Anti-theft system for a motor vehicle

Abstract

The invention relates to an anti-theft system (100) for a motor vehicle, comprising: - a module (11) for protecting the vehicle, for authenticating an electronic key (1) for accessing the vehicle, and for generating, in response, an authorization to unlock the wheels (OK1); - at least one parking brake module (13) comprising a caliper (133) and an electric motor (131); and - parking-brake control means (12) for controlling release of the caliper (133) only upon receipt of the authorization to unlock the wheels (OK1). Each parking brake module (13) is connected to the control means (12) by a power-supply cable (14) with at least two electrical power-supply lines (141A, 141B) and at least one security line (142). Each parking brake module (13) comprises a security module (132) for authenticating the control means (12) on the basis of a signal passing via the at least one security line (142), and for authorizing release of the caliper (133) only if the control means (12) have been authenticated.

Description

DESCRIPTION TITLE: ANTI-THEFT SYSTEM FOR MOTOR VEHICLES TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of motor vehicles, and more particularly that of anti-theft systems. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] UN (United Nations) Regulation No. 116, designated UN-RU 6 in English, mandates an anti-theft system on private vehicles and light commercial vehicles, which prevents maneuvering and / or moving such a vehicle without having the key to the vehicle.

[0003] This regulation authorizes the use of several techniques including the blocking of a vehicle parking brake, and in particular an automatic or electric parking brake, which replaces the manual parking brake in modern vehicles.

[0004] To meet regulatory requirements, the anti-theft system must offer a certain level of tamper resistance to prevent it from being easily or simply disabled. In the case of an anti-theft system using an automatic parking brake, it is therefore necessary to delay the release of the brake on the wheel in some way.

[0005] One weakness of the anti-theft protection provided by the automatic parking brake is the accessibility of the electrical connector of the electric brake actuator on the wheel.

[0006] An objective of the present invention is to propose an anti-theft system for a motor vehicle that exhibits increased reliability compared to prior art systems. SUMMARY OF THE INVENTION

[0007] This objective is achieved with an anti-theft system for a motor vehicle, comprising: - a vehicle protection module, configured to authenticate an electronic vehicle access key, and to generate authorization to unlock the wheels when an authorized electronic key is authenticated; - at least one parking brake module (or EPB, for Electric Park Brake), each module comprising a caliper capable of clamping a wheel of the vehicle and an electric motor configured to, in use, tighten or loosen the caliper around the wheel; and - means for controlling the parking brake, comprising a computer and a power supply, and configured to control the release of at least one caliper Confidential C only upon receipt of the unlocking authorization provided by the vehicle protection module.

[0008] In other words, the anti-theft system according to the invention comprises an automatic parking brake, including in particular at least one parking brake module equipped with a caliper and an electric motor. The caliper acts as the brake, which, when engaged, prevents the rotation of a vehicle wheel via the brake pads. When released, the caliper allows the same wheel to rotate. The electric motor acts as the electric actuator for the brake.

[0009] According to the invention: - Each parking brake module is connected to the parking brake control means by a power cable, the power cable having at least two electrical supply paths and at least one safety path; and - each parking brake module also includes a security module, configured to authenticate the means of controlling the parking brake from a signal passing through at least one security channel, and to only allow the release of the caliper by the electric motor if the means of controlling the parking brake have been authenticated.

[0010] According to the invention, a user authorized to maneuver and / or move the vehicle is identified by means of an electronic key, authenticated by the vehicle's protection module.

[0011] When an authorized user is identified via the electronic key, the vehicle protection module generates a wheel release authorization. This wheel release authorization is sent to the parking brake control system.

[0012] In response, the parking brake control system commands each parking brake module to release the caliper. This release command is activated by energizing the electric motor in the parking brake module, which acts as the caliper's electric actuator.

[0013] According to the invention, it is proposed to secure the connection between the parking brake control means and the parking brake module. The objective is to prevent the electric caliper actuator from being fraudulently controlled using an auxiliary power supply substituted for the power supply present in the parking brake control means.

[0014] One solution to secure this connection could have been mechanical, by mechanically blocking access to a connector linking together the parking brake control means and the parking brake module. Confidential C

[0015] According to the invention, an ingenious solution is proposed based rather on the addition of at least one safety channel in the power cable connecting together the parking brake control means and the parking brake module.

[0016] At least one of the safety channels is not used to power the electric motor that acts as the caliper actuator. Instead, at least one of the safety channels is used to transmit at least one specific electrical signal, intended to allow the parking brake module to authenticate the parking brake control means.

[0017] To enable this authentication, the parking brake module is also equipped with a security module containing a computer. The security module stores at least one authentication data point. It is configured to extract or measure at least one data point using the signal transmitted on at least one security channel, to compare this extracted or measured data with the authentication data, and to deduce information about whether or not the parking brake control devices are authenticated.

[0018] The safety module is configured to only allow the caliper to be released by the electric motor if it has duly authenticated the means of controlling the parking brake using a signal passing through at least one safety channel.

[0019] Therefore, simply having power to the parking brake module is not enough for the electric motor to act on the caliper. The caliper activation must also be authorized by the parking brake module's safety control system.

[0020] In practice, the safety module can, for example, control the position of a switch, or a transistor, to allow or block the passage of current between a power connector of the parking brake module, and the electric motor capable of operating the caliper.

[0021] The invention thus provides an anti-theft system for a motor vehicle, which offers increased reliability compared to prior art systems.

[0022] In a first advantageous embodiment: - the power cable includes two safety channels, connected together on the parking brake module side so as to close an electrical circuit extending further into the parking brake control means; and - the security module is configured to measure an impedance or resistance of said electrical circuit, to compare this impedance or resistance with an authentication value stored in the security module, and to deduce information relating to the authentication or not of the means of controlling the parking brake. Confidential C

[0023] In a second advantageous embodiment: - the parking brake control means are configured to generate a modulated signal containing a predetermined code; - the power cable includes a safety channel, on which the modulated signal travels during operation; and - the security module is configured to receive said modulated signal, to extract said predetermined code, to compare this predetermined code to at least one authentication code stored in the security module, and to deduce information relating to the authentication or not of the means of controlling the parking brake.

[0024] The predetermined code can be encoded into the signal modulated by pulse width modulation.

[0025] Data transfer between the parking brake control means and the safety module can be implemented using a data transmission system that complies with a LIN bus protocol.

[0026] Preferably, the anti-theft system according to the invention further comprises electronic control means for an actuator of a vehicle transmission chain, said electronic control means being configured to, in a vehicle start-up phase, prevent a user command from acting on the actuator, and only allow the user command to act on the actuator upon receipt of a transmission authorization provided by the vehicle protection module, the vehicle protection module being configured to generate said transmission authorization with the authorization to unlock the wheels, when the electronic key is authenticated.

[0027] The protection module can be configured to send the wheel unlock authorization and the transmission authorization only on a positive result of an electronic key authentication, a positive result of an authentication of the electronic control means of the actuator, and a positive result of an authentication of the parking brake control means.

[0028] The transmission chain actuator can be an electric traction or propulsion machine for the vehicle.

[0029] In an advantageous embodiment: - the user command is generated by a gear lever and corresponds to a command to switch from a neutral position to a forward or reverse position; - the system includes a computer for controlling the electrical machine; and - The electronic control means of the actuator are configured so that, during the vehicle start-up phase, they do not wake up the control unit and do not Confidential C transmitting a direction of rotation instruction for the electric machine corresponding to the user command, only upon receipt of transmission authorization.

[0030] The invention also covers a vehicle comprising at least two wheels and an anti-theft system according to the invention, with at least one of the wheels capable of being clamped by the caliper of one of the parking brake modules of the anti-theft system. BRIEF DESCRIPTION OF THE FIGURES

[0031] The figures are presented for illustrative purposes only and are in no way limiting to the invention. Figure 1 schematically illustrates an anti-theft system according to a first embodiment of the invention; Figure 2 schematically illustrates an anti-theft system according to a second embodiment of the invention. DETAILED DESCRIPTION

[0032] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0033] Figure 1 schematically illustrates an anti-theft system 100 for a motor vehicle, the system 100 comprising: - a vehicle protection module 11, configured to authenticate an electronic key 1 for vehicle access, and to generate an OK1 wheel unlock authorization when an authorized electronic key 1 is authenticated; - a parking brake module 13, comprising a caliper 133 suitable for clamping a wheel of the vehicle, and an electric motor 131 configured to, in use, tighten or loosen the caliper 133 around the wheel; - parking brake control means 12, comprising a computer 122 and a power supply 121, and configured to control the release of the caliper 133 only upon receipt of the OK1 release authorization provided by the vehicle protection module 12; and - a power cable 14 comprising two power supply paths 141 A, 141 B, and at least one safety line 142 as described below.

[0034] In nominal mode, i.e. outside of a very cold mode, when the vehicle is parked with the engine off, the parking brake module 13 locks the vehicle wheel using the caliper 133 which clamps the wheel.

[0035] The electronic key 1 refers to a portable device capable of establishing two-way communication via a short-range radio link, and storing a unique identifier. This unique identifier allows the electronic key 1, and therefore its holder, to be authenticated for access to a motor vehicle. Confidential C

[0036] The vehicle protection module 11 includes a wireless communication module (not specifically shown), enabling it to communicate with the electronic key 1. It also includes at least one control unit, which can be broken down into: - a computer 111 dedicated to user authentication, via bidirectional communication with the electronic key 1, and comparing the unique identifier sent by the electronic key 1 with at least one authorized identifier stored in a memory of said computer 111; and - a computer 112 dedicated to managing whether or not the vehicle is immobilized, configured in particular to generate an authorization to unlock the wheels, OK1, when an authorized electronic key 1 is authenticated (in other words when the computer 111 has determined that the unique identifier sent by the electronic key 1 corresponds to an authorized identifier).

[0037] Communication between electronic key 1 and vehicle protection module 11 can form an encrypted exchange of user data.

[0038] The parking brake control means 12 and the vehicle protection module 11 are connected together, preferably by wired connection.

[0039] The parking brake control means 12 include at least one computer, and are configured to send commands to tighten or loosen respectively the caliper 133 on the vehicle wheel.

[0040] The parking brake control means 12 are configured to receive the wheel release authorization, OK1, from the vehicle protection module 11 and to command in response a release of the caliper 133.

[0041] The means 12 for controlling the parking brake include in particular a computer 122, and a power supply 121 (the power supply corresponding to the supply of the internal network of the vehicle, generally at a voltage of 12V for approximately 6A nominal).

[0042] The parking brake control means 12 are connected to the parking brake module 13 by the power cable 14. The power cable has two power supply paths 141 A, 141 B, and at least one safety path 142. Preferably, the different paths are electrically isolated from each other, but housed together in the same sheath.

[0043] Upon receiving the authorization to unlock the wheels, OK1, the computer 122 controls the generation of a power supply signal, by the power supply 121. This power supply signal passes through the power cable 14, and more particularly through the two power supply paths 141 A, 141 B (receiving the neutral and the phase respectively). Confidential C

[0044] According to the invention, the parking brake control module 12 is capable of generating a safety signal, and of sending this signal to the parking brake module 13 via at least one safety channel 142 of the power cable 142.

[0045] The following describes various examples of security signals.

[0046] The parking brake module 13 includes a safety module 132, connected to the safety lane 142 and configured to: - authenticate the means 12 for controlling the parking brake from the safety signal; and - only allow the release of the caliper 133 by the electric motor if the means 12 for controlling the parking brake have been authenticated by the safety module 132.

[0047] In practice, the safety module 132 controls, for example, the position of a switch, or a transistor, to allow or block the passage of the power supply signal from the input terminals of the parking brake module 13 to the power supply terminals of the electric motor 131.

[0048] Thus, depending on whether the means 12 for controlling the parking brake have been authenticated or not, the power supply signal reaches the electric motor 131 or not, which blocks or allows the release of the caliper 133.

[0049] The security module 132 includes, at least, a computer equipped with a memory storing authentication data.

[0050] Security module 132 is configured to: - extract, or respectively measure, at least one piece of data using the security signal; - compare this extracted or measured data with the authentication data; and - to deduce information on whether or not the parking brake control methods are authenticated.

[0051] The invention thus offers additional security by ensuring that only a power signal supplied by the parking brake control means 12 can actuate the caliper 133, and thereby unlock the wheel. Conversely, a power signal supplied by an external device, connected for malicious purposes to the parking brake control module 12, will not by itself be sufficient to actuate the caliper 133 and unlock the wheel, since it will lack the safety signal necessary to authorize the transfer of energy to the motor 131.

[0052] In practice, the parking brake module 13 has at least three input terminals, each capable of being connected to one of the respective power supply and securing paths of the power cable.

[0053] For clarity, the specific case in which system 100 comprises a single parking brake module 13 has been illustrated. However, the invention also covers Confidential C Variants with multiple parking brake modules 13, as described above, each dedicated to locking a respective wheel of the vehicle. The vehicle may also include one or more auxiliary parking brake modules, without the additional safety feature that is the subject of the invention. There are generally two parking brake modules per vehicle, one for each of the two front wheels and the other for each of the two rear wheels.

[0054] When there are multiple parking brake modules 13, all are connected to the same parking brake control means 12. In this case, the parking brake control module 12 can be equipped with a power distribution unit to distribute the electrical supply lines to a plurality of outputs dedicated to the respective parking brake modules 13. In contrast, the safety lines are preferably specific to each parking brake module 13 and, in practice, carry distinct signals with distinct characteristics.

[0055] According to other variants, the supply signal from the means 12 for controlling the parking brake is a three-phase signal, and the supply cable 14 then has three supply paths.

[0056] In a first embodiment of the invention, the power cable 14 comprises two safety channels 142, connected together on the side of the parking brake module 13 so as to close an electrical circuit extending further into the parking brake control means 12. The two safety channels together can be considered to close a current loop, referred to as the safety loop.

[0057] At the level of the parking brake module 13, the safety module 132 is configured to: - measure the impedance or ohmic resistance of said electrical circuit, for example using a current sensor in the safety module 132, - compare this impedance or ohmic resistance with the value of an authentication data point, and - to deduce information relating to the authentication or not of the means of controlling the parking brake.

[0058] The value of impedance or ohmic resistance is measured simply by measuring the current (or even voltage) on an electrical signal flowing on the safety channels.

[0059] This impedance or ohmic resistance value depends on the physical characteristics of the safety circuits, but especially on the resistance and / or impedance characteristics of the components in the parking brake control means 12. Therefore, measuring this impedance or ohmic resistance value is characteristic of the parking brake control means 12 and allows for their authentication. Confidential C

[0060] In other words, the parking brake module 13 measures the ohmic resistance (or impedance) of the safety loop closed by the safety channels 142, and compares it to a known authentication value, characteristic of the parking brake control means 12. If the safety loop is opened or replaced by a source external to the vehicle, the caliper 133 remains in the engaged state even if a power signal reaches the input of the parking brake module 13.

[0061] The ohmic resistance (or impedance) value is specific to the parking brake control means 12 and is factory-calibrated. The parking brake module 13 reads this value. This value will be compared each time the caliper 133 is to be released. Therefore, an external power supply will not allow the caliper 133 to be released without the specific ohmic resistance (or impedance).

[0062] In a second embodiment of the invention, authentication is performed using data encoded in a signal. In this case, the power cable 14 may include a single security channel 142, and the parking brake control means 12 are configured to generate a modulated signal in which predetermined data, or code, is encoded.

[0063] The security module 132 is then configured to receive said modulated signal, to extract said predetermined data, to compare this predetermined data to at least one authentication data, and to deduce information relating to the authentication or not of the means of controlling the parking brake.

[0064] In other words, the safety circuit 142 allows communication of the predetermined code between the parking brake control means 12 and the parking brake module 13. Therefore, an external power supply connected to the parking brake module 13 will not be able to release the caliper 133.

[0065] The predetermined code may be specific to a safety module 132 and learned by the parking brake control means 12 in a preliminary calibration step at the factory. Alternatively, the parking brake control means 12 impose the predetermined code that will be learned by the safety module 132 in a preliminary calibration step.

[0066] Advantageously, the predetermined code is encoded in the modulated signal using pulse width modulation.

[0067] Furthermore, data transfer between the parking brake control means 12 and the safety module 132 is implemented using a data transmission system (more commonly known as a "fieldbus") adhering to a LIN bus protocol. The LIN bus (Local Interconnect Network) is a serial system bus used in vehicles. Confidential C recent automobiles. The LIN bus specifications are established by the LIN consortium. Since 2016, the LIN bus has been standardized by ISO 17987.

[0068] Alternatively, the data transfer between the parking brake control means 12 and the safety module 132 can be implemented using a data transmission system complying with a CAN bus protocol (for Control Area Network).

[0069] Advantageously, the parking brake control means 12 and the security module 132 are paired during a preliminary calibration step, carried out at the factory, in order to share information relating to the authentication data.

[0070] An additional security measure can be implemented by making the transmission of the wheel release authorization, OK1, conditional upon authentication of the parking brake control means 12 by the vehicle protection module 11. To this end, the vehicle protection module 11 and the parking brake control means 12 are capable of establishing bidirectional communication to exchange at least one authentication data point.

[0071] An anti-theft system 100' is then illustrated, with reference to Figure 2, according to a second embodiment of the invention. System 100' will only be described in terms of its differences from system 100 in Figure 1.

[0072] The 100' system in Figure 2 includes here:

[0073] - a device 16 for generating a user control signal S1 in response to a mechanical action performed by the user. The device 16 is, for example, a gear lever, capable of translating a position of the gear lever into a user command;

[0074] - electronic control means 15, implemented in at least one computer and configured to convert the user control signal S1 into a setpoint S2 for the direction of rotation in one direction or the other. The means 15 include, for example, a computer for controlling an electrical machine 18;

[0075] - a module 17 for controlling actuator 18, configured here to convert said rotation setpoint S2 into control currents S3 for an inverter, not specifically shown; and

[0076] - an actuator 18 of a vehicle transmission chain, consisting here of an electric traction or propulsion machine including here said inverter.

[0077] According to the invention, the electronic control means 15 are configured so that, during the vehicle start-up phase, the user control S1 only allows the electric machine 18 to act upon receiving a transmission authorization, OK2, provided by the vehicle protection module 11. In other words, the electronic control means 15 are configured so that, during the vehicle start-up phase, they only wake up the actuator control module 17 and transmit a command to it. Confidential C direction of rotation of the electric machine 18 corresponding to the user command S1, only upon receipt of the transmission authorization OK2.

[0078] Vehicle protection module 11 is then configured to generate said OK2 transmission authorization with OK2 wheel unlocking authorization, when electronic key 1 is authenticated.

[0079] The vehicle start-up phase here refers to the operations necessary to unlock and start the vehicle's engine, these operations being carried out in particular by the vehicle driver and the computers in the vehicle.

[0080] This embodiment is particularly advantageous, since it combines two safety features: the action on the parking brake and the action on the actuator of a vehicle transmission chain.

[0081] Furthermore, the action on the actuator of a vehicle's transmission chain is implemented solely at the level of a computer (the electronic control unit 15), thus eliminating the need for additional mechanical locking devices that could increase the vehicle's manufacturing and maintenance costs. This implementation has the advantage of preventing unauthorized users from starting the vehicle without requiring significant software changes in the actuator control module 17, which consists, for example, of the electrical control unit of the electric motor.

[0082] When a vehicle user has parked their vehicle in cold weather mode, the parking brake control means 12 are configured to keep the parking brake in the released position on the vehicle wheel during the start-up phase. In this cold weather mode, receiving an OK1 authorization to release the wheel, via the parking brake control means 12, will therefore have no effect on the vehicle wheel. However, disabling the user command intended for the drivetrain actuator 18 will always be conditional upon successful authentication of the electronic key 1. Thus, in cold weather mode, an unauthorized user may be able to move the vehicle but will not be able to turn its steering wheel or start its engine.

[0083] Locking two entities acting on the vehicle's operation, rather than a single entity, to prohibit unauthorized vehicle operation improves vehicle protection while limiting specific modifications to the vehicle.

[0084] Advantageously, gear lever 16 includes: - a neutral position N, corresponding to a user command S1 requesting the cessation of the drive wheels of the vehicle by the electric machine 18; This neutral position N is the default position of the gear lever 16 when the vehicle is stopped and asleep; Confidential C - a forward driving position D, corresponding to a user command S1 requesting the electric machine 18 to move the vehicle forward; and - a reverse gear position R, corresponding to a user command S1 asking the electric machine 18 to reverse the vehicle.

[0085] The user command S1 generated by the gear lever 16 advantageously corresponds to a command to switch from a neutral position to a forward or reverse position.

[0086] In some variants, the actuator of a vehicle transmission chain is instead an active steering actuator, in an electronically controlled steering column, or any other device capable of preventing the vehicle from rolling and / or maneuvering.

[0087] Furthermore, the invention is not limited to electric or hybrid vehicles. In the case of an internal combustion engine vehicle, the actuator of a vehicle's transmission system is, for example, the vehicle's internal combustion engine. In this case, the inhibition of the gearshift lever controls is, for example, performed by a control unit of a steering mechanism, or is replaced by the inhibition of an ignition or fuel injection system, using a control unit of the internal combustion engine vehicle.

[0088] In an advantageous variant, the protection module 11 is also suitable for: - establish bidirectional communication with the parking brake control devices 12 in order to authenticate them; and - establish bidirectional communication with the electronic control means 15 in order to authenticate the latter.

[0089] In other words, the task is to determine whether or not the means 15 (respectively 12) correspond to the means intended to collaborate with the protection module 11 within the system 100'. This determination is made by sending authentication data from the means 15 (respectively 12) to the protection module 11, and analyzing this authentication data by the protection module 11 to determine whether or not it corresponds to the data expected by the module 11 for the means 15 (respectively 12). The communication between the protection module 11 and the means 15 (respectively 12) may constitute an encrypted exchange of authentication data.

[0090] The protection module 11 is then configured to send the wheel release authorization, OK1, and the transmission authorization, OK2, only if it has duly authenticated both the electronic key 1, the parking brake control means 12, and the electronic control means 15. This can be considered a successful authentication result.

[0091] This variant offers additional security, since an additional authentication condition for the means 12 of the parking brake control and the Confidential C electronic control means 15. Despite the absence of any hardware addition to the vehicle to ensure this anti-theft protection, this variant requires a very significant amount of time to bypass the anti-theft protection, since it would be necessary to change the protection module 11, the electronic control means 15 and the parking brake control means 12, in order to replay the authentication chain necessary to unlock the vehicle wheel and the transmission chain actuator.

[0092] Advantageously, the protection module 11 is implemented in a separate control unit from at least one control unit implementing the electronic control means 15 and / or the parking brake control means 12. The use of several separate control units is particularly advantageous in the variant involving additional authentication requirements for the parking brake control means 12 and the electronic control means 15 by the protection module 11.

[0093] The control unit of the protection module 11 is advantageously a master control unit, and at least one control unit implementing the electronic control means 15 and / or the parking brake control means 12 is a slave control unit. Thus, for example, it is the control unit of the protection module 11 that wakes up at least one other control unit after authentication of the vehicle's electronic key 1, which adds an additional layer of protection against unauthorized driving of the vehicle, since the slave control units are inoperative until the vehicle's electronic key 1 is authenticated.

[0094] The invention is not limited to the examples described above, and covers many variants implementing, for example, a different number of parking brake modules, other types of actuators of a vehicle transmission chain, etc. Confidential C

Claims

DEMANDS [Claim 1] Anti-theft system (100; 100') for a motor vehicle, comprising: - a vehicle protection module (11), configured to authenticate an electronic key (1) for vehicle access, and to generate a wheel unlock authorization (OK1) when an authorized electronic key (1) is authenticated; - at least one parking brake module (13), each module comprising a caliper (133) capable of clamping a wheel of the vehicle and an electric motor (131) configured to, in use, tighten or loosen the caliper (133) around the wheel; and - means (12) for controlling the parking brake, comprising a computer (122) and a power supply (121), and configured to control the release of at least one caliper (133) only upon receipt of the release authorization (OK1) provided by the vehicle protection module (11); characterized in that: - each parking brake module (13) is connected to the parking brake control means (12) by a power cable (14), the power cable having at least two electrical supply routes (141 A, 141 B) and at least one safety route (142); and - each parking brake module (13) further includes a safety module (132), configured to authenticate the means (12) for controlling the parking brake from a signal passing through at least one safety channel (142), and to only allow the release of the caliper (133) by the electric motor (131) if the means (12) for controlling the parking brake have been authenticated. [Claim 2] Anti-theft system (100; 100') according to claim 1, characterized in that: - the power cable (14) includes two safety routes (142), connected together on the side of the parking brake module (13) so as to close an electrical circuit extending further into the parking brake control means (12); and - the security module (132) is configured to measure an impedance or resistance of said electrical circuit, to compare this impedance or resistance with an authentication value stored in the security module (132), and to deduce information relating to the authentication or not of the means (12) of controlling the parking brake. [Claim 3] Anti-theft system (100; 100') according to claim 1, characterized in that: - the means (12) for controlling the parking brake are configured to generate a modulated signal containing a predetermined code; Confidential C - the power cable (14) includes a safety channel (142), on which the modulated signal travels during operation; and - the security module (132) is configured to receive said modulated signal, to extract said predetermined code, to compare this predetermined code to at least one authentication code stored in the security module (132), and to deduce information relating to the authentication or not of the means (12) of controlling the parking brake. [Claim 4] Anti-theft system (100; 100') according to claim 3, characterized in that the predetermined code is encoded in the signal modulated by pulse width modulation. [Claim 5] Anti-theft system (100; 100') according to claim 3 or 4, characterized in that the data transfer between the parking brake control means (12) and the security module (132) is implemented using a data transmission system complying with a LIN bus protocol. [Claim 6] Anti-theft system (100') according to any one of claims 1 to 5, characterized in that it further comprises electronic control means (15) for an actuator (18) of a vehicle transmission chain, said electronic control means (15) being configured to, in a vehicle start-up phase, prevent a user command (S1) from acting on the actuator (18), and only allow the user command (S1) to act on the actuator (18) upon receipt of a transmission authorization (OK2) provided by the vehicle protection module (11), the vehicle protection module (11) being configured to generate said transmission authorization (OK2) with the wheel unlocking authorization (OK1), when the electronic key (1) is authenticated. [Claim 7] Anti-theft system (100') according to claim 6, characterized in that the protection module (11) is configured to send the wheel unlock authorization (OK1) and the transmission authorization (OK2) only on a positive result of an authentication of the electronic key (1), a positive result of an authentication of the electronic actuator control means (15), and a positive result of an authentication of the parking brake control means (12). [Claim 8] Anti-theft system (100') according to claim 6 or 7, characterized in that the actuator (18) of the transmission chain is an electric traction or propulsion machine for the vehicle. [Claim 9] Anti-theft system (100') according to claim 8, characterized in that: - the user command (S1) is generated by a gear lever (16) and corresponds to a command to switch from a neutral position to a forward or reverse position; Confidential C - the system (100') includes a computer (17) for controlling the electrical machine (18); and - the electronic control means (15) of the actuator are configured so that, during the vehicle start-up phase, they only wake up the control computer (17) and transmit to it a command (S2) for the direction of rotation of the electric machine corresponding to the user command (S1), upon receipt of the transmission authorization (OK2). [Claim 10] A vehicle comprising at least two wheels and an anti-theft system (100; 100') according to any one of claims 1 to 9, with at least one of the wheels capable of being clamped by the caliper (133) of one of the parking brake modules (13) of the anti-theft system (100 ; 100’). Confidential C

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