-specific verification device 40.
The RAM 44 is a memory used by the CPU 42 as a work area.
The pin pad 46 is an input means capable of inputting numbers or alphanumeric characters, and the owner of the IC card inputs his / her password from the pin pad 46. The display 47 is a liquid crystal screen or the like on which the CPU 42 outputs a display for requesting input of a password or the like.
[0030]
As described above, in the present embodiment, the IC card holder's password can be input to the IC card 10 using the holder-specific verification device 40.
FIG. 6 is a flowchart showing the operation of the IC card 10 and the owner-only verification device 40 when a password is input to the IC card 10 using the owner-specific verification device 40. In the figure, (A) shows the operation of the holder-specific verification device 40, and (B) shows the operation of the IC card 10. Moreover, the arrow represents that the IC card 10 and the owner-specific verification device 40 are communicating.
[0031]
First, when the IC card 10 and the owner-specific verification device 40 are connected and the owner-specific verification device 40 is turned on, the owner-specific verification device 40 supplies power to the CPU 12 and transmits a reset signal. (S100).
When the CPU 12 receives the reset signal, it initializes the RAM 14 and the like, and thereafter makes an initial response (Answer_to_reset) to the owner-specific verification device 40 (S200). Here, the initial response means transmission of information related to the type and operating characteristics of the IC card 10.
[0032]
Receiving the initial response, the CPU 42 displays on the display 47 that it is necessary to enter a password and whether password confirmation is necessary or not at the time of the next transaction, and receives input of such information from the pin pad 46 (S110). ).
[0033]
Here, “password confirmation unnecessary” means that password input / authentication is not performed when a transaction is performed between the IC card 10 and the transaction terminal device 20. For example, if the target application has a relatively low security requirement, such as a medical appointment at a medical institution, and the IC card owner determines that the password entry when using the card may be omitted This password confirmation unnecessary is selected.
On the other hand, “require password” means inputting and authenticating a password at the time of transaction. For example, if the application in question is one that requires high security such as withdrawal of bank deposits, the password confirmation requirement is selected.
[0034]
Receiving the input, the CPU 42 transmits to the IC card 10 a command “VERYFY_PW” having the password confirmation required / unnecessary, the key number corresponding to the password, and the password as an argument (S120).
[0035]
In the IC card 10 that has received the transmission of the command “VERYFY_PW”, the CPU 12 authenticates the transmitted password, and transmits the result as a response to the owner-specific verification device 40 (S210). If the authentication is successful, the CPU 12 sets the corresponding key of the unlocking information provided in the RAM 14 to “1” to unlock the key (S230). The unlocking information provided in the RAM 14 is the unlocking information area 5 described above. 5 It has the same structure as the unlocking information stored in.
[0036]
Further, the CPU 12 confirms whether the next password confirmation is set to “required” or “unnecessary” in the argument of the “VERYFY_PW” command. As a result, if it is “unnecessary”, the corresponding key in the unlocking information area 55 in the EEPROM 15 is set to “1” (S250), and the operation ends. On the contrary, if it is set to “necessary”, the CPU 12 sets the corresponding key in the unlocking information area 55 to “0” (S252), and ends the operation.
[0037]
As described above, the IC card 10 to which the password is input using the owner-specific verification device 40 is then connected to the transaction terminal device 20 and the transaction is executed.
FIG. 7 is a flowchart showing each operation when a transaction is performed between the IC card 10 and the transaction terminal device 20. In the figure, (A) is a flowchart of the operation of the transaction terminal device 20, and (B) is a flowchart of the operation of the IC card 10. Moreover, the arrow has shown that the IC card 10 and the transaction terminal device 20 are communicating.
[0038]
When IC card 10 is connected to transaction terminal device 20, transaction terminal device 20 supplies power to CPU 12 and transmits a reset signal (RESET) (S300). When the CPU 12 receives the reset signal, it initializes the RAM 14 and the like, and thereafter makes an initial response (Answer-to-reset) to the transaction terminal device 20 (S400).
[0039]
Next, the transaction terminal device 20 receives the contents of the application such as “Ox Bank Deposit Balance Inquiry”, specifies the file name of the DF to be referred to in the IC card 10 based on the contents, and the file name A command “SELECT_DF” having “” as an argument is transmitted to the IC card 10 (S310). Here, it is assumed that the file name of the specified DF is “DF1”.
[0040]
The CPU 12 that has received “SELECT_DF” refers to the unlocking information area 55 of the directory that manages DF1, and copies the unlocking information stored therein to the RAM. Moreover, CPU12 transmits the content of unlocking information to the transaction terminal device 20 (S410).
On the other hand, the transaction terminal device 20 specifies the access condition to the data required at the time of application execution from the input application content, and collates this with the transmitted unlocking information.
[0041]
Here, as an example, the access conditions specified by the transaction terminal device 20 are the conditions illustrated in “Read” in FIG. 4, and the unlocking information transmitted from the CPU 12 is illustrated in FIG. Suppose that In this case, it is the key of K1 that requires the unlocked state to be verified in the access conditions. On the other hand, in the unlocking information, the key of K1 is in an unlocked state. Therefore, the transaction terminal device 20 determines that the unlocking information satisfies the access condition (S320: YES), and proceeds to the next operation without requesting the input of a new password (S360).
[0042]
On the other hand, when the unlocking information is, for example, the one illustrated in FIG. 5B, the key of K1 is not unlocked, so the transaction terminal device 20 determines that the unlocking information is an access condition. Is not satisfied (S320: NO), and a request is made to input a necessary password through a display or the like (S330). As a result, when the password is input, the transaction terminal device 20 transmits a “VERYFY” command with the key number corresponding to the password and the input password as arguments to the IC card 10 (S340).
[0043]
In the IC card 10 that has received the transmission of the “VERYFY” command, the CPU 12 collates the transmitted password and transmits a response regarding the result to the transaction terminal device 20 (S430). If the verification is successful, the CPU 12 sets the corresponding key of the unlocking information copied in the RAM 14 (S410) to “1” (S450). Thereby, in the subsequent transaction, when the access condition is collated, the access condition is satisfied, and the data can be accessed.
[0044]
Next, transaction terminal apparatus 20 and IC card 10 authenticate each other (authentication related to the machine) according to a known method (S360, S460). When the authentication is successful, a known transaction procedure is executed between the IC card 10 and the transaction terminal device 20 (S380, S480), and the respective operations are terminated after the transaction is completed.
[0045]
As described above, in this embodiment, the unlock information area 5 is stored in the EEPROM 15. 5 And store unlocking information there. Therefore, even if the IC card 10 is not connected to the transaction terminal device 20 or the like and cannot receive power supply, the unlocking information is retained. Also, the unlocking information area 5 5 When the IC card 10 is connected to the transaction terminal device 20, the unlocking information stored in is copied to the RAM 14 before the transaction is started, and is used for checking access conditions in the subsequent transaction process. As a result, in this embodiment, the unlocking information area 5 5 By storing the unlocking information with appropriate contents, the password entry when using the IC card can be omitted, and the complicated procedure of entering the password for each transaction can be avoided.
[0046]
In this embodiment, the unlocking information area 5 5 The unlocking information stored in the key can be operated for each key by an external command. That is, in the present embodiment, the unlocking information area 5 is transmitted by transmitting the password and information regarding necessity / unnecessity of password confirmation at the time of transaction to the IC card. 5 The unlocking state of each operator key in can be arbitrarily set. Thereby, this embodiment can perform and abbreviate | omit the procedure of password input and authentication at the time of transaction as needed.
[0047]
Furthermore, in the present embodiment, the password input to the IC card 10 is performed using the portable owner-specific verification device 40 without using the transaction terminal device 20. Therefore, if the IC card owner carries the owner-specific verification device 40, it is possible to prevent a third party from making any special work on the owner-specific verification device 40 and illegally obtaining the input password. It is possible to further enhance the security of the IC card system.
[0048]
(Other embodiments)
The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
[0049]
1) In the above embodiment, the unlocking information area 5 5 The operation of the unlocking information stored in is performed using the owner-specific verification device 40, but this may be performed by the transaction terminal device 20. In this case, the operation of transaction terminal device 20 is, for example, the one in which (S330) and (S340) in FIG. 7 (A) are replaced with (S110) and (S120) in FIG. 6 (A). In other words, the transaction terminal device 20 uses the “VERYFY_PW” command instead of the “VERYFY” command to transmit the password and the information regarding necessity / unnecessity of password confirmation at the time of transaction to the IC card. It is also possible to fulfill the same function as the owner-specific collation device 40.
[0050]
2) The above embodiment is a case where the main purpose is to prevent theft of passwords. When handling an application that requires particularly high security, the IC card itself is provided with the unlocking information area 5. 5 It is also possible to delete all the contents of the unlocking information stored in the folder under certain conditions. For example, in (S220) of FIG. 5 After copying the unlocking information in the RAM 14, the CPU 12 15 Unlocking information area 5 5 It is possible to set all of the key designation bits in the "0". In this case, even when a password is input to the IC card 10 using the owner-specific verification device 40, the password must be input for each transaction, and the effect unique to this embodiment of preventing password theft is provided. High security at the same time I It can be secured.
[0051]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to omit the input of applicant information performed for each transaction at any time, and to avoid complicated procedures as necessary. became. In particular, the claims 3 Or 4 According to the invention according to the present invention, it is possible to prevent the applicant information from being illegally stolen by a third party because it is avoided to input the applicant information to the transaction terminal device or the like.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an IC card 10 and a holder-specific verification device 40 according to the present invention and a connection relationship with a transaction terminal device 20;
FIG. 2 is a block diagram showing a hierarchical structure in the EEPROM 15 shown in FIG.
FIG. 3 is a diagram showing the structure of a directory / file.
FIG. 4 is a diagram illustrating file access conditions.
FIG. 5 is a diagram illustrating unlocking information stored in an unlocking information area 55;
FIG. 6 is a flowchart showing each operation when a password is input to the IC card 10 using the owner-specific verification device 40;
FIG. 7 is a flowchart showing each operation when a transaction is performed between the IC card 10 and the transaction terminal device 20;
[Explanation of symbols]
11 I / O interface
12 CPU
15 EEPROM
20 Transaction terminal device
41 I / O interface
42 CPU
45 battery
46 pin pad

Claims (6)

A communication means capable of communicating with the outside;
Data storage means for storing data;
An authentication means for acquiring a password input by the holder via the communication means and authenticating the holder based on the password;
Temporary storage means for temporarily storing unlocking information indicating whether it has been authenticated by the authentication means;
Data management means for restricting access to data stored in the data storage means based on unlocking information stored in the temporary storage means;
In a portable information storage medium comprising:
Non-volatile storage means for storing the unlocking information,
The data management means copies the unlocking information stored in the nonvolatile storage means to the temporary storage means, and then erases the unlocking information stored in the nonvolatile storage means, Restricting the access based on unlocking information stored in a local storage means;
A portable information storage medium characterized by the above. The portable information storage medium according to claim 1,
The data management means rewrites the unlocking information stored in the nonvolatile storage means based on a command from the outside,
A portable information storage medium characterized by the above. The portable information storage medium according to claim 1 or 2,
A communication means capable of communicating with the portable information storage medium, a password input means capable of inputting a password from a holder, and a password input from the password input means to the portable information storage medium via the communication means An owner authentication command means for sending and instructing the owner to authenticate based on the password, and power for own operation and for giving to the portable information storage medium via the communication means A portable password input device having a power source for supplying power ;
A portable information storage medium system comprising:
The authentication means of the portable information storage medium authenticates the holder in response to a command by the holder authentication command means of the password input device,
The data management means of the portable information storage medium sets the unlocking information stored in the nonvolatile storage means to the unlocked state when the authentication by the authentication means is successful.
A portable information storage medium system . The portable information storage medium system according to claim 3,
A transaction apparatus for performing exchange of data stored in the data storage means of the portable information storage medium with the portable information storage medium ;
The data management means of the portable information storage medium copies the unlocking information stored in the nonvolatile storage means from before the communication with the transaction device to the temporary storage means, and then the nonvolatile storage means Erasing the unlocking information stored in the storage device, and restricting access from the transaction device based on the unlocking information stored in the temporary storage means,
A portable information storage medium system. Acquires a password input by the holder through communication with an external device , authenticates the owner based on the password, and stores data based on whether the authentication in the authentication step is successful. A data access method for a portable information storage medium comprising a data management step for restricting access to
A first storage step for storing in the nonvolatile storage means unlocking information indicating whether or not the authentication is successful in the authentication step in communication with an external first device ;
A second storage step for copying the unlocking information stored in the nonvolatile storage means in the first storage step and storing the information in the temporary storage means in communication with an external second device ;
An erasure step of erasing unlocking information stored in the nonvolatile storage means after the second storage step ;
The data management step restricts access to the data from the second external device based on unlocking information stored in the temporary storage means;
A data access method for a portable information storage medium. The data access method of the portable information storage medium according to claim 5 ,
A rewriting step of rewriting the unlocking information stored in the nonvolatile storage means based on an external command,
A data access method for a portable information storage medium.

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