EP1044433B1 - Method and system for controlling access to a resource limited to certain time frames - Google Patents

Description

The present invention relates to a method and system of access control to a resource limited to certain time slots.

It applies to access control to a resource any, accessed resource, which one wishes to control use, and whose access is to be limited to one or more several specific time slots, also known as predetermined validity, whether the resource considered is a building, a computer system, or any other object, such than a mailbox or a bank vault.

The invention applies more particularly to access control to non-autonomous accessed resources in energy and / or having only a limited potential for verification of a time slot of validity, in particular the resources without real time clock.

WO 9 321 712 discloses a system of access control limited to predetermined periods of validity.

The validity range can be either the period proper during which it is possible to access the resource, or any other parameter allowing limit in time an attack by use fraudulent use of the accessing resource.

The main advantage of a logical means of access to a resource versus physical means of residing generally in the possibility of only allowing access to the resource only within a time slot relatively short predetermined.

Under these conditions, if the electronic key is lost, stolen, assigned or duplicated, it will not allow its illegitimate holder of access to the resource outside of the predetermined time range. However, this assumes that the resource accessed is able to verify that this time slot is respected. This generally implies that the resource accessed has a real time clock.

Document FR-A-2 722 596 thus describes a system of access control limited to authorized time slots and renewable by means of a storage medium portable. This system, based on mechanisms cryptographic, allows to limit the validity period short-term access rights, in order to avoid illegitimate use in the event of loss, theft, transfer or unlawful duplication.

However, the solution described is based on the assumption, highly restrictive, whether the resource accessed is energy autonomous, to maintain a real time clock allowing him to check the validity of the time slot in which the attempt to access by the resource takes place accédante.

The object of the present invention is to remedy the aforementioned drawbacks by allowing the resource accessed check the validity range without having of a real time clock.

(a) on initialise la serrure électronique par une valeur de comptage de référence ;
   puis, lors de chaque tentative d'accès de la clé électronique à une serrure électronique :

dans la clé électronique :

(b) on lit une plage horaire prédéterminée, préalablement mémorisée dans la clé électronique ;

(c) on mémorise une valeur horaire courante délivrée par l'horloge temps réel ;

(d) on transmet de la clé électronique à la serrure électronique la plage horaire et la valeur horaire courante, et
dans la serrure électronique :

(e) on vérifie que la valeur horaire courante transmise est à l'intérieur de la plage horaire prédéterminée, et qu'elle est postérieure à la valeur de comptage de référence mémorisée dans la serrure ;

(f) si les vérifications effectuées à l'étape (e) sont satisfaites, on autorise l'accès, et on met à jour la valeur de comptage de référence, à partir de la valeur horaire courante transmise ;

(g) si la valeur horaire courante transmise est à l'extérieur de la plage horaire prédéterminée, ou si elle est antérieure à la valeur de comptage de référence mémorisée dans la serrure, on interdit l'accès de cette clé à cette serrure.

To this end, the present invention provides a method of controlling access to at least one electronic key, provided with a real-time clock delivering a current time value, to at least one electronic lock, inside a predetermined time slot, remarkable in that:

(a) the electronic lock is initialized by a reference count value;
then, on each attempt to access the electronic key to an electronic lock:

in the electronic key:

(b) a predetermined time slot is read, previously stored in the electronic key;

(c) a current hourly value delivered by the real time clock is memorized;

(d) the time range and the current time value are transmitted from the electronic key to the electronic lock, and
in the electronic lock:

(e) it is checked that the current transmitted hourly value is within the predetermined time range, and that it is later than the reference count value stored in the lock;

(f) if the checks carried out in step (e) are satisfied, access is authorized, and the reference count value is updated, from the current hourly value transmitted;

(g) if the current hourly value transmitted is outside the predetermined time range, or if it is earlier than the reference count value stored in the lock, access to this key is prohibited.

In an embodiment which provides security increased, the following additional steps are carried out.

(b1) à l'étape (b), on lit, en plus de la plage horaire, ou en lieu et place de la plage horaire, une signature électronique de la plage horaire, préalablement calculée et mémorisée dans la clé électronique ;

(d1) à l'étape (d), on transmet de la clé électronique à la serrure électronique, en plus de la plage horaire, ou en lieu et place de la plage horaire et de la valeur horaire courante, la signature et la valeur horaire courante, et dans la serrure électronique :

(e1) avant l'étape (e), on vérifie la signature transmise, à partir d'une clé de vérification spécifique ;

(f1) à l'étape (f), on n'autorise l'accès, et on ne met à jour la valeur de comptage de référence, à partir de la valeur horaire courante transmise, que si les vérifications effectuées aux étapes (e1) et (e) sont satisfaites ;

(g1) à l'étape (g), on interdit l'accès de cette clé à cette serrure si la valeur horaire courante transmise est à l'extérieur de la plage horaire, ou si elle est antérieure à la valeur de comptage de référence mémorisée dans la serrure, ou si la vérification effectuée à l'étape (e1) n'est pas satisfaite.

In the electronic key:

(b1) in step (b), we read, in addition to the time slot, or instead of the time slot, an electronic signature of the time slot, previously calculated and stored in the electronic key;

(d1) in step (d), the electronic key is transmitted to the electronic lock, in addition to the time slot, or instead of the time slot and the current hourly value, the signature and the value current timetable, and in the electronic lock:

(e1) before step (e), the transmitted signature is verified, using a specific verification key;

(f1) in step (f), access is authorized, and the reference count value is updated, from the current hourly value transmitted, only if the checks carried out in steps (e1 ) and (e) are satisfied;

(g1) in step (g), access of this key to this lock is prohibited if the current transmitted hourly value is outside the time range, or if it is earlier than the reference count value stored in the lock, or if the verification carried out in step (e1) is not satisfied.

As a variant, the order of execution of steps (e1) and (e) can be inverted.

The specific verification key used in the step (e1) can be a public or secret key.

The aforementioned time period may include several disjoint time slots.

In a particular embodiment, the range hourly is an interval with two bounds expressed each as a date in day, month, year and a schedule in hours, minutes, seconds.

• une horloge temps réel délivrant une valeur horaire courante, et
• un module de transmission à la serrure d'une plage horaire prédéterminée, et en ce que la serrure comprend
• un module de mémorisation accessible en lecture et en écriture,
• un module de comptage, ce module de comptage étant mis à jour à partir de la valeur horaire courante à chaque tentative d'accès réussie, et
• un module de comparaison de la valeur horaire courante à la plage horaire prédéterminée et à la valeur mémorisée dans le module de comptage.

The present invention also provides an electronic access control system, within a predetermined time range, comprising at least one electronic lock and at least one electronic key, remarkable in that the key comprises

• a real time clock delivering a current hourly value, and
• a transmission module to the lock of a predetermined time range, and in that the lock comprises
• a memory module accessible in read and write,
• a counting module, this counting module being updated from the current hourly value on each successful access attempt, and
• a module for comparing the current hourly value with the predetermined time slot and with the value stored in the counting module.

In an embodiment which provides security increased, the transmission module at the lock of a range predetermined schedule is accompanied by a module of transmission to the lock of an electronic signature of the time slot, and the lock further includes a module for verification of the electronic signature transmitted by the key.

In a particular embodiment, the module storage includes non-volatile memory electrically reprogrammable.

In a particular embodiment, the key communicates with the electronic lock at using a contactless transmission module, by electromagnetic induction.

This contactless transmission module can include a first electromagnetic winding provided in the key and a second electromagnetic coil provided in the lock.

These two windings can be concentric.

Other features and advantages of this invention will appear on reading the description detailed which follows of a particular embodiment, given by way of nonlimiting example.

• la figure 1 est un organigramme du procédé de contrôle d'accès de la présente invention, dans un mode particulier de réalisation ;
• la figure 2 est un organigramme du procédé de contrôle d'accès de la présente invention, dans un autre mode particulier de réalisation ;
• la figure 3 représente de façon schématique le système de contrôle d'accès de la présente invention, dans un mode particulier de réalisation ;
• la figure 4 représente de façon schématique le système de contrôle d'accès de la présente invention, dans un autre mode particulier de réalisation ; et
• la figure 5 représente de façon schématique le module de transmission sans contact permettant à la clé électronique de communiquer avec la serrure électronique, dans un. mode particulier de réalisation.

The present invention refers to the accompanying drawings, in which:

• FIG. 1 is a flow diagram of the access control method of the present invention, in a particular embodiment;
• FIG. 2 is a flow diagram of the access control method of the present invention, in another particular embodiment;
• FIG. 3 schematically represents the access control system of the present invention, in a particular embodiment;
• FIG. 4 schematically represents the access control system of the present invention, in another particular embodiment; and
• FIG. 5 schematically represents the contactless transmission module allowing the electronic key to communicate with the electronic lock, in one. particular embodiment.

In the following, we consider an electronic key used for an attempt to access a lock electronic. Electronic key and lock have of a calculation unit. The electronic key is provided with a real time clock. This real-time clock delivers current hourly value VH, expressed for example in days, month, year, hours, minutes, seconds. We want to limit access from the key to the lock at a given time slot PH, defined as the time interval between two hourly values VH1 and VH2 determined: PH = [VH1, VH2], or more broadly as a meeting of such intervals : PH = [VH1, VH2] ∪ [VH3, VH4] ∪ ... ∪ [VHn-1, VHn].

As shown in FIG. 1, a first step 1001 of the method consists in initializing the electronic lock with a reference count value VC _ref .

We then consider a situation where the key electronics is trying to access the electronic lock. This can be expressed in various ways, depending on the form and nature of the media containing the key and the lock. By way of nonlimiting example, if the key comprises a tubular or flat tab-shaped part, the access attempt is made by entering the game tubular in a tubular cavity complementary to the lock, or in a complementary slot, respectively.

A protocol for verifying the right of access of this key to this lock is then implemented successively in the key and in the lock.

In the key, as indicated in 1002 in Figure 1, we reads a predetermined time slot PH, which has been previously stored in the electronic key.

As indicated in 1003, when trying to access, the current hourly value VH is stored in the key delivered by the key's real time clock.

Then we transmit, in 1004, the validity range as well than the current hourly value VH at the lock.

The following verification steps then take place in the lock.

In 1005 and 1006, one checks, on the one hand, the consistency between the current hourly value transmitted VH and the predetermined time range PH, and on the other hand, the consistency between VH and the reference count value VC _ref stored in the lock.

For example, in the case of a time slot reduced to an interval [VH1, VH2], we verify that VH is after VH1 and before VH2, and that VH is after VC _ref .

If any of the checks performed in steps 1005 and 1006 gives a negative answer, we forbid access of this key to this lock.

If all of these checks have been satisfied, access is authorized, and VC _{ref is} updated by replacing it, for example, with the current hourly value VH.

Another embodiment of the process of the invention, which provides increased security by compared to the previous embodiment.

We consider a non-autonomous accessed resource in energy and / or having only a limited potential for verification of a right of access.

By "right of access" is meant the signature validity range. A signature electronics can be obtained using mechanisms various cryptographic, such as encryption, or authentication. She can for example be obtained using a key signature algorithm secret or public key signature algorithm.

When an "accessing resource", or "key electronic ", presents a right of access to a" resource accessed, "or" electronic lock, "a protocol for verification of the access right is implemented. In this mode of implementation, this protocol includes, in addition to the checking the validity range, checking the electronic signature of this range of validity.

In this embodiment, the validity range can be the period during which it is possible to access the resource, i.e. the period of validity of a signature key of the accessing resource allowing him to authenticate himself vis-à-vis the resource accessed, or any other parameter allowing to limit in time an attack by fraudulent use of the accessing resource.

As shown in FIG. 2, in this embodiment, a first step 2001 consists, as in step 1001 in the previous embodiment, in initializing the electronic lock with a reference count value VC _ref .

In the case where the electronic signature S used is calculated using a public key algorithm, of the RSA (Rivest Shamir Adleman) type for example, the public key K _P for verifying the signature is stored in the electronic lock .

The electronic signature S can also be calculated using a secret key algorithm, of the DES type (Data Encryption Standard) for example. In that case, unlike the previous case, the verification key which is stored in the lock at step 2001 is secret. Of this fact, it will have to be stored in a memory physically protected so that it cannot be read, nor modified by an unauthorized entity.

We then consider a situation where the key electronics is trying to access the electronic lock. Of same as in the previous embodiment, a protocol to verify the access right of this key to this lock is implemented successively in the key and in the lock.

In the key, as shown in 2002 in Figure 2, we reads or establishes an electronic signature S (PH) of the predetermined time range PH. This step takes place, either in plus, instead of step 1002 of reading the PH time range of the previous embodiment.

This electronic signature S (PH) may have been calculated beforehand, for example by an external entity signature calculation, independent of the key.

In this case, during a loading step, by example by means of a validation terminal, an entity of validation transfers and stores the signature S (PH) in the key before this key is put into service.

Alternatively, the key may itself establish the signature, if the key has been stored in the electronic key required for this operation, as well as the algorithm cryptographic signature, and if this key has the computational resources required.

As indicated in 2003, during the access attempt, we stores in the key the current hourly value VH delivered by the real time clock of the key.

Then, in 2004, we send the electronic signature S (PH) of the validity range as well as the hourly value current VH at the lock. If, at step 2002, we read the time slot PH in addition to the signature S (PH), we transmit also this time slot PH at the lock at step 2004.

The following verification steps then take place in the lock.

In 2005, we verify the signature transmitted. If the signature calculation algorithm is a public key algorithm, step 2005 consists, for the electronic lock, of applying the public key K _P , previously stored in the lock, to the verification algorithm. The positive verification of the signature makes it possible to ensure the authenticity of the range of validity [VH1, VH2], said range being obtained, either by reestablishing the message during the signature verification stage, or by simple reading if it was transmitted in clear with the signature.

In 2006 and 2007, we check, on the one hand, the consistency between the current hourly value transmitted VH and the predetermined time range PH, and on the other hand, the consistency between VH and the reference count value VC _ref stored in the lock.

For example, in the case of a time slot reduced to an interval [VH1, VH2], we verify that VH is after VH1 and before VH2, and that VH is after VC _ref .

If any of the checks performed in steps 2005, 2006 and 2007 give rise to a negative answer, we prohibit access of this key to this lock.

If all of these checks have been satisfied, access is authorized, and VC _{ref is} updated by replacing it, for example, with the current hourly value VH.

A particular embodiment of the access control according to the present invention will now be described using Figure 3.

The system includes an electronic key 1 and a electronic lock 2.

The electronic key 1 includes a module 11 power supply, of the battery or battery type by example. The module 11 supplies a real time clock internal 12 which delivers a current hourly value VH such as defined above. Key 1 also includes a memory 13, in which the validity range is stored PH.

The real-time clock 12 and the memory 13 are connected to a module 14 for communication of the key with the lock. The module 14 allows the key, during each access attempt, to transmit to a communication module 21 included in lock 2 the PH time range stored in the memory 13, as well as the current hourly value VH delivered by the clock 12.

The module 21 for communication of the lock with the key is connected to a memory 22 accessible for reading and writing. The memory 22 includes a counting module 23, in which is stored a reference count value VC _ref , initialized before the electronic lock is put into service and updated using the current hourly value VH transmitted by the key 1, on each successful access attempt. The memory 22 is for example an electrically reprogrammable memory of the EPROM or EEPROM type.

The lock 2 further comprises a comparison module 25, which receives the current hourly value VH transmitted by the key 1, and compares it to the predefined time range PH = [VH1, VH2] and to the reference count value VC _ref stored in the counting module 23. The comparison module 25 tests if VH> VH1 and VH <VH2, and if VH> VC _ref .

The power supply module 11 of the key 1 optionally supplies lock 2 with the necessary energy to the verification operations carried out by the module 25 of comparison, as well as the energy necessary for the operation to update the counting module 23 in the event of successful access attempt.

A description is given below, with the aid of FIG. 4, of another embodiment of the access control system the invention, comprising an electronic key 41 and a electronic lock 42, which provides increased security by compared to the embodiment of FIG. 3.

Elements of this system which are analogous to those of embodiment of Figure 3 bear the same reference figures, and will not be described a new time.

In this embodiment, the memory 13 of the key 41 contains not only the PH range of validity, but also the electronic signature S (PH) of this range of validity.

Module 14 for communication of the key with the lock allows the key 41, on each access attempt, to transmit to the communication module 21 included in the lock 42, not only the current hourly value VH delivered by the clock 12 and the stored PH time range in memory 13, but also the electronic signature S (PH) stored in memory 13.

The lock 42 comprises, in addition to the module 21 of communication with the key, from memory 22 comprising the counting module 23, and comparison module 25, described above, a module 24 for verifying signature.

The module 24 is connected to the module 21 for communication of the lock with the key and to the comparison module 25. The module 24 receives the signature S (PH) of the validity range and, in the case where the signature calculation algorithm used is a public key algorithm, verifies the signature S (PH) received by means of the public key K _P.

The power supply module 11 of the key 41 optionally supplies lock 42 with the necessary energy to the verification operations carried out by the module 24 signature verification and comparison module 25, as well as the energy required for the handover operation day of counting module 23 in case of access attempt successful.

Figure 5 illustrates a hardware implementation particular of modules 14 and 21 of communication between the key and lock, applicable both to the mode of embodiment of FIG. 3 than in the embodiment of the figure 4.

Key 1 (or 41 in the case of the embodiment of Figure 4) includes a rod 30 in material ferromagnetic, filled with copper windings 31 forming a first winding. This first winding is connected to the module 14 for communication of the key with the lock.

On each access attempt, key 1 or 41 comes to lodge in a tubular cavity 32 of slightly diameter greater than the diameter of the rod 30. The cavity 32 is also fitted with copper windings 33 forming a second winding, connected to the communication module 21 of the lock with key. The two windings 31, 33 are then concentric, and the information is transmitted in the form binary coded between key and lock 2 (or 42 in the case of the embodiment of FIG. 4) by induction electromagnetic.

The present invention finds an application particularly suitable for access, by the mail, to mailboxes, which are not autonomous in energy.

Security can be further strengthened access control, adding other data to signature and time slot information transmitted by the key to the lock. For example, you can add a number serial identifying the electronic key. In this case, we provides the lock with an additional counting module, associated with this serial number; we memorize in the module of additional count the start of the next track schedule during which a key bearing this number of series will be able to access the lock.

Claims (12)

1. A method of controlling access of an electronic key provided with a real time clock supplying a current time value to an electronic lock inside a predetermined time period, characterised in that:

   (a) the electronic lock is initialised (1001) with a reference counting value;
      and then, each time access of the electronic key to the electronic lock is attempted:

   in the electronic key:

   (b) a predetermined time period previously memorised in the electronic key is read (1002);

   (c) a current time value supplied by the real time clock is memorised (1003); and

   (d) the time period and the current time value are transmitted (1004) from the electronic key to the electronic lock, and
   in the electronic lock:

   (e) the method verifies (1005) that the current time value transmitted is inside the predetermined time period and after the reference counting value memorised in the lock;

   (f) access is authorised and the reference counting value is updated with the current time value transmitted if the result of the verification step (e) is positive; and

   (g) access of the key to the lock is prohibited if the current time value transmitted is outside the predetermined time period or before the reference value memorised in the lock.
2. A method according to claim 1 characterised in that:
   in the electronic key:

   (b1) in step (b), an electronic signature of the time period previously (2003) calculated and memorised in the electronic key is read (2002) in addition to or instead of said time period; and

   (d1) in step (d), said signature and the current value are transmitted (2004) from the electronic key to the electronic lock in addition to or instead of the time period and the current time value, and
      in the electronic lock:

   (e1) before step (e), the signature transmitted is verified (2005) using a specific verification key;

   (f1) in step (f), access is authorised and the reference counting value is updated to the transmitted current time value only if the results of the verification steps (e1) and (e) are positive; and

   (g1) in step (g), access of said key to said lock is prohibited if the current time value transmitted is outside said time period or if it is before the reference counting value memorised in the lock or if the result of the verification step (e1) is negative.
3. A method according to claim 2 characterised in that the order of execution of steps (e1) and (e) is reversed.
4. A method according to claim 2 or claim 3 characterised in that said specific verification key is a public key or a secret key.
5. A method according to any of claims 1 to 4 characterised in that said predetermined time period includes a plurality of non-contiguous time periods.
6. A method according to any of claims 1 to 5 characterised in that each time period is an interval with two bounds each expressed as a date in the form day, month, year and a time in the form hour, minute and second.
7. An electronic system for controlling access within a predetermined time period, the system including an electronic lock (2;42) and an electronic key (1;41), characterised in that the key (1;41) includes:

   a real time clock (12) supplying a current time value (VH), and

   means (14) for transmitting a predetermined time period (PH) to the lock (2;42), and in that the lock (2;42) includes:

   memory means (22) which can be read and written,

   counting means (23) which are updated with said current time value (VH) each time an access attempt is successful, and

   means (25) for comparing the current time value (VH) to the predetermined time period (PH) and to the value (VC_ref) memorised in said counting means (23).
8. A system according to claim 7 characterised in that:

   said transmitter means (14) of the electronic key (1;41) further include means for transmitting an electronic signature (S(PH)) of said time period (PH) to the lock (2;42), and in that:

   the lock (2;42) further includes means (24) for verifying said electronic signature (S(PH)) transmitted by the key (1;41).
9. A system according to claim 7 or claim 8 characterised in that said memory means (22) include a non-volatile electrically re-programmable memory.
10. A system according to claim 7 or claim 8 or claim 9 characterised in that the electronic key (1;41) communicates with the electronic lock (2;42) via contactless transmission means using electromagnetic induction.
11. A system according to claim 10 characterised in that said contactless transmission means include a first electromagnetic coil (31) in the key (1;41) and a second electromagnetic coil (33) in the lock (2;42).
12. A system according to claim 11 characterised in that the coils (31, 33) in the key (1;41) and in the lock (2;42) are concentric.

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