The invention relates to an apparatus providing for electronically controlled access, comprising a key unit and a receiver unit, at least one pressure generating means located in said key unit, and at least one pressure sensor located in said receiver unit and on inserting the key unit in the receiver unit, receiving and temporarily connecting to the at least one pressure generating mean of key unit and determining the current pressure value of said inserted pressure generating means, and an electronic unit including memory means, a processor and possessing processing functions, said electronic unit is con- nected to said receiver unit.

HU 223698 Bl discloses an apparatus providing for electronically controlled access and a key containing a pressure code, said key being provided on one or both sides with pressure generating means components, each of which can generate pressure conforming to one of a given number of pressure values in the pressure sensor(s) located in the house which hosts the key. The number of combinations associated with the key is determined by the number of the pressure generating means components and the number of the possible discrete pressure values of a pressure generating means.

One limit to that solution is that if the key is possessed, even temporarily, by an unauthorised person, the pressure values of the pressure generating means can be retrieved by putting the key into the house comprising pressure evaluating means, and it is possible (albeit not simple) to copy the key, that is, to make another key with pressure generating means creating similar pressure values.

Another limit to that solution is the relatively small number of possible combinations, due to the fact that only a given number of pressure sensors can be installed conven- iently on a key of finite dimensions, and there are also technical limits to the number of discrete pressure values distinguishable from one another which can be created by one pressure generating means.

Electronic systems with stepping codes used generally to open garage doors or garden gates or to operate the alarm devices of motorcars are known in other areas of security technology. Such apparatus relay electronic signals on radio frequency and hence unauthorised persons can identify the signals and break the codes by using special receivers placed in the nearby area. The objective of the present invention is to create an upgraded access apparatus in which the limits referred to above manifest themselves much less markedly, that is, the key unit cannot be copied and, furthermore, the number of possible combinations is much higher than in the case of the HU document referred to above.

The objects of the invention are achieved by an apparatus providing for electronically controlled access, comprising a key unit and a receiver unit, at least one pressure generating means located in said key unit, and at least one pressure sensor located in said receiver unit and on inserting the key unit in the receiver unit, receiving and temporarily connecting to the at least one pressure generating mean of key unit and determining the current pressure value of said inserted pressure generating means, and an electronic unit including memory means, a processor and possessing processing functions, said electronic unit is connected to said receiver unit. The apparatus is characterised in that said at least one pressure generating means in the key unit and said at least one pressure sensor in the receiver unit are arranged in a common plane which is perpendicular or nearly perpendicular to the direction of insertion of the key unit into the receiver unit, where the at least one pressure generating means is in operational relationship with each of the at least one pressure sensor along a line of operation which is parallel with the direction of insertion of the key unit into the receiver unit or encloses an angle of less than 90° with it, and if several pressure generating means are present, the pressure generating means are arranged in a plane which is perpendicular or nearly perpendicular to the direction of insertion of the key unit into the receiver unit, and the pressure generating means are arranged rotated by a pre-determined angle relative to one another around the longitudinal axis of key unit, and if several pressure sensors are present, the pressure sensors are arranged in a plane which is perpendicular or nearly perpendicular to the di- rection of insertion of the key unit into the receiver unit, and the pressure sensors are rotated in the receiver unit by a pre-determined angle relative to one another around the longitudinal axis of the key unit.

With this design, the temporary possession of the key by unauthorised persons causes no enhanced security risk, because the copy of the pressure values does not contain every piece of information needed to decode the pressure codes.

The preferred embodiments of the invention are disclosed in the dependent claims.

In one preferred embodiment, the apparatus (preferably both the key unit and the re- ceiver unit, but at least one of the two) has several pressure sensors, the sensing sensitivity of which are set at different levels to render copying more difficult and to enhance the number of combinations.

The number of combinations as well as security are multiplied if the apparatus com- prises a random-number generator associated with the individual pressure sensors, the current values of which are associated in the period of pressure sensing with the memory registry receiving the discrete data of the given pressure sensor, and the electronic unit performs a predetermined operation on the sensed pressure values and the random number generator values associated with them, and the outputs of the individual opera- tions are stored separated or stacked in the memories of both electronic units.

In this case, the cheapest and satisfactory solution is a random number generator which is a clock signal generator. Preferably, that should have a daily repetition cycle and produce at least one clock signal per second.

It is also simple and satisfactory if the operation is multiplication and the aggregate op- eration is summing up.

To enhance security, it is expedient to enter the data in the memory upon the first authorised insertion of the key unit into the receiver unit, and to make authorisation on the occasion of subsequent insertions conditional on whether identical results are produced by the comparisons of the stored and in the given case the measured values, re- spectively.

Multiple assignment (that is, of several key units to one receiver unit and/or several receiver units to one key unit) can be realised if at least a code identifying the key unit is recorded in the memory of the electronic unit of the key, and on the occasion of the first authorisation, as part of the authorisation conditions, the receiver unit stores also the identifier code of the key unit, and the receiver units also have identifier codes, stored in the memories of the authorised key units.

In the following, the present invention will be described in more detail with reference to embodiments and the accompanying drawings, in which

Fig. 1 is a schematic representation of the key unit and the receiver unit of the ap- paratus according to the invention in perspective view; Fig. 2 shows the view of the end of the key according to Fig. 1 on the side of the receiver unit;

Fig. 3 shows the differently designed end of the key according to Fig. 1 on the side of the receiver unit;

Fig. 4 is the view of the receiver unit of the apparatus from the direction of the placement of the key unit, and

Fig. 5 is the view of the differently designed receiver unit of the apparatus from the direction of the placement of the key unit.

Fig. 1 is a schematic representation of key unit 10 of the apparatus according to the in- vention, the design of which resembles in many respects the key represented in Figures 1 and 2 of HU 223698 referred to above. Key unit 10 comprises a body part 1 and a head part 2.

In the case depicted here, key unit 10 comprising a body part 1 and a head part 2 is a key unit 10 which is not unusually designed, but in an unusual way, its components necessary for the operation of the apparatus are arranged or designed not in the longitudinal direction of body part 1 but, as shown in Figures 2 and 3, at end surface 3 of the body part 1 facing receiver unit 20. Within this end surface 3, at least one and preferably several pressure generating means 4 are arranged, each of which provides stochastic and discrete pressure values different from one another. As can be seen in the sketch of the receiver unit shown by way of illustration only in Figures 4 and 5, receiver unit 20 comprises channel 21, with pressure sensors 23 arranged in its bottom 22 boundary surface. The pressure sensors may be located, as appropriate, in boundary surface 22, in a number and layout identical with that of pressure generating means 4 of key unit 10, but as will be obvious to those skilled in the art, the alteration of the number and layout of pressure generating means 4 and pressure sensors 23 provides an uncountable number of variations.

To ensure the use of the apparatus, 5 and 24 guiding markings are made on body part 1 and on receiver unit 20, respectively, which may be mechanical markings or colour codes. It is possible to place several 5 markings on body part 1, as the case may be, with which the user can provide for the adequate code sequence during the "training" and use of the key. Pressure sensors 23 may be of the same form or may have different mechanical dimensions, design and electronic parameters each. This is taken into consideration as an individual characteristic by the apparatus at the time of the "training" of the key ever, which makes it impossible for unauthorised persons to copy the key.

Of course, nothing prevents to make, in addition to the pressure generating means and pressure sensors arranged on the end surfaces and interconnected upon the insertion of the key, similar pressure sensors on the lateral surface or, in case of cylindrical design, on the jacket surface of body part 10, and to arrange pressure sensors associated with them on the cylindrical jacket surface of channel 21 of receiver unit 20. It is also advan- tageous to place not only pressure generating means, but also at least one pressure sensor in body part 10, and to place not only pressure sensors, but also at least one pressure generating means in the reception unit, to render the unauthorised manipulation of the apparatus more difficult thereby.

The pressure components are made up partly of pressure generating means 4 and partly of pressure sensors 23, so that every key unit 10 comprises at least one pressure sensor 23 and one pressure generating means 4. In head part 2 (or in some suitable part of key unit 10), an electronic unit, preferably a microcontroller, an RFID chip, or a combination of the two is placed, which has a memory of a given size and artificial intelligence. If the electronic unit can establish contactless information exchange through electro- magnetic coupling with an external unit in its environment, not outlined in the drawing, then key unit 10 can also be made without contact, but the solution whereas the connection of the electronic unit is made possible by contact or contacts formed on a suitable part of body part 10 is simpler. In the case outlined in the Figures, the size and external appearance of pressure generating means 4 and pressure sensors 23 are identical. This concealed design implies extra cost.

Pressure generating means 4 and pressure sensors 23 of a similar key unit 10 may be of different size and design, with no protective concealing used there. The design of pressure generating means 4 is preferably identical with or highly similar to the one disclosed in the Hungarian patent referred to above. Pressure sensors 23 are, for example, devices functioning on the basis of the piezoelectric or some other principle and producing analogue voltage signals under the effect of pressure, applied also in the house of the above-indicated Hungarian patent. In the interior of key unit 10, the outlets of pres- sure sensors 23 are connected to the contacts directly or with the insertion of the electronic.

Figures 4 and 5 show the schematic front view of receiver unit 20 receiving key unit 10 outlined in Figures 1-3 and establishing mechanical and electronic contact with it. On the front surface of receiver unit 20, 21 key channel is formed for the key unit 10 or its body part 1 , into which body part 1 and the pressure generating means 4 located on it can be inserted. Within reception unit 20, there is a receiver-side component series inserted into key channel 21, provided with pressure sensors which connect while being inserted (or perhaps in inserted state) with the pressure generating means of key unit 10, and which comprises at least one pressure generating means and one pressure sensor, the design of which matches the design of pressure generating means 4 and pressure sensors 23. At the appropriate place in the house, there are contacts which connect to the contacts of key unit 10 when the latter is in inserted state.

Within receiver unit 20 or connected to it, receiver-side electronic units not shown in the Figures are located, the design of which is highly similar to that of the receiver-side units described in the prior art referred to above, with the differences outlined below.

The operation and use of the apparatus according to the invention will be described on the basis of the training contained in the referenced HU patent Specification, with special emphasis on the differences relative to the solution disclosed there.

The two units of the apparatus according to the invention, that is, key unit 10 and receiver unit 20 can be fitted into one another, and the criterion of authorisation is that on the occasion of the first fitting, the typical conditions of the connection must be written into the memory contained in receiver unit 20, and upon the subsequent re-insertion of key unit 10, following the checking of the given conditions, it is sufficient to check whether the value or values recorded in advance are received again.

One of the essential differences relative to the previous solution is that the pressure generating means and pressure sensors in key unit 10 and receiver unit 20 are not located on the cylindrical or lateral surface, but at the end surfaces and the internal boundary surfaces. Each of pressure generating means 4a in component series 3 of key 10 can produce any of the pre-set number of k of pressure values. Pressure sensor or pressure sensors 15b in receiver unit 20 receive the pressure signals of the inserted pressure gen- erating means 4a in the same order and produce at their outlet a signal series corresponding to the sensed pressure, the said signal series being available after appropriate segmentation and processing in a stored way, preferably in digital format. The difference lies in that upon the insertion of key unit 10, key-side pressure sensor 4b senses also the pressure signals of pressure generating means 15a built into receiver unit 20, and a similar discrete voltage signal or its digital representation appears in it or in them. The signal produced by pressure sensor 4b can be connected to the electronic unit in receiver unit 20 directly, via the 6 -16 contact pairs, but it is more advantageous to process and store in digital format the pressure signals sensed in key unit 10 after processing in key-side electronic unit 5.

After the insertion of key unit 10, the electronic units of the two sides are interconnected and transfer to each other the pieces of information stored in them. Preferably, instead of the simple recording and comparison of these pieces of information, a figure or other quantity representing the entire set is generated from the combined information as structured data set, and this figure is stored in both electronic units.

After the first step of certification or parameter setting, whenever key unit 10 is inserted into receiver unit 20, the same operations are carried out once again, and the match of the figure series or the representative quantity generated out of it is the precondition of the establishment of authorisation.

Contrary to the known solution, at this point there is not even a theoretical possibility for someone as unauthorised possessor of key unit 10 to copy the sender values carried by pressure generating means 4a of key unit 10 to get to the point of authorisation, since pressure sensors 4b in key unit 10 are passive components, and the correct value can only be obtained from them if key unit 10 is inserted into receiver unit 20, and pressure sensors 4b can receive and store the pressure signals of pressure generating means 15a which are in receiver unit 20 and are therefore hidden. If either key unit 10 or receiver unit 20 gets into unauthorised hands, that in itself will not be sufficient for someone to acquire information permitting unauthorised access. Consequently, the reliability of the system is considerably enhanced.

The number of pressure generating means and pressure sensors in key unit 10 and in receiver unit 20, respectively, has also been increased, and hence the number of possible combinations has multiplied as well. A possible way of the further enhancement of security is to shift the discrete sensing bands of the applied pressure sensors relative to one another by one or several discrete steps. This means that, if connected to the same pressure generating means as the first one, the second pressure sensor, thus designed to be of different sensitivity, would sense discrete signals which differ according to the extent of the shift. The forger, seeing several pressure sensors of identical structure, would expect that, connected to the same pressure generating means, the sensed output signal would also be identical, but this condition no longer prevails, and the correct result can only be learned if we know the pressure signals of all the pressure generating means, their order, and also the inten- tional shift order of the pressure sensors receiving the pressure signals. This cannot be learned via the usual copying techniques.

Security can be enhanced even further if the discrete series of digital signals triggered in the pressure sensors is transformed into a very high number not directly, but following the execution of a special function transformation then, upon certification, this number is entered into the memory of the electronic unit on both sides, and on the occasion of subsequent regular uses of key unit 10, we inspect whether the numbers entered into the two electronic units match.

Next, a possible example of the execution of the function transformation will be described.

In the exemplary case, the number of elements within component series 3 is eight. In the simplest case, it is irrelevant whether the individual components are pressure generating means 4 or pressure sensors 23, as measurement and assignment take place when body part 1 is inserted in key hole 13, and connection is established between contacts 6 and 16. In this case, the pressure value of each pressure generating means is measured by the pressure sensor facing it. Of course, even in the exemplary component number of eight, the number of components may be much higher if measurement and assignment take place during the insertion of body part 1, when several pressure generating means pass one after the other in front of each pressure sensor, which indicate the pressure signal of the same pressure generating means as different values due to the different de- fault setting (sensitivity) of the individual pressure sensors.

Now let us return to the simplified component number of eight and assume that the pressure signal measured by the assigned sensor at the individual components is n(i), where i indicates the serial number of the position within the component series.

Assignment is the result of the assignment of a clock signal independent of the pressure measurement or the current value of a random number generator expressed by a variable u(i) function is assigned to the numerical value of n(i). The assignment may be any mathematical operation; let us choose now one of the simplest: multiplication.

If, at the moment of the generation of each pressure value, this pressure value n(i) is multiplied by the current value of variable u(i), a total of 8 multiplications shall be made. The KK key code created thereby can be expressed mathematically as:

KK=∑ n(i). u(i) (1) As for the value range of key code KK, the following can be said about it, if E(n) indicates the number of pressure values which can be set and E (υ ) the value range of variable υ:

K n(i) < E (n), (2)

1 < υ (i) < E (υ ) (3) E(KK) = E (n) ⁸ · E (υ) ⁸ (4)

Let the number of adjustable pressure values E (n) = 8. Let us suppose, furthermore, that the random number generator is constituted by the instant numerical value of the clock generator taking one step per second, and the clock generators make exactly 1 daily cycle, that is, they have a total of E (υ ) = 86400 possible values. Assignment here means that every pressure value being measured is multiplied by the clock signal available at the time of the appearance of that value. The number of clock signal generators is identical to the number of components, that is, it is 8, and the initial time of each of the eight clock signal generators is independent of those of the others. The total E(KK) value range of the possible results is, on the basis of correlation (4), E '(KK) = 88 ^■ 864008 , which may take up approximately 10 ⁴⁷ values. This value range corresponds approximately to a code of 208 bits, which can be multiplied even by a relatively small increase of the value sets.

This assignment-based coding can be conceived of as if, during shopping, we calculated the price of the individual items by using automatic scales, and the resulting prices were added up by the cashier. For every item, we put on the scales the given cold meat or fruits, set the given unit price on the scales, depending on the nature of the item concerned, and the scales displays and prints in bar code the price of the item after multiplying the measured weight with the unit price which is different by item. At the cash desk, the prices of the eight items are added up. In our case, weight corresponds to the measured pressure value and the price to the clock generator value.

The execution of this operation requires but simple multiplication, easy to perform for the available microcontroller. The single figure provided as a result of the multiplication and the adding up is entered into the memories of both electronic unit 5 in key unit 10 and electronic unit in receiver unit 20. Subsequently, in the simplest case, it is no longer necessary to determine the pressure values when using key unit 10: when key unit 10 is inserted into receiver unit 20, it is sufficient to check whether the stored sums are identical. Of course, it is also possible to insert several keys into receiver unit 20, and these may have different stored values. For the purpose of identification, the memory of key unit 10 comprises an identifier code typical of key unit 10 and, upon utilisation, the sys- tem first performs a simple check of the identifier codes, and access is then based on the stored values selected after the identification of key unit 10 and receiver unit 20 assigned to one another.

A single key unit 10 may also be used with several reception units 20; the number of the possibilities is limited by the capacity of the memories alone.

The simplest case outlined above is not as secure as if authorisation were done through a repeated measurement. If, instead of the sum, the eight υ (i) values of the random number generators are entered into the memories, and the sum is calculated again upon the insertion of key unit 10, then one of the multipliers used for the calculation is a stored value and the other n (i) value is a measured one. Consequently, the outcome is the product of the measured and the stored values. Such arrangement provides higher security, because in vain does an unauthorised person read the value of the memory in key unit 10, he will have no free access based on that, since a repeated measurement must also be performed to obtain the final figure.

Of course, it is not necessary to increase security beyond all limits, since that would im- ply higher costs as well.

The advantage of the solution proposed by the invention is that both the measurement and the operations to be performed are simple; the processing and storing demand does not exceed the possibilities of simple microcontrollers. The result is nevertheless unbelievably good, since the value range is an astronomical figure, and the falsifier gets no possibility of merit through the incidental unauthorised reading of key unit 10, since it can be excluded that, in addition to key unit 10, he would also obtain access to the memory in receiver unit 20 and the characteristics of the pressure generating means- pressure sensor pairs.

The actual embodiment of the solution according to the invention can be chosen at discretion. Neither the realisation, form of key unit 10, nor the design, solution of receiver unit 20 has been fixed. Hence the system can be realised by any design and at any security level, from the use of simple locks and keys through apparatus authorising hotel or company access to those for safes.

That is, the invention shall not be limited to any of its applications or embodiments, but its essence is such a association of key unit 10 and receiver unit 20 as will satisfy the enhanced security conditions described above.