CA2133743C

CA2133743C - Electronic security system

Info

Publication number: CA2133743C
Application number: CA002133743A
Authority: CA
Inventors: Richard G. Hyatt, Jr.; Douglas Trent; Charles Hall
Original assignee: Medeco Security Locks Inc
Current assignee: Assa Abloy High Security Group Inc
Priority date: 1992-04-09
Filing date: 1993-04-02
Publication date: 1998-01-20
Anticipated expiration: 2013-04-02
Also published as: EP0635182A1; KR950701169A; EP0635182B1; ATE233974T1; JPH07505988A; CA2133743A1; TW223135B; WO1993021712A1; DE69332737D1; US5745044A; EP0635182A4

Abstract

An electronic security system includes an electronic lock mechanism and an electronic key (104a) each of which is provided with a microprocessor controller (CPU) and a memory (502) storing data including an ID code and encryption key codes. The lock microprocessor may either change ID codes stored in its memory or encrypt a seed number to be used for determining access to the lock. The key can only be used to access the lock (301a) either once or for a limited number of successive times, and must thereafter be reprogrammed by a host computer (910) to be loaded with either the proper ID code or the appropriate encryption key code for that lock. The electronic lock operates a solenoid which retracts a bolt-blocking mechanism that prevents the unlocking of the volt even when a key having the correct mechanical key cuts is inserted into the lock. Power for operating the electronic lock as well as the solenoid is provided by a power supply within the key. In a preferred embodiment the key unit is composed of a handheld computer and key module interface.

Description

2 ~ 33 7~ 3 ELECTRONIC SECURITY SYSTEM

BAC~GROUND OF THE INVENTION
Field of the Invention This invention relates generally to electronic security systems, and more particularly to electronic security systems for money-containi~g devices such as pay telephones, vending machines, bill changers or the like, which must be periodically accessed by a ; collector in order to retrieve the funds accumulated in the device.
Back~round and Prior Art Typically, the collection of' money from coin or currency operated devIce~ ~uch as pay telephones, transit system fare card machines or the like is a costly and burden~ome operation. For instance, a company may own tenR or even hundreds of thousands of pay telephones for which tens or hundreds of thousands of keys must be kept in order to prevent the loss of a key from requ$ring the changing of locks on thousands of devices which would operate with the lost key.
Another problem involved with the collection of funds from currency operated devices is the possibility of fraud or theft by a collector. Typically, a collector should remove a locked coin box from the WO93/21712 ~ l ~37~3 PCT/US93/031 device and replace it with an empty lock box to which he does not have access. However, it is possible that a le...o~ed coin box will not be replaced with another lock box but rather will be replaced with an unlocked receptacle which can be later removed by that collector before turning in his key at the end of the collection shift.
Yet another cost involved in the collection process is the sheer manpower required for the task of distributing, collecting, and keeping track of many thousands of keys on a daily basis.
Although electronic security systems are known and have been used for various purposes, see e.g. U.S.
Patents 4,789,859, 4,738,334, 4,697,171, 4,438,426, applicants are unaware of any which specifically address the problems, noted above.

SUMMARY OF THE lNv~NlION
The present invention provides an electronic security system which overcomes the problems mentioned above and significantly reduces collection costs.
The present invention also provides an electronic security system which eliminates the requirement of costly rekeying in the event of a key loss.
The present invention further provides an electronic security system which substantially eliminates the possibility of internal fraud and theft.
This invention is an electronic security system comprising a lock including a bolt movable between a locked and an unlocked position, a key actuated lock cylinder having a bolt cam in contact with said bolt to prevent the bolt from moving when in a locked position, and operable upon actuation to move the bolt to the unlocked position, a retractable locking means for W093/2l712 ~ 1 3 3 7 ~ 3 PcT/usg3ro3166 preventing the bolt from moving to the unlocked position when unretracted and allowing the bolt to be moved to the unlocked position when retracted, an electrically powered solenoid operable to retract the blocking means upon switching of power thereto, a mic-.v~locessor for controlling the switrhing of power to the solenoid, and a memory coupled to the mic~.ocessor storing coded data.
~he invention further lncludes key means insertable into the lock cyl~nder for supplying power to the ~olenoid to retract the blocking mean~ and for actuating the lock cylin~r to move the bolt to the unlocked position, including a power supply for supplying power to the solenoid, a controller, a memory storing coded dats, and means for efitablishing electricsl connection between the controller and the microprocessor through contact terminals in the lock cylinder for transmission of the coded data, in which the mic~ ,ucessor include~ me~ns for comparing the coded data read from the key means with coded data stored in the coupled - y, and mean6 for enabling the power supply of the key means to power the solenoid when the means for comparing has determined that the coded data from the key means matches the coded data in the coupled memory of the lock.
In another embodiment, the invention includes the use of encryption key codes in the lock unit and in the key unit, each unit encrypting a seed number provided by the lock unit to determine whether the key has been authorized to access the lock. Upon succes~ful ~ccess, the encryption key code in the key is overwritten with date stamp information to prevent further access.

W093/21712 2 ~ 3 3 7 ~ 3 PCT/US9~03166 BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully under6tood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and are not limitative of the present invention, and wherein:
Figures lA and lB are side and end elevational views, respectively, of an electronic key with its own power supply according to one preferred embodiment of the present invention;
Figure 2 is a front elevation view of a lock cyl i n~r and as~ociated me~hAnisms (shown with the hou~ing cover removed) for operation with the key of Figure~ lA and l~;
Figure 3 i~ a schematic view of a first embodiment of ~n electronic key pl~y~mmer according to the p.eoent invention;
Figure 4 is a schematic view of another embodiment of a portable key progr~mmer According to the present invention;
Figure 5 is 8 schem~tic block diagram of the circuit elements of the electronic key of Figure lA;
Figure 6 is a schematic block diagrnm of the electronic components of the lock mechanism of Figure 2;
Figure 7 i~ a schematic block diagram of the electronic key p~g ~mmer of Figures 3 and 4;
Figure 8 is an operational flow chart diagram of the electronic lock me~hAn;~m operation;
Figure 9 i8 A ~chematic block diagram of an electronic key programmer and an electronic key unit according to a ~econd embodiment of the present invention;

WO93/21712 2 .~ i ~ 7 1 3 PCTrUS93/03166 Figure 10 i~ a flow chart diagram of the operation of the key unit 104a of Figure 9;
Figure lOa ifi a flow chart ~i A13''-~ of an alternstive routine for step 1014 of Figure 10;
Figure 11 is block di~gram of the contentR of lock memory 602 according to the second embodiment of the invention; and Figure 12 i~ a flow chart diagram of the operation of the lock unit 201 according to the ~econd embodiment of the invention.

DETAIT~n DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figures lA and 1~ illu~trate an electronic key 100 according to a fir~t embodiment of the present invention. The key has a key body 101 which contain~
logic and power transfer circuitry, and a key blade 102 with a~ iately cut key bit6 for opersting pin tumblers as i8 known in the art. The key 100 al80 c~rrie~ a spring loaded data and power electrical contact 103, which is made of a ~uitable material and i8 preferably gold plated.
Portable battery and logic housing 104 contains a battery power ~upply and electronic circuitry, a battery charging port 105, a wrist ~trap or belt clip 106, and a plug-conn~cted cable 107 for transferring power and data signals between the housing 104 and the key body 101.
Figure lB is an end view of the key body showing the orientation of the spring loaded contact 103 with relation to the key blade 102. The key 100 and connected hou6ing 104 with their components are portable and are referred to as ~key means".
~ Figure 2 illustrates a lock cylinder and bolt mechAni~m according to one embodiment of the present wo 93/21712 2 1 3 3 7 ~ 3 PCT/US9~031C6 invention, included in a housing 201 (with its cover removed). Within the housing i8 a bolt 202 operated by a lock cylin~er 203 contAini~g a key cylin~r plug 204 having a keyway 205 for key blade 102, and an electrical contact 206 which makes contact with the power and data contact 103 of the key body when the key blade 102 is inserted into the key blsde opening 205.
A bolt cam 207 i8 rotated by the lock cylinder 203 to move the bolt 202 bet~een the locked position shown and an unlocked position in which the bolt is withdrawn d~"~--rd to be 6ub~tantially within the housing 201.
The lock hou~ing 201 further includes electronic logic circuitry 208 and an electrically pow_l~d solenoid 20~.
Solenoid 209 includes a spring biased bolt blocking plunger 210 which, when e~tsn~R~, pLave"Ls bolt 202 from being withdrawn by the bolt cam into the housing 201 to it~ unlocked po~ition. Upon operation of the solenoid 209, bolt blocking plunger 210 i9 retracted toward the solenoid to enable the key 100 to be turned in the clockwise direction which rotates bolt cam 207 against the bolt 202 and cau~es the movement of the bolt 202 downward into the housing 201.
Figure ~ illustrate~ a proy- -r for writing data into and reAAi ng data from the circuitry in key body 104 through cable 107. The programmer include6 a host computer 301 which may be a minicomputer, personal computer, or any other type of computer, but which preferably is an IBM~ compstible microcomputer. A key programmer interface unit 302 i8 connected to the ~0 computer 301 by means of a cable 303 which plugs into a communication port of the computer 301. The programmer interface unit 302 contains a key receptacle 304 ha~ing electrical contact~ into which the plug end of the key cable 107 i~ inserted after being disconnected from key W093/21712 ~1337 ~ 3 PCT/US9~03166 body lOl to allow the computer to write into the memory within key housing 104. The computer 301 i~ loaded with a software ~ ~yL~m 305 for lo~in~ and retrieving files from the key logic housing 104.
S Figure 4 illustrates a portable ~Lu~.ammer interface unit 401 including a modem which enables the portable ~LO~ dmmer interface unit 401 to communicste with the computer 301 through the public switched telephone network (PSTN) via a stA~rd phone jack 402.
In this embodiment, an oper~tor in the field needing to update the content~ of file~ in the key hou~ing 104 wvuld dial up the host computer using a stAn~rd phone set 403 which is connectable via a ~ack to the ~.u~l~mmer interface 401. Once communication with the host computer 301 is established, the ~Lo~Lammer interface unit 401 operates in the same manner a8 the office ~LuyLummer interface unit 302.
Figure 5 is a schem~tic block ~i~gr~m illustrating the component~ within the electronic key hou~ing 104.
The compûnents include a micLocontroller or mi~Lo~ o~essor 501, an electrically erasable programmable read only memory (EEPROM) 502 coupled to the controller 501, an oscillator or clock 503 which provides clock signals for the operation of controller 501, and a battery power source 504 which operates the controller 501 ~s well as the solenoid 209 and the circuitry 208 within the lock mechanism housing 201.
The electronic key component6 further include an electronic switch 505 operated by the controller 501 and a power ~ensing circ~;t 506.
Figure 6 i8 a schemaiic block diagram of the electronic circuitry 208 within the lock housing 201.
Thi~ circuitry includes a mic op~oce~sor 601, an EEPROM
602 coupled to the mi~-LG~Locessor 601, an oscillator or clock 603 for providing operational clock signals to the microprocessor 601, a power filter 604, electronic switch 605 and load 606 for transmission of signals to the key controller 501 via line 607, and an electronic switch 608 for allowing power to flow from power source 504 within the key housing 104 through cable 107 and contacts 103-206 through the solenoid 209 to ground to activate the solenoid.
Figure 7 is a schematic diagram of the electronic key programmer interface unit 302. It is noted that the portable key programmer interface unit 401 contains substantially the same components as the programmer 302, in addition to the modem and telephone jack not shown. The programmer interface unit 302 includes a microcontroller 701, a clock oscillator 702, an electronic switch 703 and load 704 combination which operate similarly to the switch 605 and load 606, a power supply 705, and a standard RS-232 receiver and driver 706 which couples the programmer interface unit 302 to the host computer 301.
The operation of the system components will now be described with reference to Figures 5-7.
The electronic key 100 is inserted into the key programmer interface unit 302 or 401 to be programmed by the host computer running the customized software application 305 via cable 107 as described above.
Using the example of a lock for pay telephones for illustration, the EEPROM 502 is loaded with data corresponding to a specific collection route. The data can be entered manually through a keyboard provided with the host computer 301, or the data can be transferred to the EEPROM 502 from files on a floppy disk inserted into a standard floppy disk drive of the computer 301.

21, j 7.i~ ~, -EEPROM 502 is loaded with specially encrypted data corro~pon~ing to ~pecific ID codes stored in each of the electronic lock memories 602 of the locks on the specific collection route. Data encryption is performed by an encryption algorithm in a known manner.
E~PROM 502 also i5 losded with the date of key ~lUy ~mming, the start date as of which the key is valid, and a time window during which the key can be used, for example, 24, 48 or 72 hours from the start date. EEPROM 502 also contains an address location storing the particular key category, for example, whether the key is a collection key or service key, and a serial number for key identification. The data is encrypted using a specific algorithm performed by the software 305.
The computer 301 may also print out the particular collection route, lock key codes, time window, and stsrt date for confirmation by the p.uyLammer.
Controller 501 keep~ track of the current time and date by counting the clock inputs of oscillator 503 and using the key ~LoyLamming date as a reference.
The data i8 written into EEPROM 502 through switching of electronic switch 703 by microcontroller 701 which serve~ to incresse and decrease the amount of power consumed by the load 703 which in turn provides the logic level~ for binary "l" and "O" digital communication to the microcontroller 501. Th$s increase and decrease in power is sensed by the power ~en~e circuit 506 and is converted into digital signals readable by the microcontroller 501.
Referring now to Figure 6, the lock mechanism mic,o~loce~sor 601 iq coupled to EEPROM memory 602 which ~tores a specific ID code for that specific lock.
One important feature of the present invention is that 21~7~3 the lock mech~nism of Figure 2 contains no power supply it~elf but i~ completely powered by the power ~ource 504 of the electronic key 100. Power filter 604 is provided to supply power to the logic circuits from the key 100 over line 607, the power filter smoothing the voltage waveform 80 that power interruptions caused by data trancmi~sion over line 607 will not affect the operation of the logic circuits.
A6 an additional security feature, a solenoid activation ~witch 609 can be mechanically coupled to the bolt blocking plunger 210 of Figure 2 to detect the retraction of the bolt blocking plunger. In telephone~
equipped with a so-called "Smart Terminal" or circuit board 610, which is provided with a modem to link the telephone to the host computer over a telephone line, activation switch 609 can be used to send an alarm to the host computer when switch 609 detects the retraction of the bolt blocking plunger in the absence of generation of an enable signal by the mic- G~r oces60r 601, which would be indicative of someone tampering with the lock by trying to manually pry the bolt bloc~ing plunger away from bolt 202. An additional line 611 may be provided to e~tablish communication beL.~_~h the lock mic~u~ocessor and the smart terminal 610.
The u~e of a ~mart telephone terminal 610 al80 allows the use of a host confirmation feature as an additional feature of the present invention. Part of the data ~tored in the key memory 502 is the key~s particular serial number. Using the host confirmation feature, the hoEt computer 301 would dial up the smart terminal 610 via a modem and transmit a host confirmation message to the microprocessor 601. The mes~age may instruct the microprocessor to allow the 2~ 3374~
WO9~21712 rCTtUS93/03166 solenoid 209 to be powered by any mechanically operable key in~erted into the key slot 205, may instruct the mic~oproce~sor 601 to prevent any key at all from operating the lock by prohibiting powering of the solenoid 209, or may instruct the mi~ Locessor 601 to allow only ~ key having ~ particular serial number, transmitted by the host computer, to operste the lock by ~ Ling the ~olenoid. The host confirmation dsta msy then be stored in the memory 602 coupled to the microprocessor 601.
Referring now to Figure 8, the overall operation of the electronic lock system will be described.
After the key blade 102 is inserted into the keyway 205 and the contact 103 i9 electrically coupled to the key cylin~er contact 206, the electronic lock logic circuitry i8 powered up or aw, kene~ at step 801.
At step 802, mic.oplocessor 601 communic~tes with the mic ocontroller 501 to read the data stored in the memory 502. At 6tep 803, micro~ocessor 601 check~
whether the c~ ~nt date stored in memory 502 is ~fter the start date ~itten into memory 502 during the pl~ r ~mming mode of the key, determines whether the current time read from memory 502 is within the time window stored in memory 502 which has been ~loy-~mmed by the host computer in advance. If the start date read from the key memory is subsequent to the current date read from the key memory, or if the current time is out~ide of the time window stored in the key memory, the microproceseor advances to ~tep 809 at which the key is det~ ~ ne~ to be invalid, the microprocessor 601 is re~et, and no further action is taken. If the time and date dat~ is vslid, the microproces~or 60l proceeds to step 804 in which the list of ID codes stored in key memory 502, corresponding to the locks that key lO0 is W093~1712 PCT/US93/03166 21 ~3713 to operate on this particular collection route, is compared with the current ID code stored in the memory 602. If the ID code in memory 602 is contained in the list stored in memory 502, the process proceeds to step 805 in which the presence of a host confirmation feature is rher~e~. If not, the mic~ ocessor ~ oceeds to step 809. If the telephone is not equipped with a smart terminal 610, ~ essing proceeds to 8tep 806 in which mi~Lo~Loce~sor 601 calculates a new ID
code according to a prestored algorithm in memory 602, encrypts the new ID code and stores it in memory 602, replacing the previous ID code stored therein. At step 807, miclopLocessor 601 transmitfi a signal to electronic switch 608 which allows power to flow from power source 504 through solenoid 209, and causes bolt blocking plunger 210 to retract in the direction toward the solenoid 209 for a predetermined period of time ~uch as 5 seconds. At this time, the operator may turn the key body 101 and unlock the bolt. The microprocessor 601 then re~ets before the key body 101 is withdrawn from the insert slot 205. After the bolt is relocked, the bolt blocking plunger 210 moves back to its blocking position ~hown in Figure 2 by spring bias action.
If the coin telephone is one equipped with a smart terminal, processing proceeds from ~tep 805 to step 808. In this step, mic,vpLocessor 601 determines whether the key ~erial number matches the serial number transmitted from the host computer, or whether the host computer has sent a message to prevent all keys from operating. If the key data matches the data stored in the memory 602, processing proceeds to step 806 as described above. If the key data does not match, or W093nl712 2 ~ 3 :~ 7 ~ 3 PCT~USg3/031C6 -microprocessor 601 has received a prohibit mes~age, processing proceeds to Qtep 809.
As an additional feature, each lock may write its serial number and current time into a specific location of the memory 502 of the key in the event thst all key data i~ valid to indicate that the ~pecific lock was operated at the particular time stored with the ~erial number. Upon return of the key to the central office, the key may be re-inserted into the programmer interf~ce unit 302 and the file~ in memory 502 read by the host computer in order to maintain a list of the locks that were operated as well as those that were not operated. All of the algorithms utilized by each of the lock mi~Lo~ oces~or6 601 are stored in the host computer 301 such that aftèr the key is returned at the end of a collection cycle, the key may be lepl~y ammed with the new ID codes currently being stored in each of the operated locks, while the ID codes for the locks that have not been operated are left unchanged within the key memory 502.
Description will now be made of the second preferred embodiment of the present invention with reference to Figs. 9-12.
~ ig. 9 illustrates a progr~mmer 301a, which may be ~5 similar to the mi~.ocl ~ Ler ~lGy ~mmer 301 of Fig. 3.
The ~Yog~mmer 301a includes a CPU 901, a pair of look-up table~ 902 and 903, and a daykey encrypter 904.
Look-up table 902 contains a listing of various IDNs (identification numbers) and IDRs ~encryption key codes) for each lock of the system. Every lock is identified by a lock identification number or IDN, and has associated therewith a correspon~ing encryption key code IDK which is used by the lock to encrypt data.

WO 93~21712 PCI'/US93~03166 hl~37~1J

Look-up table 903 contains a listing of various IDNs and ID~S for each key unit 104a of the 6ystem.
Each key unit 104a i6 also identified by a key IDN and has associated therewith a corresponding encryption key 5 code ID~ which i8 used by the key unit to encrypt data.
Daykey encrypter 904 contains an arbitrary encryption key code which is changed daily in the programmer 301a ~thus the designation "daykey").
Rey unit 104a includes a key module 906, a hAn~hel~ computer 908, and optionally a modem 910. The module 906 interfsces the handheld computer 908 to the key device 101. Handheld computer 908 i~ a commercislly available device such as a Panasonic Model JT-770, and may be implemented by any other equivalent apparatu6. The computer 908 includes a key memory 502 which 6tores route stop information programmed from the ~lo~l~mmer 301a. The route stop information is organized into a route table cont~ining specific routes l~beled by date. The key interface module 906 includes the IDN and IDK for the key unit 104a.
In operation, route stops for esch collector are compiled by the ~Lvy,dmmer 301a. These route stops may be selected by 8 management operator, or may be downloaded into the programmer 301~ from a central host mansgement system. For each key unit 104a, which is identified by a particular key module IDN and co ~ in~ encryption key code IDK, the ~.og.ammer 301a compiles a set of locks which are to be serviced for collection (or other operations) by r~i n~ out a number of IDNs and associ~ted IDKs of the locks to be accessed by the particular key unit 104a, from the look-up tsble 902, to thereby generate a route table for transmission to the key unit 104a.

2:l3~7a3 WO93/21712 PCTrUSg3/03166 -The IDNS and IDKs of the various locks are el~cLy~Led by the encrypter 904 using the particular daykey encryption key code in use on that day. The daykey encryption key code is then itself encrypted using the IDK enc~y~tion key code of the specific key unit 104a for which the route table is being compiled.
The encrypted daykey, denoted as DAYKEY(IDR), i~ then also transmitted to the computer 908 of key unit 104a.
In the key unit 104a, the IDN identification number ~nd IDK encryption key code are stored in the key interface module 906, while the encrypted daykey DAYXEY(IDR) and the encrypted route tables are fitored in the key memory 502 of hAnAheld computer 908.
Referring now to Figure 11, the lock memory 602 according to the ~econd embodiment of the present invention contains the IDN or lock identification number of that particular lock, the IDR encryption code sssociated with that p~rticular lock, and an arbltrary ~eed number. The seed number i~ simply a certain numerical value, the actual value of which i8 not relevant.
In order for the encrypted IDNs and IDKs of the route tables stored in memory 502 to be decrypted, the handheld computer 908 sends the encrypted daykey to the key interface module 906, which decrypts the DAY~EY(IDR) u6ing its encryption key code IDK to obtain the de~y~Led daykey. The encrypted IDNs and IDKs are then ~ent to the module 906 to be decrypted using the daykey, and used by the module 906 in the verification proce6s with the lock.
This feature i8 intPn~e~ as an additional security measure to achieve an even higher level of security, for the reason that the module 906 is an add-on feature to the computer 908 and is removable therefrom. Thus, '21~37~13 16 in the event that the module i~ lost or stolen, neither the module nor the hAn~held computer can be used for acces6 to any informstion with respect to lock ID
codes or encryption key codes. Further, since the daykey encryption code is periodicslly changed in the ~o~l~mmer, the particular daykey stored in the module 906 is of limited use.
Operation of the second embodiment will now be described with reference to the flow chart diagrams of Figs. 10, 10A, and 12.
Upon insertion of the key 101 into the keyway of the lock at ~tep 1001, power is applied to the lock at step 1201. At step 1202, the lock sends a handshake protocol to the key, which receives the hAn~chA~e at step 1002 and sends an acknowledge to the lock at step 1003. At step 1203, the lock ~coy.~izes the acknowledge and ~ends its IDN to the key at step 1204.
The key receives the lock IDN and acknowledges at steps 1004 and 1005, and checks to see whether the lock~s IDN
exists in memory for the pre6ently valid route table at step 1006. As previously mentioned, the route tables are labeled by date, and the computer 908 includes a clock for keeping track of the current date.
At ~tep 1007, if the IDN is found, the key checks to see if the lock's correspon~ing IDK is found in memory for the particular IDN sent by the lock and acknowledges the lock if both IDN ~nd IDR have been found, at step 1008. Upon receiving the acknowledge at step 1205, the lock sends the seed number from memory 602 to the key at step 1206. The key acknowledges receipt of the seed number at step 1010, and the lock then encrypt~ the seed number with its IDX at ~tep 1208 upon receiving the acknowledge at step 1207.

37~3 W093/21712 PCT/USg3/03166 The key also encrypts the ~eed number from the lock at ~tep 1011, using the IDK found for the IDN
received from the lock. At ~tep 1012, the key sends the encrypted seed number to the lock, which receives it at step 1209. The lock then compares the encrypted seed number received from the key with the encrypted ~eed number which the lock itself generated, at step 1210. If the numbers match, the key i8 determined to be authorized to acce6s the lock. At step 1211, the key writes the encrypted seed number into the memory 602 over the old seed number. The encrypted seed number will be u~ed a6 the new seed number for the next acce6s reque6t from a key. At step 1212, the lock sends an acknowledge to the key to inform it of a ~uccessful access request, and activates the solenoid at step 1213. The lock then re~et6 at ~tep 1214. If sny of the acknowledges from the key are not received within a predetermined amount of time, the lock routine also advances immediately to ~tep 1214 for re~et.
Upon receiving the acknowledge from the lock at step 1013, the key unit writes the date of sccess into the route table at step 1014, over the IDR previously stored there. As such, the key unit will thereafter not be able to access the lock without being reprogrsmmed by the programmer 30la. Such can be accomplished either by bringing the key unit 104a back to the management center, or by calling into the ~ammer via modem 910 for ~ Uy ~mming in the field.
The key unit then proceeds to step 1015 where it is reset for the next lock access attempt.
In an alternative mode of operation, the key unit may be programmed to have a set number of accesses to each lock before requiring reprogramming. Such is WO9~21712 PCT/US93/03166 2~ ~7~3 shown in Fig. lOA, wherein a counter i~ incremented at step 1014a, and the value 6tored in the counter ic compared with a preset maximum number of acce~ses at step 1014b. If thi~ number has been reached, the lock IDK is replaced by the date of access and the key unit is reset at steps 1014c and 1015 otherwiqe the key unit is immediately reset at step 1014d. In either event, additional access to the lock may be denied upon an attempted access to another lock.
The invention being thus descri~ed, lt will be apparent to tho~e ~killed in the art that the same may be varied in many ways without departing from the spirit and scope of the invention. Any and all such modification6 are inten~ to be included within the scope of the following claim~.

Claims

WHAT IS CLAIMED IS:

1. An electronic security system, comprising:
a lock, including a lock memory storing therein an identification number of said lock, an encryption code associated with said lock, and a seed number, and means for encrypting said stored seed number with said encryption code to generate an encrypted seed number;
key means couplable with said lock for communicating therewith, including a key memory storing therein a list of lock identification numbers and corresponding encryption codes, means for receiving said identification number of said lock and said seed number from said lock, means for encrypting said received seed number with an encryption code corresponding to said received identification number to generate an encrypted seed number, and means for transmitting said encrypted seed number to said lock;
said lock further including means for comparing said encrypted seed number received from said key means with the encrypted seed number generated in said lock, and means for enabling said key means to open said lock upon determination by said means for comparing that said encrypted seed numbers match.

2. An electronic security system according to claim 1, wherein said lock further includes means for replacing said stored seed number in said lock memory with said encrypted seed number upon determination by said means for comparing that said encrypted seed numbers match.

3. An electronic security system according to claim 1, wherein said key means further includes means for replacing the encryption code corresponding to a lock identification number of a lock which has been opened.

4. An electronic security system according to claim 3, wherein said means for replacing includes means for counting the number of accesses of said key means to a specific lock and replacing said encryption code when said number of accesses has reached a predetermined value.

5. An electronic security system according to claim 1, wherein said list of lock identification numbers and corresponding encryption codes in said key memory are encrypted with an encryption code corresponding to said key means;
said key means further including means for decrypting said list of lock identification numbers and corresponding encryption codes with said encryption code corresponding to said key means to produce decrypted lock identification numbers and corresponding decrypted encryption codes.

6. An electronic security system according to claim 5, further comprising computer means for programming said key means with a specific route composed of a plurality of lock identification numbers and corresponding encryption codes.

7. An electronic security system according to claim 6 wherein said key memory stores a plurality of routes, each of said plurality of routes being valid only for a specific date;
said key means further including means for storing the current date and for retrieving only those routes determined to be valid for said current date for comparison with lock identification numbers received from respective locks.

8. An electronic security system according to claim 6, wherein said key means further comprises a modem for communicating with said computer means over telephone lines.

9. An electronic security system according to claim 6, wherein said computer means encrypts said route with a daykey encryption code generated by said computer means, encrypts said daykey encryption code with said encryption code corresponding to said key means, and transmits said encrypted daykey encryption code with said route to said key means.

10. A lock mechanism, comprising:
a bolt movable between a locked and an unlocked position;
a lock cylinder having a bolt cam in contact with said bolt to prevent said bolt from moving when in a locked position, and operable upon actuation to move said bolt to said unlocked position;

retractable blocking means in contact with said bolt for preventing said bolt from moving to said unlocked position when unretracted by blocking motion of said bolt to said unlocked position and allowing said bolt to be moved to said unlocked position when retracted;
an electrically powered solenoid operable to retract said blocking means upon switching of power thereto; and means for selectively powering said solenoid, comprising a portable key means for operating said lock cylinder and including a power supply.

11. An electronic security system, comprising:
a lock mechanism;
controller means for controlling the operation of said lock mechanism, including means for storing a code number, means for modifying said stored code number according to a stored predetermined algorithm, means for receiving an input code number, means for comparing said modified code number with said input code number, means for enabling said lock mechanism to be operated when said input code number matches said modified code number, and means for replacing said stored code number with said modified code number when said input code number matches said modified code number;
key means for operating said lock mechanism including means for storing said predetermined algorithm, means for calculating a code number according to said predetermined algorithm, means for outputting said calculated code number to said controller means as said input code number, and means for operating said lock mechanism when enabled by said controller means; and means for writing said predetermined algorithm into said key means corresponding to said predetermined algorithm stored in said controller means.

12. An electronic security system as set forth in claim 11, wherein said key means further comprises mechanical key cuts for operating said lock mechanism.

13. An electronic security system as set forth in claim 11, wherein said means for writing comprises a computer.

14. An electronic security system as set forth in claim 11, wherein said controller means comprises a microprocessor.

15. An electronic security system as set forth in claim 11, wherein said key means comprises a handheld computer and an interface module coupled to said handheld computer for interfacing said handheld computer with said lock mechanism, at least said means for outputting being located in said interface module.

16. An electronic security system, comprising:
a lock, including means for unlocking said lock based on received specific data; and key means for operating said lock, comprising a handheld computer including means for storing encoded data, and an interface module coupled to said handheld computer for interfacing said handheld computer with said lock, including means for decoding said encoded data stored in said handheld computer into decoded data and means for generating said specific data for transmission to said lock based on said decoded data.

17. An electronic security system, comprising:
a lock, including an access memory for storing access data, a data communication terminal coupled to a communication channel, microprocessor means for receiving data from said data communication terminal transmitted over said communication channel including access data, and for storing received access data in said access memory, means for receiving access data from an electronic key, means for comparing access data received from said electronic key with access data received over said communication channel and stored in said access memory, and means for releasing said lock to allow access by a holder of said electronic key if the access data received from said electronic key matches the access data received over said communication channel and stored in said access memory; and remote data processor means for sending data to said microprocessor means over said communication channel.

18. An electronic security system a set forth in claim 17, wherein said communication channel is a public telephone line, and further including modem means connected between said data communication terminal and said microprocessor means for enabling communication between said remote data processor mean and said microprocessor means.

19. An electronic security system as set forth in claim 17, wherein said lock is installed in a public telephone set.

20. An electronic security system as set forth in claim 18, wherein said access data is a serial number stored in said electronic key.