EP0385070B1 - Remote control system with a code transmitted by code words - Google Patents

Description

The invention relates to a telecontrol system with code that can be physically transmitted with the features of the preamble of patent claim 1.
In a known electronic locking device for motor vehicles comprising these features (DE 35 32 156 C2) with contactless transmission of code words between several transmitters and a vehicle-mounted receiver, the code words are generated on the transmitter and receiver side by a computer with two inputs. Current counts from a sequence of numbers generated by sequence transmitters without influence by the use of the device are applied to each computer input. At the other computer input in each case, as a fixed part of the code word, there are unchangeably stored key figures for system-specific characterization of the association of lock and key pairs.
When a transmitter is actuated, the transmitter-side computers then link the key figure with the current count from the sequence of numbers in accordance with a predetermined algorithm to form a disguised code word which passes as a signal between the transmitter and receiver.

In addition to the actual code words, each transmitter transmits an (unveiled) initialization code by pressing its send button, which, among other things, contains a transmitter-identifying order number that is stored individually for each key in the transmitter itself and in the receiver. These is not part of the actual code word, but enables the assignment of the current count on the receiver side to that of the currently used transmitter.
No statement has been made about the repeated assignment of the order numbers.

A suitable initialization code is also a prerequisite for the possible resynchronization of the count of transmitter and receiver with the known device. By means of a corresponding receiver-side circuit, after receiving a radiated code word and the appropriate initialization code, the code word received by the transmitter is analyzed in an unchangeable code number and count, and the latter is stored in the memory on the receiver side, assigned to the transmitter by means of a serial number, if an acknowledgment device by means of a mechanical device has been provided in good time beforehand Key was pressed.

The wirelessly transmitted code words of another known telecontrol system (DE 36 36 822 C1) are protected against unauthorized recording and use by synchronously advancing a portion of each code word considered to be current according to a predetermined algorithm in the receiver and in the last used transmitter. The algorithm is based on a normally unchangeable original code word ("key code word") stored in EEPROMs in both the receiver and the transmitter.
Due to the selected composition of each code word and the algorithm used, which only proceeds in one direction, a code word once used can only return identically after a very long period of time or after a very large number of increments. The unauthorized reuse of an illegally recorded code word is practically excluded.

In addition to its algorithmically changeable part, each code word of the known telecontrol system can also contain so-called system bits which are used for different distinctions - e.g. B. key types (master / secondary key), car brand, key system, currently controllable function etc. - can be used. According to a variant of the known system, these system bits are excluded from the algorithmic change. One or more system bits can, however, be changed arbitrarily by the user of the transmitter - by means of switches additionally provided on the transmitter button on the transmitter - in order to change the function which can be controlled or triggered by the transmitter without influencing the indexing algorithm.
When the vehicle door is open, the receiver can be switched manually to a "learning phase" using an electrical switch. In this, the key code word of the receiver is reprogrammed, and this necessarily includes the system bits mentioned, in that the code word transmitted next to the receiver by any transmitter suitable for the general system is re-stored. This new original code word is then accepted and stored as that which is subject to the subsequent algorithm for each subsequent code word transmission in accordance with the predetermined algorithm.

A code word stored in an existing transmitter can be completely reset by removing the battery from the transmitter. Then the "learning process" of the receiver described above - with the transmitter with reset code - can be carried out again. This is especially recommended to shorten the synchronization if the code words in the transmitter and receiver have been advanced at different distances.
An unauthorized person can of course also carry out the described reset process in the transmitter by temporarily removing the battery from the transmitter in his possession.

A telecontrol system of a central locking system is also known (DE 32 44 049 C2) which, in one embodiment with several transmitters, provides a different set of code words from transmitter to transmitter.
Since the code words of this telecontrol system are also advanced algorithmically, precautions must be taken which limit the code advance depending on the transmitter used to the limited code word supply individually assigned to it, in order to avoid unnecessary re-synchronization in the event of changing transmitter use.
For this purpose, each transmitter is assigned different identifiers, which can be emitted primarily when the respective transmitter is actuated. A decoder downstream of the receiver is equipped with a plurality of decoding channels, which correspond to the number of transmitters and which can be switched on by the transmitter identifiers, for processing the different number of code words from transmitter to transmitter.
The last-mentioned patent specification makes no statement as to the type of these transmitter identifications. They are functionally equivalent to the arbitrarily changeable system bits of the generic telecontrol system, which - as already mentioned - can also be used, among other things, to identify key types that have different locking functions.

The object of the invention is to design a generic telecontrol system so that an authorized user can continue to use the system with the same ease of use and without restriction of the high level of security against unauthorized use after the loss of a transmitter.

This object is achieved according to the invention with the characterizing features of patent claim 1.

According to the invention, a total amount of basic parts of the code words - which can be generated by the algorithmic advancement - are assigned to the object individually, object-specifically and without any write access. Since almost any number of variations of a code word component can be created by electronic coding with relatively little effort, it is possible to assign a total amount of own, nowhere recurring object-specific code word basic components to each object, ie also to each motor vehicle of a type series.
On the other hand, each transmitter belonging to the object is assigned an unchangeable basic codeword component from this total, which is different for each transmitter and is used not only for code word formation but also for transmitter identification.
The total stock of all individual basic components stored in the object or receiver is greater than the number of available transmitters, ie those supplied for independent parallel use.
Furthermore, the control device is assigned a device for arbitrary, transmitter-independent resetting of only the changeable parts of all code words stored in the memory locations of the object to certain initial states.

The characterizing features of subclaims 2 to 7 disclose advantageous developments of the telecontrol system according to the invention.

The permanent, deprived of any write access storage of the object-specific parts can, for. B. in ROMs. It can be linked in a suitable manner to the only temporary storage of the changeable parts or else be available in completely, ie also physically separate, memories.
This has the advantage that, in contrast to the prior art, not any transmitter available in the spare parts trade for storing a new current code word in the receiver can be used even after a transmitter RESET has been carried out and the mechanical fuse has been overcome. This is because the object-specific, unchangeable portions of the code words are always transmitted and checked for agreement beforehand, but under no circumstances can they cause changes in the corresponding permanent memory contents in the object or receiver.
It is obvious that the sale of replacement transmitters for such a system can be monitored much better and abuse can be made even more difficult. An exchange of the object-specific basic components once assigned is only possible by exchanging the control device or the memory.

In addition, user-specific parts can also be contained in the basic parts, which already communicate certain user data to the recipient or the object when the transmitter is actuated. Such user-specific code components are already known per se; they affect the automotive application of a telecontrol system such. B. from adjustable vehicle components such as seats or rear view mirrors.

• zum einen bereits wenigstens einmal benutzten und
• zum anderen bei einem Einlesevorgang nicht benutzten

Sender zugeteilt ist, automatisch entwertet - d. h. gesperrt oder gelöscht - wird. Diese automatische Sicherungsfunktion kann von verschiedenen Bedingungen abhängig gemacht werden:

• Die wenigstens einmalige Benutzung des Senders, dessen Codewort - Grundanteil gesperrt werden soll, kann z. B. durch Registrierung eines Codefortschaltevorgangs in dem zugordneten veränderbaren Anteil desselben Codewortes erfaßt werden.
• Die Sicherungsfunktion kann grundsätzlich bei der endgültigen Bestätigung eines mit mehreren Sendern vorgenommenen Einlesevorgangs ausgeführt werden.
• Sie kann in Abhängigkeit von der Reihenfolge des Einlesens ausgeführt werden, z. B. dann, wenn während des Einlesevorgangs eine bestimmte Reihenfolge nicht eingehalten werden kann, weil ein Sender fehlt.

Diese Option nutzt vorteilhaft die Tatsache, daß der Gesamtvorrat der im Objekt abgelegten Codewort - Grundanteile etwas größer als die Anzahl der gelieferten Sender ist. Neu zu beschaffenden Sendern für das Fernwirksystem kann dann ein weiterer, noch nicht benutzter Codewort - Grundanteil aus dem Gesamtvorrat zugewiesen werden.Unauthorized use of the telecontrol system with a lost transmitter can be warded off very effectively if every codeword - basic part that a

• on the one hand already used at least once and
• secondly, do not use it during a read-in process

Transmitter is assigned, is automatically canceled - ie blocked or deleted -. This automatic backup function can be made dependent on various conditions:

• The at least one use of the transmitter, the basic code word portion of which is to be blocked, can e.g. B. by registering a code advancement in the assigned changeable portion of the same code word.
• The backup function can always be used for the final Confirmation of a read-in process carried out with several transmitters.
• It can be carried out depending on the order of reading, z. B. if a certain order can not be followed during the reading process because a transmitter is missing.

This option takes advantage of the fact that the total stock of the codeword basic components stored in the object is slightly larger than the number of transmitters supplied. A new, unused basic code word component from the total stock can then be assigned to new transmitters for the telecontrol system.

The device for resetting the changeable code word basic components is preferably in the protected area of an object, for. B. in the passenger compartment of a motor vehicle, the central locking system is controllable by means of the remote control system.

An embodiment of a telecontrol system according to the invention is shown in the drawing and is described in more detail below.

The single figure shows the components of the telecontrol system essential for the invention in a highly schematic manner.

It also illustrates the division of the code words stored in the transmitters and the object or receiver into a fixed basic part and an algorithmically changeable part.

• aus einem festen Grundanteil CWG₁, CWG₂ etc., der objekt- und senderspezifisch ist und nicht verändert werden kann, also z. B. in ROMs abgelegt ist, und
• aus einem veränderbaren Anteil CWV₁, CWV₂ etc., der in bekannter Weise nach einem beliebigen Algorithmus veränderbar ist.

Letzterer ist für die Erfindung nicht wesentlich und wird daher hier nicht näher erläutert.
Die Speicherplätze SP... sind der Klarheit halber für die unveränderlichen Grundanteile und die veränderbaren Anteile einheitlich dargestellt, können aber durchaus verschiedene Strukturen haben, insbesondere auch physikalisch voneinander getrennt sein.In a control device 1, which is in an object to be protected, for. B. a motor vehicle K is arranged, a total of n code words CW₁ to CW _{n is} stored in n memory locations SP₁ to SP _n . It corresponds to at least a number m of associated transmitters S₁ to S _m , which for the respective object for parallel, independent use - z. B. by different people - to be delivered. The number m of transmitters S 1 to S _m can be less than or equal to n. In the chosen representation, m = 3.
Each code word CW₁ to CW _n exists

• from a fixed basic part CWG₁, CWG₂ etc., which is object and transmitter specific and cannot be changed, e.g. B. is stored in ROMs, and
• from a variable part CWV₁, CWV₂ etc., which can be changed in a known manner according to any algorithm.

The latter is not essential to the invention and is therefore not explained in more detail here.
For the sake of clarity, the memory locations SP ... are shown uniformly for the unchangeable basic components and the changeable components, but can certainly have different structures, in particular also be physically separated from one another.

The code words CW ... are clearly shown here as sequences of decimal digits; it goes without saying that the type of code used and also the way in which the code words are transmitted between transmitter and receiver are completely irrelevant to the essence of the invention. Any type of code or transmission (infrared, ultrasound, radio) can be used.
The changeable parts CWV ... of the code words also clearly differ from one another; Since these are algorithmically advanced by the control device 1 after each code transmission independently of the other changeable parts, the same changeable parts CWV ... can occur at random once in two or more code words. Of course, these code words still differ in their basic components CWG ....

Each transmitter S₁ to S₃ contains a code - transmission element, here an infrared diode IS, which can be activated by pressing a transmit key ST to transmit the current code word CW ... stored in the respective transmitter. Obviously, the current code words CW₁ to CW₃ of the transmitters S₁ to S₃ completely match those in the memory locations SP₁ to SP₃ of the control device 1.

An infrared receiver IE of the motor vehicle K forwards each received code word CW ... in a known manner to the control device, where it is before execution any function controllable by transmitter S ... B. unlocking or locking the vehicle by a symbolically indicated, connected to the control device 1 central locking ZV - with the stored in the memory locations SP ... code words CW ... to complete agreement.
If complete agreement has been found, the vehicle K is unlocked centrally in the exemplary embodiment in the execution of a controlled function “unlocking”. The control device 1 naturally does not react to code words from a foreign or desynchronized transmitter. It goes without saying that more than just one receiver IE can also be provided; but it remains with a central control device.

A reset button 2 also assigned to the control device 1 is in the protected area of the object, for. B. in the passenger compartment of the motor vehicle K, is provided. It is therefore only accessible when the object is unlocked (= open door). By means of this reset button 2, all changeable parts CWV _{1 ... n of} the code words CW _{1 ... n} in the memories SP _{1 ... n of} the control device ₁ can be reset to defined initial states - which can also be different from one another - independently of a transmitter actuation will. By resetting the vehicle owner can immediately prevent unauthorized persons from using the lost transmitter to control the function assigned to it if a transmitter is lost can. The current code words in the transmitters are of course not reset.

• das eingelesene Codewort darauf überprüft, ob wenigstens ein "passender" Grundanteil CWG... übertragen wird, und
• der jeweils neu eingelesene veränderbare Anteil CWV..., der im einlesenden Sender S... aktuell ist, zu dem im Objekt abgelegten Grundanteil eindeutig zugeordnet.

Jedes neu eingelesene Codewort muß dann vor der endgültig wirksamen Abspeicherung seines veränderbaren Anteils CWV... in einen Speicherplatz SP... mittels eines weiteren der Steuereinrichtung 1 zugeordneten Schalters 3, der eine Quittiereinrichtung darstellt, bestätigt werden.
Der Schalter 3 kann nur betätigt werden, wenn ein passender mechanischer Schlüssel 5 vorhanden ist. Dieser Schlüssel 5 steht hier symbolisch für die zugehörige mechanisch codierte Einrichtung zur Betätigung des Schalters 3. Dieser kann z. B. - in an sich bekannter Weise - in einen nicht dargestellten Schließzylinder einer Tür oder eines Zünd-/Lenkschlosses integriert sein und darin direkt mittels des Schlüssels 5 betätigt werden.
Aus der zusätzlichen mechanischen Sicherung jedes Einlesevorgangs resultiert der Vorteil, daß unbefugte Resynchronisierung der Steuereinrichtung 1 bzw. des Empfängers mit dem verlorenen Sender bereits durch Austausch der mechanischen Schlösser des Kraftfahrzeugs K verhindert werden kann.Starting from this reset state of the changeable components CWV _{1 ... n} , the memory contents of the control device ₁ must be synchronized again with the corresponding memory contents of the transmitters S ... which are still owned by the vehicle owner, in order to ensure their further usability. To do this, a new code transmission must be carried out from each of these transmitters to the receiver. As such, for example, every first code transmission carried out with a transmitter after a reset process is considered.
By means of the object and transmitter-specific code word - basic parts CWG ... is always

• the code word read checks whether at least a "suitable" basic component CWG ... is transmitted, and
• the newly read changeable part CWV ..., which is current in the reading transmitter S ..., is clearly assigned to the basic part stored in the object.

Each newly read code word must then be confirmed before the finally effective storage of its changeable portion CWV ... in a memory location SP ... by means of a further switch 3 assigned to the control device 1, which represents an acknowledgment device.
The switch 3 can only be operated if a suitable mechanical key 5 is available. This Key 5 stands here symbolically for the associated mechanically coded device for actuating the switch 3. B. - in a known manner - be integrated into a lock cylinder, not shown, of a door or an ignition / steering lock and be actuated therein directly by means of the key 5.
The additional mechanical security of each read-in process results in the advantage that unauthorized resynchronization of the control device 1 or of the receiver with the lost transmitter can be prevented by exchanging the mechanical locks of the motor vehicle K.

By a validation device 4 - the z. B. can turn on a read lock for memory locations SP or control a deletion of the respective memory content - it is possible under the specific conditions already mentioned to devalue the unchangeable basic components CWG ... or the complete code words CW ..., the lost transmitters were assigned. The validation device 4 is, for. B. activated by final actuation of the switch 3.

Claims (7)

1. Remote control system having a code transmissible by physical means via code words (CW₁ to CW_n) from a plurality of movable transmitters usable in parallel with equal status to a receiver (IE) arranged in a fixed or movable object (K) and to a control device (1), connected to said receiver, for controlling functions of devices connected downstream of said control device, in particular locking functions of a motor vehicle central locking system (ZV), in which remote control system

   - each code word consists of a portion (CWV₁ to CWV_n) alterable in accordance with a predetermined algorithm and of a basic portion (CWG₁ to CWG_n) not subject to this algorithm,

   - which portions are transmitted together upon each actuation of a transmit button (ST) of a transmitter (S₁ to S_m) and, before any function is executed, are tested for complete correspondence with the corresponding portions of a code word stored in the object (K),

   - only the alterable portion (CWV₁ to CWV_n) of a code word (CW₁ to CW_n) is capable, in a learning condition of the receiver, of being read in from a transmitter into a memory (SP₁ to SP_n) of the control device (1) in order to reestablish the synchronization of transmitter and receiver given complete correspondence of a transmitter-identifying signal stored on the transmitter side and object side,

   - there is provided on the object side an acknowledgement device (3), actuable by a mechanically coded device (5) provided for controlling the control device (1), for acknowledging a code word read-in procedure effected by a transmitter (S₁ to S_m),

   characterized in that a number n of memory locations (SP₁ to SP_n) are provided in the object (K) for unalterable storage of code word basic portions (CWG₁ to CWG_n) which are allocated in an individually object-specific fashion to said object and extracted from each write access, and a fixed memory location for exactly one of the code word basic portions (CWG₁, CWG₂ etc.) also provided for transmitter identification is provided from this total quantity in each of m transmitters (S₁, S₂ etc. to S_m), the number n of the code words (CW₁ to CW_n) stored in the object (K) being larger than the available number m of transmitters (S₁ to S_m), and in that a device (2) associated with the control device (1) is provided for the arbitrary, transmitter-independent resetting of only the alterable portions (CWV₁, CWV₂ to CWV_n) of all code words (CW₁, CW₂ to CW_n) stored in the memory locations (SP) of the object (K) to particular initial states, it being the case that the checking of the code word basic portion (CWG...) of each code word (CW...) transmitted by a transmitter (S...) to the receiver (IE) is effective even in the learning condition of the receiver (IE) or the control device (1).
2. Remote control system according to Claim 1, characterized in that the control device (1) is provided for the synchronous advancement of the alterable portion of an at least temporarily stored current code word (CW...), said code word corresponding on the object side and transmitter side at the time of the code transmission, after each code transmission in accordance with the predetermined algorithm in the transmitter and in the receiver, and for blocking the remote control system at least against code words already transmitted in the recent past by the respective transmitter (S...), the alterable portions (CWV₁, CWV₂ etc.) forming, together with in each case a basic portion (CWG₁, CWG₂ etc.), a code word (CW₁, CW₂ etc.) being advanced algorithmically in a mutually independent fashion.
3. Remote control system according to Claim 1, characterized by user-specific portions of the code word basic portion (CWG...) allocated to each transmitter (S...).
4. Remote control system according to Claim 1, characterized by storage of the object-specific basic portions (CWG...) in ROMs.
5. Remote control system according to Claim 1, characterized by mutually physically separated memories for the respective storage of the object-specific basic portions (CWG...) and of the alterable portions (CWV...).
6. Remote control system according to Claim 1, characterized by an invalidation device (4) which after termination of a code word read-in procedure invalidates a code word basic portion (CWG...), stored in a memory location (SP₁ to SP_n) of the object (K) and allocated to a transmitter (S...) already used at least once, if the transmitter provided with this code word basic portion was not used in the code word read-in procedure.
7. Remote control system according to Claim 1, characterized in that the device (2) for arbitrary, transmitter-independent resetting of the alterable code word portions (CWV₁, CWV₂ to CWV_n) is arranged in a protected area of the object, in particular in the passenger compartment of a motor vehicle.

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