Method for indicating enciphering of data transmission between a mobile communication network and a mobile station
The invention relates to a method for indicating enciphering of data transmission between a mobile communication network and a mobile station (MS) in the mobile communication network, wherein signals transferred between a mobile communication network and a mobile station are monitored, and on the basis of the signal monitored, the cipher mode is indicated to the user of the mobile station.
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This application is a division of application Ser. No. 09/827,593 filed Apr. 6, 2001 which is a continuation of application Ser. No. 08/763,970 filed Dec. 10, 1996, now U.S. Pat. No. 6,249,584 issued Jun. 19, 2001.
BACKGROUND OF THE INVENTIONThe invention relates to a method and an apparatus for indicating enciphering of data transmission between a mobile communication network and a mobile station in the mobile communication network.
In mobile networks, at least part of the data transmission is wireless communication using radio transmitter and receivers. The radio channel is a physically open resource available to anyone by means of suitable communication equipment. This involves security risks, such as eavesdropping or disclosure of privacy of location. In digital mobile networks, such as GSM networks, digital data transmission is used which is difficult to eavesdrop. Further, it is possible to use identification of the caller and enciphering in data transmission. For preventing eavesdropping in digital mobile networks, enciphering methods have been developed for enciphering the speech and data signals modified in digital form. Moreover, enciphering can be used in the transmission of other information via the radio channel, such as identification data on the mobile station (International Mobile Subscriber Identity, IMSI) and on the location (Location Area Identification, LAI). In the receiver, the enciphered signal is deciphered back to deciphered speech and data. A so-called encryption key and algorithm are advantageously known to the respective sending and receiving devices only, wherein given the effective encryption algorithms presently in use, decoding a coded signal to intelligible speech and data as well as into processing signals of the bit stream by force or illegally, i.e. without the correct encryption key and algorithm, is practically impossible.
The most common digital mobile networks are cellular networks. The base station subsystem (BSS) of the mobile network comprises base transceiver stations (BTS) and base station controllers (BSC). The mobile station (MS) communicates via the radio channel with a base station close to the respective location of the mobile station. The base station communicates with the base station controller. Data transmission between the base station and the base station controller takes place usually via a cable. One base station controller controls over a group of several base stations. The base station controller, in turn, communicates with a mobile services switching centre (MSC). Several mobile services switching centres, in turn, can communicate with each other as well as with a landline communication network centre (PSTN, ISDN). The information to be transmitted is usually divided into frames containing control information, speech and data converted into digital form, and error correction information. The frame structure can have several levels, wherein frames of a higher level are formed by arranging frames of a lower level. Enciphering can be used both with control information and with speech and data. Moreover, enciphering can be realized by using different encryption keys and algorithms at different frame levels. An example of a digital data transmission network is the GSM network, the standard of which contains definitions of the enciphering methods and algorithms to be used.
In the GSM network, making a mobile-originated call is conducted in a way that a GSM mobile station and the GSM system network give signals, i.e. transmit control and identification information required for making a call. In response to a request for a connection, the GSM mobile station is allotted a channel for signalling, if this is possible within the capacity of the GSM system network. On this channel, the GSM mobile station requests speech or data service from the GSM system network. On the side of the GSM system network, this request is transmitted to a mobile services switching centre (MSC), where the rights of the GSM subscriber are checked from a visitor location register (VLR).
Upon a mobile-terminated call e.g. from a subscription of a landline telephone network, the operator of the telephone network transmits e.g. the number of the receiving telephone to the mobile services switching centre. The mobile services switching centre finds out the rights of the GSM subscriber from the home location register (HLR) and from the visitor location register (VLR). After this, the GSM system network and the GSM mobile station transmit the control and identification information required for making a call.
Depending on the implementation and the configuration of the parameters, the visitor location register VLR can make a request via the mobile services switching centre to the GSM mobile station for exchange of identification information and start of enciphering. This request is made in a so-called cipher mode command message. It is, however, possible to make a call also without exchange of identification information and enciphering. In other words, the call is either enciphered or not enciphered depending on the network parameters set by the GSM system network operator.
In most common mobile communication networks currently available, however, enciphering is not optional to a user of the mobile communication network but usually an alternative function offered by the operator of the mobile network, wherein when current wireless data transmission equipment is used, the user has no certainty whether the data transmission is enciphered or not. Particularly when the mobile station is moving, the mobile station can be transferred from the area of one base station system to the area of another base station system, wherein the cipher mode of data transmission can be changed.
SUMMARYOne purpose of the present invention is to eliminate the disadvantages described above and to provide a method for indicating enciphering of data transmission to the user of the mobile communication network. The invention is based on the idea that control signals used in data transmission between a mobile network and a mobile station are monitored and when a control signal for enciphering is detected, the cipher mode is signalled with a cipher mode indicator connected to the mobile station. The method of the invention is characterized in that signals transferred between a mobile communication network and a mobile station are monitored, and on the basis of the signal monitored, the cipher mode is indicated to the user of the mobile station.
The apparatus according to the invention is characterized in that the apparatus comprises means for monitoring signals transferred between a mobile communication network and a mobile station, and means for indicating the cipher mode to the user of the mobile station.
The invention gives significant advantages. Using the method of the invention, the user of a data transmission device is always aware of whether the data transmission is enciphered or not. Further, by using the method of the invention, it is possible to indicate a possible change in the cipher mode during the data transmission to the user of the data transmission device.
BRIEF DESCRIPTION OF THE DRAWINGIn the following, the invention will be described in more detail with reference to the appended drawings. In the drawings,
Now referring to
During a call, it is possible to transmit so-called short message services (SMS) to the mobile station. In the transmission of short messages, the cipher mode may deviate from the cipher mode of the call in question, wherein the method of the invention can be used to indicate the cipher mode separately for the call and for the short message services. Also a change in the cipher mode can be indicated to the user both for the call and for the short message services. For indicating the cipher mode and a change in the cipher mode, signals distinguishable from each other can be used, e.g. different acoustic signals, wherein the user of the mobile station is aware of the cipher mode of both the call and the short message services.
The method according to the present invention can also be applied in a way that the existence of enciphering is indicated to the user already before starting the call. This can be implemented advantageously by providing the menu structure of the mobile station with a function whereby the user can ask the mobile communication network about the cipher mode. When this function is selected from the menu, the mobile station sends the mobile network a message inquiring the cipher mode. In practice, this can be conducted in the GSM mobile network by forcing the mobile station to a location update procedure. This procedure contains starting of enciphering if the cipher mode is active in the mobile communication network. In this way, the mobile station can send to the mobile communication network an enquiry about the current cipher mode, which is indicated to the user e.g. by an icon in the display of the mobile station.
Problems may result in countries where enciphering is not allowed to be on during speech because of legislation or for another reason. However, enciphering can thus be on for signalling, i.e. the location update procedure shows cipher-on mode although it is not on for speech. Thus the mobile station can produce an acoustic signal when it turns on the speech channel and detects a change in the cipher mode, wherein the user will be informed that speech is not transferred in enciphered form.
Data transmission from the resource control block 1 to the cipher indication data field CIND is preferably controlled by the central processing unit MCU, wherein the central processing unit MCU reads the ciphering information and transmits it to the cipher indication data field CIND via the first signal bus 4, the transmission bus 5 and the second signal bus 6. Said buses can advantageously be arranged by known solutions used in connection with microcontrollers. Said signal buses can also be placed in the microcontroller itself, wherein the microcontroller comprises a central processing unit MCU, a resource control block 1, a cipher indicator memory block 2 comprising also the cipher indication data field CIND, as well as said signal buses 4, 6 and data transmission bus 5.
The central processing unit MCU has a data transmission connection also to the user interface block UI via the first signal bus 4, the data transmission bus 5 and the third signal bus 7. Consequently, the central processing unit MCU can advantageously control also the display unit control means 9 and the control means 11 for the acoustic signal forming element situated in the user interface block UI. This control can be arranged in a way that the central processing unit MCU sets the control line of the display unit control means 9 (not shown) to a logical “0” value (ca. 0 V) when the cipher mode is off. The central processing unit MCU sets the control line of the display unit control means 9 to a logical “1” value (for example ca. 3 V) when the cipher mode is on. Acoustic signal formation can be applied in a corresponding manner. Thus the central processing unit MCU sets the control line of the control means 11 for the acoustic signal forming element (not shown) to a logical “0” value, when there are no changes in the cipher mode. When the cipher mode is changed, the central processing unit MCU sets said control line for a moment to a logical “1” value and resets said control line to an “0” value after a suitable length of time. Thus the length of the acoustic signal can be influenced by the duration of the “1” value state.
Data transmission between different blocks in the apparatus according to the invention can be arranged using methods known as such, wherein it is unnecessary to explain it in more detail in this context.
The method of the present invention can be advantageously applied also in mobile stations currently in use in a way that the functions required in the method are provided in the operational software of the mobile station. Thus no changes will be required in the hardware of the mobile station.
The invention can also be applied in a way that part of the functions required in the method are provided in the operational software of the mobile station and part of them are provided in the software of a data processor which is in transmission connection with the mobile station. One such embodiment is illustrated as a reduced block diagram in
In this embodiment, the mobile station is also used as a so-called wireless modem in connection with a data processor, such as a personal computer, wherein a data transmission connection is formed from the data processor PC via the mobile communication network e.g. to another data processor. In this case, it is advantageous to indicate the cipher mode as a certain sign on the display 12 of the data processor and possibly also as an acoustic signal by the acoustic signal forming element 13 of the data processor. The cipher indicator memory block 2 transmits information on a change in the cipher indication data field advantageously to the data processor PC by means of a mobile station connection element 14 and a PC connection bus 15. The data processor PC is provided with application software which controls that the data on the change in the cipher indication data field is read in the data processor PC from a data processor connection element 16 and processed preferably in the central processing unit 17 of the data processor. After this the data processor PC sends out a cipher mode enquiry message which is transmitted back to the cipher indicator memory block by means of the data processor connection element 16, the PC connection bus 15 and the mobile station connection element 14. In response to the enquiry message, the cipher indicator memory block 2 sends the cipher data to the data processor PC. From the data processor PC, the cipher data is read from the data processor connection element 16 and transmitted to the cipher mode indicator. The cipher mode indicator is preferably the display unit 12 and possibly also the acoustic signal forming element 13 of the data processor. Thus the cipher mode is indicated by a suitable symbol on the display unit 12 of the data processor. In a corresponding way, a change in the cipher mode is indicated e.g. as an acoustic signal by the acoustic signal forming element 13 of the data processor. Also the operation and structure of the data processor PC are generally known and need not be explained in more detail in this context.
Further, with reference to
If the cipher mode in the second mobile station MS2 is changed during a call, it sends a message on the change in the cipher mode by user-user signalling.
For enquiring the cipher mode of communication [to and from] the second mobile station MS2, also other methods can be used, such as short message services (SMS).
The ISDN telecommunication network (Integrated Services Digital Network) provides also an optional user-to-user signalling service (UUS) which makes communication possible between telecommunication terminals in a data transmission connection with each other. Thus, if a data transmission connection is made from a mobile station MS to a telecommunication terminal of the ISDN type, the mobile station MS can send the telecommunication terminal an enquiry about the cipher mode by using the user-to-user signalling service. If the telecommunication terminal does not recognize the enquiry message of the mobile station MS, the mobile station MS will not receive a response to the enquiry, or the response will consist of an unidentified command or another corresponding message. In such a case, the mobile station MS can deduce that the telecommunication terminal is not a mobile station but most probably a telecommunication terminal connected with a landline telecommunication network. In this situation, the display unit of the mobile station MS indicates the user of the mobile station for example that the cipher mode between the second telecommunication terminal and the telecommunication network is unknown.
For indicating the cipher mode and a change in the cipher mode to the user of the mobile station MS, also other methods, known as such, can be used. For example, the cipher mode can be indicated by a light source, such as a light-emitting diode (LED). Consequently, for example when the cipher mode is on, a control voltage is supplied to the LED (the LED is emitting) and when the communication is not enciphered, no control voltage is supplied to the LED (the LED is unlit). A change in the cipher mode can be advantageously indicated by flashing the LED. Thus for example when the communication is not enciphered, the LED is unlit, and when the communication becomes enciphered, the LED flashes for a moment after which the LED will emit light continuously as long as the cipher mode is on. In a corresponding manner, when the communication becomes unenciphered, the LED will flash for a moment before it is turned off.
Further, so-called vibration batteries have been developed for mobile stations whereby the mobile station can be made to vibrate in a muffled way. Thus the cipher mode of data transmission can be indicated also by a vibration battery, wherein for example upon a change in the cipher mode, a control signal is supplied to the vibration battery for a moment, which will result in vibration of the mobile station and detection of the change in the cipher mode by the user of the mobile station.
The invention is not limited only to the embodiments presented above, but it can be modified within the scope of the appended claims.
Claims
1. An apparatus capable of use within a mobile station for data communication between the mobile station and a mobile communication network, the mobile communication network and mobile station being capable of data communication in at least one enciphered mode of communication and at least one unciphered mode of communication, the apparatus comprising:
- an input, the input being capable of receiving information from the mobile communication network concerning a ciphering mode used in communication between the mobile station and the mobile communication network; and
- an output, the output being capable of conveying displayable information to the mobile station, the displayable information indicating that a ciphering mode is to be used in communication between the mobile station and the mobile communication network.
2. An apparatus according to claim 1, the apparatus configured to cause the mobile station to enter an enciphered mode of communication based upon information received from the mobile communication network.
3. An apparatus according to claim 1, the apparatus configured to output displayable information indicating that an unciphered mode of communication is to be used in communication between the mobile communication network and the mobile station based upon information received from the mobile communication network.
4. An apparatus according to claim 1, the apparatus configured to determine the ciphering mode to be used in communication between the mobile communication network and the mobile station during establishment of communication between the mobile communication network and the mobile station.
5. An apparatus according to claim 1, the apparatus configured to determine the ciphering mode to be used in communication between the mobile communication network and the mobile station prior to establishment of communication between the mobile communication network and the mobile station.
6. An apparatus according to claim 5, the apparatus configured to determine the ciphering mode to be used in communication prior to establishment of communication between the mobile communication network and the mobile station by performing a location update procedure.
7. An apparatus according to claim 1, the apparatus configured to maintain a cipher mode indication data field, the apparatus configured to set the cipher mode indication field initially into a first state indicative that an unciphered mode of communication is to be used in communication between the mobile communication network and the mobile station, and the apparatus configured to change the state of the cipher mode indication field into a second state indicative that an enciphered mode of communication is to be used in communication between the mobile communication network and the mobile station based upon information received from the mobile communication network.
8. An apparatus according to claim 1, the displayable information displayed by a display unit.
9. An apparatus according to claim 1, the displayable information displayed by a light source.
10. An apparatus according to claim 1, the apparatus configured to output displayable information indicating a change in ciphering mode.
11. An apparatus according to claim 10, the displayable information indicating a change in ciphering mode displayed by an acoustic signal forming element.
12. An apparatus according to claim 10, the displayable information indicating a change in ciphering mode displayed by a vibrating element.
13. An apparatus according to claim 1 provided in a mobile station.
14. An apparatus according to claim 1, the displayable information displayed by an external data processor arranged to communicate with a mobile station.
15. An apparatus according to claim 10, the displayable information indicating a change in ciphering mode displayed by an external data processor arranged to communicate with a mobile station.
16. An apparatus according to claim 1, the apparatus further comprising a radio resource management block and a cipher indication memory block, the radio resource management block configured to monitor signals sent from the mobile communication network to the mobile station, the cipher indication memory block comprising a cipher mode indication field, the radio resource management block configured to set the cipher mode indication data field in the cipher indication memory block based upon information received from the mobile communication network.
17. An apparatus according to claim 16, the cipher indication memory block configured to issue an interrupt request in response to a change in the cipher mode indication data field.
18. An apparatus according to claim 17, the apparatus further comprising a user interface block configured to detect the interrupt request and to send an inquiry to the cipher indication memory block to inquire about the state of the cipher mode indication data field, the cipher indication memory block configured to return an indication of the state of the cipher mode indication data field in response to the inquiry.
19. An apparatus according to claim 18, the apparatus further comprising a cipher mode indicator, the user interface block being arranged to control the cipher mode indicator according to the indication.
20. An apparatus according to claim 16, further comprising a user interface block, the cipher indication memory block configured to provide an indication of the state of the cipher mode indication data field to the user interface block when the state of the cipher mode indication data field is changed.
21. An apparatus according to claim 20, further comprising a cipher mode indicator, the user interface block configured to control the cipher mode indicator according to the indication.
22. An apparatus according to claim 16, further comprising a user interface block configured to send repeated inquiries to the cipher indication memory block about the state of the cipher mode indication data field, each inquiry being separated in time from the next by a predetermined interval, the cipher indication memory block configured to return an indication of the state of the cipher mode indication data field in response to each inquiry.
23. An apparatus according to claim 22, the apparatus further comprising a cipher mode indicator, the user interface block configured to control the cipher mode indicator according to the indication.
Type: Application
Filed: Mar 6, 2007
Publication Date: Jun 28, 2007
Applicant: NOKIA CORPORATION (Espoo)
Inventors: Jari Hamalainen (Tampere), Reijo Paajanen (Tampere), Marrku Rautiola (Tampere), Markku Rossi (Tikkakoski)
Application Number: 11/682,627
International Classification: H04K 1/00 (20060101);