JPH06231161A - System for preventing money transaction by ic card from being illegally altered - Google Patents

Abstract

PURPOSE:To prevent amount data to be paid by a payer front being altered when an IC card owner executes a money transaction by using his (or her) own IC card. CONSTITUTION:This system is constituted of an IC card 4, a terminal equipment 2 for clerk operation and a host computer 1 connected to the equipment 2 and capable of deciding whether transaction data received from the equipment 2 are legally processed or not, and the IC card 4 is provided with a keyboard 5 capable of allowing input operation when a password known only by the card owner is inputted. Various kinds of comparing/confirming means is provided for confirming that an amount inputted from the IC card 4 by card owner' s operation has been legally processed by the host computer 1 and the equipment 2 is provided with an amount data comparing means 22 for comparing whether amount data inputted from the keyboard 5 coincide with amount data inputted from the equipment 2 by clerk operation or not so as to prevent the amount data from being altered by a third person.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC card for preventing fraudulent alteration processing of transaction data which may occur by the intentional or negligent act of the operator when paying money using the IC card. The present invention relates to a fraudulent tampering prevention system for financial transactions.

[0002]

2. Description of the Related Art Various security measures have heretofore been taken when conducting financial transactions using an IC card typified by a credit card, a bank card and the like. For example, as an example of the countermeasures, in a financial transaction system using an IC card, a personal identification number is set for each IC card, and transactions with the IC card cannot be performed unless the personal identification number is entered. Yes, I
Standardization is being promoted by SO (International Organization for Standardization).

However, for example, when purchasing an item with a credit card, it cannot be guaranteed that the amount of money to be paid for the item is the same as the amount actually processed to be paid. It was a difficult task to eliminate all the possibilities of allowing the wrongdoing of the three parties. Here is an example of a case in which a fraudulent act cannot be excluded. When some kind of product is purchased with a credit card using an IC card, the IC card authentication A by the terminal device A, the authentication B of the terminal device A by the IC card, and the host computer of the credit card company are usually performed by using encryption processing technology. The authentication C of the IC card according to the above, and the MAC added to the data to ensure the validity of the data from the terminal device A to the IC card (to ensure the validity of the data to be transmitted, a predetermined code. Although the MAC calculation method is obtained by a calculation method, the MAC calculation method is a widely known technology, and therefore description thereof will be omitted.).

In this case, an input device usually connected to the terminal device A (for example, a keyboard, a bar code reader, etc.)
Inputs the amount of data to be paid, which is processed as a part of the transmission data transmitted to the host computer. Then, in this transmission data, the IC
MAC calculated by the data part using KEY _mac which is an encryption key for MAC calculation in the card
Is added and then sent to the host computer.

On the host computer side, the same encryption KE
The MAC is calculated by the data unit using Y _mac, and the validity of the transmission data transmitted from the terminal device A is confirmed. This makes it impossible to tamper with the data added with the MAC by the IC card and guarantees the monetary amount data.

[0006]

However, in the above-mentioned conventional technique, the authentication is accompanied by the data exchange between the IC card and the terminal device and the host computer of the credit company, and the amount to be paid as the price of the article. It is not possible to restrict processing operations by fraudulent acts when an employee such as a store clerk inputs data to the terminal device or when processing by the terminal device, and thus it is possible for the clerk to commit fraudulent acts. However, if an amount different from the actual amount to be paid is processed, the payer who is the holder of the IC card may be damaged.

In order to prevent such unauthorized changes in the amount by a third party, it is conceivable to add a procedure for inputting a password without fail when inputting the amount from the input device. According to this, there is a problem that not only the troublesome operation of inputting the password is required every time, but also the risk that the password is leaked to a third party increases.

The present invention has been made to solve the above-mentioned problems, and when an IC card holder makes a financial transaction using his or her own IC card, the amount data corresponding to the transaction is sent to the terminal device. A system for preventing illegal manipulation of the amount of money to be paid by fraudulent acts during the operation, and an IC card improper tampering prevention system for financial transactions using an IC card with a password that does not leak to a third party. It is intended to provide.

[0009]

In order to achieve the above-mentioned object, according to the present invention, the amount data to be paid is held only by the cardholder by the operation of the cardholder himself, not by the operation of the staff. By using a card and inputting from a keyboard that cannot be input unless a password known only to the cardholder is input, unauthorized tampering by a staff member is prevented.

That is, an IC card having a data holding unit for holding data, a reading unit for reading the data holding unit of the IC card, and an input device for inputting transaction amount data are provided, and the reading is performed by the reading unit. In order to prove the validity of each of these data to the card data and the amount data input from the input device, I
A terminal device that adds the MAC value calculated based on the data of the C card to create transmission data and sends the transmission data to the host computer, and a MAC value by the MAC calculation means based on the transmission data from the terminal device. Calculate,
The calculated MAC value is compared with the MAC value added to the transmission data by the MAC value comparison means, and when the two values match, it is recognized that the data has been normally processed, and the control unit normally ends. The system is composed of a host computer that creates response data including data indicating that the card holder has sent the data, and sends the data to the terminal device. When the cardholder makes a financial transaction using the IC card, In a fraudulent tampering prevention system for monetary transactions using an IC card for preventing monetary data from being tampered with at the processing stage, the IC card or a portable terminal device having an external interface unit that can access the IC card, A keyboard that enables input operations by entering the password and the keyboard A random number generator for generating a random number of monetary amount data, a MAC value calculating means for calculating the MAC value of the monetary amount data input from the keyboard and the monetary amount data in the response data received from the host computer, and the MAC value calculating means. The MAC value of the response data sent to the host computer with the calculated MAC value added thereto and returned when normal processing is executed on the transmission data is calculated on the IC card side by the MAC value calculation means. And a MAC value comparing means for comparing whether or not the MAC values match each other.
If the values match, the random number before sending to the host computer is compared with the random number in the response data, and when they match, it is recognized that the amount data entered from the keyboard has been processed normally and the transaction processing ends. And a money amount data input from the IC card or the keyboard of the portable terminal device and the money amount data input from an input device connected to the terminal device. A monetary amount data comparing means for comparing whether or not to do is provided.

[0011]

With the above-described structure, when the payment process is performed in the financial transaction performed using the IC card, the transaction amount is first operated by the IC card holder by operating the IC card or the keyboard provided on the portable terminal device. When data is input, a random number for this transaction amount data is generated, and the transmission data is created by adding the random number and the MAC value calculated from the amount data to the input amount data, and this transmission data is generated by the control unit. Is sent to the terminal device.

In the terminal device receiving this transmission data,
The amount data in the transmission data is compared with the amount data input by the operation of the staff from the input device provided in the terminal device, and only when they match, the transmission data is sent to the host computer. Then, the host computer calculates a random number and a MAC value based on the transmission data received from this terminal device, compares the calculated value with the transmission data, and if they match, the reception data has been tampered with. Recognize this and process payment. After this,
The host computer creates response data including the calculated random number and the MAC value including the data indicating that the payment process is performed with correct data, and the control unit causes the IC card or the portable terminal via the terminal device. Sent to the device.

The IC card or the portable terminal device receiving this response data calculates the MAC value based on the response data, and calculates the calculated MA value.
The C value is compared with the MAC value added to the response data, and if they match, the random number added to the response data and the random number generated by the IC card before sending to the host computer. Comparing with each other, when these match, it is recognized that the amount data input by the operation of the card holder from the keyboard has been normally processed by the host computer, and the transaction processing is ended.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an unauthorized tampering prevention system according to the present invention, and FIG. 2 is a block diagram showing the configuration of an IC card used in this system. 1 and 2, 1 is a host computer as a host device installed in a credit company that issues IC cards or a bank, and 2 is a terminal installed in a retail store such as a department store and operated by a clerk such as a clerk A device 3, an input device such as a keyboard and a bar code reader for inputting the transaction amount data, and an IC card 4 constitute an tamper-proof system by these constituent requirements.

First, the structure of the IC card 4 will be described with reference to FIG. Reference numeral 5 is a keyboard composed of a plurality of numerical keys and instruction keys for inputting the data of the amount of money transacted and various data such as a password to be described later, and 6 is a liquid crystal display for displaying the respective data input from the keyboard 5. Display, 7 is the terminal device 2 and an IC operated by an attendant
An external interface unit (hereinafter referred to as an I / F unit) for performing data communication with the card 4.

A control unit 8 communicates data input from the keyboard 5 through the I / F unit 7 and controls the operation of each component. Some means for processing each data input in order to prevent the tampering of the amount data in the transaction described later, that is, the MAC value of the amount data input from the keyboard 5 and the information received from the host computer described later. MAC value calculating means 8a for calculating the MAC value of the amount data in the response data, this M
Data transmission instruction means 8b for generating transmission data from the IC card to which the MAC value calculated in the AC value calculation means 8a is added and instructing to transmit this to the terminal device 2, and based on this transmitted transmission data The data comparison means 8c is provided for comparing the response data processed and returned by the host computer 1 with the data before the transmission.

Reference numeral 9 is a first memory capable of reading only, and 1
0 is a writable and readable non-volatile second memory, 11 is also a writable and readable volatile third memory, and 12 is a random number generator. The IC card 4 is configured according to the configuration requirements. The IC card 4 having the above-described configuration does not include the keyboard 5 and the display 6 in the IC card itself, but has an external interface unit (hereinafter referred to as an external IF unit) that can access the IC card.
A keyboard for data input and a display for displaying input data are provided in a portable terminal device separate from the IC card, and the IC card without the keyboard and the display is inserted into the portable terminal device. It is also possible to use a portable terminal device having a function similar to that of the IC card 4 having a display.

FIG. 3 is a block diagram showing the internal structure of such a portable terminal device. As shown in FIG. 3, the portable terminal device 13 is provided with a keyboard 5 and a display 6, and An external interface unit (hereinafter referred to as an external I / F unit) 1 for interfacing with an IC card 13 'having no keyboard 5 and display 6
4, a control unit 15 connected to the external I / F unit 14 for controlling the operation of each component inside the apparatus, a fourth memory 16 that allows only reading, a volatile device that allows writing and reading The fifth memory 17 and the fifth memory 17 are provided, and the configuration here may be the minimum that the IC card 13 'as the access partner does not have. It should be noted that, like the control unit 8 of the IC card 4, the control unit 15 includes a MAC calculation unit 15a and a transmission data transmission instruction unit 1
5b. The data comparison means 15c is provided.

The IC card 4, the portable terminal device 13 and the IC card 13 'are owned and operated by the card holder only. Next, the above I
The host computer 1 and the terminal device 2 in the prevention system for preventing illegal tampering of transactions by using the C card 4 (or the portable terminal device 13 and the IC card 13 ').
The configuration will be described by returning to FIG.

MAC calculating means 18 calculates a MAC value on the side of the host computer 1 based on transmission data transmitted from the IC card 4 (13 ') to the host computer 1 via the terminal device 2. , 19 is this M
MA for comparing whether or not the MAC value calculated by the AC calculation means 18 and the MAC value added to the transmission data transmitted from the IC card 4 (13 ') match.
C value comparison means, and 20 is the MAC value comparison means 19
When it is confirmed that the two values agree with each other, it is confirmed that the transmission data has not been tampered with, and an instruction to send the created response data to which the confirmed data is added to the terminal device 2 after the payment processing is performed is issued. Response data transmission instructing means, which is provided in the control unit 21 of the host computer 1.

Reference numeral 22 denotes a monetary amount data comparison means provided in the terminal device 2, and the monetary amount data input by the card holder's operation of the keyboard 5 of the IC card 4 (13 ') and the terminal device 2. This is to compare whether or not the amount data input by the operation of a staff member such as a store clerk from the connected input device matches. As shown in FIG. 1, first of all, in the tampering prevention system including the host computer 1, the terminal device 2, and the IC card 4 (13 ') having the above-mentioned means, the signals are transmitted and received. Between the portable terminal device 13 and the host computer 1, at least the amount data to be traded is transmitted from the IC card 4 to the host computer 1 via the terminal device 2 (data in the figure), and the host computer 1 From the above, response data (response) indicating that the amount data previously transmitted from the IC card 4 has been correctly processed is returned to the IC card 4.

The IC card 4 having the above-mentioned configuration is I
Even when used with the C card 13 'and the portable terminal device 13, the IC card 13' and the portable terminal device 13 are I
It is owned and operated by the C-card holder, and therefore, it may be considered that it is impossible for a third party to cheat the portable terminal device 13. Further, in the following description, the case where the IC card 13 'and the portable terminal device 13 are used is described. According to this, even when the IC card 4 with the keyboard 5 and the display 6 is used, it is easy. It is possible to make an analogy.

FIG. 4 shows confidential data according to the present invention, which is stored in the second memory of the IC card. In the figure, ID (1) is the IC card 13 '(4).
Unique identification number for identifying each, KEY _ID
(1) is KEY, K for encrypting and decoding the random number R
EY _mac (1) is M for transmission data including amount data
It is a key for calculating the AC value, and the password is stored following this.

The above confidential data are stored in a memory area in which only the card issuer can write and erase, and the KEY _ID (1), KEY _mac (1) and password are read out to the outside of the IC card. It is stored in an area that cannot be used. Note that the above (1) is a symbol indicating that each IC card is different. Further, FIG. 5 is a KEY provided in the host computer 1 shown in FIG.
It is an explanatory view of a file, and as shown in this figure, each information of each IC card, that is, ID, KEY
It is provided by being allocated to each area of _ID and KEY _mac . Therefore, KEY _ID (1) and KEY _mac (1) are used for processing the IC card to which the above ID (1) is assigned.

Next, FIG. 6 is an explanatory diagram showing the structure of the data shown in FIG. 1 (transmission data assembled by the IC card and transmitted to the host computer 1). It may or may not be present, and information C, D, ... May be added. Then, the information A, B ... May be added by the IC card itself or may be added from the portable terminal device 13. When added from the portable terminal device 13, the information A, B ... Is transmitted to the IC card 13 'in advance. Need to be kept.

The monetary amount data is input from the keyboard 5 of the portable terminal device 13 and the IC is input via the external I / F unit 15.
This is the data transmitted to the card 13 '. Random number R is IC
It is output data from a random number generator (not shown) in the card 13 ', which is a random value in each transaction,
Further, it is temporarily held in the IC card 13 'until the transaction processing is completed.

The MAC is a code added to ensure the validity of the information A to the random number R, and its calculation is obtained by calculation in the CBC mode of DES encryption, for example.
Since this MAC calculation method is a widely known technique as described above, the description here is omitted. KEY _mac (1) is the K that calculates this MAC.
It is designed to be used as EY.

Next, FIGS. 7 and 8 show an example of a method of expressing the amount data in the above data. First, as shown in FIG. 7, one byte is assigned to one digit of the amount of money, and the numeral of that digit is expressed by the lower 4 bits of 1 byte, and the upper 4 bits are all 1 as shown in FIG. As a result, FIG.
If the data shown in (2) is in the order of 1,000 yen, it means 3,000.

Further, the data is transmitted from the IC card 13 'to the terminal device 2, and in the terminal device 2, the amount data inputted by the staff member via the input device 3 and the IC card 1 are sent.
3'is compared with the amount data in the data, and if they match, the data is sent to the host computer 1 as it is, and if they do not match, the user is instructed to input again and the data must be input a predetermined number of times. If it ends abnormally.

In the host computer 1, the KEY _mac (1) corresponding to the ID (1) is read from the KEY file shown in FIG. 5, and the MAC value is calculated by the MAC calculation means for the information A to the random number R of the received data. The MAC value calculated by 18 and added to the data and transmitted is compared by the MAC value comparison means 19. If they match, the transaction processing is normally performed, and when this processing is completed, the host computer 1 returns a response to the terminal device 2 according to the instruction of the confirmation data transmission instruction means 20. If they do not match, an NG response is transmitted to the terminal device 2, and the transaction is deemed unsuccessful and abnormally terminated.

FIG. 9 is an explanatory diagram showing the data structure of the response from the host computer 1. As shown in this figure, the information C and D are data added by the host computer 1, and there is none. , And information E, F ... May be further added. Further, the ID (1) and the monetary amount data have the same value as the data value of the data, which is not always necessary. Random number Q is ID
This is the data obtained by encrypting the random number R received by the data using the function F using the KEY _ID (1) read from the KEY file of the host computer 1 with reference to (1). Note that the function F used here is a function that cannot be performed unless the same KEY is used for the inverse conversion. Such a function has, for example, a technique known as DES encryption processing,
Although details will not be described here, the host computer 1 calculates the MAC value for the information C to the random number Q by the MAC calculating means 18 using KEY _mac (1), and the value obtained here and the IC card 13 ’The data sent from
The AC value comparison means 19 compares and when these two data match, this MAC value data is added and sent as a response to the terminal device 2 according to the instruction of the confirmation data sending instruction means 20, and to the IC card 13 'as it is. It is returned from the terminal device 2.

On the other hand, in the IC card 13 ', the MAC values of the information C to the random number Q in the sent response are calculated by the MAC calculating means 15a before being transmitted to the host computer 1 in advance, and the third memory 17 is calculated. The MAC value stored therein is compared by the MAC value comparison means 15b. If they match, the random number Q is input, the inverse conversion of the function F used in the host computer 1 is performed using the KEY _ID (1), and the result is again stored in the random number Q and the MAC. The values are compared by the value comparison means 15b.

If they match, the IC card 13 '
The control section 15 recognizes that the money transaction has been completed without fraud, and writes data (flag G) indicating the completion of normal transaction in the second memory. Next, before the above-mentioned signal processing is performed, the structure of the keyboard 5 and the display 6 for performing the processing operation until the holder of the IC card 13 'inputs the amount data and confirms that the transaction is completed. Is shown in FIGS. 10 and 11.

First, the keyboard 5 is used to correct the amount input key for switching the mode to the state in which the amount data can be input, the ten numeric keys 0 to 9 and the input error of this numeric key. Clear key, and the input key for inputting data by pressing the numeric keys and ending the amount input mode at the same time, and the confirmation key for confirming that the amount input by this input key has been legally processed. It is configured.

On the other hand, the display 6 comprises a data display section 6a capable of displaying N digits and an OK display section 6b for confirming the contents displayed on the data display section 6a. Can be freely displayed without an instruction from the keyboard 5 provided on the portable terminal device 13, but the OK display of the OK display portion 6b can be turned on and off without permission from the keyboard 5. It is controlled so that it cannot be done.

Further, the operation of turning on / off the OK display portion 6b of the display 6 in the portable terminal device 13 can be easily controlled only by receiving the turning on / off program from the IC card 13 '. That is, the IC card 13 ′ that has recognized the end of the transaction may send a command to the control unit 15 of the portable terminal device 13 to turn on the OK display unit 6 b to turn on the OK display unit 6 b.

Next, the processing operation until the IC card holder inputs the amount data into the IC card and confirms the end of the transaction will be described based on the flowchart of FIG. First, the portable terminal device 1 held by the IC card holder
When the "amount input" key provided on the keyboard 5 of No. 3 is pressed (S1), the portable terminal device 13 enters the amount input mode.

Thus, the IC card 13 'checks whether or not the flag F in the second memory which permits the input of the amount of money is cleared (S2). If the flag F is not cleared, the OK display section 6 is displayed. Is lit to inform the cardholder that the flag F has not been cleared and prompt the clear operation (S3). If the flag F is not cleared, it is impossible to proceed to the subsequent processing. Therefore, the cardholder inputs the password from the keyboard 5 to clear the flag F (S4).

Next, the control unit 15 determines whether the password entered in S4 matches the password stored in the memory of the IC card 13 '(S
5) If they do not match, the input operation is performed again, but the number of times of mismatch is limited to 3 times (S6), and if the mismatches occur 3 times or more in succession, the card is locked (S7),
Subsequent processing is canceled.

When the passwords match, the flag F is cleared, and at the same time, the OK display portion 6b is turned off (S8). It should be noted that this process is to prevent the flag F from being cleared by a third party and forcing a re-execution of the transaction to make a double payment. When the password coincidence is confirmed in this way, the amount data can be input, and the cardholder inputs the amount data by pressing the numeric keys of the keyboard 5 (S).
9).

When the amount input is completed, the "input" key is pressed (S10) to terminate the amount input mode. As a result, the flag F in the second memory of the IC card 13 'is
And the flag G indicating the normal end of the amount data input operation are turned on, and the OK of the OK display portion 6b is turned on to notify the cardholder that the amount input operation has normally ended.
The K display is turned on (S11).

By pressing the "input" key,
The IC card 13 'generates a random number Q from a random number generator (not shown) and stores the value in the second memory.
The data is transmitted to the portable terminal device 13 side, and the portable terminal device 13 stores the data of the random number Q in the third memory 17 until the end of the transaction. On the other hand, the cardholder can use the OK display section 6
When the OK display of b is turned on, it is recognized that the amount input operation has been normally completed, and the IC card 13 'into which the data has been input is checked so that the transaction processing is performed based on the recognized data. Pass to.

When the processing of the terminal device 2 described above is completed by the operation of the staff member who receives the card for which the amount input operation has been completed from the card holder, the IC card 13 'is returned to the IC card holder again. . Next, the processing operation of the IC card and the portable terminal device 13 after receiving the IC card 13 'will be described based on the flowchart shown in FIG.

When the staff member receives the IC card 13 'which has been processed by the terminal device 2, the IC card holder inserts the IC card 13' into the portable terminal device 13 and presses the "confirm" key on the keyboard 5. Depress (S12). As a result, the portable terminal device 13 receives the random number Q previously received from the IC card 13 ′ and stored in the third memory 17.
Is transmitted to the IC card 13 ', the control unit 15 of the portable terminal device 13 clears the flag G in the second memory of the IC card 13' which indicates that the transaction is normally completed. If the response data comparing means 15c determines that the random number Q of the data received from the host computer 1 matches the data previously transmitted to the host computer 1 (S13), the IC card The flag F in 13 'is cleared, and accordingly, the OK display portion 6b of the portable terminal device 13 is
In this case, the portable terminal device 13 turns on the OK display portion 6b (S14) to display to the IC card holder that the proper transaction processing has been completed.

[0045]

As described above, according to the present invention, I
The amount data to be paid by the payer in the money transaction performed using the C card is performed by the card holder's own operation without the operation of the staff, and the card held only by the card holder is used. Input from the keyboard that has a structure that can be operated by inputting a password that only the holder knows, and the input money data is transmitted to the host computer at the intervening terminal device, It is judged that the data is sent to the host computer only when the match with the amount data entered by the staff is judged, and the data is sent to the host computer only when the match is recognized. Judgment based on the random number or MAC value etc. added to, if it is confirmed that it has not been tampered with, payment processing will be performed, The response data created based on the payment processing data thus obtained is returned to the IC card, and the IC card properly processes the returned response data from the IC card or the input amount data. The system to confirm that.

Therefore, even if a third party attempts to tamper with the amount data, the amount data is input by the cardholder, and only when the cardholder corrects the amount data, only the cardholder knows. Since the keyboard cannot be operated unless the password is entered, tampering with the monetary amount data by a third party is surely prevented. Also, the IC card has
When it is recognized that the contents processed by the host computer have not been tampered with, the IC card or the display which can be controlled only by the portable terminal device is displayed on the IC card or the portable terminal device in order to inform the cardholder of the fact. Since the IC card holder can recognize that the IC card has been legally processed, it is possible to obtain a fraudulent tampering prevention system for financial transactions by the IC card, which is excellent in security.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an unauthorized tampering prevention system according to the present invention.

FIG. 2 is a block diagram showing a configuration of an IC card used in this system.

FIG. 3 is a block diagram showing an internal structure of a portable terminal device.

FIG. 4 is an explanatory diagram showing confidential data held in a memory in the IC card.

FIG. 5 is an explanatory diagram of a KEY file provided in the host computer.

FIG. 6 is an explanatory diagram showing a structure of transmission data assembled by an IC card.

FIG. 7 is an explanatory diagram showing an example of a method of expressing monetary amount data in transmission data.

FIG. 8 is an explanatory diagram showing an example of a method of expressing monetary amount data in transmission data.

FIG. 9 is an explanatory diagram showing the structure of response data from the host computer.

FIG. 10 is a plan view of the keyboard.

FIG. 11 is a plan view of the display.

FIG. 12 is a flowchart showing the processing operation of the IC card.

FIG. 13 is a flowchart showing the processing operation of the IC card.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 host computer 2 terminal device 4 IC card 5 keyboard 6 display 8 control unit 8a MAC value calculating means 8b data transmission instructing means 8c response data comparing means 9 first memory 10 second memory 11 third memory 12 random number generator 13 portable terminal device 13 'IC card 15 control unit 18 MAC value calculation unit 19 MAC value comparison unit 20 confirmation data transmission instruction unit 22 amount data comparison unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G07F 7/12

Claims (2)

[Claims] 1. An IC card having a data holding unit for holding data, a reading unit for reading the data holding unit of the IC card, and an input device for inputting transaction amount data are provided, and the data is read by the reading unit. The card data and the amount of money input from the input device are added with a MAC value calculated based on the data possessed by the IC card in order to prove the validity of each of these data to create transmission data, which is generated by the host computer. A MAC value calculated by the MAC calculation means based on the transmission data from the terminal equipment and the transmission data from this terminal equipment, and the calculated MAC value is compared with the MAC value added to the transmission data by the MAC value comparison means. However, when the two values match, it recognizes that the data was processed normally, and the control unit ends normally. The system is configured by a host computer that creates response data including data indicating that the card holder sends the data to the terminal device, and when the card holder makes a financial transaction using the IC card, the card is In an illegal tampering prevention system for monetary transactions by an IC card for preventing monetary data from being tampered with at the stage of processing, in the IC card or a portable terminal device having an external interface unit capable of accessing the IC card, A keyboard that enables input operation by entering a password, a random number generator that generates a random number of money data input from the keyboard, and money data input from the keyboard and response data received from the host computer MAC for calculating the MAC value of monetary amount data The MAC value of the response data returned when the MAC value calculated by the MAC value calculating means and the MAC value calculated by the MAC value calculating means is transmitted to the host computer and the transmission data is normally processed, MAC
A MAC value comparison unit that compares the MAC value calculated by the value calculation unit on the IC card side to see if it matches, and further, if these two MAC values match, a random number before transmission to the host computer and a random number of response data. Compared to,
A control unit for recognizing that the money amount data input from the keyboard has been normally processed when these match, and terminating the transaction processing. Further, the terminal device includes the IC card or the portable terminal device. Is provided with an amount data comparison means for comparing whether or not the amount data input from the keyboard of the device and the amount data input from the input device connected to the terminal device are matched, and the IC card or the portable terminal device is provided. From the provided keyboard, the transaction amount data entered by the operation of the cardholder is added with the random number generated by the random number generator and the MAC value calculated from this random number and the amount data to create the transmission data, which is the control unit. To the terminal device, and the terminal device receives the amount data of the transmission data received from the IC card and the operation of the staff from the input device. By comparing the force has been money data, the transmission data only when matched sent to the host computer, from the transmission data the received host computer,
A random number and a MAC value are calculated, and when the calculated value and the transmission data match, the payment process is performed by recognizing that the amount data input from the keyboard of the IC card has not been tampered with. , The calculated random number and M including data indicating that the payment process is normally performed
The response data is created by adding the AC value and transmitted to the IC card or the portable terminal device via the terminal device by the control unit. In the IC card or the portable terminal device receiving this response data, the response data Calculates a MAC value from the calculated MAC value, compares the calculated MAC value with the MAC value added to the response data, and when they match, sends the random number added to the response data to the host computer. Compare the random numbers generated by the IC card before, and when they match, recognize that the amount data entered by the operation of the card holder from the keyboard has been normally processed and process the transaction. A system for preventing unauthorized tampering of financial transactions with IC cards characterized by being terminated. 2. The card payment process in a financial transaction using the IC card is normally performed when the transmission data created by the IC card or the IC card and the portable terminal device match the response data created by the host computer. The IC card or the portable terminal device is provided with a display which can be controlled only by the IC card or the portable terminal device in order to inform the cardholder when it is determined that the process is completed. IC described in 1
Unauthorized tampering prevention system for financial transactions by card.