JP5313754B2 - Authentication system and authentication method - Google Patents

Description

  The present invention relates to an authentication system and an authentication method used when a communication master performs personal authentication with a communication partner that is the communication partner.

  In recent years, for example, challenge response authentication (see Patent Documents 1 to 3 and the like) has been widely used as an authentication method of an authentication system for confirming whether or not a communication partner is the person. Challenge response authentication is a type of cryptographic authentication. First, the authenticator sends a random number code whose value changes every time a call is made to the receiver as a challenge. Receiving the random number code, the receiving side calculates the random number code by its own cryptographic operation formula and sends it back to the authentication side as a response. The authentication side obtains a response by using the same cryptographic operation formula for the random number code sent to the receiving side, and collates the response sent from the receiving side with the response calculated by itself. If response verification is established, communication between the two is permitted.

JP 2009-3070 A JP 2008-48166 A JP 2006-512515 A

  By the way, when this type of authentication system is used, for example, in an electronic key system of a vehicle, a plurality of electronic keys on the receiving side may be used for one authentication side, that is, the vehicle. However, in this case, since the same cryptographic operation formula is used on all receivers, for example, if the cryptographic operation formula is stolen on one receiver side, the encryption of the authentication system is interrupted at that point. That is, it will be invalidated. For this reason, there has been a demand for the development of a new authentication method in which the cryptographic operation formula is difficult to analyze.

  An object of the present invention is to provide an authentication system and an authentication method capable of making it difficult to cause an illegal analysis of a cryptographic operation expression.

In order to solve the above problem, in the present invention, a challenge is sent from the communication master to the communication terminal that is the communication partner, and the communication terminal is made to calculate the response of the challenge by the cryptographic operation formula, and after the calculation, the response Is sent back to the communication master, and the communication master calculates the response of the challenge by the cryptographic operation formula possessed by the communication master, and authenticates the two parties by comparing the responses of the two parties. in the authentication system, the communication master are the tables in which the encryption operation equation for the authentication and destination of each communication master is associated, from the pre-equipped obtained destination information to the communication master, destination communication master itself The destination confirmation means for confirming and the destination determined by the destination confirmation means That the singled out encryption arithmetic expression from the table, and the gist that a cryptographic calculation formula switching means for setting, as the encryption operation expression used this before SL during authentication.

According to this configuration, the destination confirmation means confirms the destination system (the combination of the communication terminal and the communication master) that is manufactured . From the encryption operation expression for challenge-response authentication is provided multiple cryptographic calculation formula corresponding to the destination is selected by the encryption operation equation switching means from the table, the authentication is performed by the encryption arithmetic expression. For this reason, since it is possible to change the cryptographic operation formula for authentication for each destination, it is possible to execute authentication with a different cryptographic computation formula for each destination. Therefore, it is possible to increase the resistance against illegal reading of the cryptographic operation formula, and it is possible to make the authentication difficult to analyze.

  According to this configuration, since the destination is determined from the destination information provided in advance in the communication master, it is possible to set in advance the cryptographic operation formula used for authentication regardless of whether or not the actual authentication is performed. .

In the present invention, the communication master is required to establish authentication of the challenge response with the authentication execution means for executing authentication with the communication terminal on the communication master side at the start of operation execution. A gist is that the device is connected, and the master side device executes authentication of the challenge response with the authentication execution unit by the cryptographic operation formula determined according to the destination.

  According to this configuration, when the master side device starts executing the operation, challenge response authentication is performed with the authentication execution unit using a cryptographic operation formula according to the destination. It can be made difficult to occur.

In the present invention, a challenge is transmitted from the communication master to the communication terminal that is the communication partner, and the communication terminal is caused to calculate a response of the challenge using the cryptographic operation expression. After the calculation, the response is sent back to the communication master, and the communication In the challenge response type authentication method in which the master also calculates the response of the challenge by the cryptographic operation formula possessed by the communication master, and authenticates the two parties by comparing the responses of the two parties, the communication master is directed to the table and the encryption arithmetic expression for authentication has been correlated set eclipse of the communication master, the communication master, from pre-equipped obtained destination information to the communication master, a destination of the communication master itself And calculating the cryptographic operation expression corresponding to the determined destination from the table. Fine out, and summarized in that to set as a cryptographic calculation formula to use it before SL during authentication.

  According to the present invention, it is possible to make it difficult for fraud analysis of a cryptographic operation formula used for challenge response authentication to occur.

The block diagram which shows the structure of the immobilizer system in one Embodiment. The conceptual diagram which shows that a vehicle is manufactured for every destination. The block diagram which shows the structure of a cryptography type switching system. A table that defines the relationship between destination information and cryptographic operations. The sequence chart which shows the switching operation | movement of a cryptographic operation type | formula.

Hereinafter, an embodiment of an authentication system and an authentication method embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 is provided with a key cylinder 3 as an insertion destination of a vehicle key 2 composed of a mechanical key, for example, in the vicinity of a steering wheel. In this case, when the vehicle key 2 is inserted into the key cylinder 3 and the key 2 is turned, if the key groove of the vehicle key 2 matches the key cylinder 3 and the key verification is established, The rotation of the key cylinder 3 rotor is allowed. Then, when the rotor rotational position of the key cylinder 3 is operated to the engine start position (ST position), the starter relay of the ignition switch 4 is switched from OFF to ON, and the engine ECU (overall control of the engine 5) The Electronic Control Unit) 6 is activated and the engine 5 is in the starting state. The engine ECU 6 corresponds to a master side device.

  The vehicle 1 is equipped with an immobilizer system 7 as one system for preventing the vehicle 1 from being stolen. In this case, the vehicle 1 is provided with an immobilizer ECU 8 as a control unit that manages the immobilizer system 7. A coil antenna 9 is connected to the immobilizer ECU 8 as an antenna on the vehicle side of the immobilizer system 7. The coil antenna 9 is wound a plurality of times so as to surround the key hole of the key cylinder 3. The immobilizer ECU 8 is connected to the engine ECU 6 via an in-vehicle bus 10 that is one network in the vehicle. The immobilizer ECU 8 corresponds to a communication master.

  On the other hand, the vehicle key 2 includes a transponder 11 as an ID tag capable of wirelessly transmitting a unique ID. The transponder 11 is provided with a transponder ECU 12 that supervises and manages the transponder 11 and a transmission / reception antenna 13 as an antenna of the transponder 11. In the memory 14 of the transponder ECU 12, a transponder code is registered as the above-mentioned unique ID. The transponder 11 can perform communication by so-called short-range wireless communication that communicates with the immobilizer ECU 8 while being close to each other. For example, RFID (Radio Frequency IDentification) is used as the communication format. Further, the transponder 11 is a passive type that does not have its own power source and moves using the radio wave transmitted from the immobilizer ECU 8 as a power source. The transponder 11 corresponds to a communication terminal (communication partner).

  Further, the wireless communication of the immobilizer system 7, so-called immobilizer communication, is encrypted communication encrypted by challenge response authentication. In this case, the cryptographic operation formula F (x) is registered in the memory 15 of the immobilizer ECU 8 as an arithmetic expression on the immobilizer ECU 8 side for challenge response authentication. Also, the cryptographic operation formula F (x) is registered in the memory 14 of the transponder 11 as an arithmetic expression on the transponder 11 side of challenge response authentication. The cryptographic operation formula F (x) corresponds to an encryption key or an encryption algorithm. If the vehicle 1 and the vehicle key 2 form a pair, those having the same algorithm are set.

  When the immobilizer ECU 8 confirms that the vehicle key 2 is inserted into the key cylinder 3, the immobilizer ECU 8 starts immobilizer communication. At this time, the immobilizer ECU 8 first causes the coil antenna 9 to transmit a driving radio wave Svc as a power source for the transponder 11 and a challenge code as a challenge Sch for challenge response authentication. The drive radio wave Svc and the challenge Sch are transmitted by radio waves in the LF (Low Frequency) band. The challenge code is a data string (random number code) whose value changes every time it is transmitted. When the transponder ECU 12 receives this driving radio wave Svc, it starts up using it as a power source, calculates a challenge Sch received thereafter by its own cryptographic operation formula F (x), and generates a response code. Then, the transponder ECU 12 returns this response code and its own transponder code as a response Srs to the immobilizer ECU 8 with LF band radio waves.

  On the other hand, when the immobilizer ECU 8 transmits the challenge Sch, the immobilizer ECU 8 also calculates the response Srs by calculating the challenge code by its own cryptographic operation formula F (x). When the immobilizer ECU 8 receives the response Srs transmitted from the transponder 11 by the coil antenna 9, first, the immobilizer ECU 8 compares the response code calculated by itself with the response code calculated by the transponder 11, and performs response verification. When the immobilizer ECU 8 confirms that the response codes match and the challenge response authentication is established, this time, the immobilizer ECU 8 compares the transponder code included in the same response Srs with the transponder code registered in its own memory 15. Code verification. The immobilizer ECU 8 releases the immobilizer lock when confirming that the two verifications match and the response authentication is established.

  When the immobilizer lock is released, the immobilizer ECU 8 allows the engine ECU 6 to start the engine. At this time, pairing confirmation is performed between the immobilizer ECU 8 and the engine ECU 6, and challenge response authentication is also used for this confirmation. The For this reason, the operation encryption formula F (x) is also registered in the memory 16 of the engine ECU 6 as an arithmetic expression on the engine ECU 6 side of challenge response authentication. Then, when the immobilizer lock is released, the engine ECU 6 sends a challenge Sch to the immobilizer ECU 8 to perform challenge response authentication. If this authentication is established, the engine 5 is switched to the activated state.

  As shown in FIG. 2, each vehicle 1a, 1b ... is manufactured so that each may differ. “Destination” is a kind of vehicle parameter determined by, for example, using the same manufacturer vehicle or the same vehicle type, but varying the mounting status of components, the number of components, and the like for each vehicle. In this example, the first vehicle 1a is for the first destination, the second vehicle 1b is for the second destination, the third vehicle 1c is for the third destination, the fourth vehicle 1d is for the fourth destination, and the fifth vehicle 1e is for the fourth destination. For the fifth destination, the sixth vehicle 1f is set for the sixth destination, the seventh vehicle 1g is set for the seventh destination, and the eighth vehicle 1h is set for the eighth destination.

  The destinations of the vehicles 1a to 1h are determined by the destination information D (see FIGS. 3 and 4) that the vehicles 1a to 1h have. The destination information D is an information group in which, for example, whether or not a remote engine starter can be attached, whether or not ID information registered in the vehicle 1 can be erased collectively, whether or not additional registration of a vehicle key can be determined, and the like. Therefore, the destination of the vehicles 1a to 1h is determined by a combination of various information of the destination information D. For example, when all functions are enabled, the destination information D is set so that the vehicle 1 is set to the first destination. It is set accordingly. In the case of this example, as shown in FIG. 4, if the vehicles 1a to 1h have the first to third functions, for example, when all functions are possible, the destination information D is the first destination information. When the vehicle 1 is set for the first destination by taking D1, the first function and the second function are enabled, and the third function is not, the destination information D is taken by the second destination information D2. 1 is set for the second destination.

  The vehicle keys 2a to 2h of the vehicles 1a to 1h are set as dedicated keys for the respective vehicles by matching the transponder codes on the vehicle 1 side and the key 2 side. That is, each vehicle key 2a-2h is a key corresponding to the destination by being manufactured as a dedicated key for each vehicle 1a-1h for which the destination is set. In this example, the first vehicle key 2a becomes the key of the first vehicle 1a, the second vehicle key 2b becomes the key of the second vehicle 1b, the third vehicle key 2c becomes the key of the third vehicle 1c, and the fourth vehicle The key 2d becomes the key of the fourth vehicle 1d, the fifth vehicle key 2e becomes the key of the fifth vehicle 1e, the sixth vehicle key 2f becomes the key of the sixth vehicle 1f, and the seventh vehicle key 2g becomes the key of the seventh vehicle 1g. The eighth vehicle key 2h is the key of the eighth vehicle 1h.

  As shown in FIG. 3, the vehicle 1 is provided with a cryptographic operation formula switching system 17 that switches the cryptographic operation formula F (x) according to the destination of the vehicle 1 (the destination information D). The cryptographic operation formula switching system 17 of this example prepares a plurality of cryptographic computation formulas F (x), F (x)... In the vehicle 1 in advance, and what is the destination information D each of the vehicles 1 has. The cryptographic operation formula F (x) used at the time of challenge response authentication is set to the one based on the destination information D, that is, the one corresponding to the destination of the vehicle 1.

  In this case, a table 18 in which the relationship between the destination information D and the cryptographic operation formula F (x) is defined is registered in the memory 15 of the immobilizer ECU 8. In this table 18, information about which cryptographic operation formula F (x) is used at which destination (destination information D) is written in the writing area of the table 18 in the memory 15. In the case of this example, the first cipher operation formula F1 (x) is used for the first destination information D1, the second cipher operation formula F2 (x) is used for the second destination information D2, and the third cipher operation formula is used for the third destination information D3. F3 (x) is the fourth cryptographic operation expression F4 (x) for the fourth destination information D4, the fifth cryptographic arithmetic equation F5 (x) is for the fifth destination information D5, and the sixth cryptographic operation is for the sixth destination information D6. In the formula F6 (x), the seventh cryptographic operation formula F7 (x) is allocated to the seventh destination information D7, and the eighth cryptographic arithmetic formula F8 (x) is allocated to the eighth destination information D8.

  As shown in FIG. 3, the immobilizer ECU 8 is provided with an authentication execution unit 19 that manages challenge response authentication on the vehicle 1 side. The authentication execution unit 19 sends, for example, a challenge Sch (driving radio wave Svc, challenge code, etc.) to the transponder 11, calculates a response code in the cryptographic calculation formula F (x) on the immobilizer ECU 8 side, and receives it from the transponder 11. Various operations such as authentication for checking whether the response Srs is correct and pair confirmation with the engine ECU 6 are executed. The authentication execution unit 19 corresponds to an authentication execution unit.

  Further, the immobilizer ECU 8 is provided with a destination confirmation unit 20 that confirms the destination of the own system (combination type of the vehicle 1 and the electronic key 2) from the destination information D. The destination confirmation unit 20 confirms the destination of the own vehicle from the contents of the destination information D, and outputs the confirmation result. For example, when it is confirmed that the destination information D is the first destination information D1, the host vehicle recognizes that the destination of the host vehicle is the first destination and confirms that the destination information D is the second destination information D2. Recognize that the destination is the second destination. Further, the destination confirmation unit 20 executes the destination confirmation every time challenge response authentication is performed.

  In addition, the immobilizer ECU 8 is provided with a cryptographic operation formula setting unit 21 that sets a cryptographic operation formula F (x) used during challenge response authentication. The cryptographic operation formula setting unit 21 confirms the destination of the own vehicle from the confirmation result of the destination confirmation unit 20, and reads out the cryptographic operation formula F (x) corresponding to the destination of the own vehicle from the table 18 with reference to the table 18. . Subsequently, the cryptographic operation formula setting unit 21 sets the cryptographic operation formula F (x) read from the table 18 as the cryptographic operation formula F (x) used for challenge response authentication. Then, the cryptographic operation formula setting unit 21 causes the authentication execution unit 19 to execute response verification using this cryptographic operation formula F (x).

  Furthermore, in the case of this example, the engine ECU 6 performs pairing confirmation with the immobilizer ECU 8 at the start of startup by challenge response authentication, and this challenge response authentication is also executed by the cryptographic operation formula F (x) according to the destination. Therefore, similarly to the immobilizer ECU 8, the engine ECU 6 is also provided with a table 22, an authentication execution unit 23, a destination confirmation unit 24, a cryptographic operation formula setting unit 25, and an authentication execution unit 23. The destination confirmation unit 24 confirms the destination at the time of challenge response authentication with the immobilizer ECU 8. Then, the cipher operation formula setting unit 25 sets the cipher operation formula F (x) with reference to the table 18 from the confirmation result of the destination confirmation unit 24, and sets the cipher operation formula F (x) in the authentication execution unit 23 with this cipher operation formula F (x). Let the verification run. The destination confirmation units 20 and 24 constitute destination confirmation means, and the cryptographic operation formula setting units 21 and 25 constitute cryptographic operation formula setting means.

Next, the operation performed by the cryptographic operation type switching system 17 of this example will be described with reference to FIG.
When the vehicle key 2 is inserted into the key cylinder 3, the authentication execution unit 19 first transmits a drive radio wave Svc from the coil antenna 9 as shown in FIG. The vehicle key 2 receives this drive radio wave Svc at the transponder 11. When the transponder ECU 12 receives the drive radio wave Svc, the transponder ECU 12 switches to the activated state using the drive radio wave Svc as a power source, and transmits an ACK via the LF radio wave to notify the immobilizer ECU 8 that it has entered the activated state. When the authentication execution unit 19 receives the ACK by the coil antenna 9 after the transmission of the drive radio wave Svc, the authentication execution unit 19 recognizes that the transponder 11 has been switched to the activated state by the drive radio wave Svc transmitted earlier.

  When the authentication execution unit 19 confirms that the transponder 11 has been switched to the activated state, the authentication execution unit 19 transmits a challenge code for challenge response authentication as a challenge Sch from the coil antenna 9 using LF radio waves. Upon receiving this challenge Sch, the transponder 11 calculates the response code by calculating the challenge code included in the challenge Sch using its own cryptographic operation formula F (x). When the vehicle key 2 is the first vehicle key 2a, a challenge code is calculated by the first cryptographic calculation formula F1 (x). Then, when the calculation of the response code is completed, the transponder 11 transmits the response code, which is the calculation result, and the transponder code registered in its own memory 14 as a response Srs from the transmission / reception antenna 13 by LF radio waves.

  Further, the destination confirmation unit 20 confirms what the destination of the own vehicle is when the challenge Sch is transmitted, and notifies the cryptographic operation formula setting unit 21 of the confirmation result. The destination confirmation unit 20 of this example confirms what the destination of the vehicle 1 is from the destination information D prepared in advance in the vehicle 1. For example, if the destination information D is the first destination information D1, it is confirmed that the vehicle 1 is the first destination information. If the destination information D is the second destination information D2, the vehicle 1 is the second destination information D2. Confirm that it is destined. The destination confirmation unit 20 outputs the destination confirmation result to the cryptographic operation expression setting unit 21.

  When receiving the destination confirmation result from the destination confirmation unit 20, the cryptographic operation formula setting unit 21 compares the confirmation result with the table 18 and selects and sets the cryptographic operation formula F (x) corresponding to the destination. In other words, the cryptographic operation formula setting unit 21 reads the cryptographic operation formula F (x) corresponding to the destination, and sets it in the own vehicle as the used cryptographic operation formula. For example, as shown in FIG. 4, when the destination information D is the first destination information D1, the cryptographic calculation formula is set to the first cryptographic calculation formula F1 (x), and the destination information D is the second destination information D2. In this case, the cryptographic calculation formula is set to the second cryptographic calculation formula F2 (x).

  After this cryptographic operation formula is set, the authentication execution unit 19 creates a response code by calculating the challenge code itself using the cryptographic operation formula F (x), and compares this response code with the response code received from the transponder 11. Response verification. When the vehicle 1 is for the first destination, the response code is calculated by the first cryptographic calculation formula F1 (x). When the authentication execution unit 19 confirms that the response codes match and the response verification is established, the authentication execution unit 19 subsequently executes code verification using the transponder code included in the same response Srs. When the authentication execution unit 19 confirms that the code verification is also established, the authentication execution unit 19 recognizes that the challenge response authentication is established, and releases the immobilizer lock.

  Subsequently, when the vehicle key 2 inserted into the key cylinder 3 is turned to the engine start position and operated, the engine ECU 6 is turned on, and the engine ECU 6 starts challenge response authentication with the immobilizer ECU 8 for pairing confirmation. At this time, the destination confirmation unit 24 confirms what the destination of the vehicle 1 is from the destination information D prepared in advance in the vehicle 1, and outputs the confirmation result of the destination to the cryptographic operation formula setting unit 25.

  When receiving the destination confirmation result from the destination confirmation unit 24, the cryptographic operation formula setting unit 25 compares the confirmation result with the table 22 and selects and sets the cryptographic operation formula F (x) according to the destination. That is, the cryptographic operation formula F (x) used for the challenge response authentication for pair confirmation is set in the same procedure as that for the challenge response authentication between the immobilizer ECU 8 and the transponder 11. Then, the authentication execution unit 19 performs challenge response authentication for pair confirmation using the cryptographic operation formula F (x) set by the cryptographic operation formula setting unit 21, and confirms that this authentication is established. Switch to.

  As described above, in this example, a plurality of cryptographic operation formulas F (x) for challenge response authentication are prepared for each destination information D, which is a condition for determining the destination of the vehicle 1, and the cryptographic operation formula F (x) is changed to the vehicle 1. It can be changed according to the contents of the destination information D, that is, according to the destination of the vehicle 1. For this reason, since each vehicle key 2 performs authentication with a different cryptographic calculation formula F (x), for example, compared to a case where a plurality of vehicle keys 2 share one and the same cryptographic calculation formula F (x). It is possible to increase the resistance against unauthorized reading of the cryptographic operation formula F (x). As a result, it is possible to make it difficult to analyze the cryptographic operation formula F (x), and thus it is possible to improve the security against vehicle theft.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) Since the cryptographic operation formula F (x) is prepared for each destination information D that the vehicle 1 has, it is possible to change the cryptographic operation formula F (x) used for challenge response authentication for each destination of the vehicle 1. it can. For this reason, since each vehicle 1a-1h performs authentication with a different cryptographic operation formula F (x), for example, compared to a case where a plurality of vehicles 1a-1h share the same single cryptographic operation formula F (x). Thus, it is possible to increase the resistance against unauthorized reading of the cryptographic operation formula F (x). As a result, it is possible to make it difficult to analyze the cryptographic operation formula F (x), and as a result, security against vehicle theft can be improved.

  (2) The destination determination of the vehicle 1 is determined from the destination information D that the vehicle 1 has in advance. For this reason, for example, regardless of whether or not challenge response authentication is executed, it is possible to determine the destination result of the vehicle 1 in advance. Therefore, the processing required at the time of challenge response authentication is reduced, so that the authentication processing time can be shortened.

  (3) Since the challenge-response authentication for pair confirmation performed between the immobilizer ECU 8 and the engine ECU 6 is also executed by the cryptographic operation formula F (x) according to the destination of the vehicle 1, it is only between the immobilizer ECU 8 and the transponder 11. In addition, the authentication between the immobilizer ECU 8 and the engine ECU 6 can also make it difficult to analyze the cryptographic operation formula F (x). Therefore, it is possible to make it difficult for the engine 5 to be illegally started, and it is possible to further increase the security against vehicle theft.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
The adoption target of the cryptographic operation switching system 17 is not necessarily limited to the immobilizer system 7. For example, the present invention may be applied to a so-called key operation free system in which a request is transmitted as a key reply request from the vehicle 1 and collation is performed using an ID code returned from the key 2 in response to the request.

  The vehicle 1 may include both the key operation free system and the immobilizer system 7 described above. In this case, the function of the transponder 11 of this example may be integrated into a control IC (Integrated Circuit) that manages the key operation free system.

-The number of combinations of the destination information D is not necessarily limited to three of the first function to the third function, and other numbers of combinations may be adopted.
The destination confirmation is not necessarily performed every time at the time of authentication, but may be held as a fixed value after the authentication is performed once.

-Destination confirmation is not necessarily performed at the time of authentication, but may be performed at any time.
The destination confirmation is not necessarily limited to a format derived by referring to the table 18 (22) based on the destination information D that the vehicle 1 has in advance. For example, a format for determining the destination of the vehicle 1 from the ID information transmitted from the vehicle key 2, that is, the transponder code transmitted from the transponder 11, may be adopted.

  The destination information D supplied to the immobilizer ECU 8 and the engine ECU 6 may be common to both of them, or may be supplied from a different part of each.

  The start condition for immobilizer verification is not necessarily limited to the vehicle key 2 being inserted into the key cylinder 3. For example, the start condition may be that the brake pedal is depressed while the shift lever is in the parking position.

-The frequency of immobilizer communication is not necessarily performed by radio waves in the LF band, and, for example, a UHF (Ultra High Frequency) band may be used.
The tables 18 and 22 are not necessarily in the form of a table in which the destination information D and the cryptographic operation formula F (x) are associated with each other. If it is known whether to use x), the form is not particularly limited.

  The authentication between the immobilizer ECU 8 and the transponder 11 and the authentication between the immobilizer ECU 8 and the engine ECU 6 are not necessarily limited to using the same cryptographic operation formula F (x), but the cryptographic operation formula F (x ) May be different.

As the cryptographic operation formula F (x), various types such as AES (Advanced Encryption Standard) cipher and DES (Data Encryption Standard) cipher can be adopted.
The communication format between the communication master and the communication terminal is not necessarily limited to wireless, and may be wired, for example.

  The challenge response authentication of the immobilizer ECU 8 and the engine ECU 6 is not necessarily limited to being performed with the cryptographic calculation formula F (x) according to the destination, and is performed with one fixed calculation formula by omitting this function. But you can.

  -The adoption object of the technical idea of this example is not necessarily limited to the vehicle 1, and may be applied to various apparatuses and devices. Therefore, the communication master is not limited to the immobilizer ECU 8 (vehicle 1), and the communication terminal is not limited to the transponder 11 (vehicle key 2), and various types can be adopted.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(1) In Claims 1 and 2 , the response includes a response code that is a response to the challenge response authentication and an authentication code that is a unique ID of the communication terminal. And the authentication code are used to determine whether the verification is successful. In this case, the authentication level can be higher.

  6 ... Engine ECU as master side device, 8 ... Immobilizer ECU as communication master, 11 ... Transponder as communication terminal (communication partner), 18, 22 ... Table, 19 ... Authentication execution unit as authentication execution means, 20, 24 ... Destination confirmation unit as destination confirmation unit, 21, 25 ... Cryptographic operation formula setting unit as cryptographic operation type switching unit, Sch ... Challenge, Srs ... Response, F (x) (F1 (x) to F8 (x) ) ... Cryptographic expression, D (D1-D8) ... Destination information.

Claims (3)

Sending a challenge from the communication master to the communication terminal that is the communication partner, causing the communication terminal to calculate the response of the challenge using the cryptographic operation formula, and sending the response back to the communication master after the calculation, also to the communication master In the challenge response type authentication system that performs the response of the challenge by the cryptographic operation formula possessed by the communication master and authenticates the two parties by comparing the responses of the two parties,
The communication master is
A table and the encryption arithmetic expression for the authentication and destination of each communication master is associated,
From the destination information provided in advance in the communication master, destination confirmation means for confirming the destination of the communication master itself ;
Comprising the said singled out encryption arithmetic expression from the table, the cryptographic computing expressions switching means for setting this as the encryption operation expression used before SL during authentication corresponding to the destination that has been indexed by the destination confirmation unit Authentication system. When the operation execution is started, the communication master is connected with a master side device that requires authentication of the challenge response between the communication master and an authentication execution unit that performs authentication with the communication terminal. And
2. The authentication system according to claim 1, wherein the master side device executes authentication of the challenge response with the authentication execution unit by the cryptographic operation expression determined according to the destination. Sending a challenge from the communication master to the communication terminal that is the communication partner, causing the communication terminal to calculate the response of the challenge using the cryptographic operation formula, and sending the response back to the communication master after the calculation, also to the communication master In the challenge response type authentication method for performing authentication of the two parties by comparing the responses of the two parties by calculating the response of the challenge by the cryptographic calculation formula possessed by the communication master,
Wherein the communication master table and the encryption arithmetic expression for the authentication and destination of each communication master was correlated set vignetting,
The communication master, from pre-equipped obtained destination information to the communication master, together determine the destination of the communication master itself, picked the encryption operation equation corresponding to the indexed the destination from the table, before SL authenticate this An authentication method characterized in that it is set as a cryptographic operation expression used sometimes.

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