ZA200108643B - Key and lock device. - Google Patents

Description

KEY AND LOCK DEVICE

FIELD OF INVENTION

The present invention relates generally to key and lock devices, and more specifically to an electro-mechanical key and lock device and a key device.

BACKGROUND

It is previously known a variety of lock devices that use electronic devices for increasing the security of the lock and for providing effective administration, management, and control of keys and personnel. However, the demand for lock systems with a high level of secu- rity and at the same time being easy to administer is constantly increasing.

The UK patent application GB 2 309 046 discloses a lock - that sends a random number to a key, which applies a crypto algorithm to the random number and sends a code word back to the lock. In the lock, the code word is ©. compared with a desired code word, which is generated ’ 20 by applying the same crypto algorithm to the random number. An authentication signal is then generated so long as the code word and the desired code word are substantially but not necessarily completely in agree- ment. The described key and lock system has several limitations and drawbacks. The communication between lock and key is wireless, introducing noise in the transmitted information. Therefore, the level of secu- rity is decreased as a certain degree of mismatch be- tween the results calculated in the lock and the key must be allowed. This might be allowed in a car lock application, as is the case here, but not in normal lock applications. Furthermore, the key is limited to the use with one single lock, thus making the system unusable in a master key system.

The European patent application EP 0 816 600 discloses a single key system comprising a lock, keys and a codi- fier. The lock includes an electronic circuit which stores an access code and identification codes for the keys with specific restrictions. The keys include elec- tronic circuits that store the access codes for one or several keys. However, one drawback with the described single key system is that it is possible to read out or intercept data, lowering the level of security.

SUMMARY OF THE INVENTION

. An object of the present invention is to provide an electro-mechanical lock device of the kind initially mentioned wherein the user will not see any difference to the use of a traditional all mechanical lock. :

Another object of the invention is to provide a lock ’ device that is more secure and reliable than known a locks. :

Another object is to provide a lock device wherein the assignment of keys is facilitated.

Another object is to provide for easy adding or delet- ing of authorisation of access to the operation of a cylinder by the key.

Another object is to provide an electro-mechanical lock device with a reliable transmission of data and power between the key and cylinder and with a short time delay for operation of the cylinder.

Still another object is to provide a lock device that enables easy replacement and upgrading from mechanical to electromechanical lock of an existing lock device.

Another object is to provide a lock device wherein the key system is not limited by mechanical restrictions.

The invention is based on the realisation that no secret codes are exchanged between a key and a lock but instead a random number generating the necessary information for determining whether a key is author- ised. This random number is used together with lock or key identifications in order tc achieve a lock and key combination with improved characteristics.

Thus, according to the invention there is provided a key and lock device as defined in claim 1. i 15 According to the invention there is also provided a key device as defined in claim 19.

Further preferred embodiments are defined in the .- , dependent claims,

The invention provides a key and lock device and a key device by means of which at least some of the above problems with prior art are overcome or at least mitigated.

BRIEF DESCRIPTION OF DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is an overall view of a lock and a key according to the invention;

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FIG. 2a is a side view of a first embodiment of a key according to the invention;

FIG. 2b is a side view of a second embodiment of a key according to the invention;

FIG. 3 is a block diagram of the electronic circuitry of the key and lock device according to the invention;

FIGS. 4a and 4b are an overview of electronic information elements of a key and a lock, respectively;

FIG. 5 is a flow chart describing an embodiment of the inventive authentication prccess, and

FIG. 6 is a flow chart describing an alternative embodiment of the inventive authentication process.

DETAILED DESCRIPTICN OF THE INVENTION :

In the following a detailed description of the inven- tion will be given. In FIG. 1, a key 10 and a lock 20 } are shown. Both these main parts are shaped like known : -» devices, This means that a user familiar with conven- ] tional locks will not experience any difficulties using the lock according to the invention. This also means that an existing conventional lock cylinder can be replaced by the lock cylinder shown in FIG. 1. Thus, an upgrading of the conventional, all mechanical lock can take place without encountering any problems.

Preferably, the lock is a “plug and play” cylinder or a “stand alone” cylinder with the possibility to accept keys with the right mechanical and electrical code.

One feature of the lock is that it can exclude keys from a lock electrically. A correct key can rotate the plug as long as it is fully inserted and in both direc- tions as given by the lock case or latch to which the cylinder is attached. Once the key is removed, a new authorisation cycle starts when a key is inserted - 5 again.

The lock cylinder is made up of a housing 21 and a core or plug 22 provided in a bore in the housing 21, as is conventional. The cylinder also comprises conventional mechanical blocking elements (nct shown). An electrical blocking means and an actuator 40 (shown in FIG. 3) are provided in the plug 22, wherein the function oI the actuator is to control the blocking means. The function of the mechanical and electrical blocking means is to block the operation of the lock should an inserted key present an incorrect mechanical and/or electrical code. : Thus, the particular user will not see any difference

Co to the use of a traditional mechanical key. He or she : inserts his/her key and turns until the lock latch or ) deadbolt is retracted (or moved to a locked position). . 20 The only difference is that there may be a display or other indication on the key that references the power left in the battery to indicate if the battery has been discharged to a level that desires replacement.

The type of mechanical blocking element could be any conventional element, such as a pin, sidebar, ball, and disc or by means of free rotation of the cylinder plug.

Thé default locking position is always locked (closed).

This ensures that there will be no free passage for an unauthorised person in case of e.g. electric failure.

The locked position should be mechanically ensured when the key is removed from the cylinder or when it is re- turned to insertion position for a disc cylinder.

The key 10 comprises a grip part 11 and a bit or blade part 12, see FIG. 2a. The grip 11 comprises a battery 13 and electronic circuitry 14 comprising a micro- processor chip with associated memcry etc., the func- tion of which will be described later with reference to

FIG. 3. The bit part 12 is provided at its outer end with a connector 15 adapted to co-operate with a con- nector in the lock 20. The electronic circuitry is powered by the battery 13, indicated with an inter- connecting line in FIG. 2a, and is also connected to the connector 15.

An alternative embodiment of the key according to the invention is disclosed in FIG. 2b. Therein, the connec- © tor 15 is located on the edge of the grip part 11 to co-operate with a connector on the face of the lock 20. )

In all other aspects, the connector 15 in FIG. 2b func- . tions as the one in fig 2a. )

The battery 13 provided in the key 10 is any one of ) conventional type available in stores selling cameras and/or watches, in drugstores etc. The battery is held in place by means of a conventional battery holder. In that way, it is easy to replace a used battery. The only tool needed is a coin or the like. In an alterna- tive embodiment, a seal or a high level secure opening is used, where this is preferred.

Replacing the battery will not erase data or affect functions. A clock will, however, need to be set after a battery change. This clock setting is effected by means of e.g. insertion into a key programming unit.

When the battery is almost discharged, the user is no- tified that a battery change is necessary. This is done by means of e.g. an LCD display, a buzzer, or an in- creasing number of unblocking failures. Chip tempera-

S ture is used to compensate for decreasing voltage and avoid early battery warning.

The unblocking penalty starts when the electronics de- tect a too low voltage level at normal temperature. The key will just open every second attempt and succes- sively more seldom. In that way, the user is alerted of the fact, that it is time to replace the battery.

Electronics

The electronic circuitry of the key 10 and the lock 20 will be described in detail in the following.

The electronics are well protected against any form of manipulation, illegal reading or change of information. : To this end, precautions have been made to safeguard and isolate all electrical modules from external mani- . pulations, handling, and environmental hazards. For example, the microprocessor has been designed with measures to protect the integrity of the memory on the chip.

The electronics of the key 10 will now be described with reference to FIGS. 2a, 2b and 3.

From FIG. 3 is seen that the key electronics includes a microprocessor 16 and associated memory 17 and 18 and an analogue circuit 19. The battery 13 is connected to the microprocessor 16. However, it is also connected to the connector 15, whereby power from the battery in the key can be transferred to the lock electronics.

The microprocessor 16 can be of any conventional type.

However, it is preferred that it is a custom-made circuit incorporating the parts necessary to perform the important algorithms discussed below. Also, this further increases the speed by which the authentication procedure is performed, preventing unwanted delays when operating the lock. This encryption algorithm can be implemented totally or partially hardware or software within the microprocessor 16.

There is an analogue part 19 in the key electronics, which acts as an interface to the digital electronics.

A corresponding analogue part 29 is provided in the lock, see below. In the lock, the analogue part 29 functions as an interface to the actuator 40. 15. The analogue parts also perform various additional tasks, such as to detect that a key is in contact with a lock. They also perform a very important security task; they protect the electronics and the actuator - against manipulation/opening of the lock or key by ) electronic attacks, such as high voltage, current, . repetitive codes trials, etc. This protection can be archived by a destruction of the analogue part in the key and/or lock and thus guarantees that the actuator does not enter the non-blocking position.

FIG. 3 also shows the memories 17, 18 connected to the microprocessor. The function of the first memory 17 in the key is to store data regarding key ID, lock ID, etc., see below. The second memory 18 is a tamper proof memory protected against external physical attempts to read its content. In that memory 18, all secret information elements, e.g. codes for encryption, are stored. The software could also be stored therein for better security.

For security reasons, all important data that are in the memories 17, 18 are encrypted using the algorithms discussed below. Thus, the data is difficult to inter- pret in the unlikely case that an unauthorised person has been able to read out the memory contents.

The electronics of the lock 20 is almost identical to that of the key 10 with the exception that there is no battery in the lock and, optionally, there is addi- tional actuator driver circuitry (not shown). There is the connector 25 adapted to co-operate with the connector 15 in order to enable transfer of power and data between the key 10 and the lock 20. The contact point between the connectors 15, 25 is thus used for transfer of both power and data. The key material, being of a suitable metal, serves as ground. The : connector 25 is connected to the microprocessor 26 with associated memories 27, 28. The hardware of the ; 20 microprocessor 26 is identical to that of the microprocessor 16. Thereby, cost savings are achieved and the key and the lock electronics will be easier to program.

One advantage with the key and lock device according to the invention is thus that corresponding chips can be used for key and lock. The microprocessor can operate in different modes, with and without connection to a battery, with and without continuous power, as lock or key, controlling an actuator or not etc, thus reducing costs. In that way, a battery can be provided in the key, in the cylinder or both in the key and in the cylinder.

The electronics refuses entry to everybody if the memories have been tampered with. To restore the status a system key is used together with programming software to reinstall the keys in the cylinder. Status can then be checked with a test box.

The standard function of the actuator is to electri- cally unblock (open) the blocking mechanism and to mechanically reblock (close) the mechanism when the key is retracted. Reblocking the mechanism may also be per- formed when the plug is rotated back to the locked po- sition of the cylinder. The electronics can also be used to electrically reblock the.blocking mechanism if so desired.

Information Elements

All keys and locks have a unique electronic identity or code comprising several information elements control- ling the function of the keys and the locks. The infor- mation elements of a key or a lock will now be de- . scribed with reference to FIG. 4a and 4b, respectively.

The electronic code is divided into different segments for the use of manufacturers, distributors and custom- ers. Some public elements are common for devices of a master key system while a secret segment is provided for secret information.

For the present invention, every electronic key code comprises the following relevant parts, see FIG. 4a: e¢ Public Key ID (PKID) » Secret Key ID (SKID) es Encryption Key (Kpgs)

Correspondingly, every electronic lock code comprises the following parts, see FIG. 4b: e¢ Public Lock ID (PLID) e Secret Lock ID (SLID) e Encryption Key (Kpgs)

The basic elements will now be described in more de- tail.

PKID/PLID - Public Key/lock Identit

PKID/PLID uniquely identifies a device in a master key system. As the name indicates, this information is pub- lic, i.e., there are no extra security measures taken to prevent someone from reading this information.

SKID/SLID - Secret Key/Lock Identit

The secret identity of a device is a randomly generated : number that, in the preferred embodiment, is the same for one group of devices. As the name indicates, this . information is hidden from the cutside, i.e., is non- readable information used internally of a device.

Kpes — Encryption Key

The Kpes comprises a randomly generated encryption key.

In the preferred embodiment, the DES encryption algo- rithm is used, partly because its speed, and preferably the Triple DES (3DES).

In the preferred embodiment, Kpes is identical in all devices of a master key system.

Kops 1s in no way readable from the outside and is used by the algorithms executed internally of the key and lock devices. This is a very important feature as it eliminates the possibility to copy a key just by read- ing the contents of its memory.

Kpes can used in the authorisation processes taking place between different devices, as in the embodiment described with reference to FIG. 6. Thus, for a key to be able to operate a lock, both the key and the lock must have the same Kpgs. Otherwise, the authorisation process will fail, as will be described in more detail below. :

Authorisation table

In every lock there is an authorisation table stored in N electronic memory. The authorisation table determines which keys are accepted by the lock in question. The configuration and function will now be discussed. ’ 15 In its basic form, the authorisation table simply lists keys authorised in the lock in question, see FIG. 5 under the heading “LOCK”. Thus, for initiating an . authentication procedure, the PKID of a key inserted in ’ the lock must be in the list of authorised keys. A key } is listed by its unique identity, which is determined by the PKID, as already has been explained.

As already stated, when a key is listed in the authori- sation table, the corresponding secret key identity

SKID for the key in question is stored, too. In the preferred embodiment, the SKID is the same for all keys of one group of keys and is used for security reasons.

It is not possible to read the SKID from the keys or locks without having fulfilled special authentication procedures by means of a system key.

Authentication procedure

In applications, where an authorisation table is being stored in the cylinder memory to control access privileges at the door, an identification or authentication procedure is performed. A first, basic procedure will be explained below with reference to

FIG. 5, in which steps performed in the key electronics 14 are displayed to the left and steps performed in the lock electronics 24 are displayed to the right. Before the authentication procedure is initiated, the key 10 in question is inserted inte the lock 20.

In the present example, the PKID of the inserted key is “1234” and the SKID is “0017”. The PLID is “9876”. The authorised keys list of the lock contains PLID and SLID for all authorised keys, i.e., PKID 1 and SKID 1 for a first key, PKID_2 and SKID 2 for a second key etc. In the example, data for the first key corresponds to the data for the inserted key.

First, in step 100, the PKID is retrieved from the key . 20 memory 17 and is transmitted to the lock electronics 24. In the present case, the information “1234” is transmitted, which is public information. This informa- tion is received and processed by the lock electronics 24 in step 200, looking through the authorisation table to find out whether the received PKID matches any of the entries in the table. The received PKID matches

PKID 1 and the authentication procedure can thus pro- ceed to step 210.

In step 210, the lock electronics generates a random word RND, in the present example “4711”. This random word is transmitted to the key electronics in step 220, wherein it is received and processed, step 110. Both the key and the lock electronics now have knowledge of

RND and SKID.

In the following steps, 120 for the key and 230 for the lock, code words CODE_KEY and CODE_LOCK, respectively, are calculated. In this simplified example, the code words are calculated as functions of RND and SKID and more specifically as a simple addition of RND and SKID. - This gives the following calculation:

RND 4711

SKID 0017 code-word 4728

In step 130, the key electronics sends its calculated ~ code word CODE KEY, “4728”, to the lock, which in step 240 receives and processes the information. In the lock electronics, CODE_KEY and CODE_LOCK are then compared : in step 250. If CODE_KEY and CODE_LOCK are identical, : the authentication procedure is successfully ended and the actuator 40 is moved to a non-blocking position.

Thus, the microprocessors 16 and 26 in the key and the ) lock, respectively, have a respective code and algorithm. When the random number is communicated from the lock to the key, a calculation is started in the respective microprocessor 16 and 26. The results of the calculations are compared and if they are identical, the electrical blocking mechanism is enabled by means of the actuator 40.

Thus, the key and lock functions can be expressed in the following way:

Key function (random number, secret) = result (key)

Lock function (random number, secret) = result (cylin- der)

If result (key) = result (cylinder) then OK!

In an alternative embodiment of the authentication pro- cedure according to the invention, the above-mentioned encryption key Kpgs is introduced. The introduction of

Kpes adds a further level of security. This alternative embodiment will now be described with reference to FIG. 6, in which the steps are numbered as in FIG. 5 but with an additional prime sign.

When the code word CODE_KEY has been generated by the key, this is encrypted, see step 130’. In this encryp- tion, a combination of Kpes, SKID, and RND are used for the encryption. This provides for a more safe transfer of information between key 10 and lock 20. After having : been transferred from the key 10 to the lock 20, the } encrypted CODE_KEY is decrypted, using the information . Koes, SKID_1, and RND stored in the lock, and the comparison proceeds as in the first embodiment in steps 250’ and 260’.

Further features can be added to the procedures de- scribed above with reference to FIGS. 5 and 6. For example, in step 220, also the PLID can be sent to- gether with RND. This added information can be used in more than one way. Firstly, it could be used for up- dating an audit trail in the key, i.e., for creating a list of all locks in which the key has been used. Also, there can be a list in the key memory stating all locks with which the key can be used. In case the PKID is not found in that list in the key memory, the authentica- tion prccedure is aborted in step 110.

In the described examples, the random number RND has been calculated by the lock electronics. However, it is realised that this calculation also can be performed by the key electronics.

In the described examples, SKID and RND have been used as variables when calculating the code words. It is realised that other information item can be used as well. For example, a list of authorised locks can be stored in the key, with PLID and SLID information items stored in this list. Instead of or additionally to . using the SKID for calculating the code words, the SLID can be used. This could be particularly convenient in a system of industry locks, in which there are many locks ~ but few keys.

The described algorithm for calculating the code words has for the sake of clarity and easy understanding been kept unrealistic simple. It is realised that a far more advanced algorithm will be used in practice. :

It has been stated that the entire information elements are used for e.g. calculation of the code words. It is realised that also a part of an information element can be used without sacrificing security. On the contrary, if only a part of e.g. a secret identification is used, this could in fact increase the level of security, should a fraudulent person come across the secret identification.

Thanks to the inherent security of a key and lock de- vice according to the invention, any successful attack requires very costly equipment used by very skilled and knowledgeable people. Any such successful attack has no negative influence on the use of systems other than the one under attack. The system is replaced with a new system or is totally reprogrammed, requiring the same effort for a new successful attack. To ensure such security dual identification/authentication in communi- cation between key and cylinder is provided. In addi- tion, a true random generator can be used further to increase security.

Preferred embodiments of the invention have been de- scribed above. The person skilled in the art realises that the key and lock device according to the invention can be varied without departing from the scope of the invention as defined in the claims. Thus, it should be understood that the memories 17, 18 and 27, 28 and/or the analogue parts 19, 29 could be integrated with the respective processor 16 and 26 or be separate chips, depending on the security requirements etc.

A single battery 13 has been shown in the key. However, with a battery provided in both the key and the lock, there is no need to transfer power via the connectors ’ 20 15, 25.

Claims (21)

PCT/SE00/00899 CLAIMS:

1. A key and lock device having a key and a lock, comprising: - a first device having - a first electronic processor, - a first memory connected to said first electronic processor, and - a first connector connected to said first electronic processor, - a second device having - a second electronic processor, - a second memory connected to said second electronic circuit, and - a second connector connected to said second electronic processor and adapted to mechanically co-operate with said first connector when said key is inserted in the lock so as to transfer information between said key and lock, and - a power source, - a mechanical blocking mechanism, and - an electrical blocking mechanism adapted to block operation of the lock when an unauthorised key is inserted in the lock. characterised in that : - said first memory is adapted for storing a public identity (PKID;PLID) and a secret identity AMENDED SHEET

PCT/SE00/00899 (SKID; SLID), - said second memory is adapted for storing a public : identity (PKID_ 1;PLID_1) and a secret identity (SKID_1;SLID_1) for authorised first devices, - said first electronic processor is arranged to identify itself to said second electronic processor by said public identity (PKID;PLID), and - said first and second electronic processors are arranged to exchange a random number (RND) and to calculate a respective code word (CODE_KEY, CODE_ LOCK) using at least a part of said secret identity (SKID; SLID) and at least a part of said random number (RND), - wherein said electrical blocking mechanism is brought to a non-blocking position if said code words calculated in said first and second . electronic circuits, respectively, are identical.

2. The key and lock device according to claim 1, . wherein said first device is a key and said second device is a lock.

3. The key and lock device according to claim 1, wherein said first device is a lock and said second device is a key.

4. The key and lock device according to claim 1, wherein said first and second electronic processors are arranged to encrypt said code word (CODE_KEY,CODE_LOCK) before communication thereof.

:

5. The key and lock device according to claim 4, wherein said code word (CODE_KEY,CODE_LOCK) is encrypted AMENDED SHEET

PCT/SE00/00899 ‘by means of at least a part of a DES encryption key (*pes) -

6. The key and lock device according to claim 4, wherein said code word (CODE_KEY,CODE_LOCK) is encrypted by means of at least a part of said secret identity (SKID, SLID) .

7. The key and lock device according to claim 4, wherein said code word (CODE_KEY, CODE_LOCK) is encrypted by means of at least a part of said random number (RND).

8. The key and lock device according to claim 4, wherein there is no operation for reading of secret information (Xpgg) .

9. The key and lock device according to claim 1, wherein said first and second electronic processors are identical regarding their hardware design.

10. The key and lock device according to claim 1, comprising at lest one tamper proof memory.

11. The key and lock device according to claim 10, wherein said secret identity (SKID,SLID) is stored in a / tamper proof memory.

12. The key and lock device according to claim 2, wherein said first connector is provided at the end of the key bit of the key.

13. The key and lock device according to claim 2, wherein said first connector is provided on an edge of a grip part of the key to cooperate with a connector on an outer surface of the lock.

14. The key and lock device according to claim 1, AMENDED SHEET

PCT/SE00/00899 wherein the key is operable successively more seldom when a change of power source is necessary.

15. The key and lock device according to claim 1, wherein a seal or a high level secure opening is used for the power source.

16. The key and lock device according to claim 1, : wherein the power source, such as a battery, is provided in the key.

17. The key and lock device according to claim 1, wherein the power source, such as a battery, is provided : in the lock.

18. The key and lock device according to claim 1, wherein said first and second connectors are adapted for transferring electrical power.

19. A key device comprising: - a first electronic processor, - a first memory connected to said first electronic processor, : - a first connector connected to said first electronic processor, characterised in that - © said first memory is adapted for storing a public identity (PKID) and a secret identity (SKID), - said first electronic processor is arranged to identify itself to a second electronic processor of a lock by said public identity (PKID), and - said first electronic processor is arranged to AMENDED SHEET

PCT/SE00/00899 receive a random number (RND) and to calculate a code word (CODE_KEY, CODE_LOCK) using at least a part of said secret identity (SKID;SLID) and at least a part of said random number (RND), - wherein an electrical blocking mechanism of said lock is brought to a non-blocking position if the code word calculated in said first and second electronic circuits, respectively, are identical.

20. A device according to claim 1 or claim 19, substantially a herein described and illustrated.

21. A new device, substantially as herein described. AMENDED SHEET