JP2501587B2 - IC card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an IC card with security protection.

[Conventional technology]

Recently, IC cards built into IC cards such as CPUs and memories have been proposed and are becoming popular. This IC card generally has a non-volatile programmable memory, and by storing various information as data in this memory, long-term data storage can be performed. Furthermore, the development of rewritable memory has progressed, and the data stored in the memory can be updated easily, making it possible to use the IC card itself for recycling.

The data stored in the memory of such an IC card is generally access-controlled by the CPU or an external device based on a built-in or external program.
In addition, some application programs have a configuration in which a logical or physical storage location is designated and managed in the memory of the IC card according to a predetermined interpretation on the program. Therefore, in order to record the necessary information as data, a data storage area and position according to the content of the information are defined in advance in the memory of the IC card, and the application system specifies this data storage area and position to store the information. Will read and write.

[Problems to be solved by the invention]

However, in the conventional IC card having the above-described configuration, the data written in the data storage area in the nonvolatile readable / writable memory is stored until the data is erased or another data is overwritten. Therefore, confidential information is stored in the IC card, and if this IC card is lost, the confidential information will be
Since it is stored in the IC card, there is a problem that confidential information is likely to be stolen by a third party who picks up the IC card.

Therefore, a method of providing an identification code (password) unique to the user of the IC card was considered. In this method, when accessing the IC card via an external device, first request the password input, and only when the correct password is input, consider it as an authorized card user and read the desired data on the IC card. It is a method that allows you to do the work. This approach provided a fairly high level of security.

However, even with this method, the third
If the person has a deep knowledge in the field of electronic technology, it was possible to access the data stored in the IC card, which was found by, for example, a self-made simple external device. For this reason, there is a possibility that the password may be discovered by sequentially inputting the password as much as possible, and it cannot be said that the confidentiality of the IC card is surely protected.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to obtain an IC card with high confidentiality even if it is passed to any third party.

[Means for solving problems]

An IC card according to the present invention has a CPU and a memory, first counting means for counting the number of error inputs when a code different from a preset identification code is input, and the number of times the power is turned on when the power is turned on. Second to count
Counting means, resetting means for resetting the error input count and the power-on count to predetermined initial values when a code matching the preset identification code is input, the error input count, and The predetermined number of 1 is compared, and the number of times of power-on is compared with a second predetermined number, and the number of error inputs reaches the first predetermined number, or the number of times of power-on is the second predetermined number. When it reaches the number, it is configured with a control means for disabling the IC card.

[Action]

By the control means in the present invention, the number of error input of the identification code is compared with the first predetermined number, and the number of power-on times is compared with the second predetermined number.
When the number of times of power-on reaches the second number of times of power-on, the IC card is disabled. The confidentiality protection function of can be activated.

〔Example〕

FIG. 1 is a configuration diagram of an IC card system according to an embodiment of the present invention. In the figure, reference numeral 1 is an IC card, and 2 is an external device for reading and writing information stored in or to be stored in the IC card 1 by connecting to the IC card 1 via a connector 8. The IC card 1 has three types of memories: a CPU3 as a control center, a ROM4 for storing application programs, a RAM5 for temporarily storing data during processing, an EEPROM6 for long-term storage, and an external device. It has a power-on detector 7 that informs the CPU 3 that the power is turned on every time the power is supplied to the IC card 1 by being connected to the CPU 2.

FIG. 2 is a memory configuration diagram showing a part of the EEPROM and RAM in the IC card 1 shown in FIG. 1, and FIG.
6. FIG. 6B shows the memory configuration of the RAM 5.

In the figure (a), the preset power-on count D _{ON is} set to the preset address A _n of the EEPROM ₆ , the power-ON count C _{ON is} set to the address A _{n + 1} , and the allowable error password input count is set to the address A _{n + 2.} A storage area for the value D _PW is allocated. On the other hand, in the same figure (b), a storage area for the number of error password inputs C _PW is allocated to the preset address B _m of the RAM 5.

FIG. 3 is a flowchart showing the processing procedure of the password input routine of the IC card 1 having the above-mentioned memory structure. The operation will be described below with reference to FIG. First,
By connecting the IC card 1 and the external device 2 via the connector 8, they are electrically coupled and the CPU 3, RAM 5 and the like in the IC card 1 are initialized in step S1. Then step S2
Then, the power-on detector 7 supplies a power-on detection signal to the CPU 3, so that the CPU 3 reads the power-on detection signal. Then, in step S3, the power ON count C _ON starts from the address A _{n + 1} on the EEPROM 6.
Is read out, an addition process of C _ON = C _ON +1 is performed, and then stored again. In the next step S4, the power ON count C _ON and the allowable power ON count set value D _ON (stored at address A _n in EEPROM 6)
And C _ON ≥ D _ON , step S9
Then, by moving the prohibition function, it becomes impossible to access each memory 4, 5 and 6 in this IC card, and the secret leakage to the third party is prevented.

On the other hand, if C _ON <D _ON in step S4, the process moves to step S5 to request the IC card 1 user to input the password from the external device 2 or the like. The entered password is compared with the password stored in advance in the ROM 4 or the like in the IC card 1 in step S6, and the correctness is determined. If it is determined to be “wrong”, in the next step S7, the error password input count C _PW (“0” when the power is turned on) is read from the address B _m on RAM5, and C
After the addition processing of _PW = C _PW + 1, it is stored again. Then, in step S8, the error password input count C _PW is compared with the allowable error password input count set value D _PW (stored in the address A _{n + 2} on the EEPROM 6), and if C _PW ≧ D _PW Preventing confidential information from being leaked to a third party by activating the prohibition function in step S9. On the other hand, if C _PW <D _PW in step S8, the process returns to step S5, and thereafter, steps S5 to S8 are performed until it is determined that the correct password is input in step S6 or C _PW ≧ D _PW is satisfied in step S8. repeat.

If it is determined that the correct password is input in step S6,
It is regarded as the use of a legitimate IC card 1 user, the process proceeds to step S10, the power ON count C _ON is cleared to “0”, and the error password input count C _PW is cleared to “0” which is the initial value in step S11. After that, normal data can be read and written in the IC card 1. The above-mentioned processing can be performed by the CPU 3 based on a program such as the ROM 4 in the IC card 1.

In this way, the incorrect password input count C _PW and power ON count C
Either of the two _ON parameters has a predetermined allowable set value D
_{When PW} / D _ON is reached, the prohibition function is activated automatically, so the confidentiality retention capability is dramatically improved. That is,
The third person who picks up the IC card has a deep knowledge of the electronic technology field, and even if the password is sequentially input by an external device of his own, the error is allowable. Password input count set value D _PW times For example, since the error password input count C _PW reaches the allowable error password input count set value D _PW , the IC card has a prohibit function to protect the confidentiality of the IC card. In addition, this third party forcibly turns off the power to the IC card that was found before the error password input count C _PW reaches the allowable error password input count set value D _PW ,
Even if you try to enter the identification code again after turning on the power, if the power ON count C _ON reaches the allowable power ON count set value D _ON , the IC
The confidential function in the IC card can be protected by the prohibition function of the card.

FIG. 4 is a flow chart showing the processing procedure of another password input routine in the IC card having the memory configuration shown in FIG. 2, and in this embodiment, the step of determining whether or not the password is entered correctly (step S25) is preceded by C _ON ≧ D
The determination step of whether it is _ON (step S26) is performed later. Other procedures are similar to those of the embodiment shown in FIG. By executing steps S21 to S31 as shown in FIG. 4, the same effect as that of the embodiment of FIG. 3 can be obtained.

Although the password is the identification code of the card user in the above embodiment, it may be used for other identification purposes. The allowable set values D _ON and D _PW may be variable, and their values are also arbitrary, but in general, in consideration of the case where an authorized card user turns the power ON / OFF by mistake, It is desirable to set the power ON count setting D _{ON a} little more than the allowable password input count D _PW . The control function is CP
It can be realized by using a logic circuit instead of U3. Without using the power ON detector 7, add the power ON count C _ON when the password is first input after power ON. You can also

〔The invention's effect〕

As described above, according to the present invention, the control means compares the error input count of the identification code with the first predetermined number, and also compares the power-on count with the second predetermined number to determine the error input count. Reaches a first predetermined number, or the number of power-on times reaches a second predetermined number, the IC card is disabled.

Therefore, even if the third party who picks up the IC card sequentially inputs the identification code, if the number of error inputs reaches the first predetermined number, the prohibition function (first confidentiality protection function) works on the IC card. Can protect the confidentiality of the IC card.

In addition, the third party forcibly turns off the power to the IC card before the number of error inputs reaches the first predetermined number,
Even if you try to enter the identification code again after turning on the power, if the number of times the power is turned on reaches the second predetermined number, the IC card will be protected by the prohibition function (second confidentiality protection function). You can

As a result, by operating the first and second confidentiality functions in parallel, it is possible to obtain an IC card with high confidentiality even if it is passed to any third party.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an IC card according to an embodiment of the present invention, FIG. 2 is a memory configuration diagram of EEPROM and RAM in the IC card shown in FIG. 1, and FIGS. 6 is a flowchart showing a processing procedure of a password input routine in the IC card having the memory structure shown in FIG. In the figure, 1 is an IC card, 3 is a CPU, 4 is a ROM, and 5 is an RA.
M and 6 are EEPROM. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

(57) [Claims] 1. An IC card comprising a CPU and a memory, wherein a first counting means for counting the number of error inputs when a code different from a preset identification code is input, and a power-on when the power is turned on. Second counting means for counting the number of times; reset means for resetting the error input frequency and the power-on frequency to predetermined initial values when a code matching the preset identification code is input, The error input count is compared with a first predetermined number, the power-on count is compared with a second predetermined number, and the error input count reaches the first predetermined number, or the power-on count is reached. And a control means for disabling the IC card when the number reaches the second predetermined number. 2. The memory has a volatile temporary storage memory and a non-volatile memory, both of which are readable and writable, and stores the error input count in the temporary storage memory and the power-on count in the non-volatile memory. Claim 1
IC card described in section.