JP2022032113A - Wireless key device, secure element, authentication system, and authentication method - Google Patents

Abstract

To provide a wireless key device and the like that is not analyzed by an attacker even when storing an encryption key and is not freely used even when obtained by the attacker, by performing mutual authentication with a control apparatus performing predetermined control through the mutual authentication via wireless communication.SOLUTION: A wireless key device includes a secure element having tamper-resistant, performs authentication of a user by comparing user authentication data input by the user with user authentication data stored in the secure element, and performs mutual authentication with a control apparatus using an encryption key stored in the secure element when the user is authenticated.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technical field such as a wireless key device in which a control device that performs a predetermined control is mutually authenticated via wireless communication to perform a predetermined control.

Key fobs (smart keys) that wirelessly unlock vehicles and start engines are widespread. According to the key fob, the key lock of the vehicle can be easily unlocked without inserting the key into the keyhole.

The key fob and the vehicle must be paired before use, and the vehicle manufacturer gives the car dealer the encryption key for pairing, where the key fob and the vehicle are paired. However, there is a risk that the encryption key will be stolen or leaked in this process.

Patent Document 1 discloses a method and a device for safely pairing an identifier-based key fob and a vehicle in order to solve such a problem.

Japanese Unexamined Patent Publication No. 2019-180099

However, the method disclosed in Patent Document 1 contributes to the safety at the time of pairing the key fob and the vehicle, but regarding the safety of mutual authentication between the vehicle and the key fob after pairing (after the vehicle is sold). Is not considered. That is, even if the key fob stores the encryption key, it may be analyzed by an attacker. There is also the problem that if an attacker obtains a key fob, he or she can freely operate the vehicle.

In view of these circumstances, the present invention is a wireless key device that performs mutual authentication via wireless communication with a control device that performs predetermined control via mutual authentication, and even if the encryption key is stored, the attacker can use it. An object of the present invention is to provide a wireless key device or the like that is not analyzed and is not freely used even if it is obtained by an attacker.

In order to solve the above problem, the invention according to claim 1 is a wireless key device that performs mutual authentication with a control device that performs predetermined control via wireless communication, and is secure with tamper resistance. A user authentication unit that authenticates the user by comparing the element, the user authentication data input by the user, and the user authentication data stored in the secure element in advance, and the user authentication unit a user. It is characterized by including a mutual authentication unit that performs the mutual authentication with the control device by using the encryption key stored in the secure element when the authentication is performed.

The invention according to claim 2 is the wireless key device according to claim 1, wherein the user authentication data is biometric authentication information of the user.

The invention according to claim 3 is the wireless key device according to claim 1, wherein the user authentication data is character string information.

The invention according to claim 4 is the wireless key device according to any one of claims 1 to 3, wherein the user authentication unit and the mutual authentication unit are supplied from a reader / writer of the control device. It is characterized by operating on the basis of electric power.

The invention according to claim 5 is a secure element included in the wireless key device according to any one of claims 1 to 4.

The invention according to claim 6 is an authentication system including a control device that performs predetermined control and a wireless key device that performs mutual authentication between the control device via wireless communication, and the wireless key. The device includes a secure element having tamper resistance, a user authentication unit input by the user, and a user authentication unit that authenticates the user by comparing the user authentication data stored in the secure element in advance. The user authentication unit is provided with a first mutual authentication unit that performs the mutual authentication with the control device using the encryption key stored in the secure element when the user authentication unit authenticates the user. The control device is characterized by including a second mutual authentication unit that performs the mutual authentication with the wireless key device, and a control unit that performs the predetermined control when the mutual authentication is normally completed. And.

The invention according to claim 7 is the authentication system according to claim 6, wherein the control unit controls to release the door lock of the moving body provided with the control device, or the engine of the moving body. It is characterized by controlling to start (engine / motor).

The invention according to claim 8 is the authentication system according to claim 6 or 7, wherein the wireless key device operates based on electric power supplied from a reader / writer of the control device. ..

The invention according to claim 9 comprises a control device that performs predetermined control and a wireless key device that includes a secure element having tamper resistance and performs mutual authentication with the control device via wireless communication. In the authentication method by the authentication system including, the wireless key device compares the user authentication data input by the user with the user authentication data stored in the secure element in advance to authenticate the user. A user authentication step and a mutual authentication step in which the wireless key device and the control device perform the mutual authentication using the encryption key stored in the secure element when the user is authenticated in the user authentication step. It is characterized by including a control step in which the control device performs the predetermined control when the mutual authentication is normally completed.

The invention according to claim 10 is the authentication method according to claim 9, wherein the wireless key device has the user authentication process and the mutual authentication based on the electric power supplied from the reader / writer of the control device. It is characterized by performing a process.

According to the present invention, since the encryption key is stored in the secure element having tamper resistance, the encryption key is not analyzed by an attacker, and based on the user authentication data input by the user. If the user is not authenticated, mutual authentication is not performed with the control device, so that even if the wireless key device is obtained by an attacker, it can be prevented from being freely used.

It is a block diagram which shows the outline structure example of the door lock system which concerns on this embodiment. It is a sequence diagram which shows an example of the mutual authentication processing by the door lock system which concerns on this embodiment. It is a flowchart which shows an example of the user authentication processing by the key fob which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are embodiments when the present invention is applied to a door lock system.

First, the configuration of the door lock system S according to the present embodiment will be described with reference to FIG. 1 and the like.

[1. Door lock system S configuration]
FIG. 1 is a block diagram showing a schematic configuration example of the door lock system S according to the present embodiment. The door lock system S is a system related to a door lock of an automobile, and includes a key fob 1 and a door control device 3 to which a reader / writer 31 for NFC (Near Field Communication) is connected. Wireless communication by NFC is performed between the key fob 1 and the door control device 3.

The reader / writer 31 is provided near the door lock of the automobile, and when the key fob 1 is in close proximity, the reader / writer 31 supplies electric power to the key fob 1 and is an interface on the door control device 3 side for performing wireless communication between the door control device 3 and the key fob 1. Functions as I / F).

The key fob 1 authenticates the user by the electric power supplied from the reader / writer 31, and when the user authentication is normally completed, the key fob 1 performs mutual authentication with the door control device 3 by wireless communication. Then, when the mutual authentication with the key fob 1 is normally completed, the door control device 3 releases the door lock of the automobile. For mutual authentication and secure communication between the door control device 3 and the key fob 1, for example, SCP '03' defined in the Global Platform is used.

[2. Configuration of key fob 1]
The key fob 1 includes an antenna coil 11, a biometric I / F 12, and an embedded secure element (eSE) 2. When the antenna coil 11 enters the AC magnetic field of the reader / writer 31, an AC voltage is induced, and the AC voltage is converted into a DC voltage by a converter (not shown). The biometric authentication I / F12 and the secure element 2 of the key fob 1 operate using this DC voltage as a power source. The antenna coil 11 functions as a part of the I / F when wirelessly communicating with the door control device 3 via the reader / writer 31.

The biometric authentication I / F12 receives the user's biometric authentication information (for example, information indicating features such as a fingerprint, an iris, a voice, and a face) and outputs the biometric authentication information to the secure element 2. For example, when the biometric authentication information is used as the fingerprint information, the fingerprint reading image sensor as the biometric authentication I / F12 accepts the user's fingerprint information as the biometric authentication information.

[3. Configuration of secure element 2]
The secure element 2 includes a CPU 21, a RAM 22, a non-volatile memory 23, and an I / O circuit 24. The secure element 2 has high tamper resistance. High tamper resistance means that the mechanism for processing confidential information such as keys for encryption, decryption, and signature verification is unreasonably observed / modified from the outside, and the mechanism for processing confidential information is unreasonable. It means that it is extremely difficult to modify it.

The RAM 22 is a volatile memory, and can store information when, for example, power is supplied from the door control device 3 to the secure element 2, and information can be stored when the power supply is cut off. However, the data stored up to that point will be lost. The RAM 22 stores, for example, data temporarily required for the OS and various applications to function.

For the non-volatile memory 23, for example, a flash memory or an "Electrically Erasable Programmable Read-Only Memory" can be adopted. The non-volatile memory 23 stores an OS, various applications, a program for executing mutual authentication processing, user authentication processing, etc., which will be described later. As the application, for example, an application that realizes a pairing function, a key update / addition / deletion function, a key holding function, a certificate verification function, a secure communication function, an authentication function, and a user authentication function is stored.

Further, the non-volatile memory 23 stores encryption keys such as public / private keys and session keys, and biometric authentication information of the user as a reference in the user authentication process. The encryption key and biometric authentication information are stored in a secure storage area in the non-volatile memory 23.

The I / O circuit 24 serves as a communication interface with the door control device 3 and encodes data exchanged with the door control device 3 (reader / writer 31).

[4. Mutual authentication processing by door lock system S]
Next, an example of mutual authentication processing by the door lock system S will be described with reference to FIG.

First, when the key fob 1 enters the AC magnetic field of the reader / writer 31 and receives power from the reader / writer 31 (step S101), the CPU 21 of the secure element 2 performs a user authentication process described later using FIG. 3 (step S102). ). The process performed by the CPU 21 in FIG. 2 is executed based on the power supplied from the reader / writer 31.

Next, the CPU 21 determines whether or not the normal end flag is turned ON as a result of the user authentication process (step S103). In the user authentication process, ON (“1”) is set in the normal end flag when the user is authenticated, and OFF (“0”) is set in the normal end flag when the user is not authenticated. do.

When the CPU 21 determines that the normal end flag is not ON (OFF) (step S103: NO), the CPU 21 ends the mutual authentication process. On the other hand, when the CPU 21 determines that the normal end flag is ON (step S103: YES), the CPU 21 then controls the door with information indicating that the user authentication is OK (normal end). It is transmitted to the device 3 (step S104).

When the CPU (not shown) of the door control device 3 receives the information indicating that the user's authentication is OK, the service related to the door lock system S among the applications in the key fob 1 (secure element 2) is realized. A command (digital key application selection command) instructing the selection of the digital key application (digital key application) for the operation is transmitted to the key fob 1 (step S105).

Upon receiving the digital key application selection command, the CPU 21 selects the digital key application in the non-volatile memory 23, and thereafter executes the digital key application to perform mutual authentication processing with the door control device 3. After selecting the digital key application, the CPU 21 transmits an OK response indicating that effect to the door control device 3 (step S106).

Upon receiving the OK response, the CPU of the door control device 3 (not shown) transmits the public key of the door control device 3 stored in the storage device (not shown, preferably a secure element) to the key fob 1. (Step S107).

When the CPU 21 receives the public key of the door control device 3, the CPU 21 transmits the public key of the key fob 1 stored in the secure element 2 to the door control device 3 together with an OK response (step S108). Further, the CPU 21 generates a session key (step S109). The received public key of the door control device 3 is stored in the secure element 2.

Upon receiving the OK response and the public key of the key fob 1, the CPU (not shown) of the door control device 3 generates a session key (step S110). After that, when transmitting data to the other party, the door control device 3 and the key fob 1 transmit the data encrypted with the session key (data to be transmitted) and the data encrypted with the session key by the other party's public key. do.

Next, the CPU of the door control device 3 (not shown) transmits the signature data created by the private key of the door control device 3 stored in the storage device (not shown, preferably a secure element) to the key fob 1. (Step S111).

When the CPU 21 receives the signature data from the door control device 3, the CPU 21 verifies the signature data using the public key of the door control device 3 received in the process of step S107 (step S112). If there is no problem in the signature verification, the CPU 21 transmits the signature data created by the private key of the key fob 1 stored in the secure element 2 to the door control device 3 together with the OK response (step S113). If there is a problem in the signature verification, the CPU 21 transmits an NG response to the door control device 3.

Next, when the CPU (not shown) of the door control device 3 receives the OK response and the signature data, the signature data is verified by using the public key of the key fob 1 received in the process of step S108 (step S114). If there is no problem in verifying the signature, the CPU of the door control device 3 (not shown) releases the door lock of the automobile (step S115) and ends the mutual authentication process.

[5. User authentication process by key fob 1]
Next, an example of the user authentication process by the key fob 1 will be described with reference to FIG.

First, the CPU 21 of the key fob 1 receives the biometric authentication information from the biometric authentication I / F12 (step S131). Next, the CPU 21 compares the biometric authentication information received in the process of step S131 with the biometric authentication information stored in the secure element 2 in advance (step S132).

Next, the CPU 21 determines whether or not the biometric authentication information matches (step S133). When it is determined that the biometric authentication information matches (step S133: YES), the CPU 21 sets the normal end flag stored in the RAM 22 to ON (step S134), and ends the user authentication process. On the other hand, when it is determined that the biometric authentication information does not match (step S133: NO), the CPU 21 sets the normal end flag stored in the RAM 22 to OFF (step S135), and ends the user authentication process.

As described above, mutual authentication via wireless communication with the door control device 3 (an example of the "control device") that releases the door lock (an example of the "predetermined control") according to the present embodiment. The key fob 1 (an example of a "wireless key device") is provided with a secure element 2 having tamper resistance, and the CPU 21 (an example of a "user authentication unit", a "mutual authentication unit" and a "first mutual authentication unit"). However, when the user is authenticated by comparing the biometric authentication information input by the user (an example of "user authentication data") with the biometric authentication information stored in the secure element 2 in advance, and the user is authenticated. , Mutual authentication is performed with the door control device 3 using the encryption key stored in the secure element 2.

Therefore, according to the key fob 1 of the present embodiment, since the encryption key is stored in the secure element 2 having tamper resistance, the encryption key is not analyzed by the attacker and is input by the user. If the user is not authenticated based on the biometric authentication information, mutual authentication is not performed with the door control device 3, so that the key fob 1 can be prevented from being freely used even if it is obtained by an attacker. Can be done.

On the other hand, in the door control device 3, when a CPU (an example of the "second mutual authentication unit" and the "control unit") (not shown) performs mutual authentication with the key fob 1 and normally ends the mutual authentication. Release the door lock. As a result, the user can input the biometric authentication information into the key fob 1 and bring the key fob 1 close to the reader / writer 31 to unlock the door of the automobile.

Further, the CPU 21 operates based on the electric power supplied from the reader / writer 31 of the door control device 3. Therefore, since it is not necessary to provide the key fob 1 with a battery for operating the CPU 21, the weight of the key fob 1 can be reduced, and it is possible to avoid a situation in which the door lock cannot be released due to the battery running out.

[5. Modification example]
Hereinafter, a modification of the present embodiment will be described. The modifications described below can be combined as appropriate.

[5.1. Modification 1]
In the present embodiment, the user inputs the biometric authentication information in the key fob 1, but instead of the biometric authentication I / F12, a PIN (Personal Identification Number) (an example of "user authentication data") is input. The PIN pad may be provided in the key fob 1 and the user may be asked to input the PIN. A keyboard may be provided in the key fob 1 instead of the PIN pad, and the user may be asked to enter a password (an example of "character string information"). In either case, the PIN or password is stored in the secure element 2 in advance, and the CPU 21 compares it with the PIN or password input to the user in step S132 of FIG. 3 (user authentication process).

[5.2. Modification 2]
In the present embodiment, the biometric authentication I / F 12 and the secure element 2 of the key fob 1 are operated based on the electric power supplied from the reader / writer 31, but the key fob 1 is provided with a battery, and at least a part of the battery is provided. May be operated as a power source. For example, the biometric authentication I / F 12 may be operated by using a battery as a power source, and the secure element 2 may be operated by the electric power supplied from the reader / writer 31.

When a battery is provided in the key fob 1, the processing of steps S101 to S103 in FIG. 2 (mutual authentication processing) is performed on the key fob 1 side, and then when the key fob 1 approaches the reader / writer 31, the door lock system S operates. The mutual authentication process of steps S105 to S115 may be performed. In this case, if the key fob 1 is close to the reader / writer 31 even though the user authentication has not ended normally (the normal end flag is OFF), the CPU 21 uses the digital key application selection command ( An NG response is transmitted to step S105) so that mutual authentication processing is not performed with the door control device 3.

[5.3. Modification 3]
In the present embodiment, the communication between the key fob 1 of the door lock system S and the door control device 3 is communication by NFC, but instead of NFC, communication by Bluetooth (registered trademark) or UWB (Ultra wide band) is also possible. good.

[5.4. Modification 4]
In the present embodiment, the door control device 3 decides to release the door lock when mutual authentication with the key fob 1 is normally completed, but it is a control to start an engine such as an engine or a motor in a moving body such as an automobile. The present invention can also be applied to an engine start control device for performing the above. At this time, the engine start control device starts the engine when the mutual authentication with the key fob 1 is normally completed. That is, the control device of the present invention can be applied to at least one of the door control device 3 and the engine start control device, and can also be applied to other control devices that perform predetermined control.

[5.5. Modification 5]
In the present embodiment, the case where the wireless key device of the present invention is applied to the key fob 1 has been described. However, the wireless key device of the present invention includes a non-contact IC card with biometric authentication (for example, a fingerprint reading unit and a fingerprint reading unit). It can also be applied to an IC card that authenticates a user based on the fingerprint data read in.

1: Key fob 2: Secure element 3: Door control device 11: Antenna coil 12: Biometric authentication I / F
21: CPU
22: RAM
23: Non-volatile memory 24: I / O circuit 31: Reader / writer S: Door lock system

Claims (10)

A wireless key device that performs mutual authentication via wireless communication with a control device that performs predetermined control.
Secure element with tamper resistance and
A user authentication unit that authenticates the user by comparing the user authentication data input by the user with the user authentication data stored in the secure element in advance.
When the user authentication unit authenticates the user, the mutual authentication unit that performs the mutual authentication with the control device using the encryption key stored in the secure element, and the mutual authentication unit.
A wireless key device characterized by being equipped with. The wireless key device according to claim 1.
The user authentication data is a wireless key device characterized by being biometric authentication information of the user. The wireless key device according to claim 1.
The wireless key device, characterized in that the user authentication data is character string information. The wireless key device according to any one of claims 1 to 3.
The user authentication unit and the mutual authentication unit are wireless key devices that operate based on the electric power supplied from the reader / writer of the control device. The secure element included in the wireless key device according to any one of claims 1 to 4. An authentication system including a control device that performs predetermined control and a wireless key device that performs mutual authentication between the control device via wireless communication.
The wireless key device is
Secure element with tamper resistance and
A user authentication unit that authenticates the user by comparing the user authentication data input by the user with the user authentication data stored in the secure element in advance.
When the user authentication unit authenticates the user, the first mutual authentication unit that performs the mutual authentication with the control device using the encryption key stored in the secure element, and the first mutual authentication unit.
Equipped with
The control device is
A second mutual authentication unit that performs the mutual authentication with the wireless key device,
When the mutual authentication is normally completed, the control unit that performs the predetermined control and the control unit
An authentication system characterized by being equipped with. The authentication system according to claim 6.
The control unit is an authentication system characterized in that it controls to release the door lock of a moving body provided with the control device, or controls to start the engine of the moving body. The authentication system according to claim 6 or 7.
The wireless key device is an authentication system characterized in that it operates based on electric power supplied from a reader / writer of the control device. It is an authentication method by an authentication system including a control device that performs predetermined control and a wireless key device that includes a secure element having tamper resistance and performs mutual authentication with the control device via wireless communication. ,
A user authentication step in which the wireless key device compares the user authentication data input by the user with the user authentication data stored in the secure element in advance to authenticate the user.
When the user is authenticated in the user authentication step, the wireless key device and the control device perform the mutual authentication using the encryption key stored in the secure element, and the mutual authentication step.
A control step in which the control device performs the predetermined control when the mutual authentication is normally completed.
An authentication method characterized by including. The authentication method according to claim 9.
The wireless key device is an authentication method comprising performing the user authentication step and the mutual authentication step based on the electric power supplied from the reader / writer of the control device.

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