FR2791509A1 - Antitheft device for mobile telephone using SIM card, stores handset-specific code within telephone which only operates after successful comparison with code entered by user - Google Patents

Abstract

An existing memory within the mobile phone stores a code specific to the equipment, e.g. by user programming in the case of a changeable code, or by 'etching' into the memory during manufacture for a fixed one. Each time the phone is switched on, or on each insertion of the SIM card, the user must key in the correct code to enable it to be used. Entry of an incorrect code may either block operation via software, or after several such attempts, the phone may self-destroyed through internal short-circuiting unless it is switched off.

Description

The present invention relates, in general, to the field of

  mobile phones, and more particularly relates to a device

  anti-theft device suitable for this type of telephone.

  Currently, mobile phones operate with a smart card called a "SIM" card, which in particular carries a code ("PIN" code) and defines the subscription. Also, in the event of loss or theft of the card, or of the telephone and card combination, not only the thief or the person who collects the telephone can use the subscription, but also the misuse of the card

  can be prevented by contacting the telephone network operator.

  On the other hand, until now, there have been practically no provisions aimed at preventing or limiting theft, or at least the misuse of the mobile phone itself. In the birth phase of the mobile phone market, this situation was not very serious. Indeed, operators often offered the mobile phone with the subscription, and the phones themselves had limited market value and / or were quickly made obsolete by the development of technology in this area. By cons, currently, the mobile phone technique has matured and we see the appearance of more and more sophisticated mobile phones, with sophisticated functions and, correspondingly, more and more expensive. As a result, there is now an increasing trend in theft of mobile phones, and this without any recourse to recover a stolen phone or, from the

  less, to prevent its use.

  In order to protect mobile phones against theft or unauthorized use, it has already been proposed recently to add a second code to the code specific to the "SIM" card, identifying the phone itself. In this regard, reference may be made, for example, to European patent application 0 835 007, to international patent application W0 97/22221, or to US patent 5 392 356. In all cases, checking the code d the additional identification is carried out by the mobile telephone operator, therefore by means of a transmission carried out between the mobile telephone and this operator. Such systems remain complex, without necessarily being reliable or effective, in their practical implementation. In particular, the operator can be variable, especially if the mobile phone is used in

  a country other than its country of origin, in which case the system becomes inoperative.

  The present invention aims to avoid these drawbacks by providing an anti-theft device for a mobile phone which, while being simple, can provide effective dissuasive protection in any place against theft or unauthorized use of such a phone, without passing by the operator of

mobile telephony.

  To this end, the anti-theft device for a mobile phone according to the present invention comprises, in addition to a smart card carrying a code identifying the subscription, storage means internal to the mobile phone concerned, for storing another code. , specific to this mobile phone, and means of comparison internal to the mobile phone for comparing this other code with data to be entered by the user, as well as means also internal to said mobile phone which, in the event of a mismatch of these data with the memorized code, are capable of commanding a state of non-functioning of the mobile telephone. Thus, the invention notably consists in adding a "secret code", specific to the telephone and no longer to the "SIM" card, this code being stored in an internal memory of the already existing telephone, or to be added. It can be a pre-established and invariable code, "engraved" in this memory of the phone as of its manufacture or its delivery, or on the contrary of a code chosen by the user, the code being in this case entered in the memory by the user when the phone is switched on for the first time, and which can be possibly modified later by the user (insofar as said memory can be erased

and rewritable).

  This code can be requested either each time the telephone is switched on, or, preferably, each time the smart card is inserted (card

  "SIM"), which links the card to the phone code.

  Thus, in normal use of the mobile phone concerned, if the data entered at the start-up or when the card is changed agree with the memorized code identifying the phone, the operation of this phone is authorized and, after additional introduction of the code

  "PIN" suitable, the telephone becomes effectively usable.

  Conversely, in the event of non-supply of the memorized code identifying the telephone, possibly after a small number of authorized attempts, a process of setting in non-operating state is initiated, several

solutions being possible.

  According to a first possibility, the telephone which has not recognized its identification code is automatically blocked by software. Only a return to the factory then makes it possible to return the telephone to working order. According to another possibility, the telephone which has not recognized its identification code first warns, on its display, that it cannot function and / or that it will self-destruct within a fixed period, by example of ten seconds if

  its power is not cut by the user.

  The self-destruction of the mobile telephone can consist in producing an internal short circuit, in one or more places, for example by the intermediary of a transistor, and preferably in the lower layers of its printed circuit, so as to destroy some components, without possibility

  repair, the phone thus becoming permanently unusable.

  The self-destruction warning on the phone display, before possible destruction, allows the authorized user not to

  lose the use of your telephone, in the event of involuntary false operations.

  If the authorized user has "lost" the phone's identification code, the

  system can be reactivated by returning to the factory.

  The limitation of the number of authorized attempts, and the time limit allowed, also prevents fraudulent attempts to activate the

  telephone by systematic testing of all possible codes.

  To make the system even more difficult to "force", the code can

be encrypted.

  Of course, the mobile telephone equipped with the anti-theft device that is the subject of the invention can itself carry a label or other inscription warning that this telephone is protected, so as to create a deterrent effect

vis-à-vis possible thieves.

  As follows from the above, the invention provides an effective and simple anti-theft device, which is also a reliable device in the sense that it has a certain functioning everywhere, since the operation of this device is independent of any operator. or mobile phone network,

  unlike previous proposals.

  The invention will in any case be better understood using the

  description which follows, with reference to the appended schematic drawing representing,

  as an example, an embodiment of this anti-theft device for

mobile phone.

  The only figure in the drawing shows the anti-theft device under the

  form of a functional block diagram.

  In a manner known per se, and as shown in the left-hand part of this diagram, the mobile telephone concerned comprises, as indicated in 1, a means of detecting the switching on or off of this telephone, or of changing the card chip 2 called "SIM" card. A request for the code carried by this card 2 ("PIN 'code) is made, as indicated in 3, each time the telephone is switched on or each time the card 2 is changed. In 4, the code entered by the user is compared with the code of card 2. If the code entered is "good", the situation is considered at 5 as "normal" and the use of the telephone, in particular to make a call, is authorized. does not agree with that of card 2, three attempts (for example) are authorized, as indicated in 6, to enter the "correct code". If these attempts do not allow the entry of the "correct code", a

  blocking of the "SIM" card is controlled, as indicated in 7.

  The anti-theft device, object of the invention, comprises a part

  specific, which is "grafted" on the known part previously described.

  This part also includes, as indicated in 8, a means of detecting when the mobile telephone is started or stopped, or when the "SIM" card is changed. 2. A request for the identification code N, specific to the telephone concerned and stored in a memory 9, is carried out as indicated in 10 each time the telephone is started up or each time the card 2 is changed. At 11, the data then entered by the user are compared with said identification code N. If, as a result of this comparison, the data entered agree with the identification code N of the mobile telephone, the "normal" process of activating this telephone continues, as indicated by the link 12, by the request in 3 of the code carried by the "SIM" card 2, so

known per se (see above).

  In the event of a mismatch between the data entered and the identification code N of the mobile telephone, three attempts (for example) are authorized, as indicated in 13, to enter the "correct" code. In addition, as indicated in 14, there is provided a function for switching off the telephone, for example within ten seconds, if the power supply to this telephone is not cut by the user himself. even if incorrect data is entered, which does not match the identification frame N of the telephone. If the telephone is not switched off, and the correct data is not entered during the three authorized attempts, a signal

  self-destruct command of the mobile phone is issued in 15, and the auto-

  destruction of this telephone is then carried out, as indicated in 16.

  In addition, as indicated in 17, a self-destruction control function can be provided in the event that more than ten unsuccessful attempts are made, with intermediate shutdowns

  (since only three successive attempts are authorized - see above).

  Thus, systematic tests of all possible codes are defeated.

  Of course, the invention is not limited to the single form of

  realization of this anti-theft device for mobile phone which has been described below

  above, by way of example; it embraces, on the contrary, all variants respecting the same principle, whatever the methods of introduction and recognition of data corresponding to the identification code of the

  mobile phone, and whatever the action provoking the state of non

  operation or self-destruction of the mobile phone.

Claims (9)

  1 - Anti-theft device for mobile phone, characterized in that it comprises, in addition to a smart card (2) carrying a code identifying the subscription, storage means (9) internal to the mobile phone concerned, for the storage of another code (N), specific to this mobile phone, and comparison means (11) internal to the mobile phone for the comparison of this other code (N) with data to be entered by the user, as well as means (15) also internal to said mobile telephone which, in the event of non-agreement of this data with said other code   (N) motorized, are able to control a state of non   mobile phone operation.   2 - Anti-theft device for mobile phone according to claim 1, characterized in that said other code (N) is stored in a memory   internal (9) already existing phone.   3 - Anti-theft device for mobile phone according to claim 1 or 2, characterized in that said other code (N) is a preset code and   invariable, "engraved" in the memory (9) of the telephone.   4- anti-theft device for mobile phone according to claim 1 or 2, characterized in that, said other code (N) is a code chosen by the user, this code (N) being entered in the memory (9) by the user when the phone is started for the first time, and which can possibly be modified later.   - Anti-theft device for mobile phone according to any one   of claims 1 to 4, characterized in that said other code (N) is   asked again (in 10) each time the phone is started.   6- Anti-theft device for mobile phone according to any one   of claims 1 to 4, characterized in that said other code (N) is   asked again (in 10) each time the smart card (2) is inserted.   7- Anti-theft device for mobile phone according to any one   of claims 1 to 6, characterized in that the process of preparation   phone malfunction is initiated after a low number of authorized attempts (in 13).   8 - Anti-theft device for mobile phone according to one   any one of claims 1 to 7, characterized in that the preparation   of non-functioning of the mobile phone consists of a blocking   automatically by software of this phone.   9 - Anti-theft device for mobile phone according to one   any one of claims 1 to 7, characterized in that the preparation   of non-functioning of the mobile phone consists of an auto-   destruction of this telephone (in 16).   - Anti-theft device for a mobile phone according to claim 9, characterized in that the self-destruction (at 16) of the mobile phone consists in producing an internal short circuit, in one or more places, preferably in the lower layers of sound. circuit   printed, so as to destroy certain components.   11 - Anti-theft device for mobile phone according to one   any of claims 8 to 10, characterized in that, in the event of non-   recognition of its identification code (N), the phone first warns on its display that it cannot function and / or that it will self-destruct in a   fixed time, if its power is not cut by the user.