JP2012155560A - Authentication ic tag, authentication system, host access device, and authentication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the erroneous operation of an authentication IC tag.SOLUTION: In an authentication IC tag 100 having an authentication processing state and a memory access state, the memory access state is such a state that memory access processing from a host access device 200 to a memory part 104 is executable, and the authentication processing state is such a state that authentication processing using a public key encryption system by the host access device 200 is executable, and that the memory access processing is inhibited. The authentication IC tag 100 includes: a memory part 104; an authentication processing part 106 configured to perform the authentication processing in the authentication processing state; a memory access control part 107 configured to inhibit the memory access processing in the authentication processing state, and to perform the memory access processing in the memory access state; a communication part 101 configured to acquire a command by communicating with the host access device 200; and a processing state transition control part 108 configured to perform the state transition of the authentication IC tag between the authentication processing state and the memory access state on the basis of the command.

Description

  The present invention relates to an authentication IC tag, an authentication system, a host access device, and an authentication method for performing an authentication process for managing various articles and discriminating imitations, or an authentication process such as electronic authentication for authenticating an individual. It is.

  With the widespread use of electronic devices and electronic cards, non-genuine or counterfeit products have increased greatly, which has become a social problem. One means for solving this problem is an authentication system using an encryption method using an encryption key.

  In particular, authentication systems using IC tags are widely used for authentication of electronic devices and the like. In an authentication system using a general IC tag, a secret key cryptosystem is used. For example, Patent Literature 1 and Patent Literature 2 disclose a technique for performing authentication using a secret key cryptosystem.

  In authentication using a secret key cryptosystem, a scheme such as DES (Data Encryption Standard) used in Patent Document 1 is used. In the secret key cryptosystem, the encryption key and the decryption key are common.

  Authentication using a secret key cryptosystem has the advantage that the speed of encryption and decryption is fast. In particular, due to the short processing time and the short ciphertext, authentication using a secret key cryptosystem can be applied to products relatively easily, and its application fields are diverse.

  On the other hand, authentication using a secret key cryptosystem has a demerit that key delivery is a problem. That is, if a key is stolen, it can be decrypted with the key. In addition, authentication using a secret key cryptosystem has a demerit that it is not suitable for an unspecified number of authentications because it is necessary to create as many keys as the number of counterparts. In addition, the short ciphertext also has the disadvantage that the cryptographic strength is weak.

  As described above, the secret key cryptosystem has a problem that the key is difficult to distribute because the encryption key and the decryption key are common, and the encryption strength is weak because the ciphertext is short.

  In recent years, there is a public key cryptosystem as an encryption system that changes to a secret key. In the public key cryptosystem, the key to be encrypted is different from the key to be decrypted, and the original information cannot be restored unless they are in pairs. The advantage of this public key cryptosystem is that the key is different between encryption and decryption, so that “key distribution (distribution) is easy and management is easy”.

  In order to use the mechanism of the public key cryptosystem, it is necessary to obtain the public key of the other party in advance, but even if the public key is obtained by a third party, it is not decrypted and does not cause a problem. In addition, since the ciphertext of the public key cryptosystem is longer than that of the secret key cryptosystem, there is a disadvantage that the processing time is long. On the other hand, the encryption strength is stronger than that of the secret key cryptosystem. There is an advantage of being.

Japanese Patent Laid-Open No. 2001-307055 JP 2009-171467 A

  However, the above-described conventional technique has a problem that it cannot prevent the authentication IC tag from malfunctioning.

  For example, if a command identifier (operand) is lost due to an error during communication between the host access device and the authentication IC tag or due to garbled bits, the authentication IC tag is sent to the encryption sent from the host access device. Do not decrypt the sentence. At this time, since the ciphertext encrypted by the public key cryptosystem such as NTRU is very long, the public key ciphertext contains data that matches the command identifier of the memory access instruction or the access disallowed instruction. The authentication IC tag determines that the data is a command identifier. The authentication IC tag causes a malfunction such as an unintended memory access or a reply operation.

  In particular, when the authentication IC tag and the host access device perform communication using a communication method such as start-stop synchronization, the separation in bit units is clear, but a method for indicating the start and end of a command is not defined. . For this reason, the start and end of the command are unclear, and the above-described malfunction is likely to occur.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an authentication IC tag, an authentication system, a host access device, and an authentication method that can prevent an authentication IC tag from malfunctioning. .

  In order to solve the above problem, an authentication IC tag according to an aspect of the present invention is an authentication IC tag having an authentication processing state and a memory access state, and the memory access state is predetermined from a host access device. Is a state in which a memory access process to the memory unit for storing the data is executable, the authentication process state is capable of executing an authentication process using a public key cryptosystem by the host access device, and When the memory access process is prohibited, the authentication IC tag includes the memory unit, an authentication unit that performs the authentication process when the authentication IC tag is in the authentication process state, and the authentication IC tag The memory access process is prohibited when in the authentication process state, and the memory access process is prohibited when the authentication IC tag is in the memory access state. A memory access control unit that performs processing, a communication unit that acquires a command by communicating with the host access device, and between the authentication processing state and the memory access state based on the command acquired by the communication unit And a state transition control unit that performs state transition of the authentication IC tag.

  Thereby, in the authentication processing state, the memory access processing is prohibited, so even when a part of the data received in the authentication processing state is erroneously detected as a command identifier, the memory access processing can be prevented. It is possible to prevent malfunction of the authentication IC tag. In particular, when a public key cryptosystem is used for authentication processing, ciphertext data often becomes long, so the probability of erroneous detection of a command identifier increases. For this reason, the effect of preventing malfunction by the authentication IC tag according to one aspect of the present invention has a more special effect.

  The authentication unit performs the authentication process when the authentication IC tag is in the authentication process state and the communication unit acquires an authentication request command for requesting the authentication process, and performs the memory access control. A unit that performs the memory access process when the authentication IC tag is in the memory access state and the communication unit obtains an access request command that requests the memory access process, and the state transition control unit When the communication unit acquires a transition request command for requesting a state transition to either the authentication processing state or the memory access state, the authentication IC tag performs a state transition in response to the transition request command. May be.

  Thereby, each of the authentication process, the memory access process, and the state transition process is executed when a command corresponding to each process is received from the host access device. In other words, when the transition request command is acquired, the processing state must be confirmed by executing the switching processing between the authentication processing state in which authentication processing is possible and the memory access processing state in which memory access processing is possible. For example, neither authentication processing nor memory access processing is accepted. For this reason, even if a part of the ciphertext data is erroneously detected as a command identifier by missing the command identifier, an unintended operation (malfunction) of the authentication IC tag can be prevented.

  The state transition control unit may perform state transition of the authentication IC tag when the authentication process or the memory access process is completed.

  As a result, when the authentication process or the memory access process has already been correctly executed, even if the command identifier of the state transition request is received during the process, the state transition is not performed, so that the authentication IC tag is prevented from malfunctioning. be able to.

  The state transition control unit may maintain the state of the authentication IC tag in the authentication processing state when the authentication processing is completed.

  Thereby, the authentication process can be executed continuously. That is, if the state transition process is not executed, the authentication process can be executed independently and continuously, so that a plurality of continuous authentication processes can be performed.

  The authentication IC tag may further include an output unit that outputs state transition result data indicating a result of the state transition when the state transition control unit performs state transition of the authentication IC tag. Good.

  Thereby, when the state transition process is completed, the processing status of the authentication IC tag can be notified to the host access device, so that the authentication process or the memory access process of the authentication IC tag can be executed efficiently.

  In addition, the communication unit acquires ciphertext data encrypted using a public key from the host access device in a predetermined communication unit, and the authentication unit acquires all the ciphertext data. The ciphertext data may be decrypted as the authentication process.

  Accordingly, since decryption is performed after all the ciphertext data is received, it is possible to prevent the decryption of the ciphertext data from failing.

  Further, the communication unit obtains ciphertext data encrypted using a public key from the host access device in a predetermined communication unit, and the authentication unit obtains the ciphertext data as the authentication process. You may decode for every said communication unit.

  Thereby, since it decrypts whenever it receives ciphertext data, the decryption of ciphertext data can be speeded up and the time required for the authentication process can be shortened.

  The communication unit may communicate with the host access device via a physical signal line.

  Thereby, the authentication process of the contact type authentication IC tag can be performed.

  The communication unit may communicate wirelessly with the host access device.

  Thereby, the authentication process of a non-contact type authentication IC tag can be performed.

  Further, the communication unit obtains ciphertext data encrypted using a public key from the host access device, and the authentication unit uses a secret key corresponding to the public key as the authentication process. Decrypted text data is generated by decrypting the ciphertext data, and the communication unit may further transmit the decrypted text data to the host access device.

  Thereby, it is possible to determine whether or not the decryption of the ciphertext data by the authentication IC tag is correctly performed on the host access device side. That is, the host access device can determine whether or not the authentication processing of the authentication IC tag has been correctly completed.

  Further, the communication unit obtains ciphertext data obtained by encrypting plaintext data using a public key from the host access device, and the authentication unit performs a secret corresponding to the public key as the authentication process. Decrypted text data may be generated by decrypting the ciphertext data using a key, and it may be determined whether or not the plaintext data and the decrypted text data match.

  As a result, authentication processing of the authentication IC tag can be performed on the authentication IC tag side.

  The host access device according to one aspect of the present invention performs an authentication process that is a process of authenticating an authentication IC tag including a memory unit for storing predetermined data using a public key cryptosystem. A control unit that issues a command for transitioning the state of the authentication IC tag, and a communication unit that transmits a command corresponding to the command to the authentication IC tag. The status of the IC tag includes an authentication processing state in which memory access processing from the host access device to the memory unit is prohibited and the host access device can execute the authentication processing, and the memory access processing can be executed. Issues an instruction to transition to and from the memory access state.

  Thereby, since the command for changing the state of the authentication IC tag having the authentication processing state and the memory access state is generated, the state of the authentication IC tag can be changed.

  The host access device further includes an encryption unit that generates ciphertext data by encrypting plaintext data using a public key, and the control unit includes an authentication command that requests the authentication process, And issuing a memory access command for requesting the memory access processing, and the communication unit, when the authentication command is issued by the control unit, an identification code for identifying a command corresponding to the authentication command; The ciphertext data is transmitted to the authentication IC tag, and when the memory access command is issued by the control unit, an identification code for identifying a command corresponding to the memory access command is provided. You may transmit to an IC tag.

  As a result, authentication processing, memory access processing, and state transition processing can be requested from the authentication IC tag.

  The communication unit may change the signal waveform according to a command issued by the control unit.

  As a result, the signal waveform of communication between the authentication IC tag and the host access device is changed according to the command, so that the authentication IC tag can recognize the requested command by detecting the signal waveform. .

  The host access device may include a CPU (Central Processing Unit), and the CPU may execute the functions of the control unit, the encryption unit, and the communication unit.

  Thereby, all the main functions of the host access device can be realized by a software configuration.

  A host access device that performs authentication processing of an authentication IC tag, wherein the plaintext data is encrypted by encrypting plaintext data using a control unit that issues at least one command for the authentication IC tag and a public key. To identify a command corresponding to the one or more instructions by analyzing the ciphertext data, an encryption unit that generates text data, a communication unit that transmits the ciphertext data to the authentication IC tag, and An analysis unit that determines whether data matching the identification code is included in the ciphertext data, and when it is determined that data matching the identification code is included in the ciphertext data, A changing unit that generates a changed identification code by changing the identification code, and the communication unit may further transmit the changed identification code to the authentication IC tag.

  As a result, when a part of the ciphertext data matches the command identifier, the command identifier is changed. By using the changed command identifier, a part of the ciphertext data is erroneously detected as the command identifier. This can be prevented. Therefore, malfunction of the authentication IC tag can be prevented.

  An authentication system according to an aspect of the present invention includes any one of the above authentication IC tags and any of the above host access devices.

  Accordingly, since the memory access process is prohibited in the authentication process state, the memory access process can be prevented even when a part of the data received in the authentication process state is erroneously detected as a command identifier, and the authentication IC Tag malfunction can be prevented. In particular, when a public key cryptosystem is used for authentication processing, ciphertext data often becomes long, so the probability of erroneous detection of a command identifier increases. For this reason, the effect of preventing malfunction by the authentication system according to one aspect of the present invention is a more special effect.

  The present invention can be realized not only as an authentication IC tag, a host access device, and an authentication system, but also as a method using the processing units constituting the authentication IC tag, the host access device, and the authentication system as steps.

  For example, an authentication method according to an aspect of the present invention is an authentication method for authenticating an authentication IC tag having an authentication processing state and a memory access state, and the authentication IC tag in the memory access state is transmitted from a host access device. The memory access process to the memory unit for storing predetermined data can be executed, and the authentication IC tag in the authentication process state can execute the authentication process using the public key cryptosystem by the host access device And when the memory access process is prohibited and the authentication IC tag is in the authentication process state, the authentication method performs the authentication process, and the authentication IC tag is in the authentication process state. In some cases, the memory access processing is prohibited, and when the authentication IC tag is in the memory access state, the memory access A memory access step for performing authentication, a communication step for obtaining a command by communicating with the host access device, and the authentication IC tag between the authentication processing state and the memory access state based on the command. A state transition control step for performing state transition.

  As a result, the authentication IC tag in the authentication processing state is prohibited from the memory access processing, and therefore, even when a part of the data received in the authentication processing state is erroneously detected as a command identifier, the memory access processing can be prevented. And the malfunction of the authentication IC tag can be prevented. In particular, when a public key cryptosystem is used for authentication processing, ciphertext data often becomes long, so the probability of erroneous detection of a command identifier increases. For this reason, the effect of preventing malfunction by the authentication system according to one aspect of the present invention is a more special effect.

  According to the present invention, it is possible to prevent malfunction of the authentication IC tag.

It is a block diagram which shows an example of a structure of the authentication IC tag of the public key cryptosystem which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the command classification which concerns on Embodiment 1 of this invention. It is a block diagram which shows an example of a structure of the authentication process part which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the command format which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of operation | movement of the authentication IC tag which concerns on Embodiment 1 of this invention. It is a block diagram which shows an example of a structure of the electronic device which is an example of the authentication system which concerns on Embodiment 1 of this invention. It is a sequence diagram which shows an example of operation | movement of the authentication system which concerns on Embodiment 1 of this invention. It is a sequence diagram which shows an example of operation | movement of the authentication system which concerns on Embodiment 1 of this invention. It is a sequence diagram which shows operation | movement of an authentication system when an authentication IC tag causes a malfunction. It is a flowchart which shows an example of the state transition of the authentication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the state transition of the authentication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the state transition of the authentication system which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the state transition of the authentication system which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the authentication process by the side of a host access apparatus in the authentication system which concerns on Embodiment 1 of this invention. It is a block diagram which shows an example of a structure of the electronic device which is an example of the authentication system which concerns on Embodiment 2 of this invention. It is a block diagram which shows an example of a structure of the authentication IC tag which concerns on Embodiment 2 of this invention. It is a block diagram which shows an example of a structure of the electronic device which is an example of the authentication system which concerns on the modification of embodiment of this invention. It is a block diagram which shows an example of a structure of the electronic device which is an example of the authentication system which concerns on the modification of embodiment of this invention. It is a figure which shows an example of a structure of the non-contact-type authentication system which concerns on the modification of embodiment of this invention. It is a block diagram which shows an example of a structure of the authentication IC tag which concerns on the modification of embodiment of this invention. It is a flowchart which shows an example of operation | movement of the authentication IC tag which concerns on the modification of embodiment of this invention. It is a block diagram which shows an example of a structure of the authentication process part which concerns on the modification of embodiment of this invention. It is a figure for demonstrating the authentication process by the side of an authentication IC tag in the authentication system which concerns on the modification of embodiment of this invention. It is a block diagram which shows an example of a structure of the authentication IC tag which concerns on the modification of embodiment of this invention. It is a figure which shows an example of the change of the command format by the host access apparatus which concerns on the modification of embodiment of this invention. It is a figure which shows an example of the change of the command format by the host access apparatus which concerns on the modification of embodiment of this invention.

  Hereinafter, embodiments of an authentication IC tag, an authentication system, a host access device, and an authentication method according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
The authentication IC tag according to the first embodiment of the present invention includes an authentication process using a public key cryptosystem by a host access device and a memory access process to a memory unit for storing predetermined data from the host access device. Do. The authentication IC tag includes a state transition control unit that performs a state transition of the authentication IC tag between the authentication processing state and the memory access state based on the acquired command, and an authentication unit that performs an authentication process when the authentication IC state is the authentication processing state And a memory access control unit that prohibits memory access processing when in the authentication processing state and executes memory access processing when in the memory access state.

  That is, the authentication IC tag according to the first embodiment of the present invention has an authentication processing state and a memory access state. The authentication processing state is a state in which authentication processing can be executed but memory access processing cannot be performed. The memory access state is a state in which memory access processing can be executed.

  FIG. 1 is a block diagram showing an example of the configuration of an authentication IC tag 100 of a public key cryptosystem according to Embodiment 1 of the present invention. As shown in FIG. 1, the authentication IC tag 100 includes a communication unit 101, a command identification unit 102, an identification code storage unit 103, a memory unit 104, an authentication control unit 105, an authentication processing unit 106, and a memory access. A control unit 107, a processing state transition control unit 108, an output data control unit 109, and an input / output terminal 110 are provided.

  The authentication IC tag 100 according to the first embodiment of the present invention performs an authentication process and a memory access process. The authentication process is a process using a public key cryptosystem by the host access device 200. The memory access process is an access process to the memory unit 104 by the host access device 200.

  Specifically, the authentication IC tag 100 has an authentication processing state and a memory access state. In the authentication IC tag 100 in the authentication processing state, the memory access processing from the host access device 200 to the memory unit 104 is prohibited, and the host access device 200 can execute the authentication processing using the public key cryptosystem. Further, the authentication IC tag 100 in the memory access processing state is prohibited from authentication processing using the public key cryptosystem by the host access device 200 and can execute memory access processing from the host access device 200 to the memory unit 104.

  The communication unit 101 transmits and receives data by communicating with the host access device 200. Specifically, the communication unit 101 is connected to the input / output terminal 110, receives data transmitted from the external host access device 200, and receives the received data as a command identification unit 102, an authentication control unit 105, and a memory access control. To the processing unit 107 and the processing state transition control unit 108.

  The data received by the communication unit 101 is, for example, a command generated by the host access device 200 in order to request the authentication IC tag 100 for predetermined processing. The command includes an identification code (command identifier) for identifying the command. Details of the command will be described later.

  Further, the communication unit 101 receives output data to be transmitted to the outside controlled by the output data control unit 109, and transmits it to the external host access device 200 via the input / output terminal 110. Details of the output data will be described later.

  The command identification unit 102 is connected to the communication unit 101 and identifies a command in received data transmitted from the external host access device 200. The identification of the command is to determine the type of processing for which the authentication IC tag 100 is requested by analyzing the identification code.

  Specifically, the command identification unit 102 refers to the command identification information registered in the identification code storage unit 103 to determine whether the command included in the received data is an authentication processing request or a memory access request. It is determined whether it is a processing state transition request. Then, the command identification unit 102 issues operation instructions to the authentication control unit 105, the memory access control unit 107, and the processing state transition control unit 108, respectively.

  The identification code storage unit 103 is a memory for storing a command identification code. Specifically, identification code information as shown in FIG. 2 to be transmitted to the command identification unit 102 is stored in the identification code storage unit 103. The command identification unit 102 can refer to the identification code information stored in the identification code storage unit 103 as appropriate. Note that the identification code information may share an address space with the memory unit 104 and be rewritable by a memory access instruction.

  The memory unit 104 is a memory for storing predetermined data. For example, the memory unit 104 includes a FeRAM (Ferroelectric Random Access Memory). Note that the memory unit 104 may be configured by an EEPROM (Electric Erasable and Programmable ROM) instead of FeRAM.

  Further, the memory unit 104 may be divided into a protected area and a non-protected area, for example, and information that should not be referred to from the outside may be stored as predetermined data in the protected area. For example, product information, key information for decrypting ciphertext, and the like are stored in the protected area of the memory unit 104. In the memory unit 104, all areas may be protected areas, or all areas may be non-protected areas. Further, it may be possible to dynamically change the protected area and the non-protected area according to the data to be stored.

  The authentication control unit 105 causes the authentication processing unit 106 to perform authentication processing when the authentication IC tag 100 is in the authentication processing state. Specifically, the authentication control unit 105 performs authentication processing on the authentication processing unit 106 when the authentication IC tag 100 is in the authentication processing state and the communication unit 101 acquires an authentication request command for requesting authentication processing. Let it be done.

  For example, the authentication control unit 105 receives an authentication processing instruction from the command identification unit 102 when the command included in the received data determined by the command identification unit 102 is an authentication processing request. Then, the authentication control unit 105 instructs the authentication processing unit 106 to perform authentication processing that is decryption processing of ciphertext data. The authentication control unit 105 also notifies the command identification unit 102, the memory access control unit 107, and the processing state transition control unit 108 when the authentication process is completed.

  Note that the authentication control unit 105 may prohibit the authentication process when the authentication IC tag 100 is in the memory access state.

  The authentication processing unit 106 generates decrypted text data by decrypting the cipher text data included in the received data output from the communication unit 101 in response to an instruction from the authentication control unit 105. As shown in FIG. 3, the authentication processing unit 106 includes a ciphertext decryption unit 106a and a secret key storage unit 106b.

  The ciphertext decryption unit 106a performs a decryption process using the decryption key (secret key) stored in the secret key storage unit 106b. The ciphertext decryption unit 106a is a public key cryptosystem cryptographic circuit. The public key cryptosystem indicates the above-described NTRU and the like, and hash processing may be performed after the encryption processing. The decrypted text data is output to the output data control unit 109.

  The memory access control unit 107 prohibits memory access processing from the host access device 200 to the memory unit 104 when the authentication IC tag 100 is in the authentication processing state. The memory access control unit 107 performs a memory access process from the host access device 200 to the memory unit 104 when the authentication IC tag 100 is in the memory access state. Specifically, the memory access control unit 107 performs memory access processing when the authentication IC tag 100 is in a memory access state and the communication unit 101 acquires an access request command for requesting memory access processing.

  For example, when the command included in the received data determined by the command identification unit 102 is a memory access request, the memory access control unit 107 receives an instruction for memory access processing from the command identification unit 102. The memory access control unit 107 performs a memory access process to the memory unit 104.

  Specifically, when the access request command is a write request to the memory unit 104, the memory access control unit 107 writes the write data in the received data into the address area of the received data. When the write access is completed, the memory access control unit 107 outputs a write completion signal to the output data control unit 109. It is also possible not to notify the completion of writing.

  When the access request command is a read request from the memory unit 104, the memory access control unit 107 reads the received data from the address area. When the completion of the read access is completed, the memory access control unit 107 outputs a read completion signal together with the read data to the output data control unit 109. It should be noted that the completion of reading can be notified implicitly only by returning read data.

  The processing state transition control unit 108 performs state transition of the authentication IC tag 100 between the authentication processing state and the memory access state based on the command acquired by the communication unit 101. Specifically, the processing state transition control unit 108 responds to the transition request command when the communication unit 101 acquires a transition request command for requesting a state transition to either the authentication processing state or the memory access state. The state transition of the authentication IC tag 100 is performed.

  For example, the processing state transition control unit 108 receives an instruction for processing state transition processing from the command identification unit 102 when the command included in the received data determined by the command identification unit 102 is a processing state transition request. Then, the process state transition control unit 108 performs a process state transition process.

  The processing state transition control unit 108 switches the processing state when the processing state of the authentication IC tag 100 is the authentication processing state and the next processing to be performed is changed to the memory access processing. In addition, when the processing state of the authentication IC tag 100 is the memory access processing state, the processing state transition control unit 108 switches the processing state even when the processing to be performed next is changed to the authentication processing. When the process state transition process is not performed, the previous process and the current process are the same. For example, when the previous process is an authentication process, the current process is an authentication process. The same applies to the memory access process.

  Whether the processing state transition control unit 108 performs the transition by determining whether or not a specific code (transition determination code) in the received data matches a code indicating permission or non-permission of the transition state. Determine whether or not. When the transition process is permitted, the process state transition control unit 108 causes the authentication IC tag 100 to transition from the authentication process state to the memory access state. Alternatively, the processing state transition control unit 108 causes the authentication IC tag 100 to transition from the memory access state to the authentication state.

  If the transition process is not permitted, the process state transition control unit 108 keeps the authentication IC tag 100 in the current process state. If the authentication IC tag 100 remains in the current processing state, the authentication IC tag 100 can again execute the same type of processing as the current processing. That is, the processing state transition control unit 108 maintains the state of the authentication IC tag 100 in the authentication processing state when the authentication processing is completed. Further, the processing state transition control unit 108 may maintain the state of the authentication IC tag 100 in the memory access state when the memory access processing is completed.

  Further, even when the transition process is not executed, the authentication IC tag 100 can execute the same type of process as the current process again. That is, when the transition process is not executed, the authentication IC tag 100 can continuously execute the current process. For example, after executing the first authentication process, the second authentication process can be executed.

  When the transition process is executed, the process state transition control unit 108 outputs a transition state signal indicating the execution result to the output data control unit 109. The execution result differs depending on whether the transition is from the authentication process to the memory access process or from the memory access process to the authentication process. Therefore, by determining the value of the execution result, the external host access device 200 can grasp the processing state of the authentication IC tag 100.

  Further, the process state transition control unit 108 may output the transition result even when the transition process is not permitted. The execution result when the transition process is not permitted is the current processing state of the authentication IC tag 100.

  The output data control unit 109 is an example of an output unit, selects each output data output from the authentication processing unit 106, the memory access control unit 107, and the processing state transition control unit 108, and transmits it to the communication unit 101. Specifically, the output data control unit 109 includes an authentication result signal indicating an authentication result by the authentication processing unit 106, a stored data read signal indicating data read from the memory unit 104 by the memory access control unit 107, and a process One of the transition state signals indicating the result of the state transition by the state transition control unit 108 is selected, and the selected data is transmitted to the communication unit 101. For example, when the state transition of the authentication IC tag 100 is performed, the output data control unit 109 outputs state transition result data indicating the state transition result to the host access apparatus 200 via the communication unit 101.

  The input / output terminal 110 is connected to the communication unit 101. The communication unit 101 receives reception data input from the external host access device 200 via the input / output terminal 110, and outputs output data output from the output data control unit 109 to the external host access device 200. Send.

  Next, the command type stored in the identification code storage unit 103 and the operation corresponding to the command will be described. FIG. 2 is a diagram showing an example of command types according to Embodiment 1 of the present invention.

  In the example illustrated in FIG. 2, the command types include authentication processing, transition processing, memory access processing, and processing status confirmation processing. That is, the command identification unit 102 determines whether the received command is an authentication request command, a transition request command, an access request command, or a status confirmation request command.

  The authentication request command is a command that requests authentication processing. For example, when the identification code “A0” is included in the received data, the command identification unit 102 determines that the command included in the received data is an authentication request command. Then, the command identification unit 102 notifies the authentication control unit 105 that the authentication request command has been acquired.

  The authentication control unit 105 controls the authentication processing unit 106 to decrypt the ciphertext data “X0” included in the received data. The authentication processing unit 106 decrypts the ciphertext data “X0” using the secret key corresponding to the public key to generate decrypted text data, and outputs the generated decrypted text data (authentication result signal) to the output data control unit Output to 109. Then, the output data control unit 109 outputs the decrypted text data as authentication result data “B0” via the communication unit 101.

  The transition request command is a command for requesting state transition processing. For example, when the received data includes the identification code “S0”, the command identifying unit 102 determines that the command included in the received data is a transition request command. Then, the command identification unit 102 notifies the processing state transition control unit 108 that the transition request command has been acquired.

  The process state transition control unit 108 acquires the transition determination code “S1” included in the received data, and determines whether the acquired transition determination code “S1” indicates whether the state transition process is possible. Specifically, the process state transition control unit 108 performs a state transition when the transition determination code “S1” matches a code indicating permission of the state transition process. Further, the process state transition control unit 108 does not perform the state transition when the transition determination code “S1” matches the code indicating that the state transition process is not permitted. That is, the processing state transition control unit 108 maintains the state of the authentication IC tag 100 as it is.

  For example, when the transition determination code “S1” matches the code that permits the transition from the memory access state to the authentication processing state, the processing state transition control unit 108 changes the authentication IC tag 100 to the authentication processing state. When the transition determination code “S1” matches the code that permits the transition from the authentication processing state to the memory access state, the processing state transition control unit 108 changes the authentication IC tag 100 to the memory access state.

  The processing state transition control unit 108 outputs transition result data (transition state signal) to the output data control unit 109. The output data control unit 109 outputs transition result data via the communication unit 101. For example, if the result of the transition process (or the result of the transition not permitted) or the authentication IC tag 100 is in the memory access state, the output data control unit 109 displays the transition result data “T0” indicating that it is in the memory access state. Output. When the authentication IC tag 100 is in the authentication processing state, the output data control unit 109 outputs transition result data “T1” indicating that it is in the authentication processing state.

  The access request command is a command for requesting memory access processing. For example, when the identification code “M0” is included in the received data, the command identification unit 102 determines that the command included in the received data is an access request command. Then, the command identification unit 102 notifies the memory access control unit 107 that the access request command has been acquired.

  For example, when the access request command is a write request, the memory access control unit 107 acquires a memory address “AD” and write data “WT” included in the received data. Then, the memory access control unit 107 writes the write data “WT” in the area in the memory unit 104 indicated by the acquired memory address “AD”.

  When the access request command is a read request, the memory access control unit 107 acquires the memory address “AD” included in the received data and stores it in the area in the memory unit 104 indicated by the acquired memory address “AD”. Read the stored data. Then, the memory access control unit 107 outputs the read data to the output data control unit 109 as a storage data read signal (memory data “N0”). The output data control unit 109 outputs memory data “N0” via the communication unit 101.

  The state confirmation request command is a command for confirming the current state of the authentication IC tag 100. For example, if the identification code “ST0” is included in the received data, the command identification unit 102 determines that the command included in the received data is a state confirmation request command. Then, the command identification unit 102 notifies the processing state transition control unit 108 that the state confirmation request command has been acquired.

  The processing state transition control unit 108 outputs a signal indicating the current state of the authentication IC tag 100 to the output data control unit 109. Then, the output data control unit 109 outputs status notification data indicating the current status of the authentication IC tag 100 via the communication unit 101. For example, when the authentication IC tag 100 is in the memory access state, the output data control unit 109 outputs state notification data “T0” indicating that it is in the memory access state. When the authentication IC tag 100 is in the authentication processing state, the output data control unit 109 outputs state notification data “T1” indicating that it is in the authentication processing state.

  Subsequently, an example of a command format according to Embodiment 1 of the present invention will be described. FIG. 4 is a diagram showing an example of a command format according to Embodiment 1 of the present invention.

  As shown in FIG. 4, the command includes an identification code and processing target data. FIG. 4 shows an example of the identification code “A0”, that is, an authentication request command. The authentication IC tag 100 receives the ciphertext data “X0” following the identification code “A0”.

  The ciphertext data “X0” is, for example, data obtained by encrypting plaintext data to be transmitted in a secret manner by the NTRU encryption method. The NTRU encryption method is disclosed in, for example, Patent Document 3 (Japanese Patent Laid-Open No. 2003-195755). Ciphertext data encrypted by the NTRU encryption method is generally used with a bit length of about 4000 bits in order to ensure encryption strength.

  Since public key cryptosystems include systems such as RSA and ECC in addition to NTRU, these cryptosystems may be used.

  Next, an example of the operation of the authentication IC tag 100 according to Embodiment 1 of the present invention will be described. FIG. 5 is a flowchart showing an example of the operation of the authentication IC tag 100 according to Embodiment 1 of the present invention. FIG. 5 shows an example in which the authentication IC tag 100 is in the authentication processing state in the initial state.

  First, the authentication IC tag 100 is in a waiting state for receiving an authentication request command (S101). That is, the authentication IC tag 100 stands by without doing anything until the identification code of the authentication request command is received. When the communication unit 101 acquires data including an identification code while waiting for reception, the command identification unit 102 analyzes the identification code to determine a process requested by the authentication IC tag 100. As a result, the authentication IC tag 100 enters a ciphertext acquisition state.

  Note that, for example, even if an access request command is received during this waiting period, the authentication IC tag 100 does not execute the memory access process. Further, for example, when a transition request command is received during the standby period, the authentication IC tag 100 may perform state transition processing (processing after S107). Alternatively, since the authentication process has not been completed, even if a transition request command is received, the authentication IC tag 100 may prohibit state transition.

  When the identification code of the authentication request command is acquired, the communication unit 101 receives ciphertext data (S102). The external host access device 200 transmits and receives data in a specified bit unit regardless of a contact or non-contact interface. In other words, the communication unit 101 acquires ciphertext data encrypted using the public key from the host access device 200 in a predetermined communication unit. For example, when communicating by a communication method such as start-stop synchronization, data that can be transmitted in one communication is 8 bits.

  As described above, the communication unit 101 of the authentication IC tag 100 receives the authentication request command in units of N bits. Since the ciphertext necessary for authentication has a bit length of about 4000 bits, for example, the authentication IC tag 100 receives the ciphertext data in a plurality of times. Specifically, in the case of communication in units of 8 bits, communication is performed 500 times only by transmitting / receiving ciphertext data.

  The authentication IC tag 100 repeats reception of the ciphertext data obtained by dividing the authentication request command until reception of all the ciphertext data is completed (No in S103). Specifically, the reception of the divided ciphertext data is repeated until all 4000-bit ciphertext data is acquired. For example, when receiving the divided ciphertext data in units of 8 bits from the ciphertext acquisition state, the communication unit 101 holds the divided ciphertext data in the internal storage area and counts the number of times of reception. Then, the communication unit 101 continues to acquire the divided ciphertext data up to the count number until the necessary number of bits is received.

  After receiving the ciphertext data necessary for the authentication process, the authentication processing unit 106 performs an authentication process on the received ciphertext data (S104). Specifically, the authentication processing unit 106 generates decrypted text data by decrypting the cipher text data using a secret key corresponding to the public key.

  After the authentication process is completed (S105), specifically, after the generation of the decrypted text data is completed, the output data control unit 109 performs host access using the decrypted text data as an authentication result via the communication unit 101. The apparatus 200 is notified (S106). Here, for example, the host access apparatus 200 determines whether or not the authentication is successful by comparing the decrypted text data transmitted from the authentication IC tag 100 with the plain text data held by the host apparatus. . If it is determined that the authentication is successful, a transition request command is transmitted to the authentication IC tag 100. The detailed operation of the host access device 200 will be described later.

  The communication unit 101 receives the transition request command (S107). Specifically, the command identification unit 102 analyzes the received command identification code and confirms that the command is a transition request command. Then, the processing state transition control unit 108 determines whether or not the transition determination code matches the code that permits the transition from the authentication processing state to the memory access state (S108).

  When the transition determination code does not match the code that permits the transition from the authentication processing state to the memory access state (No in S108), the processing state transition control unit 108 does not perform the state transition. That is, the authentication IC tag 100 maintains an authentication processing state, that is, a state waiting for receiving an authentication request command.

  When the transition determination code matches the code that permits the transition from the authentication processing state to the memory access state (Yes in S108), the processing state transition control unit 108 performs the state transition of the authentication IC tag 100 (S109). Specifically, the processing state transition control unit 108 causes the authentication IC tag 100 to transition from the authentication processing state to the memory access state.

  After the processing state transition is completed (S110), the output data control unit 109 notifies the host access device 200 of data indicating the result of the state transition via the communication unit 101 (S111). Since the state transition is completed, the authentication IC tag 100 is in a waiting state for receiving an access request command (S112). Here, the host access device 200 confirms that the state of the authentication IC tag 100 has changed to the memory access state, and transmits an access request command.

  When the command received by the communication unit 101 is an access request command (No in S113), the communication unit 101 outputs the memory address (and write data) included in the received data to the memory access control unit 107. Then, the memory access control unit 107 reads data from the area of the memory unit 104 indicated by the memory address, or writes data to the area (S114).

  When the authentication IC tag 100 is in the memory access state and the communication unit 101 receives a transition request command (Yes in S113), the processing state transition control unit 108 determines the transition determination code (S108), and the state Perform transition processing.

  As described above, the authentication IC tag 100 according to the first embodiment of the present invention changes the state from the authentication processing state to the memory access state or the authentication processing state from the memory access state only when the transition request command is received. State transition to.

  Note that FIG. 5 illustrates the case where the initial state of the authentication IC tag 100 is the authentication processing state, but the same applies to the case where the initial state of the authentication IC tag 100 is the memory access state. Specifically, the processing is started from the case of waiting for access request command reception in FIG. 5 (S112).

  Next, details of the authentication system including the authentication IC tag 100 and the host access device 200 according to the first embodiment of the present invention and the host access device 200 will be described.

  FIG. 6 is a block diagram showing an example of the configuration of electronic device 300 that is an example of the authentication system according to Embodiment 1 of the present invention.

  The electronic device 300 includes a main body substrate 301 and an accessory device 302. The electronic device 300 is, for example, a device such as a mobile phone or a digital camera and a battery pack, or a game main body and a controller, and the battery pack and the controller correspond to the accessory device 302. The authentication system according to Embodiment 1 of the present invention is used for the purpose of discriminating imitation products or defective products between the main device and the accessory device, and ensuring safety.

  The main body substrate 301 includes a host access device 200 that performs authentication access to the accessory device 302 and a device (not shown) for performing an operation as an electrical product. The main body substrate 301 is a substrate including, for example, a mobile phone, a digital camera, or a processing unit that functions as a game main body.

  The accessory device 302 includes the authentication IC tag 100. For example, the accessory device 302 is a battery or a controller. As shown in FIG. 6, the authentication IC tag 100 and the host access device 200 are connected by two signal lines 303 and 304.

  The signal line 303 is a signal line for transmitting reception data acquired by the authentication IC tag 100 from the host access device 200. The signal line 304 is a signal line for transmitting transmission data transmitted from the authentication IC tag 100 to the host access device 200.

  As shown in FIG. 6, the host access device 200 includes a CPU 201, a key storage unit 202, an encryption processing unit 203, a communication unit 204, an authentication acquisition unit 205, and an authentication result comparison unit 206. The host access device 200 performs an authentication process for authenticating the authentication IC tag 100 using a public key cryptosystem.

  The CPU 201 is a control unit that controls processing of the host access device 200, and issues a request to the authentication IC tag 100. For example, the CPU 201 issues a command for changing the state of the authentication IC tag 100. Specifically, the CPU 201 issues a command for changing the state of the authentication IC tag 100 between the authentication processing state and the memory access processing state.

  Further, the CPU 201 issues an authentication command requesting the authentication IC tag 100 to perform authentication processing. Specifically, the CPU 201 issues a command for instructing the cryptographic processing unit 203 to generate ciphertext data. Further, the CPU 201 issues a memory access command for the authentication IC tag 100 via the communication unit 204.

  The key storage unit 202 is a memory that stores a public key (encryption key) used for encryption of plaintext data. In the present embodiment, the key storage unit 202 stores a public key. In the NTRU cryptosystem, the key length is about 4000 bits. In the case of an encryption method such as RSA or ECC, it may be about 200 bits.

  The key storage unit 202 receives an instruction from the CPU 201 and outputs an encryption key to the encryption processing unit 203. The encryption key may be rewritten by the CPU 201.

  The encryption processing unit 203 generates ciphertext data by encrypting plaintext data using the key data stored in the key storage unit 202 in accordance with an instruction from the CPU 201. The generated ciphertext data is transmitted to the accessory device 302 via the communication unit 204. Then, the authentication IC tag 100 receives the ciphertext data as IC tag reception data.

  Specifically, the encryption processing unit 203 performs NTRU encryption processing, which is a public key encryption method. The encryption processing unit 203 receives the command from the CPU 201 and encrypts plaintext data based on the NTRU encryption method using the encryption key stored in the key storage unit 202, thereby generating ciphertext data.

  Note that the plain text data is data to be transmitted in a secret manner, and is stored in a memory in the CPU 201, for example. Alternatively, the plain text data may be separately stored in a dedicated storage area.

  The communication unit 204 is an interface that electrically connects the main body substrate 301 and the accessory device 302. For example, the communication unit 204 may be an electrode, a connector, a terminal block, or a wiring pattern such as a land or a pad.

  As a communication method performed by the communication unit 204, various communication interface circuits such as a synchronous communication interface circuit such as SMBus (System Management Bus) (registered trademark) and an asynchronous communication interface circuit can be used.

  The communication unit 204 transmits a command corresponding to the command issued by the CPU 201 to the authentication IC tag 100. For example, when an authentication command is issued by the CPU 201, the communication unit 204 authenticates an authentication request command including an identification code for identifying a command (authentication request command) corresponding to the authentication command and ciphertext data. Transmit to the IC tag 100. In addition, when a memory access instruction is issued, the communication unit 204 transmits an access request command including an identification code for identifying a command (access request command) corresponding to the memory access instruction to the authentication IC tag 100. .

  Note that the authentication IC tag 100 includes at least the authentication processing unit 106 and the memory unit 104, decrypts the ciphertext data transmitted from the host access device 200, and performs host access via the signal line 304 as IC tag transmission data. Reply to device 200. When the transmission data from the host access device 200 is a write access to the memory unit 104, the authentication IC tag 100 may transmit the data stored in the memory unit 104. Alternatively, when the transmission data from the host access device 200 is a read access to the memory unit 104, the authentication IC tag 100 may transmit the data stored in the memory unit 104 as the IC tag transmission data. .

  The authentication acquisition unit 205 receives the decrypted text data (plain text data) transmitted from the authentication IC tag 100 via the communication unit 204 and stores it in an internal memory or the like.

  Upon receiving an instruction from the CPU 201, the authentication result comparison unit 206 determines whether the decrypted text data stored in the authentication acquisition unit 205 matches the plaintext data before being encrypted by the encryption processing unit 203. To do. For example, the authentication result comparison unit 206 includes a logical operator that performs a logical product operation. Then, the authentication result comparison unit 206 performs a comparison in units of 1 bit by a logical operator, and if all comparison values are 1, all the bits match, so the plaintext data and the decrypted text data match. Is determined.

  Whether the match is possible is transmitted to the CPU 201. If the plaintext data and the decrypted text data match, the CPU 201 determines that there is no problem with authentication, and determines that the accessory device 302 is a genuine product. If the plaintext data and the decrypted text data do not match, the CPU 201 determines that there is a problem (failure) in the authentication process, and determines that the accessory device 302 is an unauthorized product or a counterfeit product.

  Next, the operation of the authentication system according to Embodiment 1 of the present invention will be described.

  FIG. 7A is a sequence diagram showing an example of operation of the authentication system according to Embodiment 1 of the present invention. In the authentication system shown in FIG. 6, a desired operation is realized by issuing a command from the host access device 200 on the main body substrate 301 side to the authentication IC tag 100 on the accessory device 302 side. It is assumed that the authentication IC tag 100 is in the authentication processing state in the initial state and the memory access processing is prohibited.

  For example, the host access device 200 performs authentication access in order to detect whether the accessory device 302 is a counterfeit (S201). The host access device 200 generates an authentication request command including a command identifier and ciphertext data as authentication access. Then, the host access device 200 sends a command identifier (for example, a bit string of “1111”) and ciphertext data (about 4000 bits in the public key cryptosystem. For example, “1234_56bc_4fbc_ABCD_... AAAA”) to the authentication IC tag 100. (S202).

  Upon receiving the authentication request command, the authentication IC tag 100 performs an authentication process using the ciphertext data and the private key held therein (S203). The authentication IC tag 100 generates authentication result data representing the result of the authentication process (S204), and returns it to the host access device 200 (S205).

  The authentication result data includes, for example, a command identifier (for example, “2222”) for determining that the host access device 200 is the authentication result from the authentication IC tag 100. The authentication result data also includes decrypted text data (for example, “ABCD... AAAA”) generated by decrypting the cipher text data.

  The host access device 200 receives the authentication result data and determines whether the authentication is successful (S206). For example, the host access device 200 determines whether the decrypted text data transmitted from the authentication IC tag 100 matches the plain text data stored in the self device. When the decrypted text data and the plain text data match, the host access device 200 determines that the authentication process has been successful. When the decrypted text data and the plain text data do not match, the host access device 200 determines that the authentication process has failed.

  If the authentication process is successful (OK in S206), the host access device 200 determines that the authentication IC tag 100 is a genuine product, and stores detailed product information, for example, product number, usage frequency, and the like. Preparation for processing for accessing the access point 104 is performed (S207).

  If the authentication process fails (NG in S206), the host access device 200 determines that the authentication IC tag 100 is an unauthorized product or a counterfeit product, and disables the corresponding accessory device 302 (S208).

  In order for the host access device 200 to perform memory access processing, it is necessary to switch the processing state of the authentication IC tag 100 from the authentication processing state to the memory access processing state. This is because the authentication IC tag 100 does not change the processing state only by the successful authentication processing, remains in the authentication processing state, and the memory access processing is prohibited.

  The host access device 200 generates a transition request command to switch the processing state of the authentication IC tag 100 (S207). The transition request command includes a command identifier (for example, “3333”) and a transition determination code. The host access device 200 transmits the generated transition request command to the authentication IC tag 100 (S209).

  The authentication IC tag 100 analyzes the command identifier to confirm that the command transmitted from the host access device 200 is a transition request command, and executes state transition processing (S210). Then, the authentication IC tag 100 analyzes the transition determination code included in the transition request command to determine whether the state transition is permitted or not permitted (S211).

  If the transition determination codes do not match (NG in S211), the authentication IC tag 100 determines that the state transition is not permitted and maintains the authentication processing state (S212). If the transition determination codes match (OK in S211), the authentication IC tag 100 determines that the processing state transition is permitted, and transitions from the authentication processing state to the memory access state (S213).

  Then, the authentication IC tag 100 returns the transition result data to the host access device 200 regardless of whether the state transition is permitted or not (S214). For example, the transition result data is a value indicating the current processing state, and “T0” is returned if the memory is in the access state, and “T1” is returned if the state is the authentication processing state (see FIG. 2). For example, when the authentication IC tag 100 returns from the authentication processing state to the authentication processing state without transition, “T1” is returned.

  The host access device 200 receives the state transition result data from the authentication IC tag 100 and confirms that the authentication IC tag 100 is in the memory access state. Then, the host access device 200 generates an access request command (S215). The access request command includes a command identifier (for example, “ABCD”), a memory address, a Read / Write attribute signal (read / write determination data), and write data. The write data is not included in the access request command when it is a read request.

  Next, the host access device 200 transmits the generated access request command (S216). The authentication IC tag 100 receives the access request command and executes a memory access process (S217).

  If the access request command has a write attribute, that is, a command that requests writing to the memory unit 104, the authentication IC tag 100 writes the transmitted write data in the area indicated by the corresponding memory address. If the access request command has a Read attribute, that is, a command requesting reading to the memory unit 104, the authentication IC tag 100 reads data from the area indicated by the corresponding memory address.

  Then, the authentication IC tag 100 returns a write completion result or read data to the host access device 200 (S218, S219).

  The process switching from the memory access state to the authentication process state is performed in the same procedure.

  Here, an example in which authentication processing is continuously performed by disabling state transition will be described with reference to FIG. 7B. FIG. 7B is a sequence diagram showing an example of the operation of the authentication system according to Embodiment 1 of the present invention. In the authentication system shown in FIG. 6, a desired operation is realized by issuing a command from the host access device 200 on the main body substrate 301 side to the authentication IC tag 100 on the accessory device 302 side. It is assumed that the authentication IC tag 100 is in the authentication processing state in the initial state and the memory access processing is prohibited. In the following, the same processes as those in FIG. 7A are denoted by the same reference numerals, and the description thereof is omitted below.

  The host access device 200 performs authentication access in order to detect whether the accessory device 302 is a counterfeit product (S201 to S206). If the authentication process is successful (OK in S206), the host access device 200 normally determines that the authentication IC tag 100 is a genuine product as shown in FIG. 7A, and provides detailed product information such as a product number, Preparation for processing for accessing the memory unit 104 in which the frequency of use is stored is made (S207).

  At this time, there is a case where the host access device 200 continuously tries the authentication process. For example, when the host access device 200 does not perform the memory access process after the first authentication process, the host access apparatus 200 performs the authentication process before performing the memory access process again.

  At this time, as shown in FIG. 7B, the host access device 200 generates a transition request command in order to switch the processing state of the authentication IC tag 100 (S207a). The transition request command includes a command identifier (for example, “3333”) and a fake transition determination code. The host access device 200 transmits the generated transition request command to the authentication IC tag 100 (S209a).

  The authentication IC tag 100 analyzes the command identifier to confirm that the command transmitted from the host access device 200 is a transition request command, and executes state transition processing (S210a). Then, the authentication IC tag 100 analyzes the transition determination code included in the transition request command to determine whether the state transition is permitted or not permitted (S211a).

  In the example of FIG. 7B, as described above, the host access device 200 transmits a false transition determination code in order to place the authentication IC tag 100 in the authentication state. Since the authentication IC tag 100 receives the false transition determination code, the authentication IC tag 100 determines that the state transition is not permitted, and returns to the authentication processing state again.

  Then, the authentication IC tag 100 does not permit the transition process, and transmits transition result data indicating that the process has returned to the original state (specifically, the authentication process state) to the host access device 200 (S214a). Specifically, the authentication IC tag 100 returns “T1” indicating the authentication processing state.

  When the host access device 200 detects that the transition result data returned from the authentication IC tag 100 is “T1”, the host access device 200 recognizes that the authentication IC tag 100 is in the authentication processing state, and performs authentication access again. (S201a).

  For example, the host access device 200 generates an authentication request command including a command identifier and ciphertext data as authentication access. Then, the host access device 200 sends a command identifier (for example, a bit string of “1111”) and ciphertext data (about 4000 bits in the public key cryptosystem. For example, “1234_56bc_4fbc_ABCD_... AAAA”) to the authentication IC tag 100. (S202a). At this time, the first ciphertext data and the second ciphertext data do not need to be the same.

  Upon receiving the authentication request command, the authentication IC tag 100 performs an authentication process using the ciphertext data and the private key held inside (S203a). The authentication IC tag 100 generates authentication result data representing the result of the authentication process (S204a), and returns it to the host access device 200 (S205a).

  Thereby, it becomes possible to implement | achieve an authentication process continuously.

  In the example of FIG. 7B, the host access device 200 has transmitted a fake transition determination code, but may transmit a transition determination code for shifting to the authentication processing state. Further, the host access device 200 may not transmit the transition determination code. In the authentication IC tag 100, since the transition determination code is not received, it can be determined that the state transition is not permitted.

  Here, an example in which a conventional authentication IC tag malfunctions will be described. FIG. 8 is a sequence diagram showing an example of the operation of the authentication system when a conventional authentication IC tag malfunctions.

  For example, when the host access device performs authentication access, the authentication IC tag may miss the command identifier “1111” due to a communication error. At this time, since the host access device cannot detect the communication error of the authentication IC tag, it continues to transmit the ciphertext data.

  When the encrypted text data includes “ABCD” that is an identifier of the access request command, the authentication IC tag sequentially receives “ABCD” that is the command identifier of the memory access while receiving the encrypted text data. False positive from.

  The erroneously detected authentication IC tag determines that an access request command has been transmitted, performs memory access processing, and returns memory data to the host access device.

  Even if the memory access process is not performed and the memory data is not read, the authentication IC tag misidentifies that the memory access request has been received, so that the memory access process has failed. The access disapproval command shown is returned to the host access device. For this reason, a malfunction always occurs.

  On the other hand, in the authentication system according to the first embodiment of the present invention, the authentication IC tag 100 skips the authentication command identifier and accesses “ABCD” in the ciphertext data when it is in the authentication processing state. Even if it is determined that the request is a command identifier, the memory access process is not executed. Further, since the authentication IC tag 100 does not mistakenly recognize that the access request command has been received, it does not return an access non-permission instruction indicating that the memory access process has failed.

  Thus, the authentication IC tag 100 according to Embodiment 1 of the present invention can prevent malfunction. In particular, when the public key cryptosystem is used, since the ciphertext data becomes long, there is a high possibility that a code that matches the command identifier is included in the ciphertext data, and there is a high possibility of malfunction. Therefore, in the authentication system using the public key cryptosystem, the authentication IC tag 100 according to the present invention has a special effect.

  Next, an example of the operation of the authentication system according to Embodiment 1 of the present invention will be described. 9A to 9D are flowcharts showing an example of state transition of the authentication system according to Embodiment 1 of the present invention.

  The authentication IC tag 100 according to the first embodiment of the present invention is in a command acceptable state in the initial state after the power is turned on or after the reset is released. The command reception state at the time of activation is either the authentication processing state or the memory access state, and it can be switched depending on the activation method of the authentication IC tag 100.

  FIG. 9A is a flowchart illustrating a case where the authentication IC tag 100 is in an authentication request command reception state, that is, an authentication processing state, as an initial state. Hereinafter, a procedure when the external host access device 200 accesses the authentication IC tag 100 will be described with reference to FIG. 9A.

  In the authentication processing state (S300), the authentication IC tag 100 accepts only an authentication request command. Commands other than the authentication request command are not accepted even if they are erroneously detected due to a communication error or the like. Note that accepting a command means performing processing according to the acquired command. That is, the authentication IC tag 100 in the authentication processing state can perform the authentication processing when receiving the authentication request command, but can perform the memory access processing or the state transition processing even when other commands are received. Can not do.

  The host access device 200 issues an authentication request command including an identification code and ciphertext data, and transmits it to the authentication IC tag 100. The authentication IC tag 100 acquires all of the ciphertext data, performs authentication processing, and transmits the authentication result to the host access device 200 (S301). Specifically, the authentication IC tag 100 generates decrypted text data by decrypting the cipher text data, and transmits the generated decrypted text data to the host access device 200. Then, the host access device 200 determines whether or not the authentication process is successful by determining whether or not the plaintext data matches the received decrypted text data.

  If the authentication process is successful (Yes in S301), the authentication IC tag 100 enters a transition request command acceptance state (also referred to as a transition process state) (S302). In the transition request command acceptance state, the authentication IC tag 100 accepts a transition request command or a processing state confirmation command (see FIG. 2). Commands other than these are not accepted even if they are erroneously detected due to a communication error or the like.

  The host access device 200 issues a transition request command including an identification code and a transition determination code, and transmits it to the authentication IC tag 100. The authentication IC tag 100 acquires all the transition determination codes and determines whether the transition determination code is valid. Then, when the transition determination code is valid, the authentication IC tag 100 switches the processing state and transmits the state transition result data to the host access device 200 (S303). Note that the transition determination code being valid means that the transition determination code received by the authentication IC tag 100 matches a code indicating permission of transition processing.

  When the transition determination code is valid (Yes in S303), the processing state of the authentication IC tag 100 is switched from the authentication processing state to the memory access permission state (S304). In the memory access permission state, the authentication IC tag 100 accepts only an access request command. Commands other than the access request command are not accepted even if they are erroneously detected due to a communication error or the like.

  The host access device 200 issues an access request command including an identification code, a memory address, read / write determination data (Read / Write attribute signal), and write data (in the case of a write request), and transmits it to the authentication IC tag 100. To do. If the read / write determination data has the write attribute, the authentication IC tag 100 writes the write data to the area of the memory unit 104 indicated by the memory address included in the access request command (S305). If the read / write determination data has the read attribute, the data is read from the area of the memory unit 104 indicated by the memory address included in the access request command, and the read data is transmitted to the host access device 200 (S305).

  As described above, in the authentication system according to Embodiment 1 of the present invention, the authentication IC tag 100 transitions in the order of the authentication processing state (S300), the transition request command reception state (S302), and the memory access state (S304). . In each state, only the corresponding command is accepted, and transition to the next state is made when processing of the accepted command is completed. That is, in each state, only a corresponding process is permitted and other processes are prohibited, so that the authentication IC tag 100 can be prevented from malfunctioning.

  In the transition request command acceptance state, a command that can accept the authentication processing state that is the immediately preceding processing state may be accepted. That is, when the authentication IC tag 100 that is in the transition request command reception state receives the authentication request command, the authentication process may be executed. As a result, the authentication system according to Embodiment 1 of the present invention can continuously perform authentication processing.

  Next, a case where the initial state of the authentication IC tag 100 is a memory access state will be described.

  FIG. 9B is a flowchart showing a case where the authentication IC tag 100 is in a memory access state as an initial state. Hereinafter, a procedure when the external host access device 200 accesses the authentication IC tag 100 will be described with reference to FIG. 9B.

  In the memory access state (S310), the authentication IC tag 100 accepts only an access request command. Commands other than the access request command are not accepted even if they are erroneously detected due to a communication error or the like.

  The host access device 200 issues an access request command including an identification code, a memory address, read / write determination data (Read / Write attribute signal), and write data (in the case of a write request), and transmits it to the authentication IC tag 100. To do. If the read / write determination data has the write attribute, the authentication IC tag 100 writes the write data to the area of the memory unit 104 indicated by the memory address included in the access request command (S311). If the read / write determination data has the read attribute, the data is read from the area of the memory unit 104 indicated by the memory address included in the access request command, and the read data is transmitted to the host access device 200 (S311).

  When the memory access process is completed (Yes in S311), the authentication IC tag 100 enters a transition request command acceptance state (S312). In the transition request command acceptance state, the authentication IC tag 100 accepts a transition request command or a processing state confirmation command (see FIG. 2). Commands other than these are not accepted even if they are erroneously detected due to a communication error or the like.

  The host access device 200 issues a transition request command including an identification code and a transition determination code, and transmits it to the authentication IC tag 100. The authentication IC tag 100 acquires all the transition determination codes and determines whether the transition determination code is valid. Then, when the transition determination code is valid, the authentication IC tag 100 switches the processing state and transmits the state transition result data to the host access device 200 (S313). Note that the transition determination code being valid means that the transition determination code received by the authentication IC tag 100 matches a code indicating permission of transition processing.

  When the transition determination code is valid (Yes in S313), the processing state of the authentication IC tag 100 is switched from the memory access state to the authentication processing state (S314). In the authentication processing state, the authentication IC tag 100 accepts only an authentication request command. Commands other than the authentication request command are not accepted even if they are erroneously detected due to a communication error or the like.

  The host access device 200 issues an authentication request command including an identification code and ciphertext data, and transmits it to the authentication IC tag 100. The authentication IC tag 100 acquires all of the ciphertext data, performs an authentication process, and transmits an authentication result to the host access device 200. Specifically, the authentication IC tag 100 generates decrypted text data by decrypting the cipher text data, and transmits the generated decrypted text data to the host access device 200. Then, the host access device 200 determines whether or not the authentication process is successful by determining whether or not the plaintext data matches the received decrypted text data (S315).

  As described above, in the authentication system according to Embodiment 1 of the present invention, the authentication IC tag 100 transitions in the order of the memory access state (S310), the transition request command reception state (S312), and the authentication processing state (S314). You can also. As in the case of FIG. 9A, in each state, only the corresponding command is accepted, and when the processing of the accepted command is completed, the process proceeds to the next process. That is, in each state, only a corresponding process is permitted and other processes are prohibited, so that the authentication IC tag 100 can be prevented from malfunctioning.

  In the transition request command acceptance state, a command that can accept the memory access state that is the immediately preceding processing state may be accepted. That is, when the authentication IC tag 100 that is in the transition request command reception state receives the access request command, the memory access process may be executed. As a result, the authentication system according to Embodiment 1 of the present invention can continuously perform memory access processing.

  Subsequently, another example when the initial state of the authentication IC tag 100 is the authentication processing state will be described.

  FIG. 9C is a flowchart illustrating another example when the authentication IC tag 100 is in the authentication request command reception state, that is, the authentication processing state, as an initial state. Hereinafter, another example of the procedure when the external host access device 200 accesses the authentication IC tag 100 will be described with reference to FIG. 9C.

  The example of FIG. 9C is different from the example of FIG. 9A in that the authentication IC tag 100 returns to the immediately previous processing state when the transition process is not permitted. Below, it demonstrates centering on a different point and abbreviate | omits description about the same point.

  The authentication IC tag 100 that is in the transition request command reception state determines whether or not the transition determination code is valid when the transition request command is acquired. If the transition determination code is not valid, the transition process is not permitted (No in S400), so the processing state of the authentication IC tag 100 returns to the state before the transition request command reception state, specifically, the authentication processing state.

  At this time, the authentication IC tag 100 notifies the host access device 200 that the current state of the authentication IC tag 100 is the authentication processing state, thereby notifying that the transition processing is not permitted. . That is, the authentication IC tag 100 returns only whether the current state is the authentication processing state or the memory access state as return data for the transition request command. Alternatively, the authentication IC tag 100 may return data indicating a non-permitted state.

  Thereby, the host access device 200 is realized by disabling switching of the processing state when the current processing is to be performed continuously. Note that there is no dependence on whether the result of the authentication process is correct or not, and whether or not the state transition process is permitted. That is, the authentication process returns a correct authentication result to the outside even if the process state switching is not permitted.

  In addition, the host access device 200 may check the current processing state without changing the processing state by issuing a processing state confirmation command and transmitting it to the authentication IC tag 100 in the processing state transition command reception state. Is possible.

  For example, when the current processing state of the authentication IC tag 100 is the authentication processing state, the authentication IC tag 100 returns reply data “T1” shown in FIG. If the current processing state is the memory access state, the authentication IC tag 100 returns reply data “T0” shown in FIG. As a result, the external host access device 200 can confirm the processing state of the authentication IC tag 100.

  Next, another example in the case where the initial state of the authentication IC tag 100 is the memory access state will be described.

  FIG. 9D is a flowchart showing another example when the authentication IC tag 100 is in the access request command reception state, that is, in the memory access state, as an initial state. Hereinafter, another example of the procedure when the external host access device 200 accesses the authentication IC tag 100 will be described with reference to FIG. 9D.

  The example of FIG. 9D is different from the example of FIG. 9B in that the authentication IC tag 100 returns to the immediately previous processing state when the transition process is not permitted. Below, it demonstrates centering on a different point and abbreviate | omits description about the same point.

  The authentication IC tag 100 that is in the transition request command reception state determines whether or not the transition determination code is valid when the transition request command is acquired. If the transition determination code is not valid, the transition process is not permitted (No in S400), so the processing state of the authentication IC tag 100 returns to the state before the transition request command reception state, specifically, the memory access state.

  At this time, the authentication IC tag 100 notifies the host access device 200 that the current state of the authentication IC tag 100 is the memory access state, thereby notifying that the transition process is not permitted. . That is, the authentication IC tag 100 returns only whether the current state is the authentication processing state or the memory access state as return data for the transition request command. Alternatively, the authentication IC tag 100 may return data indicating a non-permitted state.

  As a result, as in the case of FIG. 9C, the host access device 200 is realized by disabling the switching of the processing state when it is desired to continuously perform the current processing.

  Note that the authentication IC tag 100 may be able to accept a processing state confirmation command not only in the transition request command acceptance state but also in the authentication processing state or the memory access state. As a result, the host access device 200 can check the current state of the authentication IC tag 100 before executing either the authentication process or the memory access process.

  Here, an example of a public key cryptosystem executed by the authentication system according to Embodiment 1 of the present invention will be described. FIG. 10 is a diagram for explaining authentication processing on the host access device 200 side in the authentication system according to Embodiment 1 of the present invention.

  In the host access device 200, the encryption processing unit 203 generates encrypted text data by encrypting the plain text data using the public key stored in the key storage unit 202. The host access device 200 transmits the generated ciphertext data to the authentication IC tag 100 as IC tag reception data together with the identification code of the command requesting the authentication process via the communication unit 204.

  The authentication IC tag 100 acquires an identification code and ciphertext data via the communication unit 101. When the command identification unit 102 analyzes the identification code and determines that the request is an authentication request, the authentication processing unit 106 generates decrypted text data by decrypting the cipher text data using the secret key. The authentication IC tag 100 returns the generated decrypted text data to the host access device 200 as IC tag transmission data via the communication unit 101.

  Note that the secret key is stored in an area where reading and writing from the outside of the memory unit 104 are prohibited, for example. Alternatively, the authentication processing unit 106 may have a memory that is prohibited from being read and written from the outside, and may store a secret key in the memory.

  In the host access device 200, the authentication acquisition unit 205 acquires decrypted text data via the communication unit 204. Then, the authentication result comparison unit 206 compares the plaintext data with the decrypted text data. When the plaintext data and the decrypted text data match, the host access device 200 determines that the authentication IC tag 100 has been successfully authenticated. If the plaintext data and the decrypted text data do not match, the host access device 200 determines that the authentication of the authentication IC tag 100 has failed.

  As described above, the authentication system according to Embodiment 1 of the present invention includes the authentication IC tag 100 and the host access device 200. The host access device 200 authenticates the authentication IC tag 100 using the public key cryptosystem. I do. The authentication IC tag 100 has an authentication processing state and a memory access state, and performs state transition between the authentication processing state and the memory access state in response to a command transmitted from the host access device 200. In the authentication IC tag 100 in the authentication process state, the memory access process from the host access device 200 to the memory unit 104 is prohibited, and the authentication process is permitted.

  As a result, when a problem such as missing a command identifier due to a communication error or the like occurs by controlling the transition of the processing state, the ciphertext data encrypted with the public key is very long. Even when there is data indicating a command identifier in the sentence data, malfunction can be prevented. For example, unintended memory access from the host access device 200 can be prevented.

  For example, if the command identifier of the transition request command and a part of the ciphertext data match due to data loss, the data following the command identifier is regarded as a transition determination code, but this transition determination code is not normally valid. Since the processing state is not permitted and the current processing can be executed again, there is no problem. Specifically, it is possible to prevent the processing state from being switched by sufficiently increasing the bit length of the transition determination code.

  As described above, in the first embodiment of the present invention, since the memory access process is prohibited in the authentication process state, the memory access process is performed even when a part of the data received in the authentication process state is erroneously detected as a command identifier. Can be prevented, and malfunction of the authentication IC tag can be prevented. In particular, when a public key cryptosystem is used for authentication processing, ciphertext data often becomes long, so the probability of erroneous detection of a command identifier increases. For this reason, the effect of preventing the malfunction of the authentication IC tag according to the first embodiment of the present invention is a more special effect.

(Embodiment 2)
The host access device according to the second embodiment of the present invention encrypts plaintext data using a public key, and generates a command by analyzing the encrypted data and an encryption unit that generates encrypted data. When it is determined that the data matching the identification code for identification is included in the ciphertext data, and the ciphertext data includes data matching the identification code And a changing unit that generates the changed identification code by changing the identification code.

  FIG. 11 is a block diagram showing an example of the configuration of electronic apparatus 400 that is an example of an authentication system according to Embodiment 2 of the present invention.

  The electronic device 400 includes a main body substrate 401 and an accessory device 402. The electronic device 400 is, for example, a mobile phone or a digital camera, like the electronic device 300 according to the first embodiment. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described.

  The main body substrate 401 includes a host access device 500 that performs authentication access to the accessory device 402 and a device (not shown) for performing an operation as an electrical product. The accessory device 402 includes an authentication IC tag 600. An example of the configuration of the authentication IC tag 600 will be described later.

  The host access device 500 is different from the host access device 200 according to the first embodiment in that a ciphertext data decrypting unit 507 and a command identifier changing unit 508 are newly provided.

  The ciphertext data decryption unit 507 is an example of an analysis unit. Whether or not the ciphertext data includes data that matches an identification code for identifying one or more commands by analyzing the ciphertext data. Determine whether. That is, the ciphertext data decrypting unit 507 decrypts the ciphertext data encrypted by the cipher processing unit 203 and detects whether or not the data matching the command identifier is included in the ciphertext data. When data that matches the command identifier is detected, the ciphertext data decrypting unit 507 transmits the data that matches the command identifier to the command identifier changing unit 508. Here, the identification code is, for example, an identifier corresponding to each command for requesting authentication processing, transition processing, memory access processing, and processing status confirmation as shown in FIG.

  The command identifier changing unit 508 generates the changed identification code by changing the identification code when it is determined that the data matching the identification code is included in the ciphertext data. Specifically, the command identifier change unit 508 generates a new command identifier that does not match a part of the ciphertext data from the data received from the ciphertext data decryption unit 507. Then, the command identifier changing unit 508 transmits the authentication IC tag 600 via the communication unit 204.

  For example, when the command identifier of the authentication request command is “1111”, the ciphertext data decrypting unit 507 detects that the data string “1111” exists in the ciphertext data. In this case, the command identifier changing unit 508 changes the command identifier of the authentication request command from “1111” to “1234”, for example, and transmits it to the authentication IC tag 600.

  For example, the ciphertext data decrypting unit 507 (or the CPU 201) generates an identifier change request command and transmits it to the authentication IC tag 600. The identifier change request command includes an identification code for requesting a change of the identification code, an identification code before the change, and an identification code after the change. Alternatively, the identifier change request command may include other information for specifying the identification code before the change, instead of the identification code before the change.

  For example, after receiving a notification indicating that the identifier has been changed from the authentication IC tag 600, the host access device 500 transmits an authentication request command to the authentication IC tag 600 via the communication unit 204.

  As described above, the host access device 500 according to Embodiment 2 of the present invention transmits a command identifier that matches a part of the ciphertext data to the authentication IC tag 600 in advance. For this reason, even if the authentication IC tag 600 misses the identifier of the authentication processing command due to a communication error or the like, the ciphertext data does not include data that matches the identifier that the authentication IC tag 600 can recognize. Therefore, malfunction of the authentication IC tag 600 can be prevented.

  The new command identifier is transmitted again to the ciphertext data decryption unit 507, and the ciphertext data decryption unit 507 confirms whether the new command identifier does not match another data string of the ciphertext data. Good.

  FIG. 12 is a block diagram showing an example of the configuration of the authentication IC tag 600 according to Embodiment 2 of the present invention. The authentication IC tag 600 according to the second embodiment of the present invention is different from the authentication IC tag 100 according to the first embodiment in that an identification code changing unit 611 is newly provided.

  The identification code changing unit 611 changes the current command identifier to a new command identifier sent from the host access device 500. For example, the command identification unit 102 acquires the identifier change request command, and outputs the identification code before the change and the identification code after the change to the identification code change unit 611. The identification code changing unit 611 replaces the identification code that is stored in the identification code storage unit 103 and matches the identification code before the change with the identification code after the change.

  After completing the change of the identification code, the identification code changing unit 611 notifies the host access device 500 that the identifier changing process has been completed via the output data control unit 109 and the communication unit 101.

  Thereby, even if the authentication IC tag 600 misses the identifier of the authentication processing command due to a communication error or the like, the ciphertext data does not include data that matches the identifier that the authentication IC tag 600 can recognize. Therefore, malfunction of the authentication IC tag 600 can be prevented.

  Note that the authentication IC tag 600 according to Embodiment 2 of the present invention may not include the processing state transition control unit 108. That is, the state of the authentication IC tag 600 may not be divided into the authentication processing state and the memory access state exclusively as in the conventional case. That is, in the second embodiment of the present invention, since the host access device 200 changes the command identifier based on the contents of the generated ciphertext data, the authentication IC tag 600 uses a part of the ciphertext data as a command identifier. It can be prevented that it is mistaken.

  As described above, the authentication IC tag, the host access device, the authentication system, and the authentication method according to the present invention have been described based on the embodiments. However, the present invention is not limited to these embodiments. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to the said embodiment, and the form constructed | assembled combining the component in a different embodiment is also contained in the scope of the present invention. .

  For example, the host access devices 200 and 500 shown in FIG. 6 or 11 include a key storage unit 202, an encryption processing unit 203, an authentication result comparison unit 206, an authentication acquisition unit 205, a ciphertext data decryption unit 507, and a command identifier change unit 508. Is realized with a hardware configuration. On the other hand, these processing units may be realized as software as in the host access device 200a shown in FIG. That is, as shown in FIG. 13, the host access device 200a may include a CPU 201a and a communication unit 204.

  The host access device 200a includes, for example, a CPU 201a that executes predetermined arithmetic processing, a ROM (not shown) that stores a predetermined control program, a RAM (not shown) that temporarily stores data, and these Peripheral circuit and the like. The CPU 201a functions as a key storage unit 202, an encryption processing unit 203, an authentication acquisition unit 205, and an authentication result comparison unit 206 by executing a control program stored in the ROM.

  In addition, in the electronic devices 300 and 400 shown in FIG. 6 or FIG. 11, the main body substrate 301 or 401 and the accessory device 302 or 402 are physically connected by two signal lines 303 and 304. On the other hand, like the electronic device 300a shown in FIG. 14, the main body substrate 301a and the accessory device 302a may be physically connected by a single signal line 303a. That is, the authentication IC tag 100 and the host access device 200 may perform data communication via one signal line 303a. In other words, the authentication IC tag 100 may share the input signal line and the output signal line with the single signal line 303a.

  In each of the above embodiments, as shown in FIG. 6 or FIG. 11, the authentication IC tag 100 and the host access device 200 communicate with each other via one or more physical signal lines (wired). It is carried out. That is, in each of the above embodiments, the contact type authentication system has been described. On the other hand, the authentication system according to the modification of the embodiment of the present invention can also be realized as a non-contact type authentication system.

  FIG. 15 is a diagram illustrating an example of a configuration of a contactless authentication system according to a modification of the embodiment of the present invention.

  As shown in FIG. 15, the contactless authentication system according to the modification of the embodiment of the present invention includes a contactless authentication IC tag 700 and a contactless host access device 710. The non-contact type authentication IC tag 700 includes the authentication IC tag 100 and an antenna 701. The contactless host access device 710 includes a host access device 200 and an antenna 711.

  The host access device 200 and the authentication IC tag 100 perform wireless communication. That is, data transmitted from the host access device 200 is transmitted wirelessly from the antenna 711. The non-contact type authentication IC tag 700 receives the transmitted data with the antenna 701 and transmits it to the authentication IC tag 100.

  Further, data transmitted from the authentication IC tag 100 is transmitted wirelessly from the antenna 701. Then, the contactless host access device 710 receives the transmitted data by the antenna 711 and transmits it to the host access device 200.

  As a wireless communication system, various communication interface circuits such as the near field communication standard NFC used in the non-contact IC card standard can be used. Further, the communication speed and communication frequency comply with general standards and can be communicated.

  For example, ciphertext data generated by the cryptographic processing unit 203 in accordance with a command issued by the CPU 201 in the host access device 200 is sent to the antenna 711 via the communication unit 204 of the host access device 200. The antenna 711 transmits the ciphertext data by wireless communication, and the antenna 701 of the contactless authentication IC tag 700 receives the transmitted ciphertext data.

  The antennas 701 and 711 are directional antennas that radiate radio waves in a specific direction as transmission antennas. For example, the antennas 701 and 711 receive a carrier wave whose amplitude has changed or has not changed, and radiate it as a radio wave to the space. The antennas 701 and 711 also function as reception antennas that receive radio waves that have propagated through space.

  Specific authentication processing, memory access processing, state transition processing, and the like are the same as those in the above-described embodiment.

  As described above, the host access device and the authentication IC tag may be non-contact type as in the authentication system according to the modification of the embodiment of the present invention. In other words, the host access device and the authentication IC tag may perform wireless communication.

  Also, as shown in FIG. 16, the authentication IC tag may fix output data other than the output data corresponding to the processing state. Specifically, the authentication IC tag that is in the authentication processing state fixes the output data output when the memory access processing is performed to a predetermined value. Further, the authentication IC tag in the memory access state fixes output data to be output when authentication processing is performed to a predetermined value.

  FIG. 16 is a block diagram showing an example of the configuration of an authentication IC tag 100a according to a modification of the embodiment of the present invention. The authentication IC tag 100a is different from the authentication IC tag 100 shown in FIG. 1 in that it further includes selectors 111a and 111b.

  The selector 111 a selects either the authentication result signal or the fixed value based on the control from the processing state transition control unit 108. Specifically, when the authentication IC tag 100a is in the authentication processing state, the selector 111a selects an authentication processing result signal. Further, when the authentication IC tag 100a is in the memory access state, the selector 111a selects a fixed value, for example, 0.

  The selector 111b selects either the stored data read signal or the fixed value based on the control from the processing state transition control unit 108. Specifically, when the authentication IC tag 100a is in the memory access state, the selector 111b selects a stored data read signal. When the authentication IC tag 100a is in the authentication processing state, the selector 111b selects a fixed value, for example, 0.

  Thus, the authentication IC tag 100a fixes the output on the side that is not in the current processing state. Thereby, for example, even if the output data control unit 109 erroneously selects the data to be output, the output data can be prevented from leaking outside.

  Further, in the above embodiment, the authentication IC tag has been described to perform the decryption after acquiring all the ciphertext data. However, the authentication IC tag performs the decryption every time the ciphertext data is acquired. Also good.

  FIG. 17 is a flowchart showing an example of the operation of the authentication IC tag 100 according to the modification of the embodiment of the present invention. FIG. 17 shows an example in which the authentication IC tag 100 is in the authentication processing state in the initial state. Below, it demonstrates centering on a different point from the process shown in FIG. 5, and abbreviate | omits description about the same point.

  When the identification code of the authentication request command is acquired, the communication unit 101 receives ciphertext data (S102). Note that the host access device 200 transmits and receives data in specified bit units regardless of the contact / non-contact interface. In other words, the communication unit 101 acquires ciphertext data encrypted using the public key from the host access device 200 in a predetermined communication unit. For example, when communicating by a communication method such as start-stop synchronization, data that can be transmitted in one communication is 8 bits.

  As described above, the communication unit 101 of the authentication IC tag 100 receives the authentication request command in units of N bits. Since the ciphertext necessary for authentication has a bit length of about 4000 bits, for example, the authentication IC tag 100 receives the ciphertext data in a plurality of times. Specifically, in the case of communication in units of 8 bits, communication is performed 500 times only by transmitting / receiving ciphertext data.

  When the communication unit 101 receives the ciphertext data in units of 8 bits, the communication unit 101 transmits the received ciphertext data to the authentication processing unit 106 and sequentially executes the authentication processing (S104a). That is, the authentication processing unit 106 decrypts the ciphertext data for each communication unit. The authentication IC tag 100 counts the number of times the ciphertext data is received or decrypted, and continues to acquire and decrypt the divided ciphertext data up to the count number until the necessary number of bits is received.

  The processing after the authentication processing is completed (S105) is performed in the same manner as the processing shown in FIG.

  In this way, the authentication IC tag 100 can also sequentially decrypt the divided ciphertext data each time it is received. Thereby, since acquisition and decryption of the divided ciphertext data can be executed in parallel, the authentication process can be speeded up.

  In the authentication system according to the above-described embodiment, the host access device determines the success or failure of the authentication process, but the authentication IC tag may determine the success or failure of the authentication process.

  FIG. 18 is a block diagram illustrating an example of the authentication processing unit 806 provided in the authentication IC tag according to the modification of the embodiment of the present invention. For example, the authentication IC tag 100 illustrated in FIG. 1 includes an authentication processing unit 806 instead of the authentication processing unit 106.

  In the authentication system according to the modification of the embodiment of the present invention, plaintext data before encryption is received from the host access device 200.

  As shown in FIG. 18, the authentication processing unit 806 includes a ciphertext decryption unit 106a, a secret key storage unit 106b, and a comparison unit 806c.

  The ciphertext decryption unit 106a performs decryption processing using the decryption key stored in the secret key storage unit 106b. That is, the ciphertext decryption unit 106a generates decrypted text data by decrypting the ciphertext data transmitted from the host access device 200 using the secret key. The generated decrypted text data is transmitted to the comparison unit 806c.

  The comparison unit 806c compares the plaintext data transmitted from the host access device 200 with the decrypted text data. For example, the comparison unit 806c includes a logical operator that performs a logical product in units of bits. Then, the comparison unit 806c performs a comparison in units of 1 bit by a logical operator, and if all comparison values are 1, all the bits match, so it is determined that the plaintext data and the decrypted text data match. To do.

  FIG. 19 is a diagram for explaining an authentication process on the authentication IC tag side in the authentication system according to the modification of the embodiment of the present invention.

  First, in the host access device 200, the encryption processing unit 203 generates ciphertext data by encrypting plaintext data, which is a target to be transmitted confidentially, using a public key. The host access device 200 transmits the ciphertext data to the authentication IC tag 100 as IC tag reception data via the communication unit 204.

  In addition, the host access device 200 separately transmits plaintext data to the authentication IC tag 100. The plaintext data may be transmitted at any timing before and after transmission of the ciphertext data. Alternatively, it may be transmitted at the same timing as the ciphertext data.

  The authentication IC tag 100 receives ciphertext data as IC tag reception data. Then, the authentication processing unit 106 generates decrypted text data by decrypting the cipher text data using the secret key.

  The authentication IC tag 100 further receives plaintext data from the host access device 200 in addition to the ciphertext data. For example, the authentication IC tag 100 receives plaintext data as the same command as the reception of ciphertext data. Or you may receive the flat data transmitted continuously after ciphertext data. Note that the authentication IC tag 100 may hold plaintext data in advance.

  In the authentication IC tag 100, the comparison unit 806c determines whether the plaintext data and the decrypted text data match, and transmits the determination result to the host access device 200.

  In this way, the authentication IC tag can determine whether the authentication process has succeeded or failed.

  Further, like the authentication IC tag 900 shown in FIG. 20, a control unit 912 that performs all of these processes may be provided instead of the control unit corresponding to each of the authentication process, the memory access process, and the state transition process. Good. The authentication IC tag 900 shown in FIG. 20 is different from the authentication IC tag 100 shown in FIG. 1 in that an authentication data input / output unit 905 is used instead of the authentication control unit 105, the memory access control unit 107, and the processing state transition control unit. The memory access input / output unit 907, the processing state transition input / output unit 908, the control unit 912, and the transition processing unit 913 are different.

  The authentication data input / output unit 905 inputs ciphertext data and outputs decrypted text data. Note that data may be exchanged directly between the communication unit 101 and the output data control unit 109 without going through the authentication data input / output unit 905.

  Similar to the memory access control unit 107, the memory access input / output unit 907 generates a memory address and a memory access enable signal. Further, write data to the memory unit 104 is received from the communication unit 101 and written to the memory unit 104. The data read from the memory unit 104 is output to the output data control unit 109.

  The processing state transition input / output unit 908 inputs a transition determination code and outputs transition processing data. Note that data may be exchanged directly between the communication unit 101 and the output data control unit 109 without going through the processing state transition input / output unit 908.

  The control unit 912 receives the command identifier determination result from the command identification unit 102 and uses the authentication processing unit 106, the authentication data input / output unit 905, the memory access input / output unit 907, the processing state transition input / output unit 908, and the transition processing unit 913. In response to this, an instruction is issued to perform each operation. For example, the control unit 912 includes a CPU such as a microprocessor.

  The transition processing unit 913 performs state transition of the authentication IC tag 900. The specific process is the same as the process performed by the process state transition control unit 108 according to the first embodiment described above.

  Even with the above configuration, malfunction can be prevented. In particular, when the public key cryptosystem is used, since the ciphertext data becomes long, there is a high possibility that a code that matches the command identifier is included in the ciphertext data, and there is a high possibility of malfunction. Therefore, in the authentication system using the public key cryptosystem, the authentication IC tag 900 according to the modification of the embodiment of the present invention also has a special effect.

  Further, the host access device according to the present invention may change the signal waveform of the command according to the command transmitted to the authentication IC tag.

  Specifically, in the case where authentication is performed between the host access device and the authentication IC tag by serial communication such as start-stop synchronization, the communication unit 204 of the host access device performs authentication processing and memory access processing. Thus, the pulse width of the synchronization signal and communication data is changed. For example, as shown in FIG. 21, the communication unit 204 performs data communication with the pulse width of the authentication request command being Nms, whereas the access request command is half the pulse width of N / 2 ms.

  That is, communication necessary for authentication processing such as reception of an authentication request command and reply to the command is performed using a signal waveform having a pulse width of Nms (FIG. 21A). Further, communication necessary for memory access processing such as reception of an access request command and a reply to the command is performed using a signal waveform having a pulse width of N / 2 ms (FIG. 21B).

  In communication such as start-stop synchronization, the communication unit 204 gives a Sync pulse that defines a data width before communication data (for example, an authentication request command).

  The communication unit 101 of the authentication IC tag on the receiving side measures the pulse width of the sync pulse to be transmitted, determines the bit width of the continued communication data, and performs 0/1 bit determination. For example, in FIG. 21, the signal is determined to be 1 when the signal is at a high level and 0 when the signal is at a low level.

  For example, since it is possible to measure Sync pulses at least 500 times during transmission of 4000 bits, even if a command identifier is missed, it can be detected in the middle of ciphertext data, and unintended access Can be effectively prevented. Therefore, when changing the signal waveform of the command, the authentication IC tag does not need to perform an explicit state transition as in the second embodiment.

  Further, the host access device according to the present invention may change the command length according to the command transmitted to the authentication IC tag. For example, as shown in FIGS. 22A and 22B, the communication unit 204 of the host access device changes the command format so as to increase the bit length of the command identifier. Thereby, it is possible to reduce the probability that a part of the ciphertext data matches the command identifier.

  The host access apparatus according to the present invention may add a CRC (Cyclic Redundancy Check) to the command identifier as shown in FIG. CRC is an example of an error detection code, and can detect data errors. Therefore, even if an error occurs in the command identifier, the communication unit 101 of the authentication IC tag can prevent malfunction by detecting the error.

  Each processing unit included in the authentication IC tag and the host access device according to the first and second embodiments and the modifications thereof is typically realized as an LSI (Large Scale Integration) that is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.

  The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Further, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out integration of processing units using that technology. Biotechnology can be applied.

  Further, some or all of the functions of the authentication IC tag and the host access device according to the first and second embodiments of the present invention may be realized by a processor such as a CPU executing a program.

  Further, the present invention may be the above program or a recording medium on which the above program is recorded. Needless to say, the program can be distributed via a transmission medium such as the Internet.

  Moreover, all the numbers used above are illustrated for specifically explaining the present invention, and the present invention is not limited to the illustrated numbers. In addition, the connection relationship between the components is exemplified for specifically explaining the present invention, and the connection relationship for realizing the function of the present invention is not limited to this.

  Furthermore, although the above embodiment is configured using hardware and / or software, the configuration using hardware can also be configured using software, and the configuration using software uses hardware. Can be configured.

  The configurations of the authentication IC tag and the host access device are for illustrative purposes only, and the authentication IC tag and the host access device according to the present invention have all the above configurations. It is not always necessary to prepare. In other words, the authentication IC tag and the host access device according to the present invention need only have a minimum configuration capable of realizing the effects of the present invention.

  Similarly, the authentication method using the above authentication system is for illustrating the present invention, and the authentication method using the authentication system according to the present invention does not necessarily include all the above steps. Absent. In other words, the authentication method according to the present invention needs to include only the minimum steps that can realize the effects of the present invention. In addition, the order in which the above steps are executed is for illustration in order to specifically describe the present invention, and may be in an order other than the above. Also, some of the above steps may be executed simultaneously (in parallel) with other steps.

  INDUSTRIAL APPLICABILITY The present invention has an effect of preventing malfunction of an authentication IC tag, and can be used for, for example, an authentication IC tag and an authentication system used for article management, discrimination of imitation products, personal authentication, and the like. it can.

100, 100a, 600, 900 Authentication IC tag 101, 204 Communication unit 102 Command identification unit 103 Identification code storage unit 104 Memory unit 105 Authentication control unit 106, 806 Authentication processing unit 106a Ciphertext decryption unit 106b Private key storage unit 107 Memory access Control unit 108 Processing state transition control unit 109 Output data control unit 110 Input / output terminals 200, 200a, 500 Host access devices 201, 201a CPU
202 Key storage unit 203 Cryptographic processing unit 205 Authentication acquisition unit 206 Authentication result comparison unit 300, 300a, 400 Electronic device 301, 301a, 401 Main board 302, 302a, 402 Accessory device 303, 303a, 304 Signal line 507 Ciphertext data decryption Unit 508 command identifier change unit 611 identification code change unit 700 contactless authentication IC tags 701 and 711 antenna 710 contactless host access device 806c comparison unit 905 authentication data input / output unit 907 memory access input / output unit 908 processing state transition input / output Unit 912 Control unit 913 Transition processing unit

Claims (18)

An authentication IC tag having an authentication processing state and a memory access state,
The memory access state is a state in which a memory access process from a host access device to a memory unit for storing predetermined data can be executed.
The authentication processing state is a state in which authentication processing using a public key cryptosystem by the host access device can be executed, and the memory access processing is prohibited.
The authentication IC tag is:
The memory unit;
An authentication unit that performs the authentication process when the authentication IC tag is in the authentication process state;
A memory access control unit that prohibits the memory access process when the authentication IC tag is in the authentication process state, and performs the memory access process when the authentication IC tag is in the memory access state;
A communication unit for obtaining a command by communicating with the host access device;
An authentication IC tag comprising: a state transition control unit that performs state transition of the authentication IC tag between the authentication processing state and the memory access state based on a command acquired by the communication unit. The authentication unit performs the authentication process when the authentication IC tag is in the authentication process state and the communication unit acquires an authentication request command for requesting the authentication process,
The memory access control unit performs the memory access process when the authentication IC tag is in the memory access state and the communication unit acquires an access request command for requesting the memory access process,
When the communication unit acquires a transition request command for requesting a state transition to either the authentication processing state or the memory access state, the state transition control unit responds to the authentication IC according to the transition request command. The authentication IC tag according to claim 1, which performs a state transition of the tag. The authentication IC tag according to claim 1 or 2, wherein the state transition control unit performs state transition of the authentication IC tag when the authentication process or the memory access process is completed. The authentication IC tag according to any one of claims 1 to 3, wherein the state transition control unit maintains the state of the authentication IC tag in the authentication process state when the authentication process is completed. The said authentication IC tag is further provided with the output part which outputs the state transition result data which shows the result of the said state transition, when the state transition of the said authentication IC tag is performed by the said state transition control part. 5. The authentication IC tag according to any one of 4 above. The communication unit acquires ciphertext data encrypted using a public key from the host access device in a predetermined communication unit,
The authentication IC tag according to claim 1, wherein the authentication unit decrypts the ciphertext data as the authentication process after acquiring all the ciphertext data. The communication unit acquires ciphertext data encrypted using a public key from the host access device in a predetermined communication unit,
The authentication IC tag according to any one of claims 1 to 5, wherein the authentication unit decrypts the ciphertext data for each communication unit as the authentication process. The authentication IC tag according to claim 1, wherein the communication unit communicates with the host access device via a physical signal line. The authentication IC tag according to claim 1, wherein the communication unit communicates wirelessly with the host access device. The communication unit obtains ciphertext data encrypted using a public key from the host access device,
The authentication unit generates decrypted text data by decrypting the cipher text data using a secret key corresponding to the public key as the authentication process,
The authentication IC tag according to claim 1, wherein the communication unit further transmits the decrypted text data to the host access device. The communication unit obtains, from the host access device, ciphertext data obtained by encrypting plaintext data using a public key,
The authentication unit generates decrypted text data by decrypting the ciphertext data using a secret key corresponding to the public key as the authentication process, and the plaintext data and the decrypted text data match. The authentication IC tag according to any one of claims 1 to 9. A host access device that performs an authentication process, which is a process of authenticating an authentication IC tag including a memory unit for storing predetermined data using a public key cryptosystem,
A control unit that issues a command to transition the state of the authentication IC tag;
A communication unit that transmits a command corresponding to the command to the authentication IC tag,
The controller is
The status of the authentication IC tag includes an authentication processing state in which memory access processing from the host access device to the memory unit is prohibited and the host access device can execute the authentication processing, and the memory access processing is executed. A host access device that issues instructions for transitioning between possible memory access states. The host access device further includes an encryption unit that generates ciphertext data by encrypting plaintext data using a public key,
The control unit issues an authentication command for requesting the authentication processing, and a memory access command for requesting the memory access processing,
The communication unit transmits an identification code for identifying a command corresponding to the authentication command and the ciphertext data to the authentication IC tag when the authentication command is issued by the control unit, The host access device according to claim 12, wherein when the memory access instruction is issued by the control unit, an identification code for identifying a command corresponding to the memory access instruction is transmitted to the authentication IC tag. The host access device according to claim 13, wherein the communication unit changes a signal waveform according to a command issued by the control unit. The host access device includes a CPU (Central Processing Unit),
The host access device according to claim 13 or 14, wherein the CPU executes functions of the control unit, the encryption unit, and the communication unit. A host access device that performs authentication processing of an authentication IC tag,
A controller that issues at least one command for the authentication IC tag;
An encryption unit that generates ciphertext data by encrypting plaintext data using a public key;
A communication unit that transmits the ciphertext data to the authentication IC tag;
Analyzing the ciphertext data to determine whether the ciphertext data includes data that matches an identification code for identifying a command corresponding to the one or more instructions;
When it is determined that the data matching the identification code is included in the ciphertext data, the change unit generates a changed identification code by changing the identification code,
The communication unit further includes:
A host access device that transmits the changed identification code to the authentication IC tag. The authentication IC tag according to any one of claims 1 to 11,
An authentication system comprising the host access device according to any one of claims 12 to 16. An authentication method for authenticating an authentication IC tag having an authentication processing state and a memory access state,
The authentication IC tag in the memory access state can execute a memory access process from a host access device to a memory unit for storing predetermined data,
The authentication IC tag in the authentication process state can execute an authentication process using a public key cryptosystem by the host access device, and the memory access process is prohibited.
The authentication method is:
An authentication step of performing the authentication process when the authentication IC tag is in the authentication process state;
A memory access step for prohibiting the memory access process when the authentication IC tag is in the authentication process state, and performing the memory access process when the authentication IC tag is in the memory access state;
A communication step of acquiring a command by communicating with the host access device;
A state transition control step of performing state transition of the authentication IC tag between the authentication processing state and the memory access state based on the command;

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