JP2007129649A - Tag verification server device, tag verification system, tag verification method, and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To strengthen resistance to replay attacks in the tag technology. <P>SOLUTION: Settled update frequency information 104 showing a frequency in update of tag output information, the validity of which has been recognized by a verification server device 10 is stored in a memory 11 of the verification server device 10. A communication part 12 accepts input of tag output information being a verification object, and an extraction part 13 extracts a frequency in update of this tag output information. Next, a comparison part 14 compares the frequency in update of the tag output information being the verification object, which has been extracted by the extraction part, with the frequency in update shown by the settled update frequency information, and a judgement part 15 judges the validity of tag output information being the verification object, in accordance with a comparison result of the comparison part 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to the field of tag technology to which information security technology is applied, and more particularly to the technical field of authentication, authentication, and privacy protection.

  When assigning an identifier (for example, a product serial number, ISBN (International Standard Book Number), bar code, passport number, etc.) to an article or person, it is basically unique to one article or person or one category. Only one identifier is given. In addition, ISBN, barcodes, and the like generally have their number systems open to the public, and anyone can specify what kind of product they are by looking at their identifiers. Further, identifiers such as conventional barcodes and product serial numbers are provided by being printed on articles or tags, and the identifiers can be recognized only by those who can see the identifiers.

  On the other hand, in recent years, there are many studies on attaching an identifier to an article using an RF (Radio Frequency) tag instead of printing (for example, see Non-Patent Document 1). In general, an RF tag is a minute device including an antenna, an IC chip, and the like, and can exchange information with an external wireless device (RFID reader) by wireless communication. As long as the RF tag exists within the reach of radio, the wireless device can acquire a large amount of barcodes, product serial numbers, etc. stored in the RF tag at a time. If attached or stored in an article, the RF tag can be used for article distribution, inventory management, and the like. Also, there are many studies on authentication and authentication using RFID, such as entry / exit management systems using RFID, applications using RFID tags for high-end branded goods, banknotes, events and facility entrance tickets, etc. .

  However, in general, when managing an article using RFID, unless the RF tag function is explicitly stopped, “what kind of article the final consumer, etc. possesses”, “current position of the article (or the owner's There is a possibility that privacy information such as “Where is the current position” or “Other information provided by the RF tag (temperature, humidity, etc.)” may be illegally acquired by an external wireless device. That is, when managing an article using an RF tag, privacy information is acquired by an arbitrary third party without the owner of the article noticing, and as a result, the owner of the article unconsciously does something. It will be monitored.

Further, when authentication or authentication is performed using RFID, the RFID tag outputs an ID that can be identified by anyone according to a request from the RFID reader, so that there is a high possibility that the RFID tag is particularly unconsciously monitored. Therefore, it has been a big problem in the field of RFID to achieve both authentication and authentication using RFID and privacy protection.
In response to such a problem of RFID privacy protection, Okubo et al. Proposed the following method (for example, see Non-Patent Document 2).
Okubo et al. Preparation: Let h (x) and g (x) be two cryptographic hash functions not correlated with each other.

Tag initial setting: Random number s _i is recorded in memory area s of tag i. A set of i and s _i is key information.
Tags processing: tags i outputs When ID is requested g _{(s i),} it overwrites the h _{(s i)} in the memory area s.
Initial setting of server: The server calculates in advance a possible tag output g (h ^j (s _i )) from the correspondence table of i and s _i , and correspondence between g (h ^j (s _i )) and i Make a table.
Processing of server device: Searches correspondence table between g (h ^j (s _i )) and i using g (s _i ) given from the tag as a search key, and outputs i corresponding to g (s _i ) .

The method of Okubo et al. In which h (x) is a one-way function and g (x) is a random oracle solves the privacy problem. That is, since the tag to update the value s _i in the memory area s every time the output g (s _i), when viewed from a third party, g (s _i) to which a tag output at each time point random mutually Looks like a relationship. As a result, it becomes difficult for a third party to obtain the privacy information from the information output by the tag.
EPC global, Inc., “EPCglobal”, [online], [searched September 9, 2004], Internet <http://www.epcglobalinc.org/> Miyako Ohkubo, Koutarou Suzuki, Shingo Kinosita, "Cryptographic Approach to" Privacy-Friendly "Tags", In RFID Privacy Workshop, MIT, MA, USA, November 2003.

However, the above-mentioned method by Okubo et al. Has a problem that it is vulnerable to replay attack. That is, when a third party obtains information output from the tag, the third party can use this information illegally any number of times. In particular, when performing authentication processing using RFID, a third party can obtain unauthorized authentication simply by acquiring information output from a tag and using it.
The present invention has been made in view of these points, and an object thereof is to provide a tag technology that is resistant to replay attacks.

In the present invention, in order to solve the above-described problem, fixed update count information indicating the update count of tag output information that the verification server device has recognized is stored in the memory of the verification server device. The input unit receives input of the tag output information to be verified, and the extraction unit extracts the number of updates of the tag output information to be verified. Next, the comparison unit compares the update count extracted by the extraction unit with the update count indicated by the confirmed update count information, and the determination unit verifies the validity of the tag output information to be verified according to the comparison result in the comparison unit. judge.
In other words, the determination unit compares the number of updates of the tag output information that has already been validated and verified by the verification server device with the number of updates of the tag output information that is the verification target, and from the comparison result The validity of the tag output information to be verified is determined.

Preferably, in the present invention, the memory stores a correspondence table in which tag output information at each update time point, update number information indicating the number of updates, and fixed update number information are associated with each tag device. The extraction unit searches the correspondence table and extracts the update count information corresponding to the tag output information to be verified and the confirmed update count information.
Preferably, in the present invention, the tag output information is information that is updated every time it is output from the tag device, and the confirmed update number information indicates a maximum value of the number of updates of the tag output information that has been validated. When the update count extracted by the extractor is determined to be less than or equal to the update count indicated by the confirmed update count information, the determination unit determines that the tag output information to be verified is invalid and extracts the information. When it is determined that the update count extracted by the section is greater than the update count indicated by the confirmed update count information, it is determined that the tag output information to be verified is valid.

Here, since the tag output information is updated every time it is output from the tag device, if the tag output information currently being verified is valid, the number of updates is verified by the verification server device in the past. The number of updates of the tag output information that has been validated is not less than the number of updates. The determination unit determines this and detects a replay attack.
Preferably, in the present invention, when the determination unit determines that the tag output information to be verified is valid, information indicating the number of update times of the target tag output information is set as new confirmed update number information. .

  As described above, in the present invention, the replay attack can be detected from the tag output information, and high resistance to the replay attack can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a first embodiment of the present invention will be described.
<Overall configuration>
FIG. 1 is a block diagram illustrating the configuration of a verification system 1 according to this embodiment.
As illustrated in FIG. 1, the verification system 1 of the present embodiment outputs a tag device 20 that sequentially updates tag output information, reads the tag output information from the tag device 20, and transmits the tag output information to the verification server device 10 through the network 40. Reader device 30 that performs the verification and the verification server device 10 that verifies the validity of the transmitted tag output information. For simplification of explanation, only one tag device 20 is shown in FIG. 1, but there are actually a plurality of tag devices 20. Further, the verification server device 10 and the reader device 30 do not need to be one, and the system may be configured by two or more verification server devices 10 and reader devices 30. In addition, arrows in FIG. 1 indicate the flow of data, but the description of the flow of data input to and output from the control units 17, 25, 33 and the temporary memories 17a, 25a, 33a is omitted.

<Configuration of Verification Server Device 10>
Next, the configuration of the verification server device 10 will be described.
[Function configuration]
As illustrated in FIG. 1, the verification server device 10 includes a memory 11, a communication unit 12 (corresponding to an “input unit”), an extraction unit 13, a comparison unit 14, a determination unit 15, an update unit 16, and a control unit 17. is doing. The control unit 17 also has a temporary memory 17a, and the memory 11 stores a correspondence table 100 in which the tag identifier 101, the update count information 102, the tag output information 103, and the confirmed update count information 104 are associated with each other. ing.

[Data structure]
FIG. 2 is a diagram illustrating a data configuration of the correspondence table 100 stored in the memory 11.
As described above, the correspondence table 100 is a table in which the tag identifier 101, the update count information 102, the tag output information 103, and the confirmed update count information 104 are associated with each other.
Here, the tag identifier 101 is an identifier for uniquely identifying each tag device 20. For example, a serial number corresponding to each tag device 20 on a one-to-one basis corresponds to the tag identifier 101. In this embodiment, the tag identifier 101 is expressed by a variable i [i = 1, 2,..., N (N is the total number of tag devices 20)].

The update count information 102 is a value indicating the update count of the tag output information 103. In this embodiment, the update count information 102 is expressed by a variable j [j = 1, 2,..., M (M is the upper limit of the update count of the tag output information 103)].
The tag output information 103 is tag output information at each update time corresponding to each tag device 20. As will be described in detail later, the tag output information output by each tag device 20 is sequentially updated by each tag device 20. The tag output information 103 of this embodiment is obtained by calculating each tag output information at each update time in advance for each tag device 20. More specifically, the tag output information 103 in the example of the present embodiment includes a hash function in the seed information S _{i, 0} (i = 1, 2,..., N) corresponding to each tag device 20 on a one-to-one basis. h is j (j = 1, 2,..., M) times (h ^j (S _{i, 0} )), and g (h ^j (S _{i, 0} )) generated by applying the hash function g. . Each tag output information 103 [g (h ^j (S _{i, 0} ))] generated in this way is a tag identifier 101 (i = 1, 2,..., N) used for each generation and It is associated with the update count information 102 (j = 1, 2,..., M) (see FIG. 2). Note that the hash functions h and g are independent of each other, and a specific example of the hash functions h and g is SHA-1.

The confirmed update count information 104 is information indicating the maximum value (for each tag device 20) of the update count of the tag output information that has been validated by the verification server device 10 (details will be described later). In this embodiment, this fixed update number information 104 is expressed by a variable fj _i (i = 1, 2,..., N). Further, this fixed update count information 104 is associated with the tag identifier 101 of the corresponding tag device 20. In the example of FIG. 2, the confirmed update count information 104 of fj _i = 5 is associated with the tag identifier 101 of _i = 1, and the confirmed value of fj _i = 12 is associated with the tag identifier 101 of i = 2. Update number information 104 is associated.

[Hardware configuration]
FIG. 3 is a block diagram illustrating the verification server device 10 according to the present embodiment in terms of hardware configuration.
As illustrated in FIG. 3, the verification server device 10 according to this embodiment includes a CPU (Central Processing Unit) 10 a, an output unit 10 b, a communication unit 10 c, a RAM (Random Access Memory) 10 d, a ROM (Read Only Memory) 10 e, an auxiliary device. It has a storage device 10f and a bus 10g.

  The CPU 10a in this example includes a control unit 10aa, a calculation unit 10ab, and a register 10ac, and executes various calculation processes according to various programs read into the register 10ac. The output unit 10b is an output terminal from which data is output, a display, or the like. The communication unit 10c is a LAN card or the like controlled by the CPU 10a that has read a predetermined program. The RAM 10d is an SRAM (Static Random Access Memory), a DRAM (Dynamic Random Access Memory) or the like, and has a program area 10da for storing a predetermined program and a data area 10db for storing various data. The auxiliary storage device 10f is, for example, a hard disk, an MO (Magneto-Optical disc), a semiconductor memory, or the like, and has a program area 10fa for storing a predetermined program and a data area 10fb for storing various data. Yes. The bus 10g connects the CPU 10a, the output unit 10b, the communication unit 10c, the RAM 10d, the ROM 10e, and the auxiliary storage device 10f so that information can be exchanged.

  The CPU 10a writes the program stored in the program area 10fa of the auxiliary storage device 10f in the program area 10da of the RAM 10d in accordance with the read OS (Operating System) program. Similarly, the CPU 10a writes various data stored in the data area 10fb of the auxiliary storage device 10f to the data area 10db of the RAM 10d. The address on the RAM 10d where the program and data are written is stored in the register 10ac of the CPU 10a. The control unit 10ab of the CPU 10a sequentially reads these addresses stored in the register 10ac, reads a program and data from the area on the RAM 10d indicated by the read address, and causes the calculation unit 10ab to sequentially execute the operation indicated by the program. The calculation result is stored in the register 10ac.

  With this configuration, the functional configuration of the verification server device 10 illustrated in FIG. 1 is realized. That is, the memory 11 and the temporary memory 17a in FIG. 1 are either the data area 10fb of the auxiliary storage device 10f, the data area 10db of the RAM 10d, the register 10ac of the CPU 10a, other buffer memory or cache memory, or a combination thereof. It corresponds to a storage area. The communication unit 12 corresponds to the communication unit 10c that executes processing under the control of the CPU 10a in which the above-described program is read. The extraction unit 13, the comparison unit 14, the determination unit 15, the update unit 16, and the control unit 17 correspond to the CPU 10a in which the above-described program is read.

<Configuration of Tag Device 20>
As illustrated in FIG. 1, the tag device 20 according to this embodiment includes a memory 21, hash calculation units 22 and 23, a communication unit 24, and a control unit 25. The control unit 25 includes a temporary memory 25a.
Here, the memory 21 and the temporary memory 25a are readable / writable memories such as an EEPROM (Electronically Erasable and Programmable Read Only Memory), a FeRAM (Ferroelectric Random Access Memory), a flash memory, and an NV (Nonvolatile) RAM. The hash calculator 22 and the hash calculator 23 are integrated circuits configured to operate hash functions g and h and output the results. The communication unit 24 is hardware that outputs data to the reader device 3 wirelessly or by wire. Specifically, the communication unit 24 includes, for example, an encoding / decoding circuit that performs encoding / decoding by NRZ code, Manchester encoding, mirror code, unipolar RZ encoding, etc., ASK (Amplitude Shidt Keying), Has modulation / demodulation circuit that performs modulation / demodulation by PSK (Phase Shidt Keying), FSK (Frequency Shidt Keying), etc., dipole antenna, microstrip antenna, loop coil, cored coil, etc. Signals are transmitted and received using the frequency of (Industry Science Medical band). The control unit 25 is, for example, an integrated circuit or a CPU loaded with a predetermined program.

<Configuration of Reader Device 30>
The reader device 30 according to this embodiment includes communication units 31 and 32 and a control unit 33. The control unit 33 includes a temporary memory 33a.
Here, the communication unit 31 is, for example, hardware similar to the example of the communication unit 24. The communication unit 32 is, for example, a LAN card, a modem, a terminal adapter, or the like, and the control unit 33 is, for example, an integrated circuit or a CPU loaded with a predetermined program. The temporary memory 33a is a readable / writable memory such as NV (Nonvolatile) RAM.

<Processing of verification system 1>
FIG. 4 is a flowchart for explaining the processing of the verification system 1 of this embodiment. Below, the process of the verification system 1 is demonstrated using this.
[Preprocessing]
As preprocessing, the above-described correspondence table 100 (FIG. 2) is stored in the memory 11 of the verification server device 10. In the initial state, the fixed update count information 104 corresponding to each tag identifier 101 is set to fj _i = 0.

[Processing of tag device 20]
In the following, a process when the tag device 20 that has already updated the tag output information j times (j = 1, 2,..., M) outputs the tag output information will be described. The tag device 20 executes the following processing under the control of the control unit 25. Data used for each process is stored in the temporary memory 25a after each process or after completion, and is read into predetermined hardware as necessary.
First, the tag device 20 reads the secret value s _{i, j} from the memory 211 in the hash calculation unit 23 (step S1), and generates tag output information g (s _{i, j} ) that is the hash value (step S2). ). This tag output information g (s _{i, j} ) is sent to the communication unit 24, and from there is transmitted to the reader device 30 wirelessly or by wire (step S3).

Next, the hash calculator 23 calculates a hash value s _{i, j + 1} = h (s _{i, j} ) of the secret value s _{i, j} read from the memory 21 (step S4), and this hash value s _{i, j + 1.} Is overwritten and saved in the memory 21 (the secret value s _{i, j} in the memory 211 is deleted or saved, and the secret value s _{i, j + 1} is stored instead: step S5).
<Processing of Reader Device 30>
The reader device 30 executes the following processing under the control of the control unit 33.
First, the reader device 30 receives the tag output information g (s _{i, j} ) transmitted from the tag device 20 at the communication unit 31 (step S6) and sends it to the communication unit 32. The communication unit 32 transmits this to the verification server device 10 through the network 40 (step S7).

<Processing of Verification Server Device 10>
The verification server device 10 executes the following processing under the control of the control unit 17. Data used for each process is stored in the temporary memory 17a after each process or after completion, and is read into predetermined hardware as needed.
First, the verification server device 10 receives the tag output information g (s _{i, j} ) to be verified transmitted from the reader device 30 in the communication unit 12 (accepts input: step S8). The tag output information g (s _{i, j} ) is sent to the extraction unit 13, and the extraction unit 13 searches the correspondence table 100 stored in the memory 11 to check the tag output information g (s _{i, j} ) to be verified. It is verified whether there is data corresponding to (step S9). That is, data matching the tag output information g (s _{i, j} ) is searched from the column of the tag output information 103 in the correspondence table 100. Here verified tag output information g (s _{i, j)} if the data corresponding to the does not exist, the determination unit 15, tag output verified information g (s _{i, j)} is unjustly (NG) A determination result to the effect is output (step S11), and the control unit 17 ends the process. Note that determining that the tag output information g (s _{i, j} ) is invalid (NG) means that if the tag output information g (s _{i, j} ) is used in the authentication process, the authentication is denied. If the tag output information g (s _{i, j} ) is used for authenticity determination, it means that it is determined to be a counterfeit.

On the other hand, when there is data corresponding to the tag output information g (s _{i, j} ) to be verified, the extraction unit 13 uses the data g of the tag output information 103 that matches the tag output information g (s _{i, j} ). Update number information 101 (i), update number information 102 (j), and confirmed update number information 104 (fj _i ) associated with (h ^j (s _{i, 1} )) are extracted (step S12). ). The extracted update number information 102 (j) and confirmed update number information 104 (fj _i ) are sent to the comparison unit 14, and the comparison unit 14 verifies whether or not j> fj _i (step). S13). Here, when j> fj _i is not satisfied (when it is determined that the update number i indicated by the update number information 101 extracted by the extraction unit 13 is equal to or less than the update number fj _i indicated by the confirmed update number information 104). The determination unit 15 outputs a determination result indicating that the tag output information g (s _{i, j} ) to be verified is invalid (NG) (step S11), and the control unit 17 ends the process.

On the other hand, if j> fj _i (when it is determined that the update number i indicated by the update number information 101 extracted by the extraction unit 13 is larger than the update number fj _i indicated by the confirmed update number information 104), the determination The unit 15 outputs a determination result indicating that the tag output information g (s _{i, j} ) to be verified is valid (OK) (step S14). Further, the update unit 16 receives the update count information 101 (i) and the update count information 102 (j) extracted by the extraction unit 13, and the value of the confirmed update count information fj _i associated with this i Update the correspondence table 100 with j as j (step S15). Thereby, the definite update number information fj _i is stored as a value indicating the maximum value of the number of update times of the tag output information that the verification server device 10 has validated. Note that determining that the tag output information g (s _{i, j} ) is valid (OK) means that if the tag output information g (s _{i, j} ) is used for authentication processing, authentication is performed. If the tag output information g (s _{i, j} ) is used for authenticity determination, it means that it is not a counterfeit.

<Effect of this embodiment>
As described above, in this embodiment, paying attention to the fact that the number of updates of the tag output information used for the replay attack is less than or equal to the number of updates of the tag output information that the verification server device has determined to be valid in the past. The replay attack is detected by comparing the number of updates.
When an attacker intends to completely forge a tag device in the configuration as in this embodiment, the attacker must acquire seed information such as a pseudo-random number written inside each tag device. However, due to the nature of cryptographic pseudorandom numbers, it is difficult to execute it only from the RFID protocol.

Moreover, even if an attacker obtains tag output information from a tag device in advance and forges a tag device that transmits the tag output information, if the real tag device accesses the server device once, it is output from the forged tag device. It is determined that all the tag output information is illegal (denial or counterfeit).
[Second Embodiment]
Next, a second embodiment of the present invention will be described.
This embodiment is a modification of the first embodiment. In the first embodiment, the verification server apparatus 10 calculates the tag output information that can be assumed in advance. In the second embodiment, the verification server apparatus performs seed information each time verification is performed. Tag output information is generated from this and compared with the tag output information to be verified. This is the difference between the first embodiment and the second embodiment. Below, it demonstrates centering around difference with 1st Embodiment, and abbreviate | omits description about the matter which is common in 1st Embodiment.

<Configuration>
FIG. 5 is a block diagram illustrating the configuration of the verification system 200 according to this embodiment. In addition, the same code | symbol as FIG. 1 was attached | subjected about the part which is common in 1st Embodiment.
The only difference between the verification system 200 and the first embodiment is that the verification server apparatus 210 is used instead of the verification server apparatus 10. Only the configuration of the verification server device 210 will be described below.
The difference between the verification server device 210 and the verification server device 10 is that a memory 211 that stores the correspondence table 300 is arranged instead of the memory 11 that stores the correspondence table 100, and an extraction unit 213 is arranged instead of the extraction unit 13. It is only a point to do. Here, the correspondence table 300 is a table in which the tag identifier 301 (i), the seed information 302 (s _{i, 0} ), and the confirmed update count information 304 (fj _i ) are associated with each other. Substantial differences between the extraction unit 13 and the extraction unit 213 will be described in the description of the processing.

<Processing of Verification System 220>
Next, processing of the verification system 200 of this embodiment will be described. The processing of the tag device 20 and the reader device 30 is the same as that of the first embodiment, and thus the description thereof is omitted. Only the processing of the verification server device 210 will be described below.
[Processing of Verification Server Device 210]
FIG. 6 is a flowchart for explaining processing of the verification server apparatus 210 of this embodiment. Below, the process of the verification server apparatus 210 is demonstrated using this.

First, the verification server device 210 receives the tag output information g (s _{i, j} ) to be verified transmitted from the reader device 30 in the communication unit 12 (accepts input: step S21). Using this as a trigger, the control unit 17 assigns 1 to the variable n, and stores the variable n in the temporary memory 17a (step S22). Next, n stored in the temporary memory 17a is sent to the extraction unit 213, and the extraction unit 213 uses this to extract the seed information 302 (s _{n, 0} ) from the correspondence table 300 of the memory 211 (step S23). ). Next, the control unit 17 assigns 0 to the variable m, and stores this m in the temporary memory 17a (step S24). Next, m stored in the temporary memory 17a is sent to the extraction unit 213, and the extraction unit 213 uses this and the seed information 302 (s _{n, 0} ) to obtain g (h ^m (s _{n, 0} )). Is calculated (step S25). Next, the tag output information g (s _{i, j} ) received in step S21 is sent to the extraction unit 213, which extracts the tag output information g (s _{i, j} ) and the calculated g (h ^It is compared whether ^m (s _{n, 0} ) matches (step S26).

If it is determined that they do not match, the control unit 17 stores a value obtained by adding 1 to m stored in the temporary memory 17a as a new m in the temporary memory 17a (step S28). And the control part 17 verifies whether it is m> M (M is the upper limit of the update frequency), and if it is not m> M, it returns a process to step S25. On the other hand, if m> M, the control unit 17 verifies whether or not n stored in the temporary memory 17a is N (N is the total number of tag devices). 1 is added to the temporary memory 17a as a new n (step S31), and the process returns to step S23. On the other hand, if n = N, the control unit 17 gives a command to the determination unit 15, and the determination unit 15 outputs information indicating that the verification target tag output information g (s _{i, j} ) is invalid ( In step S34), the control unit 17 ends the process.

On the other hand, when the extraction unit 213 determines in step S27 that the tag output information g (s _{i, j} ) to be verified matches the calculated g (h ^m (s _{n, 0} )) (that is, n = I, m = j), the extraction unit 213 extracts the definite update count information 304 (fj _i ) corresponding to the seed information s _{n, 0} (ie, s _{i, 0} ) from the correspondence table 300 of the memory 211. (Step S32). This confirmed update count information 304 (fj _i ) and value j = m (corresponding to “the update count of verification target tag output information extracted by the extraction unit 213”) are sent to the comparison unit 14, and the comparison unit 14 It is determined whether j> fj _i is satisfied (step 33). This determination result is sent to the determination unit 15. If the determination result indicates that j> fj _i is not satisfied, the determination unit 15 outputs information indicating that the tag output information g (s _{i, j} ) to be verified is invalid ( Step S34), the control unit 17 ends the process. On the other hand, when the determination result is determined to be j> fj _i , the determination unit 15 outputs information indicating that the tag output information g (s _{i, j} ) to be verified is valid. (Step S35). In this case, n = i and m = j stored in the temporary memory 17 a are further sent to the update unit 16. In the correspondence table 300, the update unit 16 updates the confirmed update count information fj _i associated with _i to a value of j (step S15).
Even if it is the above structures, the effect similar to 1st Embodiment can be acquired.

[Modifications, etc.]
The present invention is not limited to the embodiments described above.
For example, in each of the embodiments described above, the tag output information is updated every time it is output from the tag device. Therefore, when the number of updates of the verification target tag output information extracted by the extraction units 13 and 213 is equal to or less than the number of updates indicated by the confirmed update number information 104 and 304, it is determined that the verification target tag output information is invalid. It was set as the structure to do. However, when the present invention is applied to a system in which the tag output information is not updated each time, the update count of the verification target tag output information extracted by the extraction units 13 and 213 is the update count indicated by the confirmed update count information 104 and 304. It is desirable that the tag output information to be verified is determined to be invalid when the number is less than 1.

Further, in each of the above-described embodiments, the maximum number of update times of tag output information that has been validated in the past is determined update number information 104 and 304. However, if the replay attack detection accuracy may be lowered, the update count information 104, 304 may be any one of the tag output information update counts validated in the past.
Further, in each of the above-described embodiments, the configuration in which the tag output information is updated by the hash function is exemplified, but the configuration in which the tag output information is updated by other functions such as common key encryption may be employed.

Moreover, the data structure of the correspondence tables 100 and 300 is not limited to that of the above-described embodiments. The correspondence tables 100 and 300 may be distributed over a plurality of tables, or may be a correspondence table to which other elements are added.
Further, the various processes described above are not only executed in time series according to the description, but may be executed in parallel or individually as required by the processing capability of the apparatus that executes the processes. Needless to say, other modifications are possible without departing from the spirit of the present invention.
Further, the program describing the above-described processing contents can be recorded on a computer-readable recording medium. The computer-readable recording medium may be any medium such as a magnetic recording device, an optical disk, a magneto-optical recording medium, or a semiconductor memory. Specifically, for example, the magnetic recording device may be a hard disk device or a flexible Discs, magnetic tapes, etc. as optical disks, DVD (Digital Versatile Disc), DVD-RAM (Random Access Memory), CD-ROM (Compact Disc Read Only Memory), CD-R (Recordable) / RW (ReWritable), etc. As the magneto-optical recording medium, MO (Magneto-Optical disc) or the like can be used, and as the semiconductor memory, EEP-ROM (Electronically Erasable and Programmable-Read Only Memory) or the like can be used.

The program is distributed by selling, transferring, or lending a portable recording medium such as a DVD or CD-ROM in which the program is recorded. Furthermore, the program may be distributed by storing the program in a storage device of the server computer and transferring the program from the server computer to another computer via a network.
As another execution form of the program, the computer may directly read the program from a portable recording medium and execute processing according to the program, and the program is transferred from the server computer to the computer. Each time, the processing according to the received program may be executed sequentially. Also, the program is not transferred from the server computer to the computer, and the above-described processing is executed by a so-called ASP (Application Service Provider) type service that realizes the processing function only by the execution instruction and result acquisition. It is good. Note that the program in this embodiment includes information that is used for processing by an electronic computer and that conforms to the program (data that is not a direct command to the computer but has a property that defines the processing of the computer).

  In this embodiment, the present apparatus is configured by executing a predetermined program on a computer. However, at least a part of these processing contents may be realized by hardware.

  As an industrial application field of the present invention, for example, authentication processing using an RFID tag, authentication determination processing, physical distribution management processing, and the like can be exemplified.

FIG. 1 is a block diagram illustrating the configuration of the verification system according to the first embodiment. FIG. 2 is a diagram illustrating a data configuration of the correspondence table in the first embodiment. FIG. 3 is a block diagram illustrating the verification server device according to the first embodiment in terms of hardware configuration. FIG. 4 is a flowchart for explaining processing of the verification system according to the first embodiment. FIG. 5 is a block diagram illustrating the configuration of the verification system according to the second embodiment. FIG. 6 is a flowchart for explaining processing of the verification server device according to the second embodiment.

Explanation of symbols

1,200 verification system 10,210 verification server device

Claims (7)

A verification server device that verifies the validity of tag output information that is sequentially updated,
A memory that stores fixed update count information indicating the update count of the tag output information that has been validated;
An input unit that receives input of tag output information to be verified;
An extraction unit for extracting the number of updates of the tag output information to be verified;
A comparison unit for comparing the number of updates extracted by the extraction unit with the number of updates indicated by the fixed update number information;
In accordance with the comparison result in the comparison unit, a determination unit that determines the validity of the tag output information to be verified,
A verification server device characterized by comprising: The verification server device according to claim 1,
The above memory is
Stores a correspondence table in which tag output information at each update time point, update number information indicating the number of times of update, and the determined update number information are associated with each tag device,
The extraction unit
Search the correspondence table, and extract the update count information corresponding to the verification target tag output information and the confirmed update count information,
The verification server apparatus characterized by the above-mentioned. The verification server device according to claim 1,
The above tag output information is
Information that is updated each time it is output from the tag device.
The above confirmed update count information
Information indicating the maximum number of updates of the tag output information that has been validated,
The determination unit is
When it is determined that the number of updates extracted by the extraction unit is equal to or less than the number of updates indicated by the fixed update number information, the tag output information to be verified is determined to be invalid, and the update extracted by the extraction unit When it is determined that the number of times is greater than the number of updates indicated by the confirmed update number information, it is determined that the tag output information to be verified is valid.
The verification server apparatus characterized by the above-mentioned. The verification server device according to claim 1,
When it is determined by the determination unit that the tag output information to be verified is valid, the update unit uses information indicating the number of updates of the target tag output information as the new confirmed update number information.
The verification server apparatus characterized by the above-mentioned. A verification system that includes a tag device that outputs tag output information and a verification server device that verifies the validity of the tag output information,
The tag device is
It has an output unit that outputs tag output information that is updated sequentially,
The verification server device
A memory that stores fixed update count information indicating the update count of the tag output information that has been validated;
An input unit that receives input of tag output information to be verified;
An extraction unit for extracting the number of updates of the tag output information to be verified;
A comparison unit for comparing the number of updates extracted by the extraction unit with the number of updates indicated by the fixed update number information;
In accordance with the comparison result in the comparison unit, a determination unit that determines the validity of the tag output information to be verified,
The verification system characterized by having. A tag verification method of a verification server device that verifies the validity of tag output information that is sequentially updated,
Storing the definite update count information indicating the update count of the tag output information that has been validated in the memory;
An input unit receiving input of tag output information to be verified;
An extraction unit extracting the number of updates of the verification target tag output information;
A step of comparing the update number extracted by the extraction unit with the update number indicated by the confirmed update number information;
A step of determining the validity of the verification target tag output information according to the comparison result in the comparison unit;
A tag verification method characterized by comprising:   The program for functioning a computer as a verification server apparatus in any one of Claim 1 to 4.

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