SYSTEM AND METHOD FOR AUTHENTICATION ON A DEVICE

Description

[0001] The invention relates to a system and a method that enable reliable authentication of a user on a device, even when the device cannot communicate with an authentication server.

[0002] An IoT (Internet of Things) device is typically connected to a server via the internet. A user of the IoT device (e.g., a service technician) can authenticate themselves to the IoT device, with the verification of authenticity usually involving an authentication server. Authentication may be necessary, for example, to prevent unauthorized access to the IoT device. US 2002 / 056747 A1 describes approaches to authentication on a server or user device. The prior art also includes EP 3474172 A1.

[0003] If an IoT device's internet connection is interrupted or unavailable, reliable and secure authentication is usually impossible (because the authentication server cannot be accessed). This document addresses the technical challenge of enabling secure and reliable authentication on a device even when the device is not connected to an authentication server via a communication link.

[0004] The problem is solved in each case by the subject matter of the independent patent claims. Advantageous embodiments are defined in particular in the dependent patent claims, described in the following description, or illustrated in the accompanying drawing.

[0005] According to one aspect of the invention, a method for authentication (of a user and / or a computer unit) on a device is described. The device, in particular the IoT device, is preferably a household appliance, especially a washing machine, a dryer, a food processor, a stove, an oven, a refrigerator and / or a dishwasher.

[0006] The process involves providing and / or receiving a certificate. The certificate can be provided by a certificate server responsible for managing access to the device. This server could, for example, be provided by the device manufacturer. In addition to the certificate, the server can also provide (current) information about the device (e.g., its current state). This information can improve the quality of subsequent access to the device.

[0007] To obtain a certificate, a server authentication process can first be performed on the server to authenticate the entity (e.g., a computer and / or a user) that wants to obtain the certificate from the server. The certificate can then be provided by the server (possibly only) after a successful server authentication process.

[0008] The certificate (provided by the server) allows a limited number N of authentication operations. The number N of possible authentication operations for the certificate, when provided by the server, is preferably between 2 and 10. Limiting the number of authentication operations allowed by a certificate ensures a high level of security (even in the event of certificate loss). Additionally, the certificate can also be limited to a specific period of time.

[0009] The procedure further includes performing an authentication process on the device (using the certificate). As part of the authentication process, the entity seeking to authenticate with the device can receive a challenge (e.g., a random number) sent by the device. The entity can then generate a response to the challenge, the response depending on the challenge and the certificate. This response can then be sent to the device, which can either authenticate the entity or reject the authentication request based on the response.

[0010] Furthermore, the procedure includes reducing the number N of possible authentication operations for the certificate. Specifically, with each authentication operation using the certificate, the number N can be reduced (by one). This reliably prevents unauthorized authentication on a device (even if there is no communication link between the device and an authentication server).

[0011] The certificate can be configured to allow a user of the certificate to access the device following a successful authentication process. The certificate can also be configured to restrict access to a subset of privileges from a total set of privileges. This subset of privileges can depend on the user's type (e.g., a device user, device service personnel, and / or a device developer).

[0012] The process can involve identifying a user type from a number of different user types. A certificate can then be issued and / or received, granting one or more access rights to the device depending on the identified user type. This further enhances the security of access to the device.

[0013] The procedure can include checking, as part of the authentication process, whether the number N of remaining possible authentication attempts is greater than zero. The authentication process on the device can be (automatically) rejected if it is determined that the number N of remaining possible authentication attempts is not greater than zero. This allows the validity of the certificate to be reliably limited.

[0014] The certificate is deployed on a hardware security module (HSM). This ensures reliable storage of the certificate.

[0015] The number N of possible authentication processes is reduced by means of a counter in the hardware security module to enable a particularly reliable limitation of the certificate's validity.

[0016] The procedure can be specifically designed to authenticate a computer unit to the device. Access to the certificate (for an authentication process) is enabled via a communication interface (e.g., a USB interface) between the computer unit and the hardware security module. This allows the certificate to be used reliably and conveniently.

[0017] According to a further aspect of the invention, a system for authenticating (a user or a computer unit) on a device is described. The system is configured to provide a certificate, wherein the certificate enables a limited number N of authentication operations. Furthermore, the system is configured to perform an authentication operation on the device (using the certificate) and to reduce the number N of remaining possible authentication operations of the certificate.

[0018] It should be noted that any aspect of the system and / or method described in this document can be combined in a variety of ways. In particular, the features of the patent claims can be combined in a variety of ways.

[0019] The invention will now be described in more detail with reference to exemplary embodiments illustrated in the accompanying drawing. Figure 1 is a block diagram of a system for authenticating a user on a device; Figure 2 is an exemplary sequence of an authentication process on a device; and Figure 3 is a flowchart of an exemplary procedure for authentication on a device.

[0020] As stated at the beginning, this document deals with the efficient and secure authentication of a user or a user's computer unit to a device. In this context, it shows Fig. 1 A system 100 for authentication on a device 105, in particular a household appliance. The system 100 includes a hardware security module (HSM) 103, which is configured to receive a certificate 102 from an authentication server 101 (step 111 in Fig. 1 The certificate 102 can grant access to a specific device 105 and / or a specific group of devices 105. Furthermore, the certificate 102 can define the scope of activities that can be performed when accessing a device 105.

[0021] Certificate 102 includes a specific (maximum) number of uses, where the number of uses indicates how frequently or how many times certificate 102 can and / or may be used for authentication on a device 105.

[0022] Certificate 102 can be stored in the HSM 103. The HSM 103 can be connected by a user to a computer unit 104 (e.g., a smartphone or laptop) via an interface 108 (e.g., USB). To enable access to a device 105, a communication connection 112 (e.g., Bluetooth and / or WLAN) can be established between the computer unit 104 and the device 105.

[0023] Device 105 can send a challenge 113 to computer unit 104 via communication link 112. The challenge 113 can, for example, be a random number. Computer unit 104 can then supplement or sign the challenge 113 using the certificate (e.g., by means of a password contained in the certificate). Based on the signed challenge 113, computer unit 104 can then send a response 114 to device 105. For example, the signed challenge 113 can be encrypted and / or a hash function of the signed challenge 113 can be generated and sent as response 114. Based on response 114, device 105 can authenticate computer unit 104 or reject authentication. Furthermore, the authentication result 115 can be communicated to computer unit 104. After successful authentication, access to device 105 can be granted to 117.

[0024] The device 105 can include a communication unit 107, through which communication with the computer unit 104 takes place. Furthermore, the device 105 can include a control unit 106, which is configured to evaluate the response 114 in order to authenticate a computer unit 104.

[0025] The HSM 103 is configured to reduce the remaining usage count of certificate 102 for each authentication operation (step 116). Furthermore, the HSM 103 can be configured to prevent further use of certificate 102 for authentication purposes when the remaining usage count of certificate 102 is zero. Alternatively or additionally, the device 105 can be configured to update the usage count of certificate 102. Furthermore, the device 105 can be configured to check the remaining usage count during an authentication operation.

[0026] The following describes a customer service call as an example of accessing a device 105, without limiting its general applicability. However, the authentication procedure described in this document for a device 105, particularly a household appliance, can in principle be used by anyone.

[0027] User 202 (see Fig. 2 A user who wishes to authenticate themselves to device 105 or to the system master SMM 205 of device 105 uses an HSM (Hardware Security Module) 103, possibly as the only hardware required. Using a (possibly freely available) web service, the user 202 can, for example, use a PC or a smartphone to authenticate themselves to a backend server 101. By providing and verifying specific information, it may be possible to differentiate between various user groups (e.g., end users, customer service, device developers, etc.). Depending on their authorization, the user can request a digital certificate 102 (step 211), for example, to perform customer service on a specific device 105 or on a defined group of devices 105. The granularity of access rights may depend on the implementation and / or properties of device 105.

[0028] Depending on the properties of the user 202 and / or the device 105 or device group, a digital certificate 102 can be created by the backend server 101 (step 212). The digital certificate 102 can be securely stored in the HSM 103 using one or more techniques provided by the HSM 103 (e.g., "PKI-as-a-Service", "Device Issuer CA", "Built-In PKI", and / or Secure Channel) (step 213). PKI stands for public key infrastructure and CA for certification authority.

[0029] Certificate 102 requests that are not considered plausible can be rejected by the backend server 101 (e.g., an excessive number of access requests or certificate requests in a single day). Requests from known, invalid users can also be rejected, which, for example, enables the effective revocation of certificates 102. This functionality is typically not achievable with an implementation without HSM 103.

[0030] To access a device 105, the user plugs the HSM 103 into a computer unit 104 (e.g., a smartphone with a USB OTG interface). A software app on the computer unit 104 can enable end-to-end communication 112 between the HSM 103 and the device 105 (step 214).

[0031] The user now proves their authorization with certificate 102 using a challenge-response procedure (steps 215, 216, 217, 219), whereby a random number (e.g., in the form of an authentication token) 203 from device 105 is signed by a private key of certificate 102 stored in HSM 103 (step 218). Access can be restricted by the HSM features "Key Use Counter" and / or "Key Restriction." With each use, an internal counter is decremented (step 116). Once the counter reaches 0, no further use is possible with the installed certificate 102. This means that the loss of HSM 103 has only a limited impact on security.

[0032] Security can optionally be further increased by using PIN management.

[0033] The measures described in this document can improve usability and increase security. Furthermore, by requiring a new certificate 102 to be obtained from a backend server 101 shortly before each access attempt, current information about a device 105 can be provided, thus improving access to the device 105. For example, information about previous access attempts and / or current software or firmware versions for a device 105 can be transmitted. As an alternative to an HSM 103, a JavaCard-compatible NFC smartcard with the HSM-relevant features can be used.

[0034] Fig. 3Figure 300 shows a flowchart of an exemplary procedure 300 for authentication (of a unit 104 and / or a user 202) on a device 105. The procedure 300 can be executed by a system 100 and / or by a computer unit 104. The procedure 300 includes the provision 301 of a certificate 102, wherein the certificate 102 allows a limited number N of authentication operations (e.g., N>1 and / or N<5, upon delivery of the certificate 102).

[0035] Furthermore, procedure 300 includes performing an authentication operation on device 105 using certificate 102. Procedure 300 also includes reducing the number N of possible authentication operations for certificate 102. With each authentication operation, the number N of possible authentication operations for certificate 102 can be reduced (by one). In this way, access to a device 105 (or a group of devices) can be enabled and / or controlled efficiently and securely.

[0036] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed system and / or the proposed method.

Claims

1. Method (300) for authentication on an appliance (105); wherein the method (300) comprises, - providing (301) a certificate (102) on a hardware security module (103); wherein the certificate (102) permits a limited number N of authentication processes; - implementing (302) an authentication process on the appliance (105); and reducing (303) the number N of still possible authentication processes of the certificate (102); wherein the hardware security module (103) can be connected to a computer unit (104) by a user by way of an interface (108), characterised in that the number N of still possible authentication processes is reduced by means of a counter of the hardware security module (103).

2. Method (300) according to claim 1; wherein the method (300) comprises, - checking, within the scope of the authentication process, whether the number N of still possible authentication processes is greater than zero; and - rejecting the authentication process on the appliance (105), if it is determined that the number N of still possible authentication processes is not greater than zero.

3. Method (300) according to one of the preceding claims, wherein the method (300) comprises, - determining a user type comprising a plurality of different user types; and - providing a certificate (102), which permits one or more access rights, dependent on the user type, to the appliance (105).

4. Method (300) according to one of the preceding claims, wherein, within the scope of the authentication process, the method (300) comprises - receiving a challenge (113) from the appliance (105); - determining a response (114) to the challenge (113); wherein the response (114) depends on the challenge (113) and on the certificate (102); and - sending the response (114) to the appliance (105).

5. Method (300) according to one of the preceding claims, wherein - the method (300) is designed to authenticate a computer unit (104) on the appliance (105); and - the method (300) comprises accessing the certificate (102) by way of a communication interface between the computer unit (104) and the hardware security module (103).

6. Method (300) according to one of the preceding claims, wherein the certificate (102) is provided by a server (101), which is responsible for managing access to the appliance (105).

7. Method (300) according to claim 6, wherein the method (300) comprises, - implementing a server authentication process on the server (101), in order to authenticate a unit, which wishes to obtain the certificate (102) from the server (101); and - providing the certificate (102) following a successful server authentication process.

8. Method (300) according to one of claims 6 to 7, wherein the method comprises providing information in respect of the appliance (105) from the server (101) together with the certificate (102).

9. Method (300) according to one of the preceding claims, wherein, when the certificate (102) is provided by a server (101), the number N of possible authentication processes of the certificate (102) is between 2 and 10.

10. Method (300) according to one of the preceding claims, wherein the appliance (105) is a household appliance, in particular a washing machine, a dryer, a food processor, a cooker, an oven, a refrigerator and / or a washing machine.

11. Method (300) according to one of the preceding claims, wherein - the certificate (102) is embodied to permit a user (202) of the certificate (102) to access the appliance (105) following a successful authentication process; and - the certificate (102) is embodied to limit the access to a sub quantity of access rights from a total quantity of access rights.

12. System (100) for authenticating on an appliance (105); wherein the system (100) is embodied, - to provide a certificate (102) on a hardware security module (103); wherein the certificate (102) permits a limited number N of authentication processes; - to implement an authentication process on the appliance (105); and to reduce the number N of still possible authentication processes of the certificate (102), wherein the hardware security module (103) can be connected to a computer unit (104) by a user by way of an interface (108), characterised in that the number N of still possible authentication processes is reduced by means of a counter of the hardware security module (103).