FR2986686A1 - Method for authentication of key with respect to CPU of car, involves evaluating presence of key inside car by emitting acoustic signal by CPU of car, and determining key to be within car when key detects acoustic signal - Google Patents

Abstract

The method involves evaluating the presence of a control device i.e. key (24) inside a car (10) by emitting an acoustic signal by a CPU (22) of the car. The key is determined to be within the car when the key detects the acoustic signal, where a part of authentication data formed by the CPU is transmitted towards the key via the acoustic signal. A request signal including authentication data is issued by the CPU to the key, where the key issues a response signal including the authentication data to the CPU. An independent claim is also included for a system for authentication of a control device with respect to a CPU of a vehicle.

Description

The present invention belongs to the field of securing access to resources, and more particularly relates to a method and a system for authenticating a control device vis-à-vis a central unit of a vehicle, for example a motor vehicle.

In the case of a motor vehicle, the control device corresponds to a key of said motor vehicle, and the authentication is prior to an action performed by the central unit, such as starting said motor vehicle. Nowadays, more and more features are built into mobile phones. It is also envisaged to integrate in a mobile phone a key of a motor vehicle. The key could then be in the form of software that can be downloaded into the mobile phone, and the authentication vis-à-vis the motor vehicle would be using wireless communication means of said mobile phone. However, the wireless communication means of current mobile phones (GPRS, UMTS, WiFi, Bluetooth, etc.) have ranges that are generally greater than ten meters. However, it is understood that it is undesirable that the starting of the motor vehicle can be made possible by the mere presence of the control device at a distance of ten meters or more from said motor vehicle. Therefore, other means must be implemented to ensure that the mobile phone incorporating the key of the motor vehicle is in the immediate vicinity of the motor vehicle. To authorize the start, it is necessary at least to ensure that the mobile phone is inside the motor vehicle. It must also be possible to determine whether the mobile phone is inside the motor vehicle in the case of an authentication intended to authorize the locking of the doors of the motor vehicle, in order to refuse the lock if the mobile phone is at the same time. inside the motor vehicle. The present invention aims to propose a solution that makes it possible to authenticate a control device vis-à-vis a central unit of a vehicle, while evaluating the proximity of said control device with respect to said central unit. . For this purpose, the invention relates, according to a first aspect, to a method of authenticating a control device vis-à-vis a central unit of a vehicle, the authentication of said control device taking place during an authentication session by exchanging authentication data between said controller and said CPU in the form of radio signals. In addition, the authentication method comprises the evaluation of the presence of the control device inside the vehicle by the emission, inside said vehicle, of an acoustic signal by the central unit, said device which can only be considered as being inside the vehicle when said control device has detected said acoustic signal. It will be understood that an acoustic signal emitted inside the vehicle can hardly be detected from the outside of said vehicle, because of absorption by walls of said vehicle and / or because of significant noise pollution outside said vehicle. vehicle. If necessary, the acoustic signal can also be calibrated, in frequency and power, so as to ensure that it can not be detected from outside the vehicle. Consequently, by evaluating the presence of the control device during an authentication session with the central unit, it will be possible to condition the execution of the envisaged action not only to the success of the authentication, but also the presence or absence of the control device inside the vehicle. If the action envisaged is the starting of the vehicle, said starting must be authorized only if the control device is considered to be inside the vehicle (subject to successful authentication). If the action is envisaged is the locking of the vehicle doors, said locking must be authorized only if the control device is considered to be outside the vehicle (subject to successful authentication). In addition, an authentication method according to the invention is more robust to relay attacks ("relay attacks" in the Anglo-Saxon literature) than the authentication methods of the prior art. It is indeed more difficult to carry out a relay attack because it is necessary not only to relay the radio signals, but also the acoustic signal emitted inside the vehicle which is moreover difficult to detect from outside the vehicle. Furthermore, it is understood that current mobile phones are all equipped with a microphone which can be implemented for the detection of an acoustic signal of frequencies included in the spectrum of audible sounds. Thus, if the control device is a mobile phone, the authentication method can be implemented by a simple software update of said mobile phone. It is also understood that current vehicles, especially motor vehicles, are generally equipped with loudspeakers which can be used for the emission of an acoustic signal of frequencies included in the spectrum of audible sounds.

According to particular modes of implementation, the authentication method comprises one or more of the following characteristics, taken separately or in any technically possible combination. In a particular embodiment, part of the authentication data formed by the central unit is transmitted from said central unit to the control device via the acoustic signal. Such arrangements make it particularly easy to ensure that authentication can only be successful if the control device detects the acoustic signal. In a particular mode of implementation, the authentication method comprises steps: of transmission, by the central unit, of a radio signal intended for the control device, called the "request signal UC", comprising authentication data, 15 - transmission, by the control device and following the receipt of the request signal UC and the acoustic signal, a radio signal to the central unit, called "signal of response ", having authentication data determined according to the authentication data included in the request signal UC and in the acoustic signal. Such arrangements make it possible to ensure, at the level of the central unit, that it is indeed the same control device which has received both the request signal UC and the acoustic signal. In fact, in the opposite case, the authentication data included in the response signal can not correspond to the authentication data expected by the central unit, and the authentication will fail. In a particular mode of implementation: the authentication method comprises a step of transmission, by the control device, of a radio signal destined for the central unit called "request signal DC", comprising verification data, the acoustic signal comprises verification data determined according to the verification data included in the request signal DC, the authentication method comprises a step of comparison, by the control device, of the data of verification. verification received in the acoustic signal with the verification data transmitted in the request signal DC.

In a particular mode of implementation, the verification data included in the request signal DC are in the form of a digital audio frame, and the acoustic signal corresponds to the analog translation of said digital audio frame.

Such arrangements make it possible to evaluate the presence of the control device inside the vehicle, including in the case of a central unit that can not send authentication data which it has itself formed in the form of an acoustic signal. This is the case, for example, if the only means of acoustic emission is a loudspeaker of a Bluetooth hands-free telephone module, such a loudspeaker generally being able to broadcast only the digital audio frames received in the form of a Bluetooth radio signal. In this case, the control device can send a digital audio frame that it has itself formed, and verify that the acoustic signal received corresponds to the analog translation of said digital audio frame. If this is the case, the control device may consider that it is inside the vehicle. In a particular mode of implementation, if the verification data received in the acoustic signal have been determined from the verification data included in the request signal DC, the authentication method includes a transmission step, by the control device, a radio signal to the central unit, called "response signal", comprising authentication data determined according to authentication data included in a radio signal previously received from the unit Central. In a particular mode of implementation, the authentication method comprises a step of transmission, by the central unit, of a radio signal intended for the control device, called "wake-up signal", the signal of wake-up being sent before emitting the acoustic signal. According to a second aspect, the invention relates to an authentication system comprising a control device to be authenticated vis-à-vis a central unit of a vehicle, said control device and said central unit each comprising: authentication module adapted to form authentication data, - a wireless communication module adapted to transmit and receive radio signals comprising authentication data. In addition, the authentication system is configured to evaluate the presence of the control device inside the vehicle by the emission, inside said vehicle, of an acoustic signal by an acoustic emission module of the vehicle. the central unit, the control device can only be considered to be inside the vehicle when the acoustic signal has been detected by the control device equipped with an acoustic reception module. In a particular embodiment, the central unit is adapted to transmit authentication data formed by the authentication module of said central unit via the acoustic emission module and / or the central unit is adapted to emit an acoustic signal corresponding to a digital audio frame received via the wireless communication module of said central unit, without passing through the authentication module of said central unit. According to a third aspect, the invention relates to a vehicle, such as a motor vehicle, comprising an authentication system according to any one of the embodiments of the invention. The invention will be better understood on reading the following description, given by way of non-limiting example, and with reference to the figures which represent: FIG. 1: a schematic representation of an example of an authentication system according to the invention, - Figure 2: a schematic representation of another example of an authentication system, according to the invention, - Figure 3: a diagram showing the main steps of an exemplary authentication method 20, according to the invention, - Figure 4: a diagram representing the main steps of another example of an authentication method according to the invention. In these figures, identical references from one figure to another designate identical or similar elements. For the sake of clarity, the elements shown are not to scale unless otherwise stated. The present invention relates to the authentication of a control device 24 vis-à-vis a central unit 22 of a vehicle, such as a motor vehicle 10. In general, this authentication aims to authorize an action to by the central unit 22. For example, the authentication aims to authorize / refuse the starting of the motor vehicle 10, or to allow / refuse the locking of doors of said motor vehicle. In both cases, it must be verified whether the control device 24 is inside the motor vehicle 10: - to authorize the starting of the motor vehicle 10 only when the control device 24 is inside. said motor vehicle, - to allow the locking of the doors of the motor vehicle 10 when the control device 24 is outside of said motor vehicle. In the remainder of the description, it is in no way restrictive in the case of an authentication to allow / refuse the start of the motor vehicle 10. Therefore, the starting of the motor vehicle must be authorized only when the The control device 24 is located inside the motor vehicle 10. Figure 1 schematically shows an exemplary authentication system. The authentication system 20 comprises a central unit 22, installed in the motor vehicle 10, and a control device 24 corresponding to a key of the motor vehicle 10. Said control device 24 is for example integrated in a mobile phone. The central unit 22 comprises an authentication module 220, adapted to form authentication data. The authentication module 220 of the central processing unit 22 comprises, for example, a processor and an electronic memory in which a computer program product is stored in the form of a set of program code instructions to be executed by the processor. In a variant, the authentication module 220 of the central processing unit 22 comprises programmable logic circuits, of the FPGA, PLD, etc. type, and / or specialized integrated circuits (ASIC). The authentication module 220 of the central unit 22 is connected to a wireless communication module 222 and to an acoustic emission module 224. The wireless communication module 222 is adapted to transmit and receive radio signals. . "Radio signal" means an electromagnetic wave whose frequencies are within the traditional radio frequency spectrum (a few hertz to several hundred gigahertz) or in neighboring frequency bands (including infrared). In the remainder of the description, one places non-limitatively in the case where the wireless communication module of the central unit 22 is a Bluetooth module. Nothing excludes, according to other examples, consider other means of wireless communication (GPRS, UMTS, WiFi, etc.). The acoustic emission module 224 is adapted to emit acoustic signals. "Acoustic signal" means a mechanical wave whose frequencies are included in the traditional spectrum of audible sounds (of the order of 20 Hz to 20 kilohertz) or in neighboring frequency bands (including ultrasound). The acoustic emission module 224 is for example a loudspeaker adapted to emit acoustic signals of frequencies included in the spectrum of audible sounds. The authentication module 220, the Bluetooth module 222 and the loudspeaker 224 of the central unit 22 form a set of means configured in software (specific computer program product) and / or hardware (FPGA, PLD, ASIC) , etc.) to implement the different steps of an authentication method 50 to be executed by the central unit 22. The controller 24 includes an authentication module 240 adapted to form authentication data. . The authentication module 240 of the control device 24 comprises, for example, a processor and an electronic memory in which a computer program product is stored in the form of a set of program code instructions to be executed by the processor. . In a variant, the authentication module 240 of the control device 24 comprises programmable logic circuits, of the FPGA, PLD, etc. type, and / or specialized integrated circuits (ASIC). The authentication module 240 of the control device 24 is connected to a wireless communication module 242 and to an acoustic reception module 244. The wireless communication module 242 of the control device 24 is adapted to transmit and receive radio signals. Further, said wireless communication module of the controller 24 is compatible with the wireless communication module 222 of the CPU 22. In other words, the wireless communication module 242 of the controller 24 is , in the example considered below, a Bluetooth module. The acoustic receiving module 244 of the controller 24 is adapted to receive acoustic signals. In addition, said acoustic reception module 244 is compatible with the acoustic emission module 224 of the central unit 22, that is to say that it is adapted to receive the acoustic signals emitted by said transmission module acoustic. In the case of acoustic signals of frequencies included in the spectrum of audible sounds, the acoustic reception module 244 is for example a microphone of the mobile telephone in which the control device 24 is integrated. The authentication module 240, the Bluetooth module 242 and the microphone 244 of the control device 24 form a set of means 35 configured in software (specific computer program product) and / or hardware (FPGA, PLD, ASIC, etc. .) to implement the different steps of an authentication method 50 to be executed by the controller 24.

In the example illustrated in FIG. 1, the authentication module 220 of the central unit 22 is connected to both the Bluetooth module 222 and the loudspeaker 224. Consequently, the authentication data formed by said module for authentication of the central unit 22 can be transmitted to the control device 24, in the form of radio signals and / or in the form of acoustic signals. Figure 2 shows an alternative embodiment of an authentication system. The authentication system illustrated in FIG. 2 uses the same elements as those described with reference to the authentication system 20 illustrated in FIG. 2. However, in the authentication system 20 illustrated in FIG. Authentication 220 is not connected to the speaker 224. However, the Bluetooth module 222 is connected to the speaker 224 and forms with the latter a Bluetooth hands-free phone module. In such a Bluetooth hands-free telephone module, the loudspeaker 224 can generally broadcast only digital audio frames that it receives as a Bluetooth radio signal. Consequently, the authentication module 220 of the central unit 22 can not transmit authentication data which it has itself formed in the form of acoustic signals. Such authentication data, formed by the authentication module 220 of the central unit 22, can only be transmitted in the form of radio signals. In general, the authentication of the control device 24 vis-à-vis the central unit 22 of the motor vehicle 10 of a vehicle is carried out during an authentication session. During the authentication session, authentication data is exchanged between the controller 24 and the CPU 22 in the form of radio signals transmitted / received by the respective Bluetooth modules 242, 222 of said controller. 24 and central unit 22. In addition, an authentication method 50 according to the invention comprises the evaluation of the presence of the control device 24 inside the automobile vehicle 10. This evaluation is carried out by the transmission , inside said motor vehicle by the central unit 22, an acoustic signal to the control device 24. Said control device can be considered as being inside the vehicle only if said control device detects said acoustic signal.

By "detecting the acoustic signal" is meant to determine that it is an acoustic signal emitted by the central unit and / or to extract without error data, such as authentication or other data, possibly included. in said acoustic signal. It should be noted that the formatting of the authentication data (encryption, hashing, etc.) is outside the scope of the invention and can implement any algorithm for formatting known authentication data. However, the authentication must be accompanied by an evaluation of the presence of the control device 24 inside the motor vehicle 10. FIG. 3 represents an exemplary implementation of a method 50 of authentication of a control device 24 vis-à-vis a central unit 22 of a motor vehicle 10. As shown in Figure 3, the method 50 of authentication comprises a step 52 of emission, by the central unit 22, a radio signal to the controller 24, said "request signal UC". Preferably, the request signal UC comprises authentication data.

The authentication method 50 also comprises a step 56 of transmission, by the central unit 22, of an acoustic signal to the control device 24. In a particular mode of implementation, the acoustic signal is emitted after the transmission of the request signal UC. Thus, the request signal UC may be used as a wake-up signal, after which the controller 24 receives an acoustic signal. Therefore, the microphone 244 of the controller 24 may, by default, be disabled, and be activated only from the reception, by said controller 24, of said request signal UC. In a preferred embodiment, part of the authentication data formed by the authentication module 220 of said central unit is transmitted via the acoustic signal. It should be noted that, in this case, the authentication method 50 must be implemented by an authentication system 20 of the type described with reference to FIG. 1. In this way, it is particularly easy to ensure that the authentication of the control device 24 can succeed only if the acoustic signal is detected by said control device 24. In fact, if the acoustic signal is not detected by the control device 24, the authentication data included in said acoustic signal will be lost. Then, the authentication can not succeed and the starting of the automobile vehicle 10 will be refused by the central unit 22. The authentication method 50 illustrated in FIG. 3 comprises a step 58 of transmission, by the control device 24 and following the reception of the request signal UC and the acoustic signal, a radio signal to the central unit 22, called "response signal". The response signal includes authentication data. In a preferred embodiment, the authentication data included in the response signal is determined by the authentication module 240 of the controller 24, based on the authentication data included in the request signal. CPU and in the acoustic signal. Such an embodiment is advantageous in that it makes it possible to ensure, at the level of the central unit 22, that it is indeed one and the same control device 24 which has received both the signal UC query and acoustic signal. FIG. 4 represents an exemplary authentication method 50 suitable for implementation by an authentication system as illustrated by FIG. 2 (that is to say in which authentication data formed by the authentication module 220 of the central unit 22 can only transmit as radio signals). As illustrated by FIG. 4, the authentication method 50 includes a step 54 for sending, by the control device 24, a radio signal destined for the central unit called the "request signal DC". with verification data.

In addition, the authentication method 50 comprises a step 56 of transmission, by the central unit 22 and following the reception of the request signal DC, of an acoustic signal to the control device 24. The signal Acoustic includes verification data which is determined based on the verification data included in the DC request signal. For example, the verification data included in the acoustic signal are identical to those included in the request signal DC, or obtained by applying one or more predefined functions to said verification data included in the request signal DC. In the particular case where the Bluetooth module 222 and the loudspeaker 224 of the central unit 22 form a Bluetooth hands-free telephony module, the verification data are for example in the form of a digital audio frame. "Digital audio frame" means the result of the digitization of an acoustic signal and its possible compression by means of a source encoder, such as an MP3 encoder, AAC, etc. The acoustic signal emitted by the central unit 22 then corresponds to the analog translation of said digital audio frame. The authentication method 50 illustrated in FIG. 4 further comprises a comparison step (not shown), by the control device 24, of the verification data received in the acoustic signal with the verification data transmitted in the request signal. DC. During the comparison step, the controller 24 determines whether the received verification data has been determined from the issued verification data. If the verification data received has been determined from the verification data transmitted, the control device 24 will consider that it is inside the motor vehicle 10. In the opposite case, the control device 24 will consider that it is located outside the motor vehicle 10 and the 10 starting of the motor vehicle will have to be refused. It should be noted that the verification data may be authentication data, or any type of data adapted to allow the control device 24 to detect the acoustic signal, and to determine whether the received verification data have been determined to from the issued verification data.

If the verification data received in the acoustic signal has indeed been determined as a function of the verification data of the request signal DC, the authentication method 50 comprises, for example, a transmission step 58, by the control device 24, a radio signal to the central unit 22, said "response signal", comprising authentication data.

The authentication method 50 preferably comprises a step 52 of transmission by the central unit 22 of a radio signal to the control device 24, called the "request signal UC". The request signal UC is sent before the response signal and the authentication data included in the response signal is preferably determined according to the authentication data included in the request signal UC. As indicated above, the authentication method 50 illustrated in FIG. 4 is particularly suitable for implementation by an authentication system 20 as described with reference to FIG. The authentication method 50 illustrated in FIG. 4 is implemented by means of, for example, an authentication system 20 as illustrated in FIG. 1. Moreover, nothing excludes, according to particular modes of implementation. to combine all or part of the steps of authentication methods 50 illustrated by Figures 3 and 4 respectively. The above description clearly illustrates that by its different features and advantages, the present invention achieves the objectives that it was fixed. In particular, the emission of an acoustic signal inside the motor vehicle 10 makes it possible to evaluate whether the control device 24 is inside said motor vehicle. Thus, the proximity of the control device 24 can be verified by the emission / detection of the acoustic signal, while all or part of the authentication data is exchanged in the form of radio signals, via communication modules. Wireless GPRS, UMTS, WiFi, Bluetooth, etc., which allow to have a larger data rate. In order to integrate the control device 24 in a mobile phone, the detection of the acoustic signal can be carried out by means of a microphone of the mobile phone, so that the detection of the acoustic signal by the mobile phone can be made possible. by a simple software update of said mobile phone.

Claims (10)

CLAIMS1 - Method (50) for authenticating a control device (24) vis-à-vis a central unit (22) of a vehicle (10), the authentication of said control device being carried out at during an authentication session by exchanging authentication data between said control device and said central unit in the form of radio signals, characterized in that it comprises the evaluation of the presence of the control device (24). ) inside the vehicle (10) by the emission, inside said vehicle, of an acoustic signal by the central unit (22), said control device (24) not being able to be considered as being the interior of the vehicle (10) only when said control device (24) has detected said acoustic signal. 10 2 - Method (50) according to claim 1, characterized in that part of the authentication data formed by the central unit (22) are transmitted from said central unit to the control device (24), by intermediate of the acoustic signal. 3 - Process (50) according to claim 2, characterized in that it comprises the following steps: - step (52) of emission, by the central unit (22), a radio signal to the device control unit (24), said "request signal UC", comprising authentication data, - transmission step (58), by the control device (24) and following receipt of the request signal UC and the acoustic signal, a radio signal to the central unit (22), said "response signal", comprising authentication data determined according to the authentication data included in the request signal UC and in the acoustic signal. 4 Method (50) according to claim 1, characterized in that: - said method comprises a step (54) of emission, by the control device (24), a radio signal to the central unit said "DC request signal", comprising verification data, the acoustic signal comprises verification data determined according to the verification data included in the request signal DC, said method comprises a comparison step, by the control device (24), verification data received in the acoustic signal with the verification data transmitted in the request signal DC. 5 - Method (50) according to claim 4, characterized in that the verification data included in the request signal DC are in the form of a digital audio frame, and in that the acoustic signal corresponds to the analogue translation of said digital audio frame. 6 - Method (50) according to one of claims 4 to 5, characterized in that, when the verification data received in the acoustic signal have been determined as a function of the verification data of the request signal DC, said method comprises a step (52) of transmission, by the control device (24), of a radio signal to the central unit (22), said "response signal", comprising authentication data determined as a function of authentication data included in a radio signal previously received from the central unit (22). 7 - Method according to one of the preceding claims, characterized in that it comprises a step (56) of emission, by the central unit (22), a radio signal to the control device (24) , said "wake-up signal", said wake-up signal being emitted before emitting the acoustic signal. 8 - Authentication system (20) comprising a control device (24) to authenticate vis-à-vis a central unit (22) of a vehicle (10), said control device and said central unit each comprising an authentication module (240, 220) adapted to form authentication data, a wireless communication module (242, 222) adapted to transmit and receive radio signals comprising authentication data, characterized in that the authentication system (20) is configured to evaluate the presence of the control device (24) inside the vehicle (10) by the transmission, within said vehicle, of a signal acoustically by an acoustic emission module (224) of the central unit (22), said control device (24) being able to be considered as being inside the vehicle (10) only when said acoustic signal has been detected by said control device (24) being an acoustic receiving module (244). 9 - System (20) according to claim 8, characterized in that the central unit (22) is adapted to transmit authentication data, formed by the authentication module (220) of said central unit, by the intermediate of the acoustic emission module (224), and / or the central unit (22) is adapted to emit an acoustic signal 35 corresponding to a digital audio frame received via the wireless communication module (222) of said unit central, without passing through the authentication module (220) of said central unit. 10 - Vehicle (10) characterized in that it comprises an authentication system (20) according to one of claims 8 to 9.