JP2002203219A - Non-contact ic card, responding method and its program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact IC card, a responding method and its program for minimizing collisions of initial response by providing a high quality random number with a simple configuration. SOLUTION: This non-contact IC card is provided with a dummy random number generating means for generating a dummy random number obtained by a part of arithmetic operations among arithmetic operations used to generate a dummy random number, a dummy random number storing means for storing a dummy random number generated by the dummy random number generating means, and a random number generating means for generating a random number from the dummy random number at the time of receiving a request from a reader/writer. The non-contact IC card, the responding method and the program are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a contactless IC card, a response method, and a program therefor.
The present invention relates to a contactless IC card that responds to a request transmitted from a reader / writer using a value calculated based on a random number, a response method, and a program therefor.

[0002]

2. Description of the Related Art Conventionally, a time slot method has been adopted for communication between a non-contact IC card which exchanges data using an electromagnetic induction method or the like and a reader / writer which recognizes the non-contact IC card. . This is a multi-contact IC
If the cards are simultaneously in the communicable area of the reader / writer and a plurality of non-contact IC cards respond to polling from the reader / writer at the same time, the response signals used for the response collide and any This is because the IC card cannot normally communicate with the reader / writer.

[0003] The communication method of the time slot method will be described below.

(1) First, the reader / writer transmits an initial response request command to the contactless IC card as a request in order to confirm the presence of the contactless IC card. The initial response request command includes the “slot number” required for controlling the timing of the initial response performed by the non-contact IC card, or a value required for calculating the “slot number”.

(2) After receiving the initial response request command, the non-contact IC card returns the initial response to a time slot (1 to “number of slots”) provided from a specific time. The time slot used for the response, that is, the timing, is determined by the contactless IC card itself using a random number.

(3) When the reader / writer detects a collision of initial responses that occurs when a plurality of non-contact IC cards select the same time slot, the reader / writer transmits the initial response request again. Here, usually, the number of time slots provided in the initial response request transmitted again is larger than the number of time slots provided earlier.

(4) The reader / writer recognizes all the non-contact IC cards by normally receiving the initial responses from all the non-contact IC cards, and completes the sequence for identifying the cards. .

As such a system, a wireless identification device (Japanese Patent Laid-Open No. 9-6934) is disclosed.

As a method similar to the time slot method, there is a slot marker method. In the slot marker method, after the reader / writer transmits an initial response request in the time slot method, the reader / writer further transmits a slot marker command indicating the start of a slot at each slot start timing.

[0010]

In the above wireless identification device (Japanese Patent Laid-Open No. 9-6934), a response signal (response signal) is received after an identification card (non-contact IC card) is polled by a transmission / reception decoder (reader / writer). ) Must be determined by a random number as described above.

Here, when a random number of poor quality as the above-mentioned random number, that is, a random number generated by a system for generating a random number when a random number is generated a plurality of times, is used, a plurality of non-contact IC cards are used. It often generates the same random number. For this reason, the collision of the initial response frequently occurs, so that not only the termination of the card identification sequence by the reader / writer is delayed, but also, at the worst, if the non-contact IC card continues to generate the same random number, the card identification sequence does not end. Have. In particular, when a user uses a system that requires a reader / writer to recognize a non-contact IC card without stopping, such as a ticket gate of a train, etc., the use of the system may be impaired due to the delay in the card identification described above. Will happen.

Therefore, avoiding the use of the above-mentioned poor random numbers,
It is necessary to use good-quality random numbers, that is, random numbers generated by a system that generates random numbers when a random number is generated a plurality of times.

However, in order to obtain the above-mentioned good-quality random numbers, it is necessary to perform more complicated calculations than to obtain the above-mentioned poor-quality random numbers. For this reason, when the high-quality random numbers are generated by software, a CPU (Cent
ral processing unit), but a large amount of power is required to use a CPU capable of high-speed processing. Here, in the power supply system of the electromagnetic induction system such as a non-contact IC card, the power that can be used per unit time by the CPU is small, and sufficient power for generating a good random number cannot be supplied. . Therefore, it takes a long time to perform a calculation for obtaining a good random number with available power, and a problem arises in that an initial response cannot be performed because the time slot ends before the calculation of the random number is completed.

Also, by generating the above-mentioned high-quality random numbers by hardware, it is generally possible to provide the random numbers in a shorter time than by software, but in this case, a special There is a problem that a circuit is required, the device becomes complicated, and the cost increases. In particular, since the non-contact IC card is limited in size and needs to have some flexibility, it can be said that the provision of random numbers by the above hardware has a great obstacle.

An object of the present invention is to provide a contactless IC card, a response method, and a program for minimizing collision of initial responses by providing high-quality random numbers with a simple configuration.

[0016]

The present invention employs the following means to achieve the above object. That is, the present invention is premised on a non-contact IC card that responds to a request transmitted from a reader / writer using a value calculated based on a random number. Here, the provisional random number generation means generates a provisional random number obtained by a part of the calculations used for generating the random number. The generated temporary random number is stored in a temporary random number storage unit, and when a request is received from a reader / writer, a random number is generated from the stored temporary random number by the random number generation unit.

As described above, the process of generating random numbers is divided,
By setting the load of the calculation for generating the random number after receiving the request to be a small calculation, it is possible to satisfy the time specification of the time slot. In addition, since a process that requires a large amount of calculation, that is, a process that can generate high-quality random numbers, can be applied to the generation of random numbers, it is possible to solve problems caused by poor-quality random numbers.

Further, since high-quality random numbers can be obtained by software without using hardware for generating random numbers, the cost of a non-contact IC card can be reduced. Further, there is no problem of design, strength, and the like caused by using hardware.

The operation for generating the temporary random number may be an operation not related to the request, and the operation for generating the random number may be an operation determined based on the request.

Further, there is a configuration in which a plurality of the temporary random number storage means are provided in addition to the above configuration, and a response is made to the request from the reader / writer by sequentially using the stored multiple temporary random numbers.

With this configuration, it is possible to use the once generated temporary random numbers again from the beginning, and to generate the random numbers immediately even when requests are continuously received from the reader / writer. An initial response can be made.

Further, the self-transmission timing determining means includes:
The temporary random number generation means determines whether or not there is a predetermined time before the timing at which it should respond, and the temporary random number generation means generates a temporary random number when the self-response timing determination means determines that there is a predetermined time before the response timing. There is a configuration to generate.

In this configuration, it is determined whether or not there is a predetermined time before the timing at which the terminal should respond, and a temporary random number is generated in a slot which is not related to the terminal but is substantially a waiting time. It becomes possible.

Further, the provisional random number storage means is made non-volatile, and the provisional random number generation means generates the provisional random number at the end of the communication processing and stores it in the non-volatile provisional random number storage means.
The random number generation means may be configured to generate a random number from the temporary random number stored in the nonvolatile temporary random number storage means when receiving the request.

In this configuration, after the non-contact IC card has completed communication with the reader / writer and is within the communicable range with the reader / writer, power can be supplied. A provisional random number can be generated in advance. In addition, since the generated temporary random number is stored in the nonvolatile temporary random number storage unit, it is possible to immediately generate a high-quality random number when it enters the communication range with the reader / writer.

Further, a temporary random number interruption flag indicating that the generation of the temporary random number is interrupted when a request from the reader / writer is received during the generation of the temporary random number, and the generation of the temporary random number after the response to the request is completed. Is provided, and a temporary random number generation flag is provided to indicate a position where the temporary random number processing is to be started, and the temporary random number generation is interrupted / started based on the temporary random number interruption flag and the temporary random number processing ongoing flag.

In this configuration, even when an initial response request is made from the reader / writer during the generation of the temporary random number, the generation of the temporary random number is interrupted in the middle, so that the initial response can be made. Can be restarted. Thereby, for example, processing at the time of starting the program can be reduced.

Further, the specific slot number holding means holds a predetermined value, and when the request is received during the generation of the temporary random number, the generation of the temporary random number is interrupted. There is a configuration that responds using a value that is present.

With this configuration, it is possible to return a response to a request within a predetermined time even if a valid temporary random number is not stored in the temporary random number storage means.

In the above configuration, the value held by the specific slot number holding means may be set to 1.

By setting the value stored in the specific slot number holding means to "1", an initial response is made in Slot 1, so that the remaining slots can be used for calculation of temporary random numbers. For this reason, even if a response signal of another contactless IC card collides with the initial response request of the first time, it is necessary to secure a temporary random number generation time sufficient to respond to the second initial response request. Becomes possible.

[0032]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
It should be noted that the following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention.

First, the processing of a non-contact IC card when the proximity non-contact IC card conforms to the international standard ISO / IEC14443 will be briefly described with reference to FIGS.

[0034] ISO / IEC14443 can be applied to, for example, a non-contact telephone card. More specifically,
As shown in FIG. 1, it is assumed that non-contact IC cards 200 and 300 having a function as a telephone card are simultaneously inserted (closed) into a reader / writer 100 functioning as a public telephone.

In the non-contact IC card recognition system of ISO / IEC14443, the non-contact IC card
The recognition of the C card is performed.

First, a reader / writer 100 which is a public telephone is used.
Sends an initial response request (request). The initial response request has a format shown in FIG.
Of the 8 bits in the RAM 302, bit1 to bit3
The number of time slots (N) is notified to the non-contact IC card by using the three bits 303 of (3). Note that APf 304 is a header indicating an initial request command, and AFI 305 indicates an adaptation class of the contactless IC card. Also, CRC (Cyclic
Redundancy Check) 306 is a CRC from APf to PARAM.

Although the non-contact IC card responds with N slots 1 to N, the description here will be made on the assumption that the number of time slots (N) is four. That is, the contactless IC cards 200 and 300 respond to the initial response request.
Selects one of the time slots 1-4,
Make an initial response.

The first card identification processing 201 shown in FIG.
First, the reader / writer 100 transmits an initial response request R1 [REQB] (202). When the contactless IC cards 200 and 300 respectively generate “1” as random numbers in response to the initial response request R1 (202), they respond with initial responses [ATQB] A21 and A31 in the time slot 1 (204), respectively. I do.
In this case, the reader / writer 100 detects the collision of the non-contact IC cards since the initial response is returned at the same timing as the non-contact IC cards 200 and 300. Therefore, the identification process is restarted.

In the second identification process 207, an initial response request R2 (203) is transmitted from the reader / writer 100. When the contactless IC cards 200 and 300 generate “3” and “2” as random numbers in response to the initial response request, the time slot 3 (20
5) and time slot 2 (2
06) and responds with the packet A32. In this case, since the reader / writer 100 does not detect the collision, all the non-contact IC cards can be identified, and the identification process is completed. The above is the card identification processing of the non-contact IC card according to the provisions of ISO / IEC14443. Note that I
According to the specification of SO / IEC14443, the time when the contactless IC card responds in the time slot 1 after receiving the initial response request command is defined as 302 μsec, and the period (time) of one time slot is 2266 μsec. Stipulates. Reader / writer 100
The timing (μsec) from the reception of the initial response request to the transmission of the initial response is given by the following calculation expression (Expression 1).

Timing (μsec) = 302 μsec + 2266 μsec × (the number of slots (N) −1): (Equation 1) (Embodiment 1) Hereinafter, the reader / writer 100 according to Embodiment 1 of the present invention and a plurality of non-contacts A non-contact IC card system including the IC cards 200, 300,... Will be described. The non-contact IC card 200,
Since the configuration of the non-contact IC 300 is the same,
This will be described using the card 200.

FIG. 4A is a diagram showing a configuration of the reader / writer 100 according to the first embodiment. Reader / writer 1
00 is an antenna 401, a transmitting / receiving circuit 402, a CPU 4
03, ROM (Read Only Memory) 404 storing a program for controlling the reader / writer, RA used as a work area when the program is executed, for example.
An M (Random Access Memory) 405 is provided.

FIG. 4B is a functional block diagram showing the configuration of the non-contact IC card 200. As shown in FIG. The non-contact IC card 200 includes an antenna 406, a transmitting / receiving circuit 4
07, a CPU 408 for executing each program, a ROM 409 for storing a control program for processing commands from the reader / writer 100, and a RAM 410 used as a work area when the program is executed. Here, when the non-contact IC card 200 enters a communicable area of the reader / writer 100 or the like, the non-contact IC card 200 operates with electric power induced by electromagnetic waves from the reader / writer 100. For this reason, as described above, a large amount of power cannot be supplied.

Next, the non-contact IC shown in FIG.
FIG. 5 shows the card 200 as a functional block diagram. That is, the non-contact IC card 200 includes an antenna unit 501, a transmission / reception unit 502, a control unit 503, a temporary random number generation unit 504 for generating high-quality random numbers, a temporary random number storage unit 505 for storing temporary random numbers, Slot number acquiring means 5 for acquiring the number of slots from the request command
06, and a random number generation unit 507 for generating a random number from the temporary random number stored in the temporary random number storage unit 505. Note that, for example, the temporary random number generation unit 504 and the slot number acquisition unit 50
6. The random number generation means 507 is the ROM shown in FIG.
The data is stored in the CPU 409 and read out and executed by the CPU 408 as necessary.

Next, processing of the non-contact IC card according to the first embodiment will be described with reference to FIG. FIG. 6 is a flowchart of a communication process executed by the non-contact IC card 200.

First, the temporary random number generation means 504 constituting the non-contact IC card 200 generates in advance a temporary random number (r) for generating a high-quality random number at a predetermined timing, for example, when starting a program. (FIG. 6: S601). Here, the provisional random number refers to a value obtained by a predetermined number of steps of calculation among a plurality of steps required for generating a random number. For example, when the number of steps required for generating the random number is 100, the value or the like derived in the preceding 90 steps of the necessary step is a temporary random number. In other words, an operation that is not related to the number of steps (N) (request) described later can be used as a temporary random number generation step.
When the program is started, the reader / writer 1
For example, when electric power is induced by electromagnetic waves from the reader / writer 100 by entering a communicable area such as 00.

It is preferable to use a method for obtaining a sufficiently high quality random number, and a specific example is shown in, for example, a random number generation method (Japanese Patent Application No. 11-177913). However, the algorithm for generating high-quality random numbers is not directly related to the present invention, and thus the details are omitted.

The provisional random number (r) generated by the provisional random number generation means 504 is stored, for example, in the provisional random number storage means 505 provided in the RAM 410 (FIG. 6: S602).

Next, it waits for an initial response request (request) to be transmitted from the reader / writer 100 (FIG. 6: NO in S603). When the antenna unit 501 receives the electromagnetic wave from the reader / writer 100 and the electromagnetic wave includes the initial response request, the initial response request meets the transmission / reception unit 502 and is received by the control unit 503. . Subsequently, the control unit 503 transmits the initial response request to the slot number obtaining unit 506, and the slot number obtaining unit 506 obtains the number of slots from the initial response request (FIG. 6: S603Y).
ES-S604). The number of slots is P
It is specified by Bit1 to Bit3 of the ARAM 302, and is a value obtained by multiplying the numerical value 2 by the number of times specified by this bit. A calculation formula (formula 2) for the number of slots is shown below.

The number of slots (N) = 2 ＾ n: (Equation 2) (n is a value from 0 to 4 represented by Bit 1 to Bit 3) The number of slots acquired (calculated) by the slot number acquisition means 506 ( N) is transmitted to the control means 503.

Subsequently, when the control unit 503 obtains the number of slots (N), the control unit 503 transmits the temporary random number (r) stored in the temporary random number storage unit 505 together with the slot number (N) to the random number generation unit 507.

The number of slots (N) and the provisional random number (r)
Is received, the random number generation means 507 generates a random number (actual random number) (R) based on the two values (FIG. 6: S60).
5). Here, in the process of generating a random number from the temporary random number (r), the remaining steps other than the predetermined step processed at the time of generating the temporary random number are executed among the operations of the plurality of steps required for generating the random number ( Operation). Here, the remaining steps cannot be processed unless the number of slots (N) is known, that is, the number of slots (N)
(Request) can be a related step.

An example of the equation for calculating the random number (R) (Equation 3)
Is shown.

Random number (R) = provisional random number (r)% number of slots (N) +1: (expression 3) (% is remainder operation) The above expression (expression 3) satisfies the definition of the response time of the time slot. If so, another arithmetic expression may be used.

The random number generated by the random number generation means 507 is transmitted to the control means 503.

As described above, the non-contact IC card 200
A desired random number (1 to the number of slots (N)) can be obtained. Thereafter, the timing (slot) based on the above random number
Is used to make an initial response to the reader / writer 100 (FIG. 6: S606). After the completion of the initial response, the process returns to step S601 for generating a temporary random number (r), and a series of initial responses is completed.

As described above, the random number generation process is divided,
By making the calculation load for generating a random number (R) after receiving the initial response request small, the ISO
/ IEC14443 can satisfy the time rule of the time slot. Moreover, to generate random numbers,
Since it is possible to apply a process that requires a large amount of calculation, that is, a process that can generate high-quality random numbers, it is possible to solve a problem caused by poor-quality random numbers.

Further, even in a non-contact IC card that cannot supply sufficient power per unit time for generating a high-quality random number, a high-quality random number can be generated by software without using hardware for generating a random number. Therefore, the cost of the non-contact IC card can be reduced. Further, there is no problem of design, strength, and the like caused by using hardware.

In the first embodiment, software is used to generate random numbers. However, high-quality random numbers may be generated by hardware. Since hardware that can generate random numbers faster than software is used, it is possible to use a high-quality random number generation method that requires more steps. In this case, the non-contact IC card 200 has a configuration in which a hardware circuit is applied to the temporary random number generation unit.

Second Embodiment Next, a second embodiment according to the present invention will be described. FIG. 7 is a flowchart of a communication process executed by the non-contact IC card 200 according to the second embodiment.

In the non-contact IC card according to the first embodiment, when the initial response request is transmitted again from the reader / writer immediately after the response to the initial response request is completed, the non-contact IC card is generating a temporary random number. In this case, there is a problem that an initial response cannot be made. The second embodiment provides a means for solving this problem. The contactless IC card according to the second embodiment is
Since it has substantially the same configuration as the non-contact IC card in the first embodiment, only different points will be described.

First, the temporary random number generation means 504 constituting the non-contact IC card 200 generates a temporary random number (r (n)) at a predetermined timing, for example, at the time of starting a program (FIG. 7: S701). Here, (r (n)) means the n-th provisional random number generated, and takes a value from 1 to a prescribed provisional random number generation number. The specified number of provisional random numbers is a value that determines how many provisional random numbers are to be generated, and is given by, for example, a constant determined programmatically, a variable stored in the RAM 410 or the ROM 409, or the like.

Further, the method of generating the provisional random numbers is the same as that of the first embodiment in that a method for producing high-quality random numbers is used.

The provisional random number (r (n)) generated by the provisional random number generation means 504 is stored in the provisional random number storage means 505 via the control means 503 (FIG. 7: S702). still,
At this time, the non-contact IC card 2 according to the second embodiment is used.
00 has a plurality of the temporary random number storage means 505,
For example, the generated temporary random number (r (n)) is assumed to be stored in the temporary random number storage unit 505 (n).

After the provisional random number is stored in the provisional random number storage means 505 (n), the control means 503 checks the number of times the provisional random number is generated using a random number generation counter (FIG. 7: S7).
03). Here, the random number generation counter is a variable for storing the number of the generated temporary random number (r (n)).
It is mounted on the RAM 410 of the C card 200.

If the number of times of generation of the provisional random number does not reach the specified number of times of provisional random number generation,
04 generates a temporary random number again based on the instruction from the control means 503 (FIG. 7: S703NO-S701).

When the number of times of generation of the provisional random number has reached the prescribed number of times of provisional random number generation, the random number use counter is initialized with 1 (FIG. 7: S703 YES-S704). Here, the random number use counter is a temporary random number (r
(N)) is a variable for storing the number, and is mounted on the RAM 410 of the non-contact IC card 200.

By the above processing, a plurality of temporary random numbers are generated and stored in the temporary random number storage means 505, respectively.

Next, the non-contact IC card 200 waits for an initial response request to be transmitted from the reader / writer 100 (FIG. 7: NO in S705). When the antenna unit 501 receives an electromagnetic wave from the reader / writer 100 and the electromagnetic wave includes the initial response request, the initial response request is transmitted to the transmission / reception unit 50.
2 is received by the control means 503 via the
3 designates the above-mentioned initial response request as the slot number acquiring means 50.
6 and the slot number acquiring means 506 acquires the slot number from the initial response request in the same manner as in the first embodiment (FIG. 7: S705 YES-S70).
6).

Subsequently, when the control unit 503 obtains the number of slots (N), the control unit 503 transmits the temporary number (r (n)) stored in the temporary random number storage unit 505 together with the number of slots (N) to the random number generation unit. I do. However, the temporary random number (r (n)) used here is a temporary random number (r (1)) based on the above-mentioned random number use counter.

The number of slots (N) and the provisional random number (r
The random number generation unit 507 that has received (1)) generates a random number (actual random number) (R) based on the two values (FIG. 7:
S708).

The following is an example of the formula for calculating the random number (R) (Formula 4)
Is shown.

This random number (R) = provisional random number (r (n))% number of slots (N) +1: (Equation 4) (% is remainder calculation, n is the value of a provisional random number use counter) The above formula (Formula 4) ) May use another arithmetic expression as long as it satisfies the definition of the response time of the time slot.

As described above, the non-contact IC card 200
A desired random number (1 to the number of slots (N)) can be obtained. Thereafter, the timing (slot) based on the above random number
Is used to make an initial response to the reader / writer 100 (FIG. 7: S709).

After the completion of the initial response, the control means 503
Increments (+1) the value of the random number use counter (FIG. 7: S710).

If the value of the random number use counter does not reach the specified number of random number generations, the reader / writer 100
Waits for an initial response request to be transmitted from (FIG. 7: S711NO-S705).

If the value of the random number use counter has reached the specified random number generation count, the random number use counter is initialized to 1 and the process waits for an initial response request again in step S50.
4 (FIG. 7: S711 YES-S712-S70)
5).

With the above operation, it is possible to use the once generated temporary random numbers again and again from the beginning, and even if the initial response requests from the reader / writer 100 continue, the random numbers can be generated immediately. An initial response can be made using a random number.

Third Embodiment Next, a third embodiment according to the present invention will be described.

FIG. 8 shows a non-contact I according to the third embodiment.
5 is a flowchart of a communication process executed by the C card 200.

In the non-contact IC card according to the first embodiment, when the initial response request is transmitted again from the reader / writer immediately after the response to the initial response request is completed, the non-contact IC card is generating a temporary random number. As described above, there is a problem that an initial response cannot be made when the above is satisfied. Further, in the second embodiment, there is a problem that a processing time for generating a plurality of temporary random numbers is required, and it takes time to receive an initial response request. In the third embodiment, a self-response timing determination unit 520 is further provided to solve this problem. The contactless IC card according to the third embodiment is
Since it has substantially the same configuration as the non-contact IC card in the first and second embodiments, only different points will be described.

First, the temporary random number generation means 504 constituting the non-contact IC card 200 generates a temporary random number (r) at a predetermined timing, for example, at the time of starting a program (FIG. 8:
S801).

The provisional random number (r) generated by the provisional random number generation means 504 is stored in the provisional random number storage means 505 (FIG. 8: S802).

Next, it waits for an initial response request to be transmitted from the reader / writer 100 (FIG. 8: S80).
3NO).

Here, when the above initial response request is received, the number of slots is obtained from the initial response request by the slot number obtaining means 506 (FIG. 8: S80).
3YES-S804).

Next, the random number generation means 507 generates a random number (R) from the number of slots (N) and the provisional random number (r) stored in the provisional random number storage means (FIG. 8: S805).

As described above, the non-contact IC card 200
A desired random number (1 to the number of slots (N)) can be obtained. The above processing is almost the same as in the first embodiment.

Subsequently, the non-contact IC card 200 determines the response timing (slot) by the self-response timing determination means 520. That is, the self-response timing determination means 520 calculates the timing at which the contactless IC card 200 should respond based on the time at which the initial response request is received and the generated random number (R), and It is determined whether there is a sufficient time (predetermined time) before the timing at which the card 200 should respond (FIG. 8: S806). The sufficient time is a time required for generating and storing the temporary random numbers.

Here, if it is determined in the above determination that there is sufficient time, the control means 503 issues an instruction to the temporary random number generation means 504 to generate a temporary random number (r), The random number is stored in the temporary random number storage means 505 (FIG. 8: S806NO-S807-S808).

If it is determined that there is not enough time in the above determination, the control means 503 makes an initial response using a slot based on the generated random number (R) (FIG. 8: S806 YES-). S809).

After the completion of the initial response or the generation of the temporary random number, the control means 503 determines the end of the time slot period. Here, the time slot period is a period from the start of the first time slot to the end of the last time slot, and is a period determined by the number of slots given from the reader / writer 100.

If it is within the time slot period, the determination is repeated from the self-response timing determination means 520 (FIG. 8: S810 YES-S806).

If the time is not within the time slot period,
The process returns to the initial response request waiting process and prepares for the initial response request (FIG. 8: S810NO-S803).

As described above, by determining whether or not there is a predetermined time before the timing at which the user himself / herself should respond, a temporary random number is generated in a slot which is not related to the user and is substantially a waiting time. It is possible to do.

Further, by using a non-volatile memory for the temporary random number storage means, for example, when there is not enough time to generate a temporary random number from the start of the program to the reception of the initial response request request. However, since provisional random numbers have already been prepared, it is possible to respond using high-quality random numbers.

It is needless to say that the technique according to the third embodiment can also be applied to the case where a plurality of temporary random number storage means according to the second embodiment are provided.

(Fourth Embodiment) Next, a fourth embodiment according to the present invention will be described.

FIG. 9 shows a non-contact type I according to the fourth embodiment.
5 is a flowchart of a communication process executed by the C card 200.

In the non-contact IC card according to the first embodiment, when the initial response request is transmitted again from the reader / writer immediately after the response to the initial response request is completed, the non-contact IC card is generating the temporary random number. As described above, there is a problem that an initial response cannot be made when the above is satisfied. Further, in the second embodiment, there is a problem that a processing time for generating a plurality of temporary random numbers is required, and it takes time to receive an initial response request. In the fourth embodiment, in order to solve this problem, provisional random number storage means 5 constituted by a nonvolatile memory
05. The non-contact IC according to the fourth embodiment
The card is a non-contact I in the first, second, and third embodiments.
Since it has almost the same configuration as the C card, only different points will be described.

First, the control means 503 initializes a random number use counter to 1 (FIG. 9: S901).

Next, when an initial response request is received, the slot number calculating means 508 acquires the number of slots from the initial response request (FIG. 9: S9).
02YES-S903).

Subsequently, the control means 503 extracts the random number (r (n)) of the random number use counter stored in the nonvolatile temporary random number storage means 505, and
7 generates a random number (R) from the temporary random number (r (n)) and the number of slots (N) (FIG. 9: S904 to S90).
5). The procedure for storing the temporary random number (r (n)) will be described later.

As described above, the non-contact IC card 200
A desired random number (1 to the number of slots (N)) can be obtained. Thereafter, the timing (slot) based on the above random number
To make an initial response to the reader / writer 100 (FIG. 9: S906).

After the completion of the initial response, the control means 50
3 increments the value of the random number use counter (+1)
(FIG. 9: S907).

If the value of the random number use counter is equal to or less than the specified number of random number generations, the process waits again for receiving an initial response request (FIG. 9: S908 NO-S902).

When the value of the random number use counter has reached the specified number of random number generations, the random number use counter is initialized to 1 and the system waits again to receive an initial response request (FIG. 9:
S908YES-S909-S902).

The processing described above is the same as the processing in S704 to S702 in the second embodiment.

If the control means 503 does not receive an initial response request after initializing the random number use counter to 1, it determines whether or not a communication end request 1001 has been received (FIG. 9: S902 NO-S910). ). Here, the communication end request 1001 has the format shown in FIG. 10 and is information transmitted from the reader / writer 100 when the communication between the reader / writer 100 and the non-contact IC card 200 ends. The communication end request 1001 has fields of S-BLOCK 1002, CID (card ID) 1003, and CRC 1004. The S-BLOCK 1002 has a system command (communication end), and the CID 1003 has a contactless IC card. The card ID of 200 and the CRC of the S-BLOCK 1002 and the CID 1003 are stored in the CRC 1004.

Here, when the communication termination request is not received from the reader / writer 100, an initial response request (or another request: not shown in FIG. 9)
Wait for reception of the message (FIG. 9: S910NO-S90).
2).

However, when a communication end request is received, the reader / writer 100 and the non-contact IC card 200
In order to indicate that the communication with the
04 generates the temporary random number (r (n)) (FIG. 9: S
911). Here, n indicates the number of times of generation of the n-th temporary random number, and takes a value from 1 to the specified number of times of provisional random number generation as in the second embodiment. The provisional random number generation means 504
The temporary random number (r (n)) generated by is stored in the nonvolatile temporary random number storage unit 505 (FIG. 9: S912).

Next, the control means 503 determines whether or not the number of times of provisional random number generation has reached the provisional number of provisional random number generation.

If the number of times of generation of the provisional random number has not reached the prescribed number of times of provisional random number generation, provisional random number generation means 504 again generates a provisional random number (FIG. 9: S913 NO-S).
911).

When the number of times of generation of the provisional random number has reached the prescribed number of times of provisional random number generation, the system is stopped (the processing is terminated).

As described above, after the non-contact IC card has completed communication with the reader / writer and is within the communicable range with the reader / writer, power can be supplied. , It is possible to generate a temporary random number in advance. Further, since the generated temporary random number is stored in the non-volatile storage means, it is possible to immediately generate a high-quality random number when it enters the communicable range with the reader / writer next time. Therefore, for example, processing at the time of starting the program can be reduced. As a result, the time required to wait for the initial response request can be further reduced.

(Fifth Embodiment) Next, a fifth embodiment according to the present invention will be described.

Here, FIG. 11A shows a process at the time of initialization of the non-contact IC card 200, FIG. 11B shows a process at the time of interruption of the non-contact IC card 200, and FIG. .

The non-contact IC card according to the fifth embodiment is
Regarding the initial response method, the same processing as in the above-described first to fourth embodiments is performed, but here, the generation of the temporary random number can be interrupted. In other words, by combining the technique shown in the fifth embodiment with the first to fourth embodiments, it is possible to freely interrupt and start the generation of the temporary random number.

First, the control means 503 operates the non-contact IC card 20 at a predetermined timing, for example, when starting a program.
0 initialization processing is performed. The initialization process includes a process of setting Flag to 1 during provisional random number processing and a provisional random number interruption F
lag is set to 0 (FIG. 11A: S1).
101-S1102).

The flag during the provisional random number processing is a variable indicating a state in which the provisional random number is being generated, and indicates a state of the generation process of the generation operation having three stages (generation operation 1, generation operation 2, generation operation 3). I have. That is, when the flag during the provisional random number processing is 1, generation operation 1 is performed, when the flag during provisional random number processing is 2, generation operation 2 is performed, and when the flag during provisional random number processing is 3, generation operation 3 is performed. Note that the above generation operations 1 to 3 are those in which the processing required to generate the provisional random number (r) is divided into three interruptable processings. Here, three processings are used. May be.

The temporary random number interruption Flag is a variable that is changed by interruption to the control means 503. If it is 0, the temporary random number generation does not need to be interrupted.
In other cases, it indicates that the generation of the temporary random numbers needs to be interrupted. Flag during temporary random number processing, Temporary random number interruption Fla
Both g are provided in the RAM 505 of the non-contact IC card 200.

The above is the preparation necessary for interrupting the process of generating the temporary random number.

Subsequently, when a request (command) is transmitted from the reader / writer, the control means 503 determines the content of the request (command) (FIG. 11B: S111).
0). Usually, the request is transmitted at any time, so that the request is processed in the interrupt processing.

If the request (command) is an initial response request, the control means 503 sets the temporary random number interruption F
lag is set to 1 (FIG. 11B: S1110YE)
S-S1111).

If the request (command) is not an initial response request, 0 is set in the provisional random number interruption Flag (FIG. 11B: S1110NO-S1112).

The above is the processing performed when an interrupt occurs.

Next, a description will be given of, for example, processing performed by the temporary random number generation means 504 in the first to fourth embodiments when generating a temporary random number.

First, when the provisional random number is generated by the provisional random number generation means 504, it is determined whether or not to suspend the process.
The determination is made based on lag (FIG. 12: S1201).

Here, when the temporary random number interruption Flag is 1, since the process is performed after receiving the initial response request, the temporary random number generation process is interrupted (FIG. 12: 1201 YES).
-Provisional random number generation completed).

Here, when the temporary random number interruption Flag is 0,
Since the initial response request has not been received, the provisional random number generation means 504 performs a provisional random number generation process (FIG. 12: 1201).
NO-S1202).

Next, the calculation of the provisional random number generation processing is divided into three calculations, and the control means 503 determines which of the three calculations is to be performed based on the flag during the provisional random number processing (FIG. 12: 1202).

Here, if Flag during the provisional random number processing is 1, the first provisional random number generation calculation 1 is performed.
In order to store that the second provisional random number calculation is performed, the value of the Flag during the provisional random number processing is incremented (+1) (FIG. 12: 1202 (1) -S1203-S1204). Hereinafter, similarly, the provisional random number generation operation 2 (FIG. 12: 1202 (2)
-S1205-S1206), a temporary random number generation operation 3 (FIG. 1)
2: 1202 (3) -S1207), and after the provisional random number generation operation 3 is completed, the value of the Flag during the provisional random number processing is initialized.
That is, 1 is substituted for Flag during provisional random number processing, and the generation of provisional random numbers is completed (FIG. 12: S1208).

As described above, the provisional random number generation processing by the provisional random number generation means is divided into a plurality of interruptible operations, and the provisional random number generation processing is interrupted based on the provisional random number interruption Flag and the provisional random number processing Flag. By starting, even if an initial response request is made from the reader / writer during the generation of the temporary random number, the generation of the temporary random number is interrupted halfway,
An initial response can be made and then the generation of the provisional random number can be resumed. Thereby, for example, processing at the time of starting the program can be reduced.

Further, it is possible to always perform the provisional random number generation processing when the power is supplied from the reader / writer and no other processing needs to be performed, that is, during the waiting time.

In the technique described in the first to fifth embodiments, in the case where a temporary random number is generated in advance and stored in a nonvolatile memory, the non-contact IC card 200 is used first. , There may be a situation where the above temporary random numbers are not present. In addition, the case where the provisional random number is generated before the initial response request, and the case where the initial response request is received immediately after entering the communicable range of the reader / writer. In such a case, it is impossible to respond to the first initial response request.

Therefore, the following measures are conceivable.
That is, in order to cope with the case described above, the above R
A specific slot number holding unit is provided in the OM 409 or the RAM 410, and a predetermined slot number is stored in the specific slot number holding unit. The slot number is
A value that does not require any calculation may be used.

Next, when an initial response request is received from the reader / writer during the generation of the temporary random number, the control means 503 determines that no valid temporary random number is stored in the temporary random number storage means 505. If it is determined, the control unit 503 responds using the slot of the value stored in the specific slot number holding unit.

As described above, it is possible to return a response to an initial response request within a predetermined time even when a valid temporary random number is not stored in the temporary random number storage means. The provisional random number interruption flag and the provisional random number processing flag are set so that the provisional random number generation means can interrupt the provisional random number generation process when the initial response request is received.
It is desirable to interrupt the process of generating the provisional random number using.

Further, by setting the value stored in the specific slot number holding means to 1, an initial response is made in Slot 1, so that the remaining slots (for example, Slot 2
To 4) can be used for calculation of provisional random numbers. For this reason, other non-contact IC
Even if the response signal of the card collides, 2
It is possible to secure a temporary random number generation time that can sufficiently respond to the initial response request of the second time.

Although the above-described first to fifth embodiments have been described on the assumption that the time slot system is adopted, the present invention can be applied to the slot marker system.

[0139]

As described above, by dividing the random number generation process and reducing the load of the operation for generating the random number after receiving the request, the time regulation of the time slot can be satisfied. It is possible. In addition, since a process that requires a large amount of calculation, that is, a process that can generate high-quality random numbers, can be applied to the generation of random numbers, it is possible to solve problems caused by poor-quality random numbers.

Further, since high-quality random numbers can be obtained by software without using hardware for generating random numbers, the cost of a non-contact IC card can be reduced. Further, there is no problem of design, strength, and the like caused by using hardware.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of usage of a contactless IC card of the present invention.

FIG. 2 shows a reader / writer of a non-contact IC card and a non-contact IC.
Time chart showing the communication status of the C card

FIG. 3 is a format diagram of an initial response request according to the embodiment;

FIG. 4 is a diagram showing a configuration of a reader / writer and a non-contact IC card which constitute a non-contact IC card recognition system;

FIG. 5 is a functional block diagram showing a configuration of a non-contact IC card.

FIG. 6 is a flowchart of an initial response process executed by the contactless IC card according to the first embodiment.

FIG. 7 is a flowchart of an initial response process executed by the non-contact IC card according to the second embodiment.

FIG. 8 is a flowchart of an initial response process executed by the non-contact IC card according to the third embodiment.

FIG. 9 is a flowchart of an initial response process executed by the non-contact IC card according to the fourth embodiment.

FIG. 10 is a format diagram of a communication end request.

FIG. 11 is a flowchart of non-contact IC card initialization processing and interrupt processing according to the fifth embodiment.

FIG. 12 is a flowchart of provisional random number generation processing according to the fifth embodiment.

[Explanation of symbols]

 200 Non-contact IC card 409 ROM 410 RAM 501 Antenna unit 502 Transmission / reception unit 503 Control unit 504 Temporary random number generation unit 505 Temporary random number storage unit 506 Slot number acquisition unit 507 Random number generation unit 520 Self-response timing determination unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinji Kawano 3-10-18 Kagamiyama, Higashihiroshima City Matsushita Electric Information System Hiroshima Laboratory F-term (reference) 2C005 MA22 MA25 MB05 NA06 SA30 5B035 BB09 CA22 CA23 5B058 CA15 CA23 CA25 5K028 AA11 BB04 CC05 DD01 DD02 EE09 JJ05 LL02 MM13 NN43

Claims (12)

[Claims] 1. A contactless IC card which responds to a request transmitted from a reader / writer by using a value calculated based on a random number, wherein a non-contact IC card obtained by performing a partial operation among operations used for generating a random number. Provisional random number generation means for generating a random number, provisional random number storage means for storing a provisional random number generated by the provisional random number generation means, and upon receiving the request from the reader / writer,
A non-contact IC card comprising: a random number generation unit configured to generate a random number from the stored temporary random number. 2. The non-contact IC according to claim 1, wherein the calculated value is a response timing calculated using the number of slots included in the request and a random number generated by the random number generating means. card. 3. The method according to claim 1, wherein the operation for generating the temporary random number is an operation not related to the request, and the operation for generating the random number is an operation determined based on the request. Non-contact IC described
card. 4. The contactless IC card according to claim 2, further comprising a plurality of said temporary random number storage means, wherein said response is made by sequentially using a plurality of temporary random numbers stored in response to a request from said reader / writer. 5. Self-transmission timing determining means for determining whether or not there is a predetermined time before a timing at which the self-response should be made, wherein the temporary random number generating means determines the response time by the self-response timing determining means. The non-contact IC card according to claim 2, wherein the temporary random number is generated when it is determined that there is a predetermined time. 6. The non-volatile temporary random number storage means, wherein the temporary random number generation means generates the temporary random number at the end of communication processing and stores the temporary random number in the non-volatile temporary random number storage means. 3. The non-contact IC card according to claim 2, wherein the generation unit generates a random number from the temporary random number stored in the nonvolatile temporary random number storage unit when receiving the request. 7. A provisional random number interruption flag indicating that the generation of the provisional random number is interrupted when a request from the reader / writer is received during the generation of the provisional random number; 3. The method according to claim 2, further comprising a provisional random number processing flag indicating a position where the generation of the random number is to be started, wherein the provisional random number is interrupted / started based on the provisional random number interruption flag and the provisional random number processing flag. Contact IC card. 8. The apparatus further comprises a specific slot number holding means for holding a predetermined value, wherein when the request is received during generation of the provisional random number,
8. The non-contact IC card according to claim 7, wherein the generation of the temporary random number is interrupted, and a response is made using a value held by the specific slot number holding unit. 9. The non-contact IC card according to claim 8, wherein the value held by said specific slot number holding means is 1. 10. A non-contact IC card response method for responding to a request transmitted from a reader / writer using a value calculated based on a random number, the method comprising: A provisional random number generation step of generating a provisional random number obtained by an operation, and when the request is received from the reader / writer,
A random number generation step of generating a random number from the provisional random number. 11. A non-contact IC card that responds to a request transmitted from a reader / writer by using a value calculated based on a random number, comprising: A temporary random number generating step of generating a random number; and upon receiving the request from the reader / writer,
A random number generation step of generating a random number from the temporary random number. 12. A non-contact IC card that responds to a request transmitted from a reader / writer by using a value calculated based on a random number, to provide a non-contact IC card with a temporary obtained by a part of operations used for generating a random number. A temporary random number generating step of generating a random number; and upon receiving the request from the reader / writer,
A computer-readable recording medium recording a program for executing a random number generation step of generating a random number from the temporary random number.