GB2118614A

GB2118614A - Method of code changing for electronic lock

Info

Publication number: GB2118614A
Application number: GB08306602A
Authority: GB
Inventors: Leonard Joseph Genest
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-04-16
Filing date: 1983-03-10
Publication date: 1983-11-02
Also published as: GB8306602D0; FR2525268A1; BE896489A; DE3313609A1; AU1323083A

Abstract

A combination changing method is used in an access control system which includes one or more keys encoded at a central console with a function code, a key identification code, a modifier code and a key combination code and one or more locks having at least one memory level in which a lock identification code and a lock combination code are stored. A key is initially inserted into a selected lock and the data from the key transferred to the lock. The lock identification code is first compared with the key identification code. If there is no correspondence, power to the lock is turned off. If the identification codes correspond, the key combination code is compared with the lock combination code. If the combination codes correspond, the lock opens. If the identification codes correspond but the combination codes do not, the modifier code and the lock combination code are combined according to a predefined set of logical and/or arithmetic operations to generate a computed combination code which is compared with the key combination code. If the comparison is successful, the computed combination code is stored in the lock in place of the lock combination code and the lock opens <IMAGE>

Description

SPECIFICATION Method of code changing for lock system This invention relates to methods of operating a security system and more particularly to a method for opening and changing the combination of specific security devices in the security system.

Numerous electronic security lock systems have been developed wherein specific locks are operable in response to a key coded with combination information. Such coded keys are inserted into a lock which reads and compares that information with prestored combination information in the lock. If correspondence exists, then the lock opens.

However, in order to change a lock combination, the individual lock combinations in each door must be reset manually by changing switches or electrical connections before a new coded key will operate the lock.

Several different approaches have been tried.

For example, in one type of electronic lock system, a central console is electrically connected to each of the individual door locks. The central control unit is then used to remotely set and change the individual lock combinations as well as to sense the combination code on a key inserted into the lock. However, such systems are vulnerable to system failure since a failure of the central console will cause all of the locks to become inoperable.

Furthermore, such systems require that each individual lock be electrically wired to the central control unit resulting in greatly increased expense particularly when retrofitting older buildings.

In another type of electronic lock system, the combination of the lock can be changed or otherwise replaced by data on the coded key inserted into the lock. For example, in Hinman et al. Patent No. 3,860,911 a coded key actuated automatic code changing system is described whereby each lock unit includes a key decoder with a functionally assigned pair of registers containing prestored combination codes The first register of the pair stores the current combination code. The other register of the pair stores the next or change combination code. When a key coded with both the current and the change combinations is inserted, the current combination carried by the key is compared with the data stored in each register. If a comparison is made with the first register or the second register an appropriate access enable signal is provided.In addition, if a comparison is made with the second register the change combination code in the second register is transferred to the first register thus becoming the current combination code. A similar code changing system is disclosed in Zucker et al. Patent No. 3,800,284.

Still another code changing system is disclosed in Sabsay Patent No. 3,821,704 wherein the key includes a key combination and an authorization code and each lock has stored therein a combination code. If the key combination' corresponds to the combination code in the lock, then the lock opens. However, if the key combination does not correspond to the combination code stored in the lock the authorization code from the key is compared with the combination code from the lock. If correspondence occurs then the key combination is transferred to the lock and stored in place of the previously stored combination code.

Yet another combination changing system is disclosed in Genest et al. Patent No. 4,213,1 18 wherein each code combination stored in a lock has a first and second field and each key card contains a code combination having a first and second field. When the key is inserted into the lock the initial field of the stored combination code and the combination code from the key are compared and the lock opens if correspondence exists. If correspondence does not exist then the second field of the stored combination code and the first field of the key combination code are compared. If there is correspondence at this stage an appropriate signal is generated to store the two fields of the key combination code in the lock memory in place of the two fields of the stored combination code thereby updating the combination of the lock.

By contrast to each of the above systems, the locks in the present system actually compute a new combination code using data from both the key card and from the lock. If the computed combination code corresponds to a combination code on the key then that lock combination code is updated and replaced by the computed combination code. Increased security is provided because the key contains no information regarding the way in which the data from the key and the data from the lock are combined to generate the computed combination code. As such, it would be extremely difficult if not impossible for an unauthorized user to read the data from the key card, analyze that data, and be able to derive the computed combination code for a particular lock.

Furthermore, unlike the systems disclosed in Genest and Sabsay, the memory level from which data is obtained for comparison with the data on the key card is selected based upon additional independent data stored on the key. Thus, testing for correspondence does not sequence through each memory level in the lock thereby increasing the possibility of an unauthorized opening.

Summary of the Invention A method of operating an electronic security lock device having a multilevel memory comprises the steps of first storing a lock identification code and a lock combination code in each -memory level of the multilevel memory in the security device.

Next, a function code, a key identificåtion code, a key combination code and a modifier code are applied to the security device from an external source such as a coded key. The security device then senses the value of the function code and based thereon selects one of the memory levels having stored therein a lock identification code and a lock combination code. The selected lock identification code and the key identification code are then initially compared and a first compare signal generated if the selected lock identification code and the key identification code correspond. If a first compare signal is not generated the power to the security device is turned off. If a first compare signal is generated the selected lock combination code is compared against the combination code from the key.A second compare signal is generated if the selected lock combination compares with the key combination code. The security device is opened if the second compare signal is generated. If a second compare signal is not generated, however, a computed combination code is generated from the modifier code of the key and the selected lock combination code according to a predefined operation set. A computed combination code is therefore generated only if a first compare signal is generated and a second compare signal is not generated.

The computed combination code is then compared with the key combination code and a third compare signal generated if the key combination code corresponds to the computed combination code. Upon occurrence of the third compare signal the computed combination code is stored in the multilevel memory in place of the selected lock combination code and the security device is open.

The operation set may comprise one or more arithmetic operations, one or more logical operations, or a combination of both arithmetic and logical operations whereby the modifier code and the selected lock combination code are combined.

Brief Description of the Drawings A complete understanding of the present invention and of the above and other advantages thereof may be gained from a consideration of the following description of the preferred embodiments taken in conjunction with the accompanying drawings in which: Figure 1 is a simplified block diagram of a security system in connection with which the method of the present invention may be used.

Figure 2 is a functional block diagram of a security device interconnected to operate in accordance with the method of the present invention.

Figure 3 is an illustration of the data word coded on the key and read into the security device of Figure 2.

Figure 4 is a simplified flow chart illustrative of the method in accordance with the invention.

Detailed Description The present invention is a method for changing the lock combination of one or more locks for securing limited access areas such as the rooms in a hotel. in general, each limited access area will have a lock which are operable in response to a coded key electronically read by the lock. Data from the coded key is compared with data stored in the lock and a decision made as to whether the lock should be opened or not. Electronic lock systems which are particularly adaptable to the use of the method of the present invention include the systems disclosed in U.S. Patent No.

3,926,021, U.S. Patent No. 4,213,1 18 and U.S.

Patent No. 4,283,710.

Systems in connection with which the method of the present invention will be usefui may be represented as shown in Figure 1. Specifically, such systems include a central console 10 which generates and stores all of the combination codes, identification codes, function codes and modifier codes required for each of a plurality of locks 12.

Each lock 1 2 stores an identification code and a code combination for each of a plurality of memory levels in the lock. The central console transfers the required data for a selected lock to a coded key 14 such as a key card or other electronic storage device which is given into the possession of the individual or individuals authorized to have access to a limited access area secured by one of the locks 12. The coded keys 14 may be encoded in any of a number of different ways either by the central console 10 or by some external coding mechanism which cooperates with the central console 10 so that the data stored on a coded key 14 for a particular lock 12 will correspond to the data stored in the central console 10 for that particular lock 12.

Referring to Figure 2, the operational elements and interconnections required to enable the electronic lock to operate in accordance with the method of the invention is illustrated. Each such lock 12 includes a key reader 20, an electronic processor unit 22 coupled to receive data from the key reader 20, and a lock bolt assembly 24 which is operable to mechanically move a bolt to allow accessing to an area secured by the lock bolt assembly 24. Although the electronic processor 22 will preferably be a programmed general purpose processing unit having the necessary memory and processing logic, various functional blocks have been illustrated in Figure 2 to facilitate explanation of the method in accordance with the invention.

Each lock 12 is provided with one or more memory levels each for storing an identification code and combination code. Each memory level represents a different level of access for that particular lock. For example, the level 0 identification code and combination code may be common to all locks in a hotel so that data on a coced key which corresponds to the identification code and combination code data stored in the level 0 memories will open any lock in the hotel.

Similarly, the identification code and the combination code stored in the next level may be common to a group of rooms so that a key card with data corresponding to the data in a second level of memory will open any of the rooms in that group. Still another level of memory in the lock may contain an identification code and a combination code which is unique to that lock. A key card with corresponding identification code and combination code data will therefore open only one lock in the hotel.

Of course, each lock may have any number of memory levels where each memory level contains data which if matched by the data from a coded key will enable the lock to open.

Turning again to Figure 2, the operation of the method in accordance with the invention may be described as follows: Initially, an identification code and a combination code is stored in each level of the memory of the processor 22 with corresponding data being stored in the central console. For example, a level 0 identification code is stored in a memory 50 and a level 0 combination code is stored in a memory 52, a level 1 identification code is stored in a memory 54 and a level 1 combination code is stored in a memory 56 and so forth with the level N identification code stored in a memory 58 and the level N combination code stored in a memory 60.

When a coded key 14 is inserted into the lock, a key reader 20 reads the data from the coded key 14 and transfers that data to a suitable holding register 62. The particular key reader and the coded key may be an optical, magnetic, electronic or mechanical system without departing from the spirit of the invention. Such card reading systems are well known and will therefore not be further described herein.

Control logic and timing 64 is coupled either to the holding register 62 or the reader 20 to sense when the key reader has completed reading the coded key 14 and transferring the data to the holding register 62. The control logic ar'd timing 64 then receives the function code data from the holding register and based upon that function code, selects the particular memory level from which the lock identification code and the lock combination code will be obtained for comparison with the key identification code and key combination code stored in the holding register 62. For example, if the function code has a value of one, then the control logic and timing 64 may be programmed to select or otherwise address the level 0 identification and combination codes.On the other hand, if the function code has a value of two, then the control logic and timing 64 may be programmed to select or otherwise address the level 1 identification and combination codes.

Other values of the function code will similarly cause the control logic and timing 64 to address other memory levels for comparison with the key identification code and key combination code data stored in the holding register 62.

After a particular memory level has been selected, the control logic and timing 64 enables the lock identification code from that memory level to be transferred to an identification code comparator 66 where it is compared with the key identification code from the holding register 62. If the selected lock identification code corresponds to the key identification code a first compare signal is generated and sensed by the control logic and timing 64. If a compare signal is not received by the control logic and timing 64 or if the compare signal which is received indicates a lack of correspondence between the selected lock identification code and the key identification code, the control logic and timing 64 will power down the lock 12 for a period of time.

On the other hand, if there is correspondence between the selected lock identification code and the key identification code the control logic and timing 64 will transfer the lock combination code from the same selected memory level to a combination code comparator 68 where it is compared with the key combination code from the holding register 62. If the selected lock combination code corresponds to the key combination code then a second compare signal will be generated and sensed by the control logic and timing 64 whereupon an open signal will be transferred to the lock bolt assembly 24 enabling the lock bolt assembly 24 to open.If the second compare signal is not generated the control logic and timing will generate a signal which enables transfer of the modifier code from the holding register 62 and the transfer of the selected lock combination code to an operator logic and memory 70.

The operator logic and memory 70 is programmed to perform any of a number of arithmetic or logical operations on the selected lock combination code and the modifier code to generate a new or computed combination code.

For example, the new or computed combination code could be simply the sum of the modifier code and the selected lock combination code. The computed combination code is then transferred to the combination code comparator 68 where it is compared with the key combination code from the holding register 62. If the computed combination code corresponds to the key combination code a compare signal is sent to the control logic and timing 64 which then causes the computed combination code to be transferred to the selected memory level and replaces the selected lock combination code with the computed combination code. In addition, the control logic and timing 64 enables the lock bolt assembly 24 to open.

By way of specific illustration, if the function code read from the coded key 1 4 is a one, then the control logic and timing 64 enables the lock identification code from the level 0 memory 50 to be transferred to the identification code comparator 66. The control logic and timing 64 also enables the key identification code from the holding register 62 to be transferred to the identification code comparator 66. If the two identification codes are found to correspond, the control logic and timing 64 enables the lock combination code from the level 0 memory 52 to be transferred to the combination code comparator 68 and further enables the key combination code from the holding register 62 to be transferred to the combination code comparator 68.

If the two compared combination codes corresponded, then the control logic and timing sends a signal to the lock bolt assembly 24 enabling the lock bolt assembly 24 to open. If correspondence between the two compared combination codes did not exist then the control logic and timing 64 enables the transfer of the modifier code and the lock combination code from the level 0 member 52 to the operator logic and memory 70. The level 0 combination code and the modifier code are combined according to a predefined set of arithmetic and/or logical operations to generate a computed combination code. The computed combination code is then compared with the key combination code in the combination code comparator 60 as previously described. If correspondence occurs then the computed combination code is stored in the level 0 combination code memory and the lock bolt is opened.

It will be appreciated, of course, that the modifier code must be computed by the central console prior to being stored on the coded key 14 to assure that a correspondence will occur when the computed combination code is compared with the key combination code in the combination code comparator 68. By way of illustration, when it is desired to generate a new combination code for a particular level in a particular lock, the central console will first randomly generate a new combination code. The console then combines the existing combination code of the lock (which is also stored in the central console) and the newly generated combination code according to a predefined set of arithmetic and logical operations. The result will be the modifier code.

The new combination code and the modifier code are then stored on the coded key. the coded key may then be inserted in the key reader and the data transferred to the holding register 62 as previously described. The operator logic and memory 70 in the lock Will be coded to reverse the arithmetic and logical operations performed by the central console when generating the modifier code. The computed code will therefore correspond to the new combination code generated by the central console.

By way of specific illustration, if the operation performed by the operator logic in memory 70 is an addition of the selected lock combination code and the key combination code then the operation performed by the central console to generate the modifier code will be a subtraction. Thus; the central console will first generate in a random way a new combination code. The new combination code is then subtracted from the lock combination code stored in the selected memory level of the selected lock to obtain the modifier code. The modifier code and the newly generated combination code are then stored on the coded key. When the new combination code and the modifier codes stored on the key are transferred to the appropriate lock, the operator logic and memory 70 of that lock will add the modifier code to the existing combination code memory to yield a computed combination code.If the selected lock combination code is equivalent to the previously stored lock combination code in the central console, then the resultant computed combination code will be equal to the key combination code.

Thereafter, by storing the computed combination code in the selected memory level of the lock, the code combination for that level and hence the lock is changed.

Referring to Figure 4, a flow chart of the abovedescribed method is illustrated. Specifically, the lock is turned on upon the insertion of a coded key into the lock's reader (block 80). Thereafter, the function code, identification code, combination code and modifier code are read from the coded key and stored in the holding register as illustrated in block 82. The particular memory level is then selected based upon the function code in block 84. The lock processor then compares the identification code from the selected memory level of the lock with the identification code from the coded key. If correspondence does not exist, then the lock power is turned off. If correspondence does exist, then the processor compares the lock combination code from the selected memory level of the lock with the key combination code from the coded key (block 88).If correspondence exists, then the lock opens. However, if correspondence does not exist, then additional steps are undertaken to determine whether the combination code in the selected memory level of the lock is to be changed. Accordingly, in block 90 a new combination code is computed from the modifier code and the selected lock combination code according to a preprogrdmmed set of logical or arithmetic operations. The new computed combination code is then stored in a suitable scratch pad memory as indicated in block 92 after which the computed combination code is compared with the combination code from the coded key (block 94). If correspondence does not exist, then the lock power is turned off. However, if correspondence does exist, then the lock opens and the computed combination code is stored in the selected memory level of the lock in place of the selected lock combination code (block 96).

Claims

1. A method of operating an electronic security device having a multilevel memory comprising the steps of: (a) storing a lock identification code and a lock combination code in each memory level of the multilevel memory in the security device; (b) applying key identification code, a key combination- code and a modifier code to the security device; (c) selecting one of the memory levels having stored therein a lock identification code and a lock combination code; (d) comparing the selected lock identification code with the key identification code and generating a first compare signal if the selected lock identification code and the key identification code correspond;; (e) comparing the selected lock combination code with the key combination code if the first compare signal is generated and generating a second compare signal if the selected lock combination code corresponds to the key combination code; (f) opening the security device if the second compare signal is generated; (g) generating a computed combination code from the modifier code and the selected lock combination code according to a predefined operation set if a first compare signal is generated and a second compare signal is not generated; (h) comparing the computed combination code with the key combination code and generating a third compare signal if the key combination code corresponds to the computed combination code; and (i) storing the computed combination code in the multilevel memory in place of the selected lock combination code and opening the security device when the third compare signal is generated.

2. The method of claim 1 comprising the further step of making the security device inoperative in the locked position for a predefined period of time if the first compare signal is not generated.

3. The method of claims 1 or 2 wherein the operation set comprises at least one arithmetic operation.

4. The method of claims 1 or 2 wherein the operation set comprises at least one logical operation.

5. A method of operating an electronic security device having a memory in which is stored a lock identification code and a lock combination code, the method comprising the steps of: (a) applying a key identification code,"a key combination code and a modifier code to the security device; (b) comparing the lock identification code with the key identification code and generating a first compare signal when the lock identification code and the key identification code correspond; (c) comparing the lock combination code with the key combination code if the first compare signal is generated and generating a second compare signal if the lock combination code corresponds to the key combination code; (d) opening the security device if the second compare signal is generated;; (e) generating a computed combination code from the modifier code and the lock combination code according to a predefined operation set if the first compare signal is generated and the second compare signal is not generated; (f) comparing the computed combination code with the key combination code and generating a third compare signal if the key combination code corresponds to the computed combination code; and (g) storing the computed combination code in the security device in place of the lock combination code and opening the security device when the third compare signal is generated.

6. The method of claim 5 comprising the further step of making the security device inoperative in the locked position for a predefined period of time if the first compare signal is not generated.

7. The method of claims 5 or 6 wherein the operation set comprises at least one arithmetic operation.

8. The method of claims 5 or 6 wherein the operation set comprises at least one logical operation.