GB2540173A - Encrypted locks - Google Patents

Abstract

An access control apparatus (10) comprising a locking means (22) operatively connected to, and controlled by an output signal of a mobile telephony transceiver (12), the mobile telephony transceiver being uniquely identifiable on a mobile telephony network (14), such as via a subscriber identity module (SIM card). A mobile telephony connection is provided between the transceiver and a remote control centre (16); the remote control centre being adapted to transmit, and the mobile telephony transceiver (12) being configured to receive, via the mobile telephony network, lock and unlock commands, such that upon receipt of a lock or unlock command, the mobile telephony transceiver is configured to output the output signal to lock or unlock, respectively, the locking means. The mobile telephony transceiver is number-locked such that it can only communicate with one or more pre-designated telephone numbers of the remote control centre via the mobile telephony network. A look-up table of pre-designated telephone numbers can be used to check an incoming communication and call-barring is provided to communications from telephone numbers not in the look-up table. The access control apparatus can be used in a manlid or cover for a manhole and have sensors to detect intrusion events or tampering.

Description

Title: Encrypted locks

Description:

This invention relates to encrypted locks, and in particular, but without limitation, to encrypted locks suitable for use in outdoor installations, such as street furniture, manhole covers and the like.

There is an ever-increasing need for improved security in outdoor installations that goes beyond a conventional key-operated lock. As the world becomes more and more dependent on core infrastructure, so increases the risk of attack by criminals, activists, terrorists and other organisations.

Much of the world's core, public infrastructure is relatively unprotected. For example, street cabinets housing telecommunications lines can be relatively easy to break into, thus affording opportunities to hack phone lines or to install "packet sniffers" on broadband lines. In respect of core infrastructure services, this can pose a serious security hazard, which are presently counteracted by encryption measures and the like. Nevertheless, in most instances, software/encryption security measures are not present, making street cabinets a prime target for cyber-attacks.

In another example, manlids (also known as "manhole covers") provide relatively easy access to underground utilities, such as gas and water supplies, power and data cabling, etc.. This poses a security risk (especially in high-security areas, such as financial trading centres, data centre environs, military installations, and so on), inasmuch as it is relatively easy to gain illicit access to underground utilities, or to place devices that could have serious adverse effects, such as improvised explosive devices (lEDs), electromagnetic pulse (EMP) devices, poisons, power/data tapping/disruption devices and so on.

It will be readily apparent from the foregoing, therefore, that adequate physical countermeasures are required that can be used to supplement extrinsic (e.g. encryption) security measures, and/or that address the shortcomings of existing security measures.

It has been proposed to install locking devices on outdoor installations, such as unit (e.g. cabinet/manlid) -specific keys (that avoid an illicitly appropriated master key from being useable with any unit); combination locks whose codes can be changed regularly, or automatically at intervals, and so on. The main drawback of existing enhanced security measures is that information, such as keys/codes, need to be shared, and the sharing of such information is itself susceptible to cyber-attack. As such, there is no solution currently on the market that adequately secures public infrastructure using existing technology. A need therefore exists for a solution to one or more of the above problems, and/or a device and/or method that attempts to address some of the shortcomings of known security measures, and/or an alternative solution to known security measures.

Various aspects of the invention are set forth in the appendent claims. A first aspect of the invention provides an access control apparatus comprising a locking means operatively connected to, and controlled by an output signal of a mobile telephony transceiver; the mobile telephony transceiver being uniquely identifiable on a mobile telephony network and providing a mobile telephony connection between the transceiver and a remote control centre; the remote control centre being adapted to transmit, and the mobile telephony transceiver being configured to receive, via the mobile telephony network, lock and unlock commands, such that upon receipt of a lock or unlock command, the mobile telephony transceiver is configured to output the output signal to lock or unlock, respectively, the locking means, characterised in that the mobile telephony transceiver is number-locked such that, in use, it can only communicate with one or more pre-designated telephone numbers of the remote control centre via the mobile telephony network. A second aspect of the invention provides an access control method comprising the steps of transmitting, via a mobile telephony network, a lock or unlock command from a remote control centre to a uniquely identifiable mobile telephony transceiver; the mobile telephony transceiver receiving the lock or unlock command and in response thereto, outputting a output signal to a locking means to lock or unlock, respectively, the locking means; characterised by the step of number-locking the mobile telephony transceiver to the remote control centre such that, in use, mobile telephony transceiver can only communicate with one or more pre-designated telephone numbers of the remote control centre via the mobile telephony network.

By number-locking the mobile telephony transceiver to one or more pre-designated numbers of the remote control centre, the opportunities for unauthorised persons to determine the telephone number of the mobile telephony transceiver, and to send lock or unlock commands to it, is greatly reduced: this can only happen if the person dialling the mobile telephony transceiver does so from one or more of the pre-designated telephone numbers. Put another way, the invention adds an additional layer of security, which can sit alongside other, existing security measures, such as encryption.

Suitably, the mobile telephony transceiver is uniquely identifiable on a mobile telephony network. This may be accomplished, in certain embodiments, by the provision of a subscriber identity module (SIM) of the mobile telephony transceiver.

The mobile telephony transceiver communicates with the remote control centre via mobile telephony network, which can be of any suitably type, such as GSM, GPRS, 3G, 4G, satellite, etc., although it will be appreciated that any public telephony network can be used that is capable of conveying the lock or unlock commands from the remote control centre to the mobile telephony transceiver.

In certain embodiments of the invention, the locking means comprises an actuator adapted, in use, to cause a latch of a lock to move between locked and unlocked positions. Suitably, the locking means comprises a solenoid or motor-actuated latch that can be used to selectively lock and release a door, hatch, manlid etc., to or from, respectively, its frame, housing or surround.

The mobile telephony transceiver is operatively connected to the locking means, for example via one or more wires. Thus, the mobile telephony transceiver can be configured to receive and optionally decrypt and parse a lock or unlock command broadcast, or transmitted over, the public telephony network, and in response thereto, output a control signal, for example, a voltage and current for actuating an actuator of the locking means. In other embodiments of the invention, the output signal comprises a further command data signal, which is received by an I/O interface of the locking device, which then parses and/or decrypts the further command signal to actuate the locking means. A third aspect of the invention provides a remote locking system comprising an access control apparatus as described herein, and further comprising first and second relatively moveable parts that are releasable locked or released by the operation of the locking means. In certain embodiments of the invention, the first and second relatively moveable parts comprise and one or more of the group comprising: a manlid and a manhole surround; a street cabinet and a door of the street cabinet; a drain grid and a surround for the drain grid; and a door and door frame. It will be appreciated, nevertheless, that whist the invention is particularly suited for use in outdoor/street furniture applications, it could equally be used in other applications, such as door entry control, safe security, etc.

In preferred embodiments of the invention, the mobile telephony transceiver comprises a bi-directional transceiver that is adapted not only to receive commands from the remote control centre via the mobile telephony networks, but also to transmit one or more data signals overt the mobile telephony network. Because the mobile telephony transceiver and the remote control centre are number-locked to one another, the likelihood of an unauthorised person, for example, using a mobile telephone, being able to transmit a false/fraudulent data signal to the remote control centre is greatly reduced.

In certain embodiments of the invention, the access control apparatus comprises one or more sensors, which are suitably adapted to detect intrusion events and/or tampering. The sensors may comprise any one or more of the following, but it will be appreciated that the following is not an exhaustive list: a motion sensor adapted to detect movement; a vibration sensor; an accelerometer; a microphone; a temperature sensor; a pressure sensor; a gas sensor; a camera; and a video camera. A processor is suitably used to interpret the sensor readings, and to generate alarm signals in the event of a detected unauthorised intrusion or tampering. Alarm signals can be transmitted, via the mobile telephony network, from the mobile telephony transceiver of the invention to the remote control centre, to alert the remote control centre of a possible attack/intrusion. In certain embodiments of the invention, upon receipt of an alarm signal, the remote control centre is configures to alert emergency services of the fact.

Thus, in certain embodiments of the invention, an intrusion sensor and processor adapted to detect one or more intrusion events, is operatively connected to the transceiver which, upon detection of an intrusion event, is adapted to transmit an intrusion warning signal, or alarm signal, to the remote control centre.

In preferred embodiments of the invention, the command and/or alarm signals sent over the mobile telephony network are encrypted, and thus the remote control centre and the mobile telephony transceiver suitably comprise encryption/decryption means to encrypt and/or decrypt the command and/or alarm signals. This configuration may be particularly advantageous in high-security applications because the invention provides triple layer protection, namely: the physical locking means; number-locking of the transceiver to a specific remote control centre; and encryption of command and alarm signals over the telephony network.

Embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic system diagram illustrating an embodiment of an access control system in accordance with the invention;

Figure 2 is a schematic perspective view of a street cabinet in accordance with the invention; and

Figure 3 is a schematic exploded perspective view of a manhole in accordance with the invention.

Referring to Figure 1, an access control system 10 in accordance with the invention comprises a wireless mobile telephony transceiver 12 connected, via a mobile telephony network 14, to a corresponding transceiver 16 of a remote control centre. The mobile telephony transceiver 12 comprises an I/O interface 13 that operatively connects it to complementary I/O interface 15 of a processor 18, which in turn controls an actuator 20 of a locking device 22.

The locking device 22 comprises a bolt 24 that can be moved, by the actuator 20, between a locking position (as shown in the drawing) in which a tip of the bolt 24 engages a keep 26 of a second part 28 that is selectively lockable by the access control system 10.

The wireless mobile telephony transceiver 12, in the illustrated embodiment, comprises a GSM transceiver (although any type of mobile telephony unit connected, via a mobile telephony network 14, to the remote control centre 16 could be used, although the ubiquity of GSM renders this type of transceiver suitable for most applications). The GSM transceiver 12 comprises a subscriber identity module (SIM) 30, which is preferably integrated into the transceiver 12 so that it is factory-installed, and is thus more difficult to swap. The SIM 30 gives the transceiver 12 a uniquely-identifiable telephone number, which can be addressed via the mobile telephony network 14.

The GSM transceiver 12 and/or the SIM 30 is configured with a set of call-barring restrictions that bar incoming and outgoing calls, data and messages, except from and to certain pre-designated telephone numbers, which are stored, for example, in a lookup table 32. The non-barred, or authorised number(s) correspond to the telephone number(s) of telephones of authorised operatives 34, i.e. authorised controllers, and where there are several authorised operatives 34, their corresponding telephone numbers will be entered into the lookup table 32 as an authorised user group 36. Conversely, calls to and from non-authorised users 38 will be barred 40 by the call-barring rules defined in the lookup table 32, thus inhibiting or preventing communications 42 between non-authorised users (i.e. any telephone number that is not included in the lookup table 32).

Conveniently, one of the authorised numbers included in the lookup table 32 corresponds to a call centre 50 telephone number, thereby permitting access to the access control system 10 of the invention by a number of authorised users 34, 36, via a permitted (i.e. non-barred) telephone number 16.

In use, therefore, an authorised person 34 is able to send a lock/unlock command, for example, via an SMS code sent over the telephony network 14, to the access control system 10. Depending on the specific implantation, in one embodiment of the invention, the access control system's 10 call-barring rules may prevent reception of incoming SMS messages from non-authorised telephone numbers, in which case the SMS message will be returned to the sender as "undeliverable", "barred" or "number not in service". Such a configuration advantageously prevents reception of unauthorised messages or calls, but does alert the unauthorised sender 38 of the fact, which may be disadvantageous in certain situations. In other embodiments of the invention, the call-barring rules are implemented by the processor 18 of the access control system 10, rather than by the transceiver 12, in which case a message from an unauthorised user 38 would be acknowledged as "sent", thus avoiding alerting the unauthorised user 38. However, the processor 18, in this implementation, crosschecks the telephone number of incoming calls and messages against the permitted numbers in the lookup table 32, and if the number is validated (i.e. a match against an entry in the lookup table is found), then it processes, and acts upon the message appropriately. If, however, the cross-check reveals a non-match against an entry in the lookup table 32, the processor 18 is configured to compile an alert message, which is transmitted via the transceiver 12, to one or more authorised users 36 in the authorised users group 36 as defined by the lookup table 32, thus alerting an authorised user of a potential, or attempted, security breach by an non-authorised user. In preferred embodiments of the invention, the alert message contains the telephone number, date, time and content of the unauthorised message, so that authorised users 34 can take further action, as desired.

It will be appreciated that the invention affords a great many advantages over existing access control systems, which will be apparent to those skilled in the art.

In a preferred embodiment of the invention, the processor 18 comprises an encryption/decryption engine 44, which is preferably a hardware encryption/decryption engine 44, but which could equally be a software encryption/decryption engine 44. The call centre 50 suitably comprises a complementary encryption/decryption engine 46, and the encryption/decryption engine 44 of the access control system 10 and the encryption/decryption engine 46 of the call centre 50 suitably exchange encryption keys periodically. This configuration provides an additional layer of security, enabling encrypted SMS messages to be sent between the transceivers 12,16. For example, a plan text or numerical code could be encrypted prior to transmission, such that even if the SIM 30 of the access control system 10 were to be "cloned" 30' by an unauthorised user 38, without the encryption key as well, the unauthorised user 38 would not be able to control the locking means 22 to gain access to the protected facility.

It will be noted that the access control system 10 of the invention shown in the embodiment of Figure 1 comprises one or more sensors 60, which can be configured to sense environmental conditions and/or intrusion attempts. The processor 18 receives signals from the or each sensor 60 and, using software, interprets the sensor readings to detect alert situations, in which case, an alert signal can be sent to the remote control centre 60 as previously described, alerting authorised users 34 or authorised user groups 36 of the fact.

In certain embodiments, the sensor 60 comprises an intrusion sensor, such as a tilt sensor; a microphone, a temperature sensor; a vibration sensor, a CCTV camera, etc.. The processor 18 is thus adapted to interpret the sensor readings as alert/non-alert situations. For example, a tilt sensor could be used to detect the lifting of a manlid from its surround; a microphone could be used for detecting hammering, drilling of a street cabinet; a temperature sensor could be used for detecting cutting or welding operations; a vibration sensor could be configured for detecting hammering, drilling & cutting, etc.. The processor 18 software is able, via filters and the like, to distinguish between alert and nonalert events e.g. to distinguish between road traffic passing over the manlid from a crowbar attack), suitably by cross-checking against other sensor inputs, to raise appropriate alerts at appropriate times.

In certain embodiments of the invention, the sensor 60 comprises an environment sensor, such as a gas detector, fire detector, a pollution sensor, flood sensor, etc., and thus the processor 18 may be configured to raise an alarm in the event of these sensor readings falling outside predefined parameters.

Referring now to Figure 2 of the drawings, a street cabinet 60 in accordance with the invention comprises a main body 62 for housing telephone and/or data connections (not shown) and a pair of doors 64, 66. An access control system 10, as previously described, is affixed to one of the doors 64, and the second part 28 of the lock 22 is affixed to the other door 66 with the bolt 24 forming a releasable locking connection between the two 64, 66.

The cabinet 60 can be locked or unlocked by the remote control centre 50 via an encrypted SMS message sent to the transceiver 12 of the access control system 10 via the mobile telephony network 14, or by an authorised user 34 carrying a mobile telephone with a number in the authorised number list of the lookup table 32.

In Figure 3 of the drawings, a manhole 70 in accordance with the invention comprises a main chamber 72 formed from sheet steel or aluminium, which is located below ground level, and which forms a secure enclosure for utilities (not shown). The main chamber 72 is welded and bolted to an upper frame 74, which is concreted into the ground (not shown) to secure the manhole 70 in position in the ground. A manhole cover 76 locates within the upper frame 74, and comprises a base tray portion 78 into which is placed an inner tray portion 80 formed as an open-topped hollow box which houses various components, as shall be described below. The manhole cover is closed by an upper surface plate 82, which forms a road or floor surface, and whose underside is sealed to an upper peripheral lip 84 of the base tray portion 78 by an O-ring seal 82. The manhole cover 76 can thus be dropped into, and seated within the upper frame 74, with the upper surface plate 80 lying flush with the road or floor surface.

The manhole cover 76 can be releasably locked into the upper frame 74 by bolts 24 that are actuated by solenoid-operated actuators 20, the bolts 24 being arranged to extend through (when in a locking positon) through aligned through holes 84 in the upper frame 74 and the manhole cover's base tray portion 78. The solenoid-operated actuators 20 are located within the base tray portion 78 of the manhole cover 76 under the peripheral lip 84 of the base tray portion 78. Thus, the inner tray portion 80 is able to drop into the base tray portion 78 without fouling the solenoid actuators 20.

The inner tray portion 80 thus forms a waterproof enclosure for various sensors 60, a central processing unit 18, a wireless mobile telephony transceiver 12 and a rechargeable battery pack 90.

It will also be noted from Figure 3 of the drawings that the upper surface plate 82 comprises an aperture 92, which is closed by a transparent window 94 which is sealed to the upper surface plate 82 by an O-ring seal 96. The aperture 92 forms an opening for a display screen (not shown) for the central processing unit 18 and/or a photovoltaic panel (not shown) for recharging the battery pack 90.

It will be appreciated from Figure 3 of the drawings, that the manhole 70 of the invention is considerably more secure than existing manholes due to its robust construction, its multi-point locking system 20 and its securement 74 into the ground. Further, because the manhole cover 76 locked to the surround, which is in turn bolted and welded to the chamber 72, even if the manhole 70 were to be dug out of the ground, it would in effect, be a locked "safe" which could not be opened without a valid unlock code sent from an authorised user.

By making the electronics battery-operated, even in the event of a power outage, the locks 20, processor 18 and transceiver 12 remain operational, as do the sensors 60. Thus, various utilities can be placed securely in the chamber 72 and in the event of an actual or attempted attack, the system can still alert a control centre 50 via secure messages sent via the mobile telephony network 14.

The sensors 60 have not been described in any great detail up to this point, but it will be appreciated that various sensor combinations and/or configurations could be used. Envisaged embodiments of the invention, although this is not an exhaustive list, comprise: GDNI: The sensors 60 comprise gas sensors adapted to sense levels of gas in the vicinity of the chamber 72 and/or in the vicinity of the unit. Gas explosions are typically caused by leaking pipes which often happen underground going unrecorded for significant periods of time. Flowever, the invention is capable of monitoring sensed gas levels in real time and can transmit those readings to an operator 36, who can interprets the data and take appropriate action. Thus, the invention can help to prevent gas building up to levels likely to cause explosions, it can inform utility companies in a timely fashion of issues in real time, and in certain embodiments of the invention, the aperture 92 can be remotely opened to vent the chamber 72 should engineers not be able to get to site due to other emergencies. This can help to safeguard the workforce and members of the public. ECCM: In this configuration, the sensors 60 are configured to monitors a mains electricity supply, recording power surges. Since incorrect installation of cables causing electrical faults, combined with underground gas can lead to explosions, the invention can help to safeguard against this. AGUA: In this embodiment, the sensors 60 comprise water flow, pressure and/or quality sensors adapted to measure various parameters of a water supply. The ability to check the water supply and water levels, as well as providing data in real time has numerous benefits to utility companies and emergency services, thus helping to maintain a safe and effective water supply. The invention can be used to protect against contamination of the water supply, as well as to provide realtime warnings about water shortages and flooding. By installing AGUA systems at intervals in a water supply network, it is possible to identify and locate leaks. SARM: In this embodiment of the invention, the sensors 60 comprise seismic sensors allowing real-time monitoring of seismic activity to be performed. MDPS: In this embodiment, the sensors 60 comprise motion sensors, such as accelerometers, vibration sensors and the like. These sensors 60 can be used to detect vermin in underground chambers, the passage of traffic and footfall, and by liking this to a remote control entre 50, data about crows, traffic congestion and the like can be obtained in real-time. VISI: In this embodiment of the invention, the sensors 60 comprise CCTV cameras aimed below ground, or up through the aperture 92 in the upper surface plate 80. Combined with automatic number plate recognition (ANPR), the invention enables the police and emergency services to monitor activity in the streets in a relatively unobtrusive manner. The use of CCTV can also be of benefit to engineers, who are able to remotely inspect a facility, this reducing or avoiding the need for a site visit. AGENT: In this embodiment, the sensors 60 comprise nuclear, biological and/or chemical sensors, which can relay real-time data to a secure remote control centre 50. EMCS: In another embodiment of the invention, there are provided electronic countermeasures, such as electromagnetic pulse devices, which can be used to temporarily knock-out radio telecommunications, thus assisting in averting remote detonation of explosive devices and the like. LCDD: In this embodiment of the invention, the display screen previously described can be used to provide visual information for passers by, such a direction arrows on the floor indicating escape routes, or data for emergency services operatives to see. The display screen could, in certain embodiments, be used for advertising purposes. POWS: In this embodiment of the invention, the system comprises data repeaters, such as WiFi access points, mobile telecoms repeaters and the like, which can be used to supplement existing infrastructure and/or to provide a backup system in the event of an outage.

It will be appreciated that any combination or permutation of the sensors and actuators described above could be used in a given system. The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary of the invention. For example, the invention could be applied in a range of systems other than manhole covers and street cabinets, and the combinations of sensors are not restricted to the non-exhaustive lists mentioned herein.

Claims (31)

Claims:

1. An access control apparatus comprising a locking means operatively connected to, and controlled by an output signal of a mobile telephony transceiver; the mobile telephony transceiver being uniquely identifiable on a mobile telephony network and providing a mobile telephony connection between the transceiver and a remote control centre; the remote control centre being adapted to transmit, and the mobile telephony transceiver being configured to receive, via the mobile telephony network, lock and unlock commands, such that upon receipt of a lock or unlock command, the mobile telephony transceiver is configured to output the output signal to lock or unlock, respectively, the locking means, characterised in that the mobile telephony transceiver is number-locked such that, in use, it can only communicate with one or more pre-designated telephone numbers of the remote control centre via the mobile telephony network.

2. The access control system of claim 1, wherein the mobile telephony transceiver comprises a subscriber identity module.

3. The access control system of claim 1 or claim 2, wherein the mobile telephony transceiver comprises any one or more of the group comprising a GSM transceiver; a GPRS transceiver; a 3G transceiver; a 4G transceiver; and a satellite telephony transceiver.

4. The access control system of any preceding claim, wherein the locking means comprises an actuator adapted, in use, to cause a latch or bolt of a lock to move between locked and unlocked positions.

5. The access control system of claim 4, wherein the locking means comprises a solenoid actuator.

6. The access control system of claim 5, wherein the actuator is arranged to move a bolt between a locked positon in which it engages a keep of a second part and an unlocked position in which the bolt is retracted into a first part, the first and second parts being affixed to relatively moveable parts of an item to be secured, namely a manlid and a manhole surround; a street cabinet and a door of the street cabinet; a drain grid and a surround for the drain grid; or a door and door frame.

7. The access control system of claim 6, wherein the manlid and manhole surround comprises: a main chamber located below ground level forming a secure enclosure, an upper frame fixed into the ground to secure the main chamber in the ground; a manhole cover locatable within the upper frame comprising a base tray portion housing an inner tray portion and which is sealingly closed by an upper surface plate forming a road or floor surface; the manhole cover being releasably locked into the upper frame by solenoid-actuated bolts arranged to extend through aligned holes in the upper frame and the manhole cover's base tray portion.

8. The access control system of claim 7, wherein the inner tray portion forms a waterproof enclosure for sensors, a central processing unit, the wireless mobile telephony transceiver and a rechargeable battery pack.

9. The access control system of claim 7 or claim 8, wherein the upper surface plate comprises an aperture closed by a transparent window portion which is sealed to the upper surface plate.

10. The access control system of claim 9, further comprising a display screen located behind the transparent window portion.

11. The access control system of claim 9 or claim 10, further comprising a photovoltaic panel for recharging the battery pack located behind the transparent window portion.

12. The access control system of any of claims 8 to 11, wherein the sensor comprises any one or more of the group comprising: a gas sensor; a voltmeter adapted to sense the voltage of a mains electricity supply; an ammeter adapted to sense the current of a mains electricity supply; a water flow meter; a water pressure sensor; a water quality sensor; a seismic sensor; a motion sensor; an accelerometer; a vibration sensor; a CCTV camera; an ANPR camera; a nuclear, biological and/or chemical sensor.

13. The access control system of any preceding claim, further comprising an output means comprising any one or more of the group comprising: an electronic countermeasure device; a display screen; a speaker; a data repeaters; a Wi-Fi access point; and a mobile telecommunications transceiver.

14. The access control system of any preceding claim, further comprising a processing unit.

15. The access control system of claim 14, wherein the processing unit comprises an encryption/decryption engine adapted, in use, to encrypt or decrypt the lock and unlock commands.

16. The access control system of any preceding claim, wherein the mobile telephony transceiver comprises a bi-directional transceiver adapted to receive lock/unlock commands from the remote control centre via the mobile telephony network, and to transmit one or more data signals over the mobile telephony network to the remote control centre.

17. The access control system of claim 16 when dependent on claim 12, wherein the processor is adapted to interpret the sensor readings, and to generate alarm signals in the event of a detected unauthorised intrusion or tampering.

18. The access control system of claim 17, wherein the alarm signals are transmitted, via the mobile telephony network, from the mobile telephony transceiver to the remote control centre.

19. The access control system of claim 18, wherein the alarm signal is encrypted.

20. The access control system of any of claims 14 to 19, wherein the processor comprises a lookup table containing a list of the pre-designated telephone numbers.

21. An access control method comprising the steps of transmitting, via a mobile telephony network, a lock or unlock command from a remote control centre to a uniquely identifiable mobile telephony transceiver; the mobile telephony transceiver receiving the lock or unlock command and in response thereto, outputting a output signal to a locking means to lock or unlock, respectively, the locking means; characterised by the step of number-locking the mobile telephony transceiver to the remote control centre such that, in use, mobile telephony transceiver can only communicate with one or more pre-designated telephone numbers of the remote control centre via the mobile telephony network.

22. The method of claim 21, comprising storing a list of pre-designated telephone numbers in a lookup table of a processor operatively connected to the mobile telephony transceiver and assigning send and receive call-barring restrictions to the mobile telephony transceiver to all numbers not in the lookup table.

23. The method of claim 21, comprising storing a list of pre-designated telephone numbers in a lookup table of a processor operatively connected to the mobile telephony transceiver, receiving a lock/unlock command and cross-checking the telephone number from which the lock/unlock command was sent against the numbers in the lookup table; and if the telephone number from which the lock/unlock command was sent appears in the lookup table, actioning the lock/unlock command; or if the telephone number from which the lock/unlock command was sent appears does not appear in the lookup table, not actioning the lock/unlock command.

24. The method of claim 23, wherein if the telephone number from which the lock/unlock command was sent appears does not appear in the lookup table, sending an alert message to the remote control centre via the mobile telephony network.

25. The method of claim 24, wherein the alert message comprises the telephone number, date, time and content of the unauthorised message.

26. The method of any of claims 21 to 25, further comprising the step of decrypting an incoming message.

27. The method of any of claims 21 to 26, further comprising the step of encrypting an outgoing message.

28. The method of claim 26 or claim 27, further comprising periodically exchanging encryption keys between the mobile telephony transceiver and the remote control centre.

29. The method of any of claims 21 to 28, further comprising receiving a sensor output from a sensor, interpreting the sensor output and determining an alert situation based on the sensor output, and transmitting an alert signal to the remote control sensor.

30. The method of claim 29, wherein the alert signal comprises data corresponding to the date, time and nature of the alert.

31. An access control system substantially as hereinbefore described, with reference to, and as illustrated in, the accompanying drawings.