EP1104496B1 - Device for access control between electronic key and lock - Google Patents

Abstract

The invention concerns a device for controlling access between an electronic key (1) and lock (2). The key (1) comprises an electric power source (10), a key computing unit (11), a module for transmitting and-receiving signals controlling access to the key (12), and the lock (2) a central lock processing unit (21) and a lock transmission-reception module (22). The key (1) further comprises a module (13) for generating a power signal, a key transfer circuit (14), and the lock (2) comprises a lock transfer circuit (24), said circuits (14 and 24) enabling the two-way transfer of signals controlling access to key and lock and one-way transfer signal of electric power carried by the power signal between the key (1) and the lock (2). The invention is useful for controlling special high security access.

Description

The present invention relates to a device for access control between an electronic key and lock, or, more generally, between a portable object and a fixed object, provided with control functions access and playing the role of a key and a lock e.

Enclosure access control systems closed to protect and protect fiduciary values have given rise to many developments to date. This is particularly the case with regard to concerns mailboxes for which systems opening - mechanical closing then, more recently, electronic, for speakers protected, have been implemented.

Among electronic systems, some developments in particular proposed a remote feeding process of the portable object, the key, from the fixed base, the lock and the protected enclosure, due the possibility of integrating power sources electric at the fixed base, if there is no problem major technique relating to such integration.

The aforementioned mechanical systems do not allow to provide a satisfactory level of security. The degree of security relies, in this case, on the degree of complexity manufacturing the key, which is likely to be reproduced. In addition, if such a key is stolen, invalidation of the latter, or a reproduction of this can only be achieved by a modification adequate set of locks associated with this key.

With regard to electronic systems such than those described in particular in EP-0 505 084 and EP-0 288 791, the remote key supply process by the lock poses maintenance constraints, change or recharging electrical energy resources, or of implementation, integration of an electrical energy source at the lock level, in particular, when the number of locks is important as in the case of boxes urban letter writing, for example.

The object of the present invention is to remedy the aforementioned drawbacks of mechanical and electronic systems of the prior art by the implementation of a device of access control between a key and a lock electronic in which any presence of a source electrical energy at the electronic lock, if necessary the fixed base of the support for this lock electronic, can be deleted.

Another object of the present invention is, in consequence, the implementation of a control system of access between an electronic key and lock in which any periodic change or intervention recharging of an electrical energy source at the electronic lock can be removed.

Another object of the present invention is also the implementation of an access control device between an electronic key and lock allowing, in link with the energy supply process of the device, the implementation of control protocols high security access.

Another object of the present invention is also the implementation of an access control device between an electronic key and lock allowing the implementation of an access control process by exchange of digital data between the key and the lock electronic, in the absence of any electrical contact between the electronic key and lock.

Another object of the present invention is finally the implementation of an access control device between an electronic key and lock in which the process supply of electrical energy to the device is implemented in the absence of electrical contact between the electronic key and lock.

The access control device between a key and an electronic lock, object of the present invention, this electronic key comprising at least one electrical energy source, a logical unit of calculation of key, a module of emission - reception of signals of key access control and this electronic lock comprising at least one logical unit for calculating a lock and a transmission module - reception of control signals lock access for the implementation of a security protocol access control between this electronic key and lock, is remarkable in that, on the one hand, the key electronics also includes a generator module power signal supplied by the electric power source and controlled by the logical key calculation unit and a key transfer module for control signals key and lock access and power signal, and in that, on the other hand, the electronic lock comprises additionally a signal lock transfer module key and lock access control and signal power and an energy storage module carried by the power signal, which provides unidirectional energy transfer electric carried by the power signal of the key electronic to electronic lock and transfer bidirectional key access control signals and between the electronic key and the electronic lock.

The access control device between a key and an electronic lock, object of the present invention, finds application in the production industry and the management of fiduciary security vaults, in particular mailboxes, and access control high security in general.

• la figure la représente, sous forme de schéma fonctionnel, une vue générale du dispositif de contrôle d'accès entre une clef et une serrure électroniques, conforme à l'objet de la présente invention ;
• la figure 1b représente, à titre de premier exemple non limitatif, un diagramme séquentiel du processus d'alimentation de la serrure par la clef électronique puis de transfert bidirectionnel de données entre la clef et la serrure électroniques dans un dispositif conforme à l'objet de la présente invention ;
• la figure 2a représente une variante de mise en oeuvre du dispositif de contrôle d'accès entre une clef et une serrure électroniques, conforme à l'objet de la présente invention, dans lequel une fonction de veille de la serrure électronique est assurée grâce à une source auxiliaire d'énergie électrique intégrée à la serrure électronique ;
• la figure 2b représente, à titre de deuxième exemple non limitatif, un diagramme séquentiel du processus d'alimentation de la serrure par la clef électronique dans le cas de l'existence d'une fonction de veille allouée à la serrure électronique, conformément au mode de réalisation de la figure 2a ;
• la figure 3a représente un diagramme temporel des opérations de transfert unidirectionnel d'énergie et bidirectionnel de données entre la clef et la serrure électroniques en liaison avec la forme d'onde du signal de puissance engendré par la clef électronique, ces opérations pouvant correspondre à celles exécutées selon le diagramme séquentiel représenté en figure 1b ;
• la figure 3b représente un diagramme temporel des opérations de transfert unidirectionnel d'énergie et bidirectionnel de données entre la clef et la serrure électroniques en liaison avec la forme d'onde du signal de puissance engendré par la clef électronique, dans une variante préférentielle de mise en oeuvre dans laquelle ces opérations sont alternées ;
• la figure 4a représente une vue en perspective d'une clef électronique, conforme à l'objet de la présente invention, dans un mode de réalisation matérielle préférentiel non limitatif ;
• la figure 4b représente une vue en perspective d'une serrure électronique, conforme à l'objet de la présente invention, dans un mode de réalisation matérielle préférentiel non limitatif ;
• la figure 4c représente une vue partielle du dispositif de contrôle d'accès entre une clef et une serrure électroniques, conforme à l'objet de la présente invention, lorsque la clé et la serrure électroniques sont mises en présence en vue d'une tentative d'accès ;
• la figure 5a représente un schéma électrique de l'ensemble des modules fonctionnels de la clef électronique dans un mode de réalisation donné à titre d'exemple non limitatif ;
• la figure 5b représente un schéma électrique de l'ensemble des modules fonctionnels de la serrure électronique dans un mode de réalisation donné à titre d'exemple non limitatif ;
• la figure 5c représente, à titre illustratif, une image de la forme d'onde du signal de puissance en mode de transfert unidirectionnel de puissance entre la clef et la serrure électroniques ;
• la figure 6a représente un organigramme relatif à un protocole de contrôle d'accès entre une clef et une serrure électroniques constitutives d'un dispositif conforme à l'objet de la présente invention ;
• la figure 6b représente, à titre purement illustratif, un mode de mise en oeuvre spécifique du protocole de contrôle d'accès, objet de l'invention, tel que représenté en figure 6a.

It will be better understood on reading the description and on observing the drawings below, in which:

• Figure la shows, in the form of a functional diagram, a general view of the access control device between an electronic key and lock, in accordance with the object of the present invention;
• FIG. 1b represents, as a first nonlimiting example, a sequential diagram of the process of supplying the lock with the electronic key and then bidirectional transfer of data between the electronic key and lock in a device conforming to the object of the present invention;
• FIG. 2a represents an alternative embodiment of the access control device between an electronic key and lock, in accordance with the object of the present invention, in which a standby function of the electronic lock is ensured by means of a auxiliary source of electrical energy integrated into the electronic lock;
• FIG. 2b represents, as a second nonlimiting example, a sequential diagram of the process of supplying the lock with the electronic key in the case of the existence of a standby function allocated to the electronic lock, in accordance with the mode of FIG. 2a;
• FIG. 3a represents a time diagram of the operations of unidirectional energy and bidirectional transfer of data between the electronic key and lock in connection with the waveform of the power signal generated by the electronic key, these operations possibly corresponding to those executed according to the sequential diagram shown in Figure 1b;
• FIG. 3b represents a time diagram of the operations of unidirectional energy and bidirectional data transfer between the electronic key and lock in connection with the waveform of the power signal generated by the electronic key, in a preferred variant of setting in which these operations are alternated;
• FIG. 4a represents a perspective view of an electronic key, in accordance with the object of the present invention, in a non-limiting preferential hardware embodiment;
• FIG. 4b represents a perspective view of an electronic lock, in accordance with the object of the present invention, in a non-limiting preferential material embodiment;
• FIG. 4c shows a partial view of the access control device between an electronic key and lock, in accordance with the object of the present invention, when the electronic key and lock are brought together for an attempt to 'access;
• FIG. 5a represents an electrical diagram of all the functional modules of the electronic key in an embodiment given by way of nonlimiting example;
• FIG. 5b represents an electrical diagram of all the functional modules of the electronic lock in an embodiment given by way of nonlimiting example;
• FIG. 5c represents, by way of illustration, an image of the waveform of the power signal in unidirectional power transfer mode between the electronic key and lock;
• FIG. 6a represents a flowchart relating to an access control protocol between a key and an electronic lock constituting a device in accordance with the object of the present invention;
• FIG. 6b represents, purely by way of illustration, a specific mode of implementation of the access control protocol, object of the invention, as shown in FIG. 6a.

A more detailed description of a access control between an electronic key and lock, in accordance with the subject of the present invention, will now given in connection with Figures 1a and 1b.

As shown in FIG. 1 a, the electronic key 1 comprises at least one source of electrical energy 1 ₀ , this source consisting for example of a storage battery with which is associated a battery management module, this module management can present, in a manner known as such, more or less elaborate functions for managing the energy contained in the storage battery. For this reason, the storage battery management module will not be described in detail in the present description.

The electronic key 1 also includes a module for transmitting - receiving 1 ₂ of key access control signals. This module 1 ₂ may comprise, advantageously, a transmission module of key access control signals and a module for receiving the lock access control signals, these signals being transmitted digitally, as well as 'It will be described in more detail later in the description. By convention, the key access control signals designate the access control signals emitted by the key towards the lock and the lock access control signals designate the access control signals emitted by the lock towards the key.

The electronic key 1 finally comprises a logical key calculation unit, bearing the reference 1 ₁ , this logical unit being responsible for controlling all of the operating operations of the electronic key.

As also shown in FIG. 1a, the electronic lock 2 comprises at least one logic unit for calculating a lock, bearing the reference 2 ₁ , and a transmission / reception module 2 ₂ of lock access control signals. Conventionally, the logic unit for calculating the lock 2 ₁ also makes it possible to control all of the operating operations of the electronic lock 2. Thus, under the respective control of the logic calculation unit 1 ₁ and the logic unit 2 ₁ calculation of the electronic key and lock, the transmission module - reception 1 ₂ of the key access control signals, the transmission module - reception 2 ₂ of the lock access control signals , allow the implementation of an access control protocol between the key and the electronic lock 1, 2 above.

With reference to the same FIG. 1a, it is indicated that the access control device, object of the present invention, further comprises, at the level of the electronic key 1, a module generating a power signal, bearing the reference 1 ₃ , this generator module being supplied by the electrical energy source 1 ₀ and being able, of course, to be controlled by the logical key calculation unit 1 ₁ . Thus, all of the functional modules for managing the battery 1 ₀ , transmitting - receiving 1 ₂ of key access control signals and power generator 1 ₃ are connected by a link to the logical calculation unit. 1 ₁ key and controlled by the latter.

In addition, as shown in the same figure 1a, the electronic key 1 comprises a key transfer circuit, bearing the reference 1 ₄ , key access control signals and lock as well as, in accordance with a particularly aspect advantage of the access control device, object of the present invention, of the power signal generated by the generator module 1 ₃ . More specifically, it is indicated that the aforementioned key transfer circuit 1 ₄ is connected, on the one hand, to the module generating the power signal 1 ₃ and, on the other hand, to the transmission - reception module of key access control signals 1 ₂ under conditions which will be explained in more detail later in the description.

As is also shown in FIG. 1 a, the electronic lock 2 comprises, for the purpose of constituting the access control device, object of the present invention, a circuit for transferring the lock of the access control signals from key and lock and the aforementioned power signal. This lock transfer circuit has the reference 2 ₄ .

Finally, the electronic lock 2 also includes a module 2 ₅ allowing the storage and therefore the recovery of the electrical energy conveyed by the power signal. The lock 2 can, as shown in a nonlimiting manner in FIG. La, be further provided with a module for recovering a clock signal, bearing the reference 2 ₃ , this clock signal being able to be recovered at starting from the power signal, as will be described in a nonlimiting manner later in the description.

Of course, the functional modules constituting the electronic lock 2, that is to say the transmission module - reception of the lock access control signals 2 ₂ , the electrical energy storage module 2 ₅ and, where appropriate, the clock recovery module 2 ₃ , are connected via a link to the logic unit for calculating the lock 2 ₁ . With regard to the lock transfer circuit 2 ₄ , it is indicated that the latter is of course connected, on the one hand, to the transmission - reception module 2 ₂ of the lock access control signals, and, d on the other hand, to the module 2 ₅ for storing electrical energy as well as, if necessary, to the module 2 ₃ for clock recovery, as will be described in more detail later in the description.

It is thus understood that the control device access, object of the present invention, allows the implementation work of an access control protocol in which are carried out, on the one hand, a unidirectional transfer of the electrical energy carried by the power signal from the electronic key to the electronic lock, and, on the other hand, the bidirectional transfer of signals from key and lock access control between the electronic key 1 and the electronic lock 2, as it will be described below.

Advantageously, without limitation, as shown in FIG. La, the key transfer circuit 1 ₄ and the lock transfer circuit 2 ₄ are advantageously constituted by at least one primary winding and at least one secondary winding of a transformer. Under such conditions, the primary windings, denoted L ₁ , and secondary, denoted L ₂ , are then electromagnetically coupled when the electronic key and the electronic lock are brought into contact, this bringing together being carried out to make an attempt access.

The operating mode of the access control device, object of the present invention, as shown in FIG. 1a, can be illustrated, by way of nonlimiting example, as shown in Figure 1b. We note in particular that in the case of the implementation of the device access control, object of the present invention, and in a simplified embodiment, the lock 2 does not has no permanent source of electrical energy, the entire transfer of electrical energy from the key electronic with electronic lock to provide the necessary electrical energy needs, so to conduct the access control protocol in accordance to the subject of the present invention. In such a case, as well as shown in Figure 1b, the unidirectional transfer electrical energy carried by the power signal from the electronic key to the electronic lock, this power signal being noted PS, can be performed prior to bidirectional signal transfer key and lock access control between the electronic key 1 and electronic lock 2. In a such case the transfer of a quantity of electrical energy sufficient for the implementation of the control process access proper, conducted during bidirectional transfer data, then appears as a necessary condition to the implementation of the entire protocol access control in accordance with the object of the present invention. Consequently, in FIG. 1b, the operations of unidirectional transfer of energy from the key to the lock then bidirectional data transfer between the electronic lock and the electronic key, and vice versa, are represented in figure 1b by two substantially distinct successive stages.

However, as represented in FIG. 2a, a more elaborate embodiment of the access control device, object of the present invention, can consist in providing, at the level of lock 2, a source of auxiliary electrical energy, carrying the reference 2 ₀ . In general, this auxiliary energy source, at the level of the lock 2, makes it possible to ensure a standby function of the latter. To this end, the auxiliary electrical power source 2 ₀ is adapted so as to allow, at least, the supply of the logic unit for calculating the lock 2 _{1 as} well as the reception part of the transmission - reception module 2 ₂ , to enable the standby function to be carried out under the authority of the lock calculation logic unit 2 ₁ .

FIG. 2b shows a sequential diagram of an access control protocol implemented by the access control device, object of this invention, represented in FIG. 2a, in the case of the existence of a watch function at the lock 2.

In accordance with the aforementioned figure, the transfer bidirectional key access control signals and lock, or at least part of it, between the electronic key 1 and the electronic lock 2 is made prior to the unidirectional transfer of the electrical energy carried by the power signal PS from electronic key 1 to electronic lock 2. By way of nonlimiting example, during the function standby of lock 2, and on attempt to access the electronic key 1, lock 2 can thus transmit to the electronic key 1 an identification request message, noted RID. In response to the identification request message above, the electronic key 1 can transmit a MID identification message to lock 2 and, on identification criterion satisfied with this identification message, lock 2 transmits in response a message from identification response to electronic key 1, this message being denoted ACKID in Figure 2b. This accused message can then allow the conduct of the unidirectional energy transfer process via of the PS signal between the electronic key 1 and the electronic lock 2. Under these conditions, the transfer unidirectional energy is achieved conditionally at least two-way transfer success partial data during the standby function. Following the Unidirectional energy transfer, the control protocol access, in accordance with the object of the present invention, can then be chased between the lock electronic 2 and electronic key 1 according to a process specific access control consisting of a succession to exchange messages, encrypted or not, the key electronic 1 and the electronic lock 2 can be provided with encryption means - decryption, as well that it will be described in more detail later in the description.

The operating modes as illustrated in figure 2a and 2b sequentially will be explained now in conjunction with FIGS. 3a and 3b respectively, the aforementioned figures making it possible to introduce a definition more detailed temporal of the different sequences implemented.

In Figures 3a and 3b, there is shown in a particularly advantageous embodiment, the signal PS power, this signal, in this embodiment advantageous, consisting of an asymmetrical periodic signal and therefore comprising substantially a half period of high amplitude, amplitude denoted M, and a half period of low amplitude, noted m.

In general, and in the case of a mode corresponding to the access control device as shown in FIG. 1a, this corresponding operating mode to that shown in Figure 1b, the transfer unidirectional energy between the key and the lock electronic can advantageously be performed on a plurality of half periods of high signal amplitude PS power, one-way transfer step energy key / lock bearing the reference 1 in the figure 3a. The number of successive half amplitude periods high during which the unidirectional transfer of energy between the electronic key 1 and the electronic lock 2 is performed can then be calculated based of the total energy required to drive the Bidirectional data transfer between the electronic key 1 and the electronic lock 2 for implementation of the access control protocol itself by transfer bidirectional key / lock data, as shown in figure 1b this step bearing the reference 2 in Figure 3a.

In the above-mentioned figure, it will be noted that, during the step of bidirectional data transfer between the electronic key and electronic lock, transmission of the power signal PS is shown in dotted lines. Such a transmission can indeed be maintained during the bidirectional transfer step of data between the key and the lock, step 2. Indeed, the simultaneous transmission of the PS power signal and data between electronic key and lock can be carried out without difficulty insofar as clipping of the signal caused by the transmission of the signal PS power does not interfere with the bidirectional transfer of data. Under these conditions, the electrical energy transmitted to electronic lock 2 can thus be maintained at a substantially constant level for the conduct of the entire access control protocol, subject of the present invention. However, the data is transmitted on several consecutive periods because the frequency modulation must be low compared to the carrier frequency.

However, a preferred mode of implementation of the operating method of the access control device, object of the present invention, can also be carried out, as shown in connection with Figure 3b.

In this embodiment, the unidirectional transfer electrical energy carried by the signal PS power and bidirectional signal transfer key and lock access control can be alternately performed over substantially half a period of high amplitude and substantially half a period of low amplitude respectively. In these conditions, step 1 of unidirectional energy transfer key / lock is sort of distributed on all half periods of high amplitude of the power signal PS, while step 2 of bidirectional transfer from key / lock data is itself distributed over the half periods of low amplitude, the stages of transfer unidirectional key / lock energy and bidirectional transfer of key / lock 2 data then being nested as shown in Figure 3b, and performed alternately. An access control protocol corresponding will be described in more detail later in the description.

A more detailed description of a key and electronic lock allowing the implementation of a access control device, in accordance with the subject of the present invention, will now be given in connection with Figures 4a and 4b in a hardware embodiment not limiting.

As shown in FIG. 4a, the electronic key can be produced in the form of a block of molded material, bearing the reference B ₁ , the block of molded material being for example injected around a printed circuit board, denoted PIC. ₁ , on which are mounted the various functional modules previously mentioned in the description in conjunction with FIGS. 1a or 2a, these functional modules bearing for this reason the same references and being represented, as well as the printed circuit board, in dotted lines.

It is noted in particular that the block B ₁ constituting the body of the electronic key can then be provided for example with an on / off switch, noted ON / OFF, as well as with a serial or parallel interface, noted PI, this interface serial or parallel being connected, by a link by BUS, to the logical unit for calculating key 1 ₁ , in order to allow for example the programming of the aforementioned electronic key. This programming can also be carried out via the primary winding of the transformer. Is understood in particular that the logic unit key of track 1 _1, consisting for example a microcontroller, associated with conventional elements such as RAM and ROM, not shown in the drawings. Specific programs such as programs for conducting the access control protocol in accordance with the object of the present invention can be stored in the ROM. The electronic key 1 notably comprises the module generating the power signal PS, referenced 1 ₃ , and of course the key transmission-reception module 1 ₂ , the assembly being controlled by the key calculation unit 1 ₁ . With regard to the operating mode of the assembly and the concept of control by the logical unit for calculating the key 1 ₁ , it is indicated that the implementation of the access control protocol of the device, object of the present invention , can be achieved by simple commissioning of the power supply for all of the aforementioned functional modules. In particular, it is indicated that the operation of the module generating the power signal 1 ₃ triggered by this start-up can then be free, that is to say in the absence of effective control of the logic calculation unit of key 1 ₁ , as will be described later in the description. In such a case, however, the power signal generator module is not connected to the key calculation logic unit.

With regard to the key transfer circuit 1 ₄ of the key and lock access control signals, it is indicated, as shown in FIG. 4a above, that this can be achieved by means of a winding. 140 mounted on a sleeve 141 shown projecting in FIG. 4a, this sleeve being implanted in the injected block B ₁ , which ensures a suitable mechanical maintenance of the assembly constituted by the sleeve 141 and the winding 140. The connection of the winding 140 to the power signal generator module 1 ₃ and the key transmission-reception module 1 ₂ is produced by a wired link, which is also embedded in the injected block B ₁ .

Finally, and in a nonlimiting manner, the housing B ₁ can be provided with an inspection hatch, denoted TV, allowing access to the accumulator battery constituting the electrical energy source 1 ₀ . The winding 140 is itself formed by contiguous turns by means of an electrically insulated copper wire. The sleeve 141 is advantageously made of a magnetic material such as a ferrite rod for example.

As regards the electronic lock 2, as shown in FIG. 4b, a comparable embodiment can be envisaged from a housing B ₂ made of molded injected plastic material, this housing B ₂ being integrated into the letter box or to the BL enclosure, access to which is reserved. The housing B ₂ can, in the same manner as in the case of FIG. 4a, be injected around a printed circuit board PIC ₂ comprising all of the functional modules represented in FIGS. 1a or 2a, 2 ₁ , 2 ₂ , 2 ₃ and 2 ₅ , if applicable 2 ₄ and 2 ₀ .

A manufacturing method can then consist in providing the printed circuit board PIC ₂ with a notch, denoted ENC, in which the lock transfer circuit 2 ₄ is mounted. In the same way as in the case of FIG. 4a, the key transfer circuit 2 ₄ is constituted by a winding with contiguous turns, which is fixed and maintained in the notch ENC and suitably connected to the functional modules 2 ₃ , 2 ₅ and 2 ₂ previously mentioned in the description. The injection of the housing B ₂ then makes it possible to obtain a compact block and a cylindrical cavity 241 can then be produced by suitable bore, subject to the usual precautions, in order to produce a suitable cylindrical cavity. In addition, in the aforementioned cylindrical cavity 241, can then be inserted a hollow tube 242 constituting for the winding 240 constituting the transfer circuit 24 ₄ a sleeve to which can be optionally imparted electromagnetic properties. The hollow tube and / or the cavity 242 can for this purpose be made of a magnetic ferrite material such as the sleeve 141 relative to FIG. 4a.

Of course, other embodiments, both of electronic key and lock, can be considered. In particular, the male character of the key, represented by the protruding sleeve 141 in FIG. 4a, and the female character of the lock, represented by the cavity 241, enabling the key and the lock for attempted access, can be reversed or even neutral, ie flat. Other modes non-limiting embodiments can also be considered. In particular, the sleeve 141 and the cavity 241, as well as the hollow tube 242, can have a section of revolution, circular, or polygonal.

In an experimental embodiment, the electrically insulated copper wire, making it possible to carry out the winding 140 and the winding 240 of the key and lock transfer circuits, was a copper wire with a diameter of 0.5 mm, the sleeve 141 had a total length of 30 mm, the part of the protruding sleeve emerging from the housing B ₁ over a length of 25 mm. The diameter of the assembly constituted by the sleeve 141 and the winding 140 had a value of 11 mm.

With regard to the cavity 241, this being provided with the hollow tube 242 as shown in FIG. 4b, this cavity had an inside diameter dimension 11 mm, allowing the insertion of the protruding sleeve of the same dimension.

In particular, the implementation of the cavity 241 is not limited to an implementation by boring. Indeed, it is also possible to perform the injection of the material constituting the block B ₂ around the printed circuit board PIC ₂ by introducing into the coil 240 a rod of suitable diameter. The removal of the rod then makes it possible to form the aforementioned cavity 241. This operating mode then makes it possible to adjust the thickness of injected material separating the winding from the cavity thus produced, which makes it possible to improve the coupling of the windings 240 and 140 when the key and the lock are brought into contact.

In Figure 4c, there is shown, in a sectional view, the relative position of the electronic key and the electronic lock when the key is placed in the presence of the lock to perform an access attempt. It is noted in particular that the windings 140 and 240 constituting the key transfer circuits, respectively of the lock, are placed opposite, the positioning of the latter being established accordingly. In addition, a specific, non-limiting embodiment may consist, at the level of the lock, of providing separate windings for the energy recovery module 2 ₅ and for the transmission-reception module 2 ₂ , these two modules being then completely separated.

A more detailed description of an embodiment advantageous functional modules of the key and of the electronic lock will now be given in connection with Figures 5a and 5b.

With regard to the electronic key 1, the source of electrical energy 1 ₀ can be constituted by a rechargeable battery. This battery can be a battery of the type intended for portable telephones, with a nominal voltage of 4.8 V and a capacity of 600 mAh. The storage battery can be recharged by electrical contact from external terminals accessible, for example at the parallel interface, or, if necessary, via the contactless connection of the key, i.e. via the transfer circuit 1 ₄ . The battery management module can then manage the recharging operation.

Regarding the starting and stopping of the electronic key, it indicates that the stop / start button ON / OFF has the effect of powering the circuits other than any circuits that are continuously powered, such as a real-time clock for example. Another solution may be to implements an automatic start / stop following automatic detection of a lock by the key. A such function can be realized, by electromagnetic detection the presence of the key and a lock for example. Under these conditions, the module of battery management, represented in FIG. 1a or 2a, can incorporate such a detection system in order to proceed when the battery is switched on / off for ensure the supply of the whole. The above function can also be implemented by detecting a significant variation in electrical impedance seen at terminals of the winding of the key, when contacting electronic key and lock.

As regards the logical key calculation unit ₁₁ , it is indicated that this is constituted by a microcontroller, or microprocessor, with which is associated an external oscillator of the quartz oscillator type for example. Such an associated system, known as such, will not be described in detail nor shown for this reason in the drawings. The crystal oscillator / microcontroller assembly, from an oscillation frequency of 4 MHz, makes it possible to deliver a so-called carrier signal by frequency division at 250 kHz for example. This carrier is used for the transmission of electrical energy from the key to the lock and, in particular, for the constitution of the power signal PS.

As regards the power signal generator module 1 ₃ , as shown in FIG. 5a, this comprises a current amplifier device constituted by two bipolar transistors Q ₁ and Q ₂ connected in follower elements between the supply voltage VCC and the reference voltage denoted 0, the bases and the emitters of these transistors being connected together, these transistors being of opposite conduction type. The base of the aforementioned transistors receives the aforementioned carrier signal, delivered by the key calculation logic unit 1 ₁ and delivers a signal amplified in current, which corresponds substantially to a square signal at the frequency of 250 kHz. The power module 1 ₃ also comprises a MOS transistor of the FET type, referenced M ₁ , connected between the reference voltage and the winding 140, denoted L ₁ , of the transfer circuit 1 ₄ of the power signal PS and the control signal access key and lock. The MOSFET transistor M ₁ is connected in series with the above-mentioned winding L ₁ and the gate of the transistor M ₁ is connected to the amplified carrier signal delivered by the bipolar transistors Q ₁ and Q ₂ . The drain electrode of the MOSFET transistor M ₁ is thus connected in series with the winding constituting the inductance L ₁ , which itself is connected in series with a load resistance R ₁ of low value connected to the supply voltage. Vdc.

More specifically, it is indicated that the resistor R ₁ as represented in FIG. Sa constitutes a load resistor for the MOSFET transistor M ₁ constituting an element of the transmission part of the transmission-reception module 1 ₂ of the key electronic, as will be described in more detail later in the description.

The command applied to the gate electrode of the MOSFET transistor M ₁ ensures alternating switching of the latter, this transistor causing the passage of a current in the inductance L ₁ , which, when it is in the presence of the 240 corresponding winding of the lock, in fact constitutes a transformer therewith. The blocking of the transistor M ₁ then causes the appearance of an overvoltage on the drain electrode of the latter and, consequently, on the windings of the aforementioned transformer. The MOSFET transistor M ₁ is chosen so as to have a series resistance in conduction of less than 0.5 Ohm, a breakdown voltage of the order of 100 V and an admissible peak current of the order of 25 A, in order to d '' ensure correct operation of the switching transients.

When the transistor M ₁ MOSFET is conductive, the voltage across the primary of the transformer, that is to say of the inductance L ₁ , is close to the supply voltage Vcc whereas, when the conduction, the overvoltage that appears on the same inductor L ₁ is transmitted to the inductor L ₂ formed by the coil 240 at the lock. The aforementioned received voltage, at the lock, is therefore asymmetrical and the amplitude generated during the blocked alternation of the MOSFET transistor M ₁ is greater than that generated during its alternation in conduction.

The bidirectional transmission of key and lock access control signals between the electronic key and the electronic lock is carried out, at the level of the electronic key 1, by virtue of the transmission part and the reception part of the module 1 ₂ d ' transmission-reception, and, at the level of the electronic lock 2, thanks to the transmission part and to the reception part of the transmission-reception module 2 ₂ . In particular, in the embodiment described in connection with FIG. 5a, the emission part of this module 1 ₂ comprises, in addition to the resistance R ₁ already mentioned, a MOSFET transistor, referenced M ₂ , including the drain and source electrodes are connected in parallel on the aforementioned resistor R ₁ . The gate electrode of the MOSFET transistor M ₂ is controlled by a current amplifier, of structure similar to that described above, and constituted by the bipolar transistors Q ₃ and Q ₄ , the common base electrode of which is controlled by the output of the logical calculation unit ₁₁ , that is to say of the microprocessor or the microcontroller. This output then delivers a signal representative of the bits of the key access control signals, that is to say of the access control signals emitted by the key towards the lock. The common point of the transmitters of the transistors Q ₃ and Q ₄ delivering a signal amplified in current representative of the transmission of the data, that is to say of the key access control signal, then controls the gate electrode of the MOSFET transistor M ₂ . Under these conditions, the data signals, that is to say the key access control signal, causes, by means of the current amplifier constituted by the transistors Q ₃ and Q ₄ , a switching of the MOSFET transistor M ₂ and, consequently, an all-or-nothing modulation of the load, that is to say of the resistance R ₁ , seen by the inductance L ₁ . The aforementioned inductance constituting the primary circuit of the transformer is then charged by a variable impedance according to the binary information transmitted. The effect of this process is to modulate the power output impedance seen by the transformer primary, this type of modulation being close to an amplitude modulation of the carrier. The MOSFET M ₂ may have characteristics similar to those of the MOSFET M ₁ , with however a lower maximum admissible current not exceeding one ampere. Under these conditions, the transmission bit rate is 9,600 baud. The binary information of the key access control signal is coded in a Manchester code for example, the useful bit rate of the information then being 4,800 baud. With regard to the reception part of the transceiver module 1 ₂ , it is indicated that this part is directly connected to the common point of the resistor R ₁ and the inductor L ₁ previously mentioned. This common point delivers a received signal, that is to say the lock access control signal when it is emitted by the lock. The signal received is the image of the current consumed in lock 2, that is to say in fact the image of the load modulation brought into the lock in a manner similar to that which is carried out at the level of the key previously. described in the description. The reception part of the transceiver module 1 ₂ is connected via a capacitor C ₁ to the aforementioned common point R ₁ L ₁ and an inhibition circuit Q ₅ , Q ₆ and R ₂ , R ₃ . A resistance bridge R ₄ , R ₆ , R ₇ and a decoupling capacity C ₂ make it possible to fix the DC component of the received signal at the value half of the supply voltage Vcc. The capacitor C ₁ / polarization bridge assembly constitutes a high-pass filter. The signal received after alignment at half the supply voltage via the above-mentioned resistance bridge is then subjected to filtering by means of a filtering stage constituted by an operational amplifier A ₁ constituting, with the resistors R ₅ , R ₈ and capacitors C ₃ and C ₄ , a second order low pass filter of the BUTTERWORTH type. The aforementioned filtering stage is followed by a gain voltage amplifier 10, ie 20 dB, formed by an operational amplifier A ₂ and by resistors R ₉ and R ₁₀ , a capacitor C ₅ being connected in parallel on the resistor R ₁₀ . Finally, a shaping comparator A ₃ and a resistance bridge formed by the resistors R ₄ , R ₆ , R ₇ and the decoupling capacity C ₂ to constitute a reference level as a function of the signal received, makes it possible to deliver a bit stream at the reception input of the microcontroller, that is to say of the logical key calculation unit 1 ₁ . The rest state is fixed by a voltage offset generated by the resistive bridge R ₁₁ , R ₁₂ .

The input impedance of the filtering stage is taken high enough not to weaken the useful signal. Capacities C ₃ , C ₄ and resistors R ₅ , R ₈ in the filtering stage, give the latter a low-pass type structure with a cutoff frequency of 50 kHz. Resistors R ₁₁ and R ₁₂ ensure a shift of the signal to the reference voltage. Comparator A ₃ is chosen so as to require a low supply voltage, 3 V, and low consumption. The output delivered by the latter can then be directly connected to the input of the microprocessor, or microcontroller, constituting the logical key calculation unit 1 ₁ , the resistor R _12a constituting a bias resistance of the output of the comparator.

As regards the electronic lock 2, as shown in FIG. 5b, the power recovery modules 2 ₅ and the reception part of the transmission-reception module 2 ₂ of the lock 2 are connected to the constituent winding of the transfer circuit 2 ₄ , key and lock access control signals, that is to say the inductance L ₂ mentioned in the description above.

With regard to the energy recovery module 2 ₅ , as shown in the aforementioned FIG. 5b, the energy is restored from the secondary winding L ₂ via a diode bridge, denoted D ₁ , D ₂ , D ₃ and D ₄ , mounted symmetrically. The diode bridge is referenced 250. The common point of the diodes D ₁ , D ₂ is connected to a first terminal of the winding L ₂ , the common point of the diodes D ₂ and D ₃ is connected to the reference voltage and the common point of the diodes D ₁ and D ₄ delivers, from the secondary of the transformer, that is to say from the winding L ₂ , a rectified voltage corresponding to that generated by the switching of the MOSFET transistor M ₁ on the primary winding L ₁ .

The common point of the diodes D ₃ and D ₄ is connected to a resistor R ₁₅ , load resistor, this resistor itself being connected to the reference voltage by a bipolar transistor Q ₈ , which is at rest non-conductive. At rest, the blocking of transistor Q ₇ causes that of transistor Q ₈ . The other terminal of the secondary winding L ₂ is also connected to the common point of the two diodes D ₃ and D ₄ . It is also connected to a resistor R _15a intended to fix the potential of the winding L ₂ when the transistor Q ₈ is blocked.

Finally, the common point of the diodes D ₁ and D ₄ delivering the rectified voltage is connected to the input of a voltage regulator 251, which makes it possible to deliver a regulated voltage, denoted Vreg, intended to supply the power to the set of circuits of the electronic lock 2. The capacitors C ₇ and C ₈ are capacitors of high capacity with regard to the carrier frequency and respectively of specific cut-off frequency enabling energy storage at the input and the stabilization of the voltage at the output of the voltage regulator 251.

When the power signal PS is transmitted via the transformer constituted by the windings L ₁ and L ₂ , the two half-waves of the signal are then used. The conducting state of the MOSFET transistor M ₁ generates a voltage of the order of 8V across the terminals of the secondary L ₂ , this voltage source having a low output impedance. The blocked state of the MOSFET transistor M ₁ generates a higher voltage, but the Thévenin generator equivalent to the terminals of the inductor L ₂ then has a higher output impedance.

In general, as shown in FIG. 5c, the recovery of electrical energy from the power signal PS therefore takes place essentially during the half period of high amplitude, this recovery of energy being able to be carried out at 80% within 10% of the start of the duration of the high amplitude half period due to the phenomenon of transient overvoltage generated by the switching of the MOSFET transistor M ₁ . While FIG. 5c represents the voltage developed on the drain of the MOSFET transistor M ₁ , at the common point of the coil L ₁ and of the aforementioned MOSFET transistor ₁ , the power signal PS can be represented from FIG. 5c by anamorphosis graph, taking into account the DC voltage Vcc and temporal axis affinity due to the presence of the resistor R ₁ . However, as mentioned previously, the two alternations of the signal can be used thanks to the diode bridge 250, the diodes used being SCHOTTKY rectifying diodes for example. Due to the equivalent generator speed of each high and low voltage amplitude of the power signal PS, one of the alternations is comparable to a source of high amplitude voltage and impedance and the other to a source. amplitude voltage and low output impedance. The regulator 251 can be chosen as a regulator with a low waste voltage in order to supply the regulated voltage Vreg, which can be taken equal to the voltage Vcc previously mentioned relative to the supply of the electronic key 1.

With regard to the transmission part of the transmission-reception module 2 ₂ of the lock, in addition to the load resistors R ₁₅ and the transistor Q ₈ of the bipolar type previously mentioned, it is indicated that the above-mentioned transmission part circuit further comprises a bipolar transistor Q ₇ whose emitter is connected to the voltage supplied regulated Vreg by the regulator 251. The transistor Q ₇ is mounted as a common emitter by means of a collector resistor R ₁₄ connected to the reference voltage. The base of the bipolar transistor Q ₇ then receives, via a resistor R ₁₃ the binary signal delivered by the logic unit for calculating the lock 2 ₁ , this binary signal being representative of the data, that is to say say of the lock access control signal delivered by the electronic lock 2. The logic unit for calculating the lock 2 ₁ can be constituted by a microprocessor. The bit stream delivered on the base electrode of the transistor Q ₇ then ensures, through the latter, the switching of the load resistor R ₁₅ on a midpoint of the diode bridge 250, that is to say tell the connection point of the diodes D ₄ and D ₃ . When the load resistor R ₁₅ is switched, a current variation is then induced in the winding L ₁ of the electronic key 1 via the transformer. This current variation is transformed into a voltage variation on the resistance R ₁ of the load of the winding L ₁ above, that is to say at the input of the reception part 1 ₂ of the transmission-reception module. 1 ₂ , as shown in Figure 5a.

Finally, as regards the reception part of the transmission / reception module 2 ₂ of the lock, it is indicated that this part is connected to the common point of the secondary winding L ₂ and to the common point of the diodes D ₃ and D ₄ of the diode bridge 250 via a diode D ₅ , which has characteristics similar to those of diode D ₁ .

Indeed, the information transmitted by the electronic key 1 is perceived by the electronic lock 2 as an amplitude modulated signal. Consequently, the useful signal is not taken at the output of the diode bridge, common point of the diodes D ₁ , D ₄ of the diode bridge 250, because this signal is distorted by the filtering and regulation capacities associated with the regulator. 251, namely capacities C ₇ and C ₈ .

On the contrary, as shown in FIG. 5b, the received signal is taken at the midpoint of the aforementioned diode bridge 250 and in particular on the branch of the diode bridge 250 which rectifies the alternation of lower amplitude, c ' i.e. the branch D ₁ , D ₃ or D ₂ , D ₄ . This alternation corresponds to the conductive state of the MOSFET switching transistor M ₁ of the electronic key 1. This alternation is chosen because it is not clipped by the rectification capacities of the lock, the capacities C ₇ and C ₈ . Under these conditions, the alternation of higher amplitude provides energy as a priority. Thus, the two asymmetrical half-waves are rectified, but as long as a too high current consumption by the lock 2 does not intervene, only the half-wave supplying the highest voltage is used to supply the power supply to the lock. Under these conditions, the alternation supplying the lowest voltage can then be used to receive the information delivered by the winding L ₁ of the transformer primary, that is to say the key access control signal. .

However, when the current demand by the lock can no longer be satisfied by the branch providing the highest voltage, the second branch of the bridge of diodes 250 then supplies current. Operation mode aforementioned may then no longer allow separation to be ensured of energy supply and information by use of signal amplitude asymmetry PS power.

Regarding the received signal, it is transmitted by the diode D ₅ to a processing chain. The processing chain, as shown in FIG. 5b, comprises a demodulation stage formed by the resistor R ₁₆ , the capacitor C ₉ and the resistor R ₁₇ . This demodulation stage performs an amplitude demodulation at the cutoff frequency of 50 kHz and plays the role of a low-pass filter. C ₁₀ is a bonding capacity. An inhibition circuit formed by the transistors Q ₅ , Q ₆ and the resistors R ₂ , R ₃ , similar to the inhibition circuit of FIG. Sa can also be inserted between the capacitor C ₁₀ and the common point of the resistance R ₁₆ of the capacitance C ₉ and of the resistance R ₁₇ , as will be described in more detail later in the description.

A bias bridge formed by the resistors R ₁₈ , R ₂₀ , R ₂₁ and the decoupling capacity C ₁₁ at the reference voltage makes it possible to adjust the average value of the signal to the value half of the regulated supply voltage Vreg. In connection with the capacitance C ₁₀ , the aforementioned stage introduces a capacitive bond and constitutes a high-pass filter. For this reason, it is necessary to respect in the binary message an alternation of high and low level, the coding of Manchester coding type being then used.

The aforementioned processing chain also includes a second order low-pass 50 kHz filtering stage produced by means of the operational amplifier A ₄ , resistors R ₂₂ and R ₁₉ and capacitors C ₁₂ and C ₁₃ . This filtering ensures rejection of the carrier at 250 kHz while maintaining the shape of the square signal. The filtering stage produced constitutes a BUTTERWORTH filter.

The aforementioned filtering stage is followed by an inverting amplifier constituted by an operational amplifier A ₅ and by the resistors R ₂₃ , R ₂₄ , the capacitor C ₁₅ . A resistance-capacitance filter formed by resistors R ₂₅ , R ₂₆ and capacitance C ₁₄ , makes it possible to provide a voltage offset making it possible to assign to a comparison stage, constituted by comparator A ₆ , a stable state in the absence of a signal, due to the voltage offset introduced by the above-mentioned resistive bridge. At rest, the voltage applied to the positive input of comparator A ₆ is substantially equal to half of the supply voltage, that is to say the regulated voltage Vreg. The offset and comparison stage delivers at its output to the microcontroller constituting the logic calculation unit 2 ₁ of the lock, the key access control signal received by the lock.

With regard to the clock recovery module 2 ₃ , it is indicated that it can be introduced into the lock in order to allow the generation of a time base punctuating the work of the microcontroller constituting the logical calculation unit 2 ₁ . It is understood in particular that this time base is obtained by detection of the carrier, that is to say of the power signal PS. This module can be produced from a phase locked loop controlled by the fundamental frequency of the power signal generated by the electronic key 1 in order to generate a frequency multiple of the latter. In the case of the integration of a clock recovery module 2 ₃ in the lock 2, it is then possible to delete the quartz oscillator normally associated with the logic calculation unit, that is to say tell the microcontroller or microprocessor 2 ₁ .

The embodiment of the key circuits and lock, as shown in FIGS. 5a and 5b have enabled, thanks to the adapted choice of physical parameters of components, optimum power transfer and of electrical energy, between the key and the lock, for a impedance brought back by the transformer constituted by the windings L1, L2 between 100 Ω and 200 Ω. The yield obtained was, under these conditions, equal to 0.76 for a transmitted power of 370 mW. Power values higher transmissions can be obtained.

Finally, inhibitor circuits can be introduced in order to make the reception part of the key and the lock insensitive, the signals transmitted by the key not being perceived by the latter, and vice versa for the lock, in order to reduce the time of turnaround. The turnaround time is defined as the minimum duration of rests to be respected between the end of a transmission and the start of a reception so as not to cause a collision between the corresponding messages. Thanks to the introduction of inhibition circuits, the turnaround time is reduced from 500 ms to 25 ms. In such conditions, an uninterrupted dialogue between the key and the lock can be carried out. An inhibition circuit formed by the transistors Q ₆ and Q ₅ and the resistors R ₂ , R ₃ , can thus be introduced at the input of the reception part of the transmission-reception module 1 ₂ of the key respectively 2 ₂ of the lock, as previously mentioned. The transistor Q ₅ controlling the conduction respectively the non-conduction of the transistor Q ₆ to ensure, from a command signal of inhibition circuit SCD respectively of the command signal of the inhibition circuit SCD *, at the time of transmission / reception or reversal switching time, the blocking of the entry of the reception part of the reception transmission module 1 ₂ of the key respectively 2 ₂ of the lock is obtained when the transmission part of the transmission-reception module 1 ₂ of the key respectively the transmission part of the transmission-reception module 2 ₂ of the lock are active in transmission.

Description of an access control protocol between an electronic key 1 and an electronic lock 2 constituting an access control device, compliant to the subject of the present invention, will now be given in a preferred embodiment in conjunction with Figures 6a and 6b.

In general, we indicate that the key electronic 1 allows to generate and transmit in a way unidirectional to electronic lock 2 signal of power such as the PS signal including a period is shown in the right part of FIG. 6a. This signal consists of an asymmetrical periodic signal as shown in Figure 5c.

Following a first initialization step consisting of for example to initialize a count variable r at value 1, this counting variable representing for example the rank of successive periods of the signal PS power consisting of a half period of high amplitude and a half period of low amplitude, the protocol, object of the present invention is to transmit in a step 1000, referenced a), the key electronic 1 to electronic lock 2, the signal of PS power so as to supply over at least a half high amplitude period at electronic lock 2 the electrical energy carried by the power signal during this half period of high amplitude. We recall that of course the power transfer takes place especially in the specific embodiment of figure 5a at 80% during the 10% of the start time of the aforementioned half high amplitude period.

Associated with step 1000 is a step 1001 also bearing the reference b), for storing the electrical energy carried by the power signal PS, this storage occurring at the level of the electronic lock 2. Of course, depending on the physical phenomenon implemented to transfer and store energy mentioned above, it is indicated that in fact steps 1000 and 1001 of FIG. 6a can be concomitant, the transmission of electrical energy and storage of this energy at the lock, especially by through the input capabilities of the regulator voltage delivering the regulated voltage Vreg in the case of embodiment of FIG. 5b are substantially concomitant for the duration of the half amplitude period high considered. However, for the sake of clarity of the sequence diagram shown in Figure 6a, the steps a) and b), i.e. 1000 and 1001, are shown successive.

The above steps are then followed during the next half period of low amplitude of a transfer bidirectional key access control signals and lock between the electronic key and lock. Well heard, it is indicated that this bidirectional transfer of data is carried out according to an access control process non-limiting specific for which transfer 1002 bidirectional access control signal corresponds to all or part of the aforementioned access control process. In other words, step 1002, referenced c), can consist of, either in a complete access control process between the electronic key and the electronic lock, either at a slice of rank r of a control process full access. This process is thus distributed over several successive slices of corresponding rank r and performed for half periods of low amplitude PS power signal. We understand that the protocol of access control between an electronic key and a electronic lock, object of the present invention, can thus be implemented thanks to a nested distribution of the energy transfer and storage process electric key and lock, followed by all or part of an actual access control process between the electronic key and lock.

In case the bidirectional signal transfer key and lock access control to part of the access control process, as well as previously mentioned, the access control protocol, in accordance with the subject of the present invention, comprises in in addition to the steps of memorizing at the electronic key and lock calculation results intermediaries corresponding to the part of the process access control, i.e. to the implementation part for the Tr tranche of access control signals of key and lock. The step of memorizing the results of intermediate calculations is not shown in the figure 6a because it is a classic step in terms of data processing.

In the case cited above, steps a), b), c), i.e. 1000, 1001, 1002 shown in figure 6a, are then repeated on a succession of pairs of half periods of high amplitude and low amplitude of the PS power signal to actually ensure completeness the conduct of the access control protocol.

In order to introduce a high level of security of the access control protocol, consistent with the purpose of the present invention, it is indicated that the repetition step steps a), b), c) previously mentioned, as well understood that the step of memorizing the intermediate calculations, can then be made conditional on satisfaction of a completeness test criterion of the part of the access control process.

In FIG. 6a, this step or this criterion of test bears the reference 1003. On negative response to the test completeness of the part of the access control process, the access control protocol, in accordance with the object of the present invention is then terminated by an end step consisting of a referenced access refusal 1004. Indeed, it is thus possible to make access conditional to the enclosure confined to the success of all tranches successive bidirectional transfer of signals from electronic key and lock access control.

Thus, the aforementioned test 1003 can then be followed of a test 1005 relating to the completeness of the conduct of the access control protocol and achieving this last successfully. The 1005 test is of course performed on positive response to the previous test 1003.

On negative response to the above test 1005, the process of complete access control not being completed and a fortiori the access control protocol in accordance with the object of the present invention, a step 1006 is provided, which authorizes the passage to the range of signals of access control of next row by the classic operation r = r + 1. Step 1006 allows you to return to step Previous 1000, for iterative protocol management access control.

On a positive response to the above test 1005, the protocol access control was completed with success and the latter introduces an end step 1007 in which access is accepted.

By way of nonlimiting example, it is indicated that the access control protocol; object of the present invention, can be implemented for example in accordance with the access control process described in document FR-2 774 833 to which a person skilled in the art can refer to for details as to its implementation. It will be recalled in particular, with reference to FIG. 6b, that the access control process described in the aforementioned document consists, by way of nonlimiting example, in performing in a first tranche, denoted T ₁ , a transmission step by the electronic key, noted 1 _kj , of an identification request message, noted A _ki . This identification request message is transmitted to the lock marked 2 _i .

The above-mentioned tranche T ₁ is followed by a tranche T ₂ consisting for example of the transmission of a random variable message, noted a _ij , by the electronic lock 2 _i to the electronic key 1 _kj .

The aforementioned step T ₂ can then be followed by a section T ₃ , which consists, from initial validation data V _j of the electronic key 1 _kj , in performing a calculation of the signature of the random variable message, this signature being noted Ci = S _k's (a _ij ), then of transmission of this signature C _i and of specific authentication data DA _j . This transmission is carried out from the electronic key 1 _kj to the electronic lock 2 _i .

The slice T ₃ can then be followed by a slice T ₄ , which is then carried out at the level of the electronic lock 2 _i from initial validation data V _i , this slice T ₄ then consisting in a verification of the authenticity the signature value based on specific authentication data.

With reference to French patent application FR-2 774 833 previously cited in the description, it is indicated that the steps of data transmission carried out at the slices T ₁ , T ₂ , T ₃ , T ₄ are for example carried out during the step 1002, referenced c in FIG. 6a, each step being of course carried out during the half period of low amplitude of the power signal PS and having been previously preceded by a step of transferring energy storage corresponding to the steps a) and b), that is to say 1000 and 1001 of the same figure 6a. It will be understood in particular that, depending on the calculation load to be carried out to conduct the calculation of the signature C _i , it is also possible to modulate the amount of energy transferred from the electronic key 1 _kj to the electronic lock 2 _i as a function of this computation load necessary for the implementation of each corresponding slice, and in particular of the computation time of the microprocessor, or microcontroller, equipping the logic computation unit 2 ₁ of the electronic lock. This modulation can be carried out in accordance with the protocol as defined above in the description in conjunction with Figures 1b and 2b for example.

With reference to the French patent application cited above in the description, it is indicated that the slice T ₃ of calculation and transmission of the electronic key 1 _kj to the electronic lock 2 _i of the signature value C _i of the random variable message d incitement to authentication and authentication data can be carried out for the calculation of the signature from a private signature key and these specific authentication data DA _j , as described in the aforementioned French patent application.

In the same way, the slice T ₄ of verification by the electronic lock 2 _i of the authenticity of the signature value as a function of the specific authentication data, can be implemented in accordance with the teachings given in the French patent application supra.

It is indeed indicated that, for any electronic key 1 _kj , the references k and j correspond respectively to an address or physical reference of the key and to a validation address of the key in accordance with the indications given in the aforementioned French patent application. Similarly, the index i of each electronic lock 2 _i corresponds to a physical address assigned to the corresponding electronic lock.

Finally, the signature calculation operations C _i and signature calculation verification are carried out for example using private keys K'S and public keys KP, K'P, under the conditions mentioned in the aforementioned French patent application. .

We have thus described an access control device between an electronic key and lock implements a particularly access control protocol efficient insofar as complex operations of encryption - decryption of data can be associated and made conditional on prior operations energy transfer allowing alone empowerment to conduct calculation operations for aforementioned signature and verification.

The access control device between a key and an electronic lock and control protocol of access, objects of the present invention, appear particularly well suited to managing a number very important electronic locks from a set reduced electronic keys programmed for this purpose. They appear particularly well suited to the mailbox management, especially in rural areas, where mailboxes can be moved away from sources power supply. In addition, depending on the complexity of encryption algorithms - decryption retained, the access control device between a key and an electronic lock and control protocol access, objects of the present invention, can be put implemented to manage reserved access enclosures requiring high security control.

Claims (10)

1. A device for access control between an electronic key (1) and an electronic lock (2), the electronic key including an electrical power supply (1₀), a key calculation logic unit (1₁), and a key access control signal send-receive module (1₂) and the electronic lock including a lock calculation logic unit (2₁) and a lock access control signal send-receive module (2₂) for implementing an access control protocol between said electronic key and said electronic lock, characterized in that said electronic key further includes:

   means (1₃) supplied with power by said electrical power supply for generating a power signal in the form of an asymmetrical periodic signal comprising a half-period of high amplitude and a half-period of low amplitude; and

   means (1₄) for transferring said key and lock access control signals and said power signal; and in that said electronic lock further includes:

   means (2₄) for transferring said key and lock access control signals and said power signal; and

   means (2₅) for storing electrical power conveyed by said power signal enabling the unidirectional transfer of electrical power conveyed by said power signal from the electronic key to the electronic lock and bidirectional transfer of key and lock access control signals between the electronic key and the electronic lock, unidirectional transfer of electrical power conveyed by said power signal and bidirectional transfer of key and lock access control signals being effected alternately, over substantially a high-amplitude half-period and substantially a low-amplitude half-period, respectively.
2. A device according to claim 1, characterized in that said transfer means of said key (1₄) and said lock (2₄) include a primary winding and a secondary winding of a respective transformer which are electromagnetically coupled when the electronic key and the electronic lock are brought together.
3. An electronic key (1) including an electrical power supply (1₀), a key calculation logic unit (1₁), a key access control signal send-receive module (1₂) for implementing an access control protocol between said electronic key and an electronic lock on the basis of lock access control signals generated by said electronic lock, characterized in that said electronic key further includes:

   means (1₃) supplied with power by said electrical power supply and controlled by said key calculation unit for generating a power signal; and

   means (1₄) for transferring said key and lock access control signals and said power signal including a winding mounted on a sleeve and connected to said power signal generator means and via said send-receive module.
4. An electronic lock (2) including a lock calculation logic unit (2₁) and a lock access control signal send-receive module (2₂) for implementing an access control protocol between said electronic lock and an electronic key on the basis of key access control signals and a power signal generated by said electronic key, characterized in that said electronic lock further includes:

   means (2₄) for transferring said key and lock access control signals and said power signal including a winding in a cylindrical cavity and connected to said lock access control signal send-receive module; and

   means (2₅) for storing electrical power conveyed by said power signal connected to said winding.
5. A device according to any of claims 1 and 2, characterized in that said device includes an electronic key (1) according to claim 3 and an electronic lock (2) according to claim 4 and the sleeve of the key transfer means and the cavity the lock transfer means are formed from a magnetic material.
6. An access control protocol between an electronic key according to claim 3 and an electronic lock according to claim 4, the electronic key generating and transmitting unidirectionally to the electronic lock a power signal in the form of an asymmetric periodic signal. comprising a half-period of low amplitude and a half-period of high amplitude, characterized in that said protocol includes:

   a) transmitting (1000) said power signal from the electronic key to the electronic lock to supply electrical power conveyed by said power signal to said electronic lock during a high-amplitude half-period;

   b) storing (1001) said electrical power conveyed by said power signal in said electronic lock during the next low-amplitude half -period; and

   c) bidirectionally transferring (1002) access control signals between the electronic key and the electronic lock in accordance with a specific access control method, said bidirectional transfer of key and lock access control signals corresponding to all or a portion of said access control method.
7. An access control protocol according to claim 6, characterized in that when said bidirectional transfer of key and lock access control signals corresponds to a portion of said access control method, said access control protocol further includes the steps of:

   d) storing intermediate calculation results corresponding to said portion of said access control method in the electronic key and the electronic lock; and

   e) repeating steps a), b), c) and d) over a succession of pairs of high-amplitude and low-amplitude half-periods of said power signal for complete execution of said access control protocol.
8. An access control protocol according to claim 7, characterized in that step e) of repeating steps a), b), c) and d) is conditional on a criterion testing the completeness of said portion of the access control protocol.
9. An access control protocol according to claims 6, 7 or 8, characterized in that, if the lock does not include an electrical power supply, unidirectional transfer of electrical power conveyed by said power signal from the electronic key to the electronic lock is effected before bidirectional transfer of key and lock access control signals between the electronic key and the electronic lock.
10. An access control protocol according to claims 6, 7 or 8, characterized in that, if the lock includes an auxiliary electrical power supply enabling a standby function, key and lock access control signals are transferred bidirectionally between the electronic key and the electronic lock before electrical power conveyed by said power signal is transferred unidirectionally from the electronic key to the electronic lock and said unidirectional transfer is conditional on successful completion of said bidirectional transfer, constituting the access control protocol.

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