GB2387998A

GB2387998A - Mobile communication system with external electronic key that prevents unauthorised change of handset PIN code

Info

Publication number: GB2387998A
Application number: GB0209683A
Authority: GB
Inventors: Paul Gerrard Wilson
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2002-04-26
Filing date: 2002-04-26
Publication date: 2003-10-29
Also published as: GB0209683D0

Abstract

A mobile radio communications unit including a controller, a memory for storing a user PIN (personal identification number) code, a PIN code comparator for comparing a PIN code entered with the stored PIN code, the controller being operable to provide (i) and enabled state when the PIN code entered matches that stored by the memory and (ii) a disabled state when the PIN code entered does not match that stored by the memory; and wherein the communications unit is operable when in a disabled state and connected to an external electronic key to enable data communication to take place between the communications unit and the electronic key to establish recognition of related identity between the two, the communications unit being operable to produce an unlock signal when such related identity has been established to enable the state of the communications unit to be changed form its disabled state. An electronic key for use with the communications unit is also described. The electronic key may be part of a battery charger device.

Description

TITLE: RADIO COMMUNICATIONS UNITS AND A METHOD AND

APPARATUS FOR USE WITH SUCH UNITS

FIELD OF THE INVENTION

The present invention relates to radio communications units and a method and apparatus for use with such units.

BACKGROUND OF THE INVENTION

10 An increasing number of portable radio communications units, particularly mobile telephones, are being stolen, and the security offered by such units today is clearly not enough to deter would-be thieves. Such units are currently protected with a PIN (personal identification number) code 15 that locks the telephone after a number of, usually three, consecutive failed attempts to enter the code correctly.

However thieves are able (using a false ID or other method) to take the unit to a service centre that will unlock the unit and reset the PIN code for a small charge. The 20 unlocked unit can then be used as normal and can be sold on at a good profit, making the theft of mobile telephones attractive. SUMMARY OF THE INVENTION

According to the present invention in a first aspect there is provided a portable or mobile radio communications unit including a controller which controls operational functions of the unit, a memory associated with 30 the controller for storing a user PIN (personal identification number) code, means for entering a user PIN

code into the unit, a PIN code comparator coupled to the controller for comparing the PIN code entered with the stored PIN code, the controller being operable to provide (i) an enabled state in which functions of the unit are 5 enabled when the PIN code entered matches that stored by the memory and (ii) a disabled state in which functions of the communications unit are disabled or locked when the PIN code entered does not match that stored by the memory; and wherein the communications unit is operable when in a 10 disabled state and connected to an external electronic key to enable data communication to take place between the communications unit and the electronic key to establish recognition of related identity between the two, the communications unit being operable to produce an unlock 15 signal when such related identity has been established to enable the state of the communications unit to be changed from its disabled state.

The functions of the communications unit may be disabled or locked after a specific number of failed 20 attempts, e.g. three failed attempts, to enter the PIN code correctly, i.e. by using a code which does not match that stored. The communications unit may for example comprise a portable or mobile radiotelephone or a portable or mobile 25 radio transceiver unit.

The controller may comprise a suitably programmed control device, e.g. a signal processor such as a processing chip or plurality of processing chips as used in control of functions within a conventional communications 30 unit. The controller may include the PIN code comparator.

The controller of the communications unit according to the invention may be operable to change the state of the

communications unit when the unlock signal has been produced and received by the controller. The controller may change the state of the unit to an administration mode in which the PIN code stored by the memory may be changed by 5 the user entering a new PIN code via the means for entering. The means for entering the PIN code may comprise a conventional mechanical keypad or a so-called 'soft' keypad formed as an image on a touch senstive display. Optionaly, 10 entry of the code may include one or more other buttons, keys (hard or soft) or the like. The code entered is provided as a signal to the controller in a known manner.

The electronic key may be incorporated in a hardware device such as a docking station kept in the possession of 15 the user. The electronic key may include a memory which is operable to store a product identity code which, when correctly matched to a particular communications unit,is the same code as a product identity code stored by the communications unit.

20 The communication unit and the device including the electronic key when connected together may form a communicating pair. Data communication between the two may be initiated by entry of a control by the user.

Alternatively, data communication may be initiated 25 automatically by a sensor which senses that the two are connected together. The sensor may comprise a device incorporated within the communications unit which operating in a known manner detects a change of electrical potential or current flow resulting from the connection. For example, 30 a contact normally pulled to a high potential internally within the communications unit may drop to a low potential

when connected to an external device including the electronic key.

When connected to an external device including the electronic key, the communications unit may issue a data 5 message including a stored product identity code number uniquely identifying the unit. The electronic key may be operable to return a response message which includes a product identity code number stored by the electronic key.

Where the key uniquely matches the unit the code number 10 produced by the key will be identical to that produced by the communication unit. A comparator may be included in either the communication unit or the key which is operable to compare the code numbers produced by the key and the communications unit. When it detects identity of the two 15 code numbers, the comparator may be operable to issue a common identity signal which may be employed as the unlock signal referred to earlier.

Preferably, the electronic key and the communications unit are operable to produce messages (in which the code 20 number is included for comparison by the comparator) which are encrypted messages produced by an identical encryption procedure. The controller of the communications unit may be operable to convert the operational mode or state of the 25 communications unit to an administration mode when it receives the common identity signal. In the administration mode, the user PIN code stored in the communications unit may be reset. A prompt may be automatically generated to allow the user the possibility of changing the stored user 30 PIN code.

The electronic key may, in a preferred embodiment, be incorporated within the battery charger unit provided for

use with the communications unit rather than in a separate piece of hardware for the following reasons: l) The hardware key needs power to perform processing of the message received from the communications unit. A 5 separate piece of hardware would need a battery, a transformer, or source of power from the communications unit itself.

2) An option to disable the battery charging mechanism can be implemented if the connected communications unit 10 fails to be identified. This provides further security whereby the mobile can only be recharged by the correct supplied charger.

3) There is no need to ship and support a further new piece of hardware.

15 Thus, the present invention beneficially provides a practical solution to the problem of mobile communications units which are stolen being easy to use.

Embodiments of the present invention will now be described by way of example with reference to the 20 accompanying drawings, in which: BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure l is a schematic block circuit diagram of a 25 mobile radiotelephone handset embodying the present invention. Figure 2 is a schematic block circuit diagram of a battery charger unit including an electronic key embodying the present invention for use with the handset shown in 30 Figure 1.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A mobile radiotelephone handset is operable in the known manner described earlier whereby if the handset 5 becomes stolen the person who acquires the handset eventually has to enter a PIN code number to enable operation of the functions of the handset. If multiple, e.g. three, incorrect PIN code entries are tried the handset is electronically locked such that its operational 10 functions are disabled. The handset has to be connected to an electronic key to unlock the handset. The key is uniquely matched to the particular handset. In other words, the handset cannot be unlocked by any key other than its own. 15 In a preferred embodiment of the invention, the electronic key comprises a device embedded within a battery charger unit for use with the handset. Such a charger unit is acquired by the user as a package with the handset.

Under all normal circumstances, the electronic key must be 20 shipped and supplied with the handset since it must be uniquely used in combination with and matched to the handset. When the handset and the associated hardware containing its electronic key are connected together, and 25 the connection state allows communication between the two exists, an electronic communication takes place between the two in an attempt to identify each other. Only if this identification is successful can the handset PIN code be reset. In this way, both the handset and the hardware 30 containing its electronic key (e.g. its battery charger unit) is needed even by a service centre in order to for the handset to be unlocked.

A procedure for unlocking the handset may be as follows. 1. The handset is connected to the hardware in which its electronic key is incorporated in a manner such that 5 electronic data messages may be sent between the two.

2. The handset detects that the hardware is connected and sends a data message comprising a request for a Mobile Identification Key (MIK) to the electronic key.

3. The electronic key receives and verifies the MIK 10 request and sends as a data message a MIK response to the handset. 4. The handset receives and verifies the MIK response and checks that the response is that expected, i.e. that common identity is established between the handset and the 15 electronic key.

5. If the response is that expected, the handset is placed into a nonsecure administration mode in which the handset PIN code may be reset, e. g. in a manner similar to that used in the prior art.

20 6. If the response is incorrect the handset remains securely locked.

A detailed description of an embodiment of the

invention operating in this manner is as follows.

Figure l is a block diagram of the relevant 25 functional components of a mobile radiotelephone handset embodying the invention. The handset indicated by reference numeral l is connectible to its battery charger unit 3 (described in more detail later with reference to Figure 3) by a serial interface connection unit 5 comprising a 30 plurality of electrical connectors between the handset l and the charger unit 3. In practice, the charger unit 3 and the connection unit 5 may form a single constructional

unit. The handset 1 includes a battery 7 which is connected to the charger unit 3 to be charged thereby via conventional charging connectors 5a, 5b of the connection unit 5.

5 A connector pin 5c of the connection unit 5 becomes contacted to a connection sensor 10 of the handset 1 when the charger unit 3 is connected by the connection unit 5 to the handset 1. The sensor 10 is connected in turn to a message controller 11. The sensor 10 operates in one of 10 the ways described earlier.

The handset 1 also includes a serial communication driver 9 connected to the charger unit 3 via a connector Ed (which may in practice comprise a plurality of connector pins) via which data messages may be sent back and forth.

15 The message controller 11 is connected to the serial communication driver 9 and controls sending of data messages to the charger unit 3 and receipt of data messages from the charger unit 3. The message controller 11 is connected to and receives inputs from an encryptor 15 which 20 is connected in turn to a random number generator 13 which generates very large random binary numbers. The random number generator 13 is also connected to the message controller 11. The encryptor 15 is also connected to a memory 17 which stores a product unique identity code 25 number which uniquely identifies the handset 1.

The message controller 11 is also connected to a result comparator 21. The encryptor 15 is also connected to the result comparator 21. Outputs from the message controller 11 (received from the charger unit 3 as 30 described later) and from the encryptor 15 may thereby be applied as inputs to the result comparator 21.

In operation, a MIK messaging procedure is initiated by the message controller 11 when it receives a signal from the sensor 10 indicating that the sensor 10 has detected that the handset 1 is connected to the charger unit 3 (via 5 the connector pin 5c of the connection unit 5). The message controller 11 sends a message to the encryptor 15 to request production of an encrypted message. A very large random number is generated by the random number generator 13. The random number is provided to the encryptor 15 and 10 also to the message controller 11. Using an encryption algorithm (which may be known per se) the encryptor 15 combines the random number together with the product unique identity code number which is provided by the memory 17.

The resultant combination is provided to the comparator 21.

15 The same random number (as sent combined with the product unique identity code to the comparator 21) is sent in a message by the message controller 11 to the charger unit 3 via the driver 9 and connector 5d.

The charger unit 3 is shown in more detail in Figure 20 2. The unit 3 includes a conventional charger device 25 which when connected to the battery 7 by the connectors 5a, 5b of the connection unit 5 charges the battery 7. The circuit comprising the battery 7, the charger device 25 and the connectors 5a and Sb may include a separate on/off 25 switch (not shown) if required. The connector pin 5c is also connected to the charger device 25.

The data connector 5d of the connection unit 5 is coupled in the charger unit 3 to a combination of components forming an electronic key 3a (indicated by a 30 dashed line) as follows. A serial communication driver 27 similar to the driver 9 of the handset 1 is included in the key 3a of the charger unit 3. Incoming data messages

received by the driver 27 are delivered to a message controller 29. The message controller 29 is connected to an encryptor 31 and sends a request message to the encryptor 31 to produce an encrypted message. The message controller 5 29 provides to the encryptor 31 the random number as received in the message from the handset 1. A memory 33 stores a product unique identity code number which corresponds identically with that stored by the memory 17 if the correct charger unit is used.

10 The encryptor 31 applies exactly the same encryption algorithm as applied by the encryptor 15 of the handset 1.

The product unique identity code obtained from the memory 33 and the random number contained in the incoming message forwarded by the message controller 29 are combined by the 15 encryptor 31 and provided as an encrypted combination to the message controller 29. A data message containing the encrypted combination is returned by the message controller 29 to the handset 1 via the driver 27 and the connector 5d.

Referring to Figure 1 again, the incoming encrypted 20 data message comprising the response from the charger unit 3 is received by the driver 9 via the connector 5c. The incoming encrypted message is passed to the message controller 11 and thence to the result comparator 21. Thus, an encrypted message issued by the encryptor 31 and an 25 encrypted message issued by the encryptor 15 are fed as inputs to the result comparator 21 in which they are compared. If the two inputs match one another the comparator 21 produces a '1' output signal. If the two inputs do not match, the comparator 21 produces a '0' 30 output signal. The output signal produced by the result comparator 21 is fed to a controller 23 which controls operations of the handset 1. When the output signal from

the comparator 21 is a '1' (the unlock signal referred to earlier) the controller 23 converts the locked state of the handset 1 into an administration mode. If the comparator 21 produces a 'O' output signal, the controller 23 maintains 5 the handset 1 in a locked state.

Thus, the controller 23 will set the handset 1 into its administration mode only if the product unique identity code number stored in the handset 1 (the memory 17) is found by the encrypted message comparison procedure to 10 match that stored by the electronic key 3a (the memory 33) .

The encrypted message procedure described above provides a highly secure identification procedure since the random numbers used in the MIK request and MIK response messages are different every time the handset 1 is 15 connected to the electronic key 3a provided by the charger unit 3.

In practice, the items shown as blocks in Figure 1 other than the battery 7 may be provided as one or more appropriately programmed signal processing units as used in 20 modern handset electronics. Similarly, the items shown in Figure 2, other than the charger device 25 and its connectors, which together constitute the electronic key 3a may also be provided as one or more appropriately programmed signal processing units.

25 In an alternative embodiment of the invention (not shown), the random number generator may be incorporated within the charger unit 3 and the random number it generates may be sent in a message to the handset 1.

Further, the result comparator may be incorporated within 30 the charger unit 3 to compare an encrypted message generated within the unit 3 with one received from the handset 1. The purpose in both cases is the same as

described with reference to Figures 1 and 2, namely to check that the product unique identification code number stored in the charger unit 3 matches that stored in the handset 1.

5 In the alternative embodiment wherein the result comparator is incorporated within the electronic key 3a, the key 3a generates a MIK request and the handset 1 responds with a MIK response. This is compared in the comparator in the key 3a and the comparison result must be 10 communicated to the controller 23 of the handset 1. This extra communications message is desirably also encrypted otherwise the comparison result (which is critical to enabling the administration mode) returned to the controller 23 would be vulnerable to would-be hackers. The 15 encryption procedure used in this case is known to both the key 3a and the handset 1 so that the message can be suitably decrypted in the handset 1 for use in the controller 23 of the handset 1.

When the handset 1 has entered its administration mode 20 in one of the ways described above, the user PIN code may be reset. The user may be prompted to do this by a message generated by the controller 23 and displayed on a conventional display (not shown) of the handset 1. The message may for example show the question 'Reset PIN?'.

25 Alternatively, an administration menu of other normally restricted options may be displayed.

Software operational routines to produce this information are held by the handset 1 only. Such routines are not stored in the electronic key 3a of the charger unit 30 3. The connection between the electronic key 3a provided by the charger unit 3 and the handset 1 should remain in place whilst the handset 1 is in administration mode but has no

purpose other than to grant access to the administration mode. If the electronic key 3a provided by the charger unit 3 is disconnected, the handset 1 may be operable to exit this mode automatically.

5 The new PIN code if entered when the handset 1 is in its administration mode, e.g. via a keyboard optionally with one or more other keys or buttons as for the usual PIN code entry as described earlier, is stored in a memory (which may be part of the memory 17 or another memory unit) 10 in a known manner. The handset 1 is then ready for use by further entry of the PIN code at any time by the user (without connection of the charger unit 3) for comparison with the newly stored PIN code.

Claims

1. A portable or mobile radio communications unit including a controller which controls operational functions of the unit, a memory associated with the controller for storing a user PIN (personal identification number) code, 10 means for entering a user PIN code into the unit, a PIN code comparator coupled to the controller for comparing the PIN code entered with the stored PIN code, the controller being operable to provide (i) an enabled state in which functions of the unit are enabled when the PIN code entered 15 matches that stored by the memory and (ii) a disabled state in which functions of the communications unit are disabled or locked when the PIN code entered does not match that stored by the memory; and wherein the communications unit is operable when in a disabled state and connected to an 20 external electronic key to enable data communication to take place between the communications unit and the electronic key to establish recognition of related identity between the two, the communications unit being operable to produce an unlock signal when such related identity has 25 been established to enable the state of the communications unit to be changed from its disabled state.

2. A communications unit according to claim 1, which comprises a portable or mobile radiotelephone or a radio transceiver unit and the controller comprises a digital 30 signal processor.

3. A communications unit according to claim l or claim 2 wherein the PIN comparator is included within the controller.

4. A communications unit according to claim l, claim 2 or 5 claim 3 and wherein the controller is operable to allow two or more consecutive incorrect attempts up to a predefined maximum number of incorrect attempts to be made to match the entered PIN code with the stored PIN code.

5. A communications unit according to any one of the 10 preceding claims and wherein the controller is operable to change the state of the communications unit when the said unlock signal has been produced.

6. A communications unit according to claim 5 and wherein the controller is operable upon receiving the unlock signal 15 to change the state of the unit to an administration mode in which the PIN code stored by the memory may be changed by the user entering a new PIN code via the means for entering.

7. A communications unit according to any one of the 20 preceding claims wherein the means for entering the PIN code comprises a conventional mechanical keypad or a 'soft' keypad formed as an image on a touch sensitive display.

8. A communications unit according to any one of the preceding claims and which includes a sensor operable to 25 sense connection of the communications unit to an electronic key or a conducting connector associated therewith and to generate a connection sensing signal and includes a message controller which is operable to receive the connection sensing signal and thereby automatically to 30 initiate sending of data messages between the communications unit and the electronic key.

9. A communications unit according to any one of the preceding claims and which includes a comparator operable to receive a data message which includes a product identity code from an electronic key and to compare the received S code with a product identity code stored by a memory of the communications unit.

lo. A communications unit according to claim 9 and wherein the received message is an encrypted message and the communications unit includes an encryptor operable to

10 produce an encrypted message which includes the product identity code stored by a memory of the communications unit, the encrypted message being encrypted in a manner identical to that in which the received message has been encrypted, the encryptor being connected to provide an 15 output message to the comparator whereby the messages compared by the comparator are encrypted messages including the said stored product identity codes.

ll. A communications unit according to claim 9 or claim lo and wherein the comparator is operable to produce the 20 unlock signal when the said codes match and wherein the comparator is connected to the controller and the controller is operable when it receives the unlock signal from the comparator to change the state of the communications unit to an administration state or mode in 25 which the stored user PIN code may be changed.

12. A communications unit according to claim l and substantially as described herein with reference to Figure l of the accompanying drawings.

13. An electronic key for use with the communications unit 30 according to any one of the preceding claims which key includes a memory to store a product identity code and which key is operable to communicate with the

communications unit by data messages when connected to the communications unit, whereby the code stored by the memory of the key may be compared with a product identity code stored by the communications unit.

5

14. An electronic key according to claim 13 which includes a comparator for comparing the product identity code stored by the memory of the key with that stored by the communications unit.

15. An electronic key according to claim 14 and which 10 includes means for sending to the communications unit an encrypted data message which includes a component indicating the result of the comparison by the comparator of the electronic key.

16. An electronic key according to claim 13, claim 14 or 15 claim 15 and which is part of a hardware device which is connectible to the communication device by conducting connectors.

17. An electronic key according to any one of claims 13 to 16 and which is part of a unit which also includes a 20 battery charger device.

18. An electronic key according to claim 13 and substantially as described with reference to Figure 2 of the accompanying drawings.

19. A communication unit and an electronic key therefor 25 which store identical product identity codes and which when connected together form a communicating pair, wherein the communications unit is a unit according to any one of claims 1 to 12 and the electronic key is an electronic key according to any one of claims 13 to 18.