JPH1115936A - Prepaid ic card system and prepaid ic card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive prepaid card capable being prevented from being forged or altered fraudulently and to provide a prepaid IC card system having simple constitution. SOLUTION: A non-contact IC card 20 and a reader/writer 10 to be cooperated with the card 20 are verified by a verification key using a random number or the like and a value stored in a memory 22 built in the card 20. Then whether the data of the memory 22 are altered/forged or not is checked by using the value as a key inherent in the memory 22. After the end of the check, a transaction using the card 20 is executed and the contents of the memory 22 in the card 20 are updated based on an accounting result or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a prepaid IC card system and a prepaid IC card using an IC card as a prepaid card. The IC card of the present invention is used, for example, as a prepaid non-contact IC card for a public telephone.

[0002]

2. Description of the Related Art Recently, prepaid cards have been widely used as a substitute for cash. Because of the value of this type of prepaid card and vouchers, counterfeiting problems are encountered. At present, most of prepaid cards widely used are so-called magnetic cards using magnetic information. Of course, various forgery prevention measures are also taken for magnetic cards, but since magnetic data can be changed relatively easily, forgery such as magnetically rewriting data is often performed. Also have limitations. For example, current telephone cards and the like using magnetic recording are relatively easy to forge. For this reason, prepaid cards using magnetic cards are limited in use as low-cost prepaid cards, which are less affected by forgery.

On the other hand, prepaid IC telephone cards using a microcomputer or an IC card composed of a logic circuit and a memory are used in Europe and the like. For example, a so-called third-generation IC card typified by Siemens SLE4436, which includes card-specific data (card ID data), card-specific secret key data, and random number data input from a card external device Thus, the card outputs authentication data using an authentication data generation algorithm for confirming the card validity, and the card external device confirms the validity of the card. In these IC cards, a microcomputer or a logic circuit processes a signal of an identification code of the IC card itself, for example, a serial number or the like to improve security against forgery, data falsification, and the like. As these IC cards, both a contact type and a non-contact type are known.

[0004]

However, the method is only an authentication of whether or not the IC card is correct.
In the case where the value data recorded in the memory of the C card, for example, when used as a telephone card, it is not determined whether or not the frequency data is correct.
That is, even if the Value data of the real card is falsified, for example, if the remaining number is changed from 1 to 50, no fraud is found. To prevent this, online, a card-specific number (Card I
D data) and its residual count must always be managed by a center (center computer). It is enormous cost to grasp all of a large number of cards such as telephone cards, and the amount of information flowing through the communication network is limited. It is enormous and virtually impossible to implement.

Therefore, in order to prevent forgery of the IC card, the applicant of the present invention, as in the “Prepaid IC card system” filed on May 6, 1997, judges the validity of the IC card, Has proposed a prepaid IC card system capable of confirming the amount of memory in the inside. In this IC card system, for example, the card outputs authentication data by an authentication data algorithm for validity verification, based on card-specific data, card-specific secret key data, and random number data input from an external device (reader / writer). Then, an external device such as a reader / writer determines the validity of the card. Based on the VALUE value data stored in the memory of the IC card, the reader / writer generates authentication data by a VALUE authentication data generation algorithm and records the authentication data on the card.
When an IC card is used, VALUE data and VA
The LUE value authentication data is read, and it is determined whether the VALUE value is correct. Therefore, whenever the VALUE value data is rewritten (in the case of a telephone card, when the frequency is reduced), the VALUE value authentication data must also be rewritten.

[0006] The VALUE authentication data generation algorithm is kept secret, and even if an unauthorized person who attempts to tamper with the VALUE data can tamper with the VALUE data,
Mismatch with authentication data occurs and fraud is discovered. VAL
The UE value data generation algorithm is DES (Data E
It is conceivable that the security is further improved by using a more complicated and advanced algorithm such as an ncryption standard encryption algorithm. Also, VA
The LUE value authentication data generation algorithm that an external device (reader / writer) has usually has a SAM (Sequence).
currency Authentication Mod
ule), which is stored in a modularized unit, and cannot be analyzed by any unauthorized person. This SAM
Also stores the master key data and the card-specific secret key data generation algorithm.

However, the above-described prepaid IC card system has a complicated configuration, and it is costly to apply to a simple prepaid system.

An object of the present invention is to provide a prepaid IC card system and a prepaid IC card which overcome the above disadvantages and have a simple structure and are durable against tampering.

[0009]

According to the present invention, a unique key, an initial value of a prepaid amount, a VALUE value including a previous balance and a current balance, and authentication data generated from these values are stored. Prepaid IC card having a memory, a prepaid IC card having an arithmetic circuit, and a reader / writer having an arithmetic processing means for updating the amount of the prepaid IC card corresponding to the amount used by exchanging information with the IC card. In the system, the arithmetic circuit of the IC card and the arithmetic processing means of the reader / writer include: an authentication key generated by the reader / writer;
The validity is authenticated using the VALUE and the value authentication data recorded in the memory of the C card, and after the authentication operation, the arithmetic circuit of the IC card executes the previous V
After confirming that the ALUE value has not been tampered with, the arithmetic processing means of the reader / writer checks the VA of the IC card.
When the LUE value has not been tampered with, use of the IC card is permitted, and data corresponding to the used amount is stored in the I
A prepaid IC card system is provided in which the data is transmitted to a C card and the arithmetic circuit of the IC card updates data corresponding to the amount of money from the reader / writer into the memory.

[0010] Preferably, the authentication key generated by the reader / writer is an arbitrary random number.

Specifically, the arithmetic circuit of the IC card uses (the initial value of the prepaid amount-the current balance) as the VALUE value at the time of the authentication operation, and compares the VALUE value at the time of checking for alteration of the VALUE value.
(The initial value of the prepaid amount-the current balance) is used as the E value authentication data. Or, specifically, the arithmetic circuit of the IC card is configured to execute the VALUE operation at the time of the authentication operation.
Using (value of prepaid balance) as the value,
(Current balance) is used as VALUE authentication data to be compared when checking for value tampering.

Preferably, at the time of the authentication operation, the IC
The card and the reader / writer are respectively the VA
The authentication key generated by the reader / writer is signal-processed to the LUE value, and when the tampering in the IC card is checked, the IC card performs signal processing of the VALUE-specific key to the key unique to the IC card and performs collation. .

Preferably, the reader / writer has an antenna for transmitting and receiving a signal at a predetermined high frequency. The antenna transmits operating power for the IC card and a transmission signal, receives a reception signal, and receives the prepaid signal. The IC card is a non-contact type IC having an antenna for transmitting and receiving signals at a predetermined high frequency.
A card, and the power received by the IC card is used for the IC.
Powers the circuit inside the card, extracts the clock signal,
The extracted clock signal is used as a clock signal of a circuit in the IC card.

Further, according to the present invention, a memory storing a unique key, a VALUE value including an initial value of a prepaid amount, a previous balance and a current balance, and VALUE value authentication data, and an arithmetic circuit are provided. Means for checking validity using an authentication key received from a cooperating reader / writer and the VALUE, and determining whether data in the memory has been tampered with using the unique key and the VALUE. There is provided a prepaid IC card having means for checking and means for updating a VALUE value of the memory based on update data from the reader / writer when there is no forgery or tampering.

Preferably, the prepaid IC card is a non-contact IC card having an antenna.

Further, according to the present invention, a memory for storing a unique key, a VALUE value including an initial value of a prepaid amount, a previous balance and a current balance, and VALUE authentication data, and an arithmetic circuit are provided. A signal processing method in a prepaid IC card system comprising: a prepaid IC card having the same; and a reader / writer having an arithmetic processing means for updating the amount of the prepaid IC card corresponding to the amount used by exchanging information with the IC card. hand,
The arithmetic circuit of the IC card and the arithmetic processing means of the reader / writer include an authentication key generated by the reader / writer and the VA recorded in a memory of the IC card.
The authenticity is authenticated using the LUE value. After the authentication operation, the arithmetic circuit of the IC card confirms that the previous VALUE value has not been tampered with, and the arithmetic processing means of the reader / writer executes the IC processing. When the VALUE value of the card has not been tampered with, the use of the IC card is permitted, data corresponding to the used amount is sent to the IC card, and the arithmetic circuit of the IC card uses the amount from the reader / writer. And a signal processing method in a prepaid IC card system for updating data corresponding to the above to the memory.

[0017]

By using a non-contact IC card having a prepaid function and a reader / writer, the validity of the IC card is determined and the balance of the prepaid is confirmed. The balance is confirmed using the difference between the current prepaid balance amount and the initially set amount, or the prepaid balance amount used last time.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, a first embodiment of a prepaid IC card system and a prepaid IC card of the present invention will be described. FIG. 1 shows a prepaid non-contact I as a first embodiment of a prepaid IC card system according to the present invention.
It is a block diagram of a C card system. In the first embodiment, an example in which a non-contact IC card is used as an IC card will be described. The prepaid non-contact IC card system illustrated in FIG. 1 includes a reader / writer 10 as an external device.
And a non-contact IC card 20 as a prepaid card. As a first embodiment of the present invention, a non-contact I
A non-contact type I card which is used as a prepaid card for a public telephone as the C card 20 and in which "VALUE data" such as an available balance value and a remaining number of the public telephone are recorded.
The C card is exemplified. An example of an external device for a non-contact IC card is a reader / writer 10 that is attached to a public telephone and performs signal processing on the non-contact IC card as a prepaid card for the public telephone.

The reader / writer 10 includes a computer 11 as arithmetic means, a memory 12, a modulation circuit 13,
It has a demodulation circuit 14, a transmission / reception antenna 15, a clock signal generation circuit 16, and a power supply 17. The contactless IC card 20 includes a processing circuit 21 implemented by a microcomputer or a logic circuit, a memory 22, and a modulation circuit 23.
, A demodulation circuit 24, a transmission / reception antenna 25, a clock extraction circuit 26, and a power supply circuit 27.

It is assumed that the following data is stored in the memory 22. The ID number is, for example, a manufacturing number determined at the manufacturing stage of the non-contact IC card 20, the initial value of the prepaid card is, for example, $ 10000, the balance up to the previous time, for example, $ 6000. Stores programs and other data.

Reader / writer 10 and non-contact IC card 2
The basic operation with 0 will be described. In the reader / writer 10, the modulation circuit 13 modulates a predetermined signal from the computer 11 and a clock CLK from the clock signal generation circuit 16 using a carrier signal of a predetermined frequency from a transmission / reception antenna 15 and a modulation circuit 13. Is emitted. When the non-contact IC card 20 approaches the electromagnetic field of the transmitting / receiving antenna 15, the transmitting / receiving antenna 25 receives the signal in response thereto. Transmitting and receiving antenna 2
The received signal of No. 5 is rectified in the power supply circuit 27 to generate a DC voltage, which is used as a power supply for operating the non-contact IC card 20. The clock extraction circuit 26 is a power supply circuit 2
A clock CLK equivalent to that generated by the clock signal generation circuit 16 is extracted from the high-frequency signal applied to 7. When the voltage from the power supply circuit 27 reaches a predetermined value and the normal clock CLK is extracted from the clock extraction circuit 26, the computer 11, the modulation circuit 23, and the demodulation circuit 24 operate.
The demodulation circuit 24 demodulates the signal received by the transmission / reception antenna 25 and applies the signal to the processing circuit 21. When the transmission signal from the reader / writer 10 is appropriate, the processing circuit 21 outputs an ATR (Answer To Reset) signal and sends a response signal to the modulation circuit 23, as described later. The signal from the processing circuit 21 is modulated using the signal, and transmitted to the transmitting / receiving antenna 15 of the reader / writer 10 via the transmitting / receiving antenna 25. The transmission / reception antenna 15 of the reader / writer 10 receives the ATR signal from the transmission / reception antenna 25 of the non-contact IC card 20,
Demodulates the received signal and applies it to the computer 11. Thereby, the computer 11 understands that the non-contact IC card 20 has approached. Next, the computer 11 determines whether the demodulated signal is appropriate or not, and
It is determined whether or not a signal transmission / reception described below will be performed.

Hereinafter, signal processing of the computer 11 of the reader / writer 10 and signal processing of the processing circuit 21 of the non-contact IC card 20 will be mainly described. The transmission operation in the reader / writer 10 is performed by the modulation circuit 13 and the transmission / reception antenna 15, and the reception operation is performed by the transmission / reception antenna 15 and the demodulation circuit 14. However, in the following description, these operations are omitted. I do. Similarly, the transmission operation of the non-contact IC card 20 is performed by the modulation circuit 23 and the transmission / reception antenna 25, and the reception operation is performed by the transmission / reception antenna 25 and the demodulation circuit 24. These operations will be described in the following description. Is omitted. In addition, the reader / writer 10 and the non-contact I
It is assumed that both the C card 20 and the C card 20 are at a distance and a position where transmission and reception are possible via the transmission / reception antenna 15 and the transmission / reception antenna 25.

FIG. 2 is a flowchart illustrating signal processing between the computer 11 and the processing circuit 21 according to the first embodiment. Steps 1 to 9 show the operation of the computer 11, and steps 11 to 19 show the operation of the processing circuit 21.

Step 1: Generation of Authentication Key and Transmission The computer 11 of the reader / writer 10 co-located with the public telephone determines an arbitrary authentication key. In the present embodiment, the authentication key is, for example, an arbitrary random number. Since the reader / writer 10 is provided with the computer 11, a somewhat complicated random number can be used. However, when the processing circuit 21 of the non-contact IC card 20 is constituted by a logic circuit or the like, a simple random number is desirable. Examples of random numbers include, for example, (1) the time at that time (time tt,
Minute mm, second ss), (1) an arbitrary random number by the Monte Carlo method, (2) current month (MM), day (DD), time (time tt, minute mm, second ss), (3) these times Data, that is, a number obtained by squaring a 10-digit MMDD ttmmss and extracting only the center 4 digits can be used. As described above, the authentication key using the random number is not fixed but changes according to the time. By doing so, the confidentiality, in other words, the security against forgery, falsification, etc. is further improved than using a fixed authentication key.
Therefore, a simple random number may be used. The modulation circuit modulates the authentication key with the carrier signal. A modulated signal including the authentication key is transmitted from the transmitting / receiving antenna 15 to the reader / writer 10 to the space.

Step 11: Receiving Authentication Key When the non-contact IC card 20 serving as a prepaid public telephone approaches the electromagnetic field of the antenna 15 for transmitting and receiving the authentication key , the transmitting and receiving antenna 25 modulates including the authentication key generated from the random number. Upon receiving the signal, the demodulation circuit 24 demodulates the demodulated result including the authentication key and applies the demodulated result to the processing circuit 21.

Step 12: First value authentication data
Over to the memory 22 of the generation and transmission contactless IC card 20 of the motor, as described above as the VALUE value, serial number of the ID code,
The prepaid initial value = $ 10000 and the balance up to the previous time = $ 6000 are recorded. When a valid authentication key is received, the processing circuit 21 determines the value authentication data (first value authentication data or IC value) based on the received authentication key and the VALUE stored in the memory 22.
Card / VALUE authentication data). As a method of generating the first value authentication data from the authentication key and the value, for example, as described above, the authentication key generated by a random number and the value are added, or both are multiplied, or a logical value is added. Various operations such as summing can be performed. When the processing circuit 21 is realized by a simple logic circuit, it is preferable that the generation of the value authentication data be a simple operation. On the other hand, when the processing circuit 21 is realized by a microcomputer or the like, a somewhat complicated operation may be performed. When the first value authentication data is determined by performing signal processing in this way, the amount such as the balance is directly converted to VAL.
Confidentiality is higher than when used as UE value authentication data. That is, the first V encrypted as described above
Since the ALUE value authentication data does not mean the remaining amount as it is, the confidentiality is high. The first VA generated as described above
The LUE value authentication data and the monetary information used therein, for example, the current balance, are modulated by a predetermined carrier signal by the modulation circuit 23 and transmitted from the transmitting / receiving antenna 25 to the reader / writer 1.
Sent to 0.

[0027] Specific examples of the first embodiment of the first embodiment VALUE value. In this example, VALUE value data (initial value-current balance)
Is used. VALUE value authentication data using this VALUE value is generated by, for example, the following calculation. That is, an exclusive OR (Exclusive OR) operation is performed on the received authentication key based on the result obtained by subtracting the current balance from the initial value of the prepaid card $ 10000. Since the above difference calculation and exclusive OR operation can be realized by a simple logic circuit, the circuit configuration of the processing circuit 21 is simple. In addition,
(Initial value-current balance) signal processing of the authentication key
As described above, the method of generating the VALUE authentication data can perform an appropriate operation such as a simple sum, difference, or multiplication in addition to the exclusive OR.

[0028] Specific examples of the second embodiment of the second embodiment VALUE value. In this example, (current balance) is used as VALUE data. VALUE value authentication data using this VALUE value is generated by the following calculation. Current balance ¥ 5000 EXOR Authentication key, that is, an exclusive OR (Exclusive OR) operation is performed on the authentication key received on the current balance of the prepaid card. Since the above difference calculation and exclusive OR operation can be realized by a simple logic circuit, the circuit configuration of the processing circuit 21 is simple. In addition, as described above, in addition to the exclusive OR, a simple sum, difference,
An appropriate operation such as multiplication can be performed.

Comparison between the first embodiment and the second embodiment The first embodiment also considers the initial value of prepaid,
Applies to prepaid cards issued for any amount.
For example, in this case, the initial value itself may be falsified. Therefore, the initial values are also subject to signal processing. On the other hand, the second embodiment is suitable for a prepaid card issued at a fixed price. In this case, even if the initial value is falsified, it can be easily detected. In any of the embodiments, the first V
Since the ALUE value data is signal-processed in this way, and the balance is not used directly, the confidentiality (confidentiality) is high.
In the first and second embodiments, the first value authentication data generated as described above and the monetary information such as the current balance are modulated by the modulation circuit 23 with a predetermined carrier signal and transmitted from the transmitting / receiving antenna 25. It is sent to the reader / writer 10.

Step 2: First and second value recognition
Transmitting and receiving antenna 15 of generating the reader / writer 10 testimony data receives the transmitted signal from the transmitting and receiving antenna 25. The demodulation circuit 14 decodes the reception signal of the transmission / reception antenna 15 and applies the demodulation result to the computer 11. Computer 11
Is the VALUE authentication data (second VALUE authentication data or reader value) in the reader / writer 10 based on the authentication key sent to the non-contact IC card 20 stored in the memory 12 and the monetary information received from the reader / writer 10. / Writer / VALUE authentication data). The method of generating the second value authentication data is as follows.
Same as 1. In this case, the same arithmetic processing as in the first embodiment or the second embodiment is performed. The computer 11 uses the non-contact IC card 20 as an authentication key.
And the one stored in the memory 12 is used.

Step 3: The authentication computer 11 of the reader / writer 10 collates the first value authentication data received from the non-contact IC card 20 with the second value authentication data generated by the self, and makes one It is determined whether or not they are in compliance. Since the authentication key is the same, the authentication data generation algorithm of the computer 11 and the processing circuit 2
If the authentication data algorithm matches the first authentication data algorithm, the first
VALUE value authentication data and the second VALUE value authentication data match. In other words, the reader / writer 10 and the non-contact IC card 20 can be recognized as valid associates who process with the same algorithm. That is, it can be confirmed that the reader / writer 10 is communicating with the correct non-contact IC card 20. Therefore, it is possible to proceed to the following operation.

Step 4: Second value authentication data
When the authentication operation in the data transmission reader / writer 10 is completed, the computer 11 transmits the second value authentication data to the non-contact IC via the modulation circuit 23 and the transmission / reception antenna 25.
Send it to the card 20.

Step 13: Second value authentication data
The processing circuit 21 of the non-contact IC card 20 receives and verifies the received second
VALUE authentication data and the reader / writer 1
0 and the first value stored in the memory 22
Check with value authentication data. If the authentication key is the same and the authentication data generation algorithm of the computer 11 matches the authentication data algorithm of the processing circuit 21,
The first value authentication data matches the second value authentication data. That is, the reader / writer 10
Can be confirmed to be communicating with the correct non-contact IC card 20. Therefore, when the first value authentication data matches the second value authentication data, the processing circuit 21 determines that the reader / writer 10 is a valid reader / writer that can communicate.

By the above operation, it can be confirmed that the reader / writer 10 and the non-contact IC card 20 are mutually reliable communicating parties. In the present embodiment, VALUs are generated using random numbers that change with time.
Since the E value is changed, a non-contact IC of the same operation method
This method employs a method that enhances the confidentiality that the card 20 and the reader / writer 10 can communicate with each other. In particular, since encrypted data using random numbers is communicated, even if it is eavesdropped, it is difficult for a third party to understand the actual meaning. Further, even if there is an unauthorized user trying to falsify the VALUE value data stored in the memory 22 of the non-contact IC card 20, the authentication of the non-contact IC card 20 and the authentication of the reader / writer 10 are not completed. , The VALUE described below cannot be rewritten. By performing authentication between the reader / writer 10 and the non-contact IC card 20, for example, the impersonated non-contact IC card 20 or the data of the authorized non-contact IC card 20 is falsified by the impersonated reader / writer 10. Abuse can be prevented in advance. Next, an operation of confirming the validity of the VALUE value is performed.

Step 14: Third using a unique key,
Generation of Fourth Value Authentication Data In the memory 22 of the non-contact IC card 20, key data unique to the data contact IC card 20 stored, for example, the third VALUE authentication key is stored by the previous valid procedure. I do. Hereinafter, specific examples of the first and second embodiments will be described.

First Embodiment Third VA in the processing circuit 21 as the first embodiment
As the generation of the LUE value authentication data, VALUE value = initial value−current balance is used, and the VALUE value and the non-contact IC are used.
Addition to the serial number (unique key) of the card 20 is performed.
The processing circuit 21 adds the previous balance stored in the memory 22 and the key data unique to the non-contact IC card 20, that is, the serial number, to generate fourth value authentication data. Instead of the above addition, subtraction, multiplication,
Other logical operations can be performed.

Second Embodiment A third VA in the processing circuit 21 according to a second embodiment.
The generation of the LUE value authentication data uses VALUE = current balance, and adds this VALUE to the serial number of the contactless IC card 20. The processing circuit 21 includes a memory 22
And the contactless IC card 2 stored in the
By adding the unique key data of 0, that is, the serial number, the fourth value authentication data is generated. Note that, instead of the above addition, subtraction, multiplication, and other logical operations can be performed.

Step 15: The tampering check processing circuit 21 compares the third value authentication data with the fourth value authentication data, and confirms that the money information in the memory 22 has not been tampered. The fourth V
Check whether the value authentication data is the same as the third value authentication data. If the third value authentication data is the same as the fourth value authentication data, the value of the contactless IC card 20 has not been tampered with. In this case, the public telephone can be used properly using the non-contact IC card 20. At this time, a signal indicating a valid non-contact IC card is transmitted from the non-contact IC card 20 to the reader / writer 10. Since the previous balance and the current balance are determined not by the amount itself but by using unique key data, the confidentiality against tampering is high.

Step 16: Transmission of Value Value Normal When the processing circuit 21 determines that the money information in the memory 22 is normal, it sends the normal information to the reader / writer 10.

Step 5: When the contents of the memory 22 of the non-contact IC card 20 are correct, the reader / writer 10 permits the call using the non-contact IC card 20, and performs a charging process corresponding to the charge of the used public telephone. Start.

Step 6: In Reader / Writer 10
Charging Process During use of the public telephone, the computer 11 charges an amount corresponding to the call, and when the call ends, the computer 1
1 is a non-contact IC card 2 corresponding to the amount used
Send to 0.

Step 17: The balance update processing circuit 21 receives the usage amount from the reader / writer 10, updates the previous usage amount in the memory 22, and updates the value authentication data in the memory 22. As described above, the balance of the non-contact IC card 20 has been properly updated.

Step 7: Abnormal processing (not shown) If the fourth value authentication data does not match the third value authentication data, it means that the data has been tampered with. In this case, a signal indicating a valid non-contact IC card is not transmitted from the non-contact IC card 20 to the reader / writer 10. After transmitting the second value authentication data, the reader / writer 10 transmits the non-contact IC
Since the card 20 does not receive a valid signal, the value of the non-contact IC card 20 is determined to be not valid, and an alarm signal, for example, an abnormal sound is emitted, and the non-contact IC
The update with the card 20 is interrupted.

Effects of the First Embodiment As described above, a card is a VALU based on VALUE value data and data (authentication key 1) of a card external device.
E value recognition data is created, recorded in the memory of the non-contact IC card, and the VALUE value data and the VALUE value authentication data are transmitted to the reader / writer 10 (external device) so that the reader / writer 10 again receives the VALUE value authentication data. And the reader / writer 10 and the non-contact IC card 20
The validity of the non-contact IC card 20 is determined based on the coincidence of the VALUE authentication data of the two. Therefore, for example, when the non-contact IC card 20 is forged, the validity cannot be confirmed, and such a non-contact IC card 20 cannot be used, and the prepaid IC card system has high reliability. Therefore, the forged contactless IC card 20 cannot be used,
It is difficult for the forged reader / writer 10 to falsify the data in the memory 22 of the non-contact IC card 20. Even if the VALUE value stored in the memory 22 of the non-contact IC card 20 has been altered, the VALUE value authentication data generation algorithm in the processing circuit 21 is kept secret. Inconsistency with the value authentication data with respect to the balance this time occurs, and unauthorized use is discovered. In particular, non-contact IC
The inside of the card 20 confirms that the current balance has not increased from the previous balance, thereby preventing the falsification of the VALUE value data. Further, the processing of the non-contact IC card 20 is simple, and the configuration is also simple. Therefore, it can be manufactured at low cost and can be applied as a relatively low-cost prepaid card. Moreover, the confidentiality is high. Further, in the above embodiment, only the reader / writer 10 and the non-contact IC card 20 can authenticate the non-contact IC card 20 and check for falsification of the VALUE value in the memory 22. No need to use.

[0045]

Second Embodiment As a first embodiment, a reader / writer 10 and a non-contact IC card 20 have been exemplified. The second embodiment of the present invention exemplifies a case where a contact-type IC card is used instead of the non-contact IC card 20. However, when a contact type IC card is used, it is the same as the above-described prepaid IC card system except that wireless communication is performed via the transmitting / receiving antenna 15 and the transmitting / receiving antenna 25. When a contact-type IC card is also used, the connection relationship is easily understood visually and the connection is easy.
They tend to be falsified compared to C cards. Conversely, the non-contact IC card 20 has a high confidentiality because it is difficult to connect to a falsification reader / writer without knowing the conditions such as the radio frequency to be used. However, except for this point, the second embodiment is also the first embodiment.
This is the same as the embodiment.

[0046]

[Other Application Examples] As a prepaid IC card system, a prepaid card for a public telephone has been illustrated as an example, but the prepaid IC card and the prepaid IC card system of the present invention can be applied to various prepaid cards and prepaid systems.

[0047]

As described above, according to the present invention, in the IC prepaid card system, both the prepaid card and the reader / writer that processes the prepaid card are authenticated. Highly confidential processing can be performed.

Further, in the present invention, it is difficult to falsify the data of the prepaid card.

The prepaid IC card system of the present invention can process prepaid cards only with a reader / writer, and does not need to be connected to, for example, a large computer at a central center. Therefore, this is a prepaid IC card system that can realize high confidentiality with a simple configuration.

Since the prepaid card of the present invention can be manufactured at a low price, it can be used as a wide range of prepaid cards.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a prepaid IC card system of the present invention.

FIG. 2 is a flowchart as an embodiment of the prepaid IC card system illustrated in FIG. 1;

[Explanation of symbols]

 10. reader / writer 11. computer 12. memory 13. modulation circuit 14. demodulation circuit 15. transmission / reception antenna 16. clock signal generation circuit 17. power supply 20. non-contact IC card 21. -Processing circuit 22-Memory 23-Modulation circuit 24-Demodulation circuit 25-Antenna for transmission and reception 26-Clock extraction circuit 27-Power supply circuit

Claims (11)

[Claims] 1. A unique key, an initial value of a prepaid amount,
A memory in which a VALUE value including a previous balance and a current balance and authentication data generated from the VALUE are stored;
A prepaid IC card system comprising: a prepaid IC card having an arithmetic circuit; and a reader / writer having an arithmetic processing means for exchanging information with the IC card and cooperating to update the amount of the prepaid IC card corresponding to the amount used. The arithmetic circuit of the IC card and the arithmetic processing means of the reader / writer are provided with an authentication key generated by the reader / writer and the VA recorded in a memory of the IC card.
The validity is authenticated using the LUE value and the VALUE authentication data. After the authentication operation, the arithmetic circuit of the IC card confirms that the current VALUE has not been tampered with, and calculates the reader / writer. When the value of the IC card has not been tampered with, the processing means permits the use of the IC card and sends data corresponding to the used amount to the IC card, and the arithmetic circuit of the IC card A prepaid IC card system for updating data corresponding to the amount of money from a reader / writer into the memory. 2. The prepaid IC card system according to claim 1, wherein the authentication key generated by the reader / writer is an arbitrary random number. 3. The arithmetic circuit of the IC card uses (an initial value of a prepaid amount-current balance) as the VALUE value at the time of the authentication operation, and compares the VA at the time of checking for falsification of the VALUE value.
As LUE value authentication data (initial value of prepaid amount-
3. The prepaid IC card system according to claim 1, wherein a current balance is used. 4. The arithmetic circuit of the IC card uses (a prepaid balance) as the VALUE during the authentication operation, and compares the VA when checking whether the VALUE has been tampered with.
3. The prepaid IC card system according to claim 1, wherein (current balance) is used as LUE value authentication data. 5. In the authentication operation, the IC card and the reader / writer perform signal processing on an authentication key generated by the reader / writer for the VALUE value, respectively, and when the IC card is checked for tampering, Said I
The prepaid IC card system according to claim 3, wherein the C card performs signal processing on a key unique to the IC card against the VALUE value and performs collation. 6. The reader / writer has an antenna for transmitting / receiving a signal at a predetermined high frequency, and the IC / IC is provided from the antenna.
The card transmits operating power and a transmission signal, and receives a reception signal. The prepaid IC card is a non-contact IC card having an antenna for transmitting and receiving a signal at a predetermined high frequency, and a power received by the IC card. 6. The prepaid IC card system according to claim 1, wherein power is supplied to a circuit in the IC card, a clock signal is extracted, and the extracted clock signal is used as a clock signal for a circuit in the IC card. 7. A memory for storing a unique key and a VALUE value including an initial value of a prepaid amount, a previous balance and a current balance, and an arithmetic circuit, and receives from a cooperating reader / writer. Authentication key and V
Means for checking the validity using an ALUE value; means for checking whether or not data in the memory has been tampered with using the unique key and the VALUE value; Means for updating a VALUE value in the memory based on update data. 8. The prepaid IC card according to claim 1, wherein said prepaid IC card is a non-contact IC card having an antenna. 9. A prepaid IC card having a unique key and a VALUE value including an initial value of a prepaid amount, a previous balance and a current balance, a prepaid IC card having an arithmetic circuit, and the IC card and information A signal processing method in a prepaid IC card system comprising: a reader / writer having an arithmetic processing means for updating an amount of a prepaid IC card corresponding to an amount of money exchanged and used, the arithmetic circuit of the IC card And the arithmetic processing means of the reader / writer, the authentication key generated by the reader / writer and the VA stored in the memory of the IC card.
After the authenticating operation, the arithmetic circuit of the IC card confirms that the previous VALUE value has not been tampered with, and the arithmetic processing means of the reader / writer executes the IC processing after the authentication operation. When the VALUE value of the card has not been tampered with, the use of the IC card is permitted, and data corresponding to the used amount is sent to the IC card. The arithmetic circuit of the IC card uses the amount of money from the reader / writer. A signal processing method in a prepaid IC card system for updating data corresponding to the above into the memory. 10. A prepaid IC that uses an IC card having a prepaid function and a reader / writer to determine the validity of the IC card and to confirm the prepaid balance amount.
Card authentication method. 11. The authentication data obtained by signal processing of a difference between a current prepaid balance amount and an initial set amount and key data unique to an IC card, or a prepaid balance amount used last time and an IC card 11. The prepaid IC card authentication method according to claim 10, wherein the balance is confirmed using authentication data obtained by signal processing of unique key data.