JP5965749B2 - Mobile communication method and mobile station - Google Patents

Description

  The present invention relates to a mobile communication method and a mobile station.

  Conventionally, ETWS (Earthquake and Tsunami Warning System), CMAS (Commercial Mobile Alert System), KPAS (Korean Public Alert System, etc.), EU-Alert (Eurp).

  At present, security for PWS is not defined. However, as security for PWS, studies are being made in the direction of using a public key and a digital signature.

  Further, in the current PWS, a new key is used for each “Warning message”, and there is rarely an opportunity to transmit the “Warning message”. Therefore, the mobile station UE updates the key (re-keying). It is assumed that there is sufficient time for performing the process, and that the public key is transmitted by the “NAS Security Mode Command” in the attach process (Attach).

3GPP TS 33.869, “Technical Specification Group Service and System Aspects; Security Aspects of Public Warning System (PWS)”

  However, even in the present situation, it is assumed that the generated “Warning message” is continuously updated in PWS.

  For example, in the case of ETWS, a case where the time difference between the “Primary message” and the “Secondary message” is small is assumed.

  In addition, in the case of CMAS and ETWS, “Warning message (Secondary message)” is configured to be repeated periodically, and thus a case where such a repetition cycle is short is assumed.

  Further, CMAS stipulates that “Warning messages” having different contents can be transmitted in parallel.

  As described above, even in the current PWS, a case where “Warning messages” having different contents are transmitted one after another is assumed. In such a case, the mobile station UE does not have sufficient time to update the key, and the mobile station There has been a problem that a case in which the UE cannot receive the “Warning message” may occur.

  In addition, every time a “Warning message” is transmitted, in order to perform a key update procedure for all mobile stations UE, there is a problem that the network load increases.

  Therefore, the present invention has been made in view of the above-described problems, and in the PWS, while avoiding an increase in network load, the mobile station UE appropriately receives “Warning messages” transmitted with different contents one after another. It is an object of the present invention to provide a mobile communication method and a mobile station that can be used.

  A first feature of the present invention is a mobile communication method in which a radio base station notifies the mobile station of the warning information and a digital signature generated based on the counter together with the warning information and the counter. The mobile station performs a verification process on the digital signature using a predetermined public key, compares the received counter with a held counter, and the mobile station A step of displaying the received warning information when the verification process is successful and the received counter is determined to be the same as or more advanced than the held counter. Is the gist.

  According to a second aspect of the present invention, there is provided a mobile station that is configured to receive a warning information and a digital signature generated based on the counter together with the warning information and the counter from the radio base station. And a verification unit configured to perform verification processing on the digital signature using a predetermined public key, and to compare the received counter with a held counter, and the verification processing And when the received counter is determined to be the same as or more advanced than the held counter, the received warning information is displayed. And a display unit.

  As described above, according to the present invention, in the PWS, the mobile station UE can appropriately receive “Warning message” transmitted with different contents one after another while avoiding an increase in network load. A method and a mobile station can be provided.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 3 is a functional block diagram of a mobile station according to the first embodiment of the present invention. FIG. 3 is a sequence diagram showing an operation of the mobile communication system according to the first embodiment of the present invention. FIG. 3 is a sequence diagram showing an operation of the mobile communication system according to the first embodiment of the present invention. 3 is a flowchart showing an operation of the mobile station according to the first embodiment of the present invention.

(Mobile communication system according to the first embodiment of the present invention)
A mobile communication system according to a first embodiment of the present invention will be described with reference to FIG. 1 to FIG.

  In the present embodiment, an LTE mobile communication system will be described as an example. However, the present invention is not limited to such a mobile communication system, and is applicable to other mobile communication systems.

  As shown in FIG. 1, the emergency information delivery system according to the present embodiment includes a cell broadcast entity CBE (Cell Broadcast Entity), a cell broadcast center CBC (Cell Broadcast Center), a mobility management node MME (Mobility Management Entity), and A radio base station eNB and a mobile station UE.

  As illustrated in FIG. 2, the mobile station UE includes a transmission unit 10, a reception unit 11, a verification unit 12, and a display unit 13.

  The transmission unit 10 is configured to transmit various signals to the radio base station eNB. For example, the transmission unit 10 is configured to transmit “Attach Request” and “TAU (Tracking Area Update) Request” addressed to the mobility management node MME to the radio base station eNB.

  The receiving unit 11 is configured to receive various signals from the radio base station eNB. For example, the receiving unit 11 is configured to receive “NAS Security Mode Command” and broadcast information (Broadcast Information) from the radio base station eNB.

  Specifically, the reception unit 11 is generated based on the “Warning message” and “Counter cw” together with the “Warning message (warning information)” and “Counter cw (counter)” via the broadcast information. It is configured to receive a “Signature (digital signature)”.

  The receiving unit 11 is configured to receive a “counter cs (counter)” and a predetermined public key Pk in an attach process or a location registration (TAU) process.

  Furthermore, the receiving unit 11 is configured to receive a new “counter cs” via the broadcast information at a predetermined timing. The new “counter cs” may be given a digital signature.

  In the mobile communication system according to the present embodiment, the predetermined public key Pk may be configured not to be transmitted at a timing other than the attach process and the position registration process.

  Further, the network can transmit “Counter cw” at a predetermined timing, that is, at a timing other than the attach processing and the location registration processing (for example, timing when transmission of a series of “Warning messages” is completed). It is configured.

  Note that “Counter cw” and “counter cs” are counters incremented by the network, and are configured to take numerical values within a predetermined range. Here, “Counter cw” and “counter cs” are configured to return to the minimum value when incremented from the maximum value.

  The verification unit 12 is configured to perform verification processing on “Signature” received by the reception unit 11 using a predetermined public key Pk.

  The verification unit 12 is configured to compare “Counter cw” received by the receiving unit 11 with “counter cs” held by itself.

  Here, the verification unit 12 is configured to hold “counter cs” and a predetermined public key Pk received by the reception unit 11 in the attach process or the position registration process.

  The verification unit 12 is configured to newly hold “counter cs” received by the reception unit 11 at a predetermined timing.

  That is, the verification unit 12 includes only the new “Counter cw” (incremented “Counter cw”) in the broadcast information received from the radio base station eNB (including the new predetermined public key Pk). The stored “counter cs” may be updated, and the predetermined public key Pk held may be used for the verification process for “Signature” without being updated. .

  Note that the verification unit 12 may be configured to compare “Counter cw” and “counter cs” only when the above-described verification process is successful.

  The display unit 13 is configured to display the “Warning message” received by the receiving unit 11.

  For example, the display unit 13 may be configured to display the content of the “Warning message” on the display, or may be configured to output audio information corresponding to the content of the “Warning message”. Good.

  Further, the display unit 13 determines that the verification unit 12 determines that the verification process is successful, and that “Counter cw” is the same as “counter cs” or advanced than “counter cs”. In such a case, the “Warning message” is displayed.

  Here, the display unit 13 determines that “Counter cw” is the same as “counter cs” or more advanced than “counter cs” even when the verification unit 12 succeeds in the verification process for “Signature”. If not, the “Warning message” may be configured to be discarded.

  The network may be configured to be able to transmit “Warning messages” having a plurality of different contents without incrementing “Counter cw”.

  Hereinafter, the operation of the mobile communication system according to the present embodiment will be described with reference to FIGS. 3 to 5.

  First, with reference to FIG. 3, an operation of an attach process or a position registration process in the mobile communication system according to the present embodiment will be described.

  As illustrated in FIG. 3, in step S1001, the mobile station UE transmits “Attach Request” or “TAU Request” to the mobility management node MME via the radio base station eNB.

  In step S1002, “ESP AKA procedure” is performed between the mobile station UE and the mobility management node MME.

  In step S1003, the mobility management node MME transmits “NAS Security Mode Command” to the radio base station eNB.

  Here, the “NAS Security Mode Command” includes a predetermined public key Pk (latest), “counter cs”, “signing entity ID”, and the like.

  In step S1004, the radio base station eNB transmits “NAS Security Mode Command” to the mobile station UE.

  Here, the “NAS Security Mode Command” includes a predetermined public key Pk (latest), “counter cs”, “signing entity ID”, and the like.

  Here, the mobile station UE holds a predetermined public key Pk and “counter cs” included in the received “NAS Security Mode Command”.

  In step S1005, the mobile station UE transmits “NAS Security Mode Command Complete” to the radio base station eNB. In step SS1006, the radio base station eNB sends “NAS Security Mode Mode” to the mobility management node MME. Command Complete ”is transmitted.

  In step S1007, the mobile station UE transmits “Attach Accept” or “TAU Accept” to the mobility management node MME via the radio base station eNB.

  After that, the network notifies the mobile station UE of a new “counter cs” via the broadcast information at a predetermined timing in order to update the “counter cs” held in the mobile station UE. can do. However, in the mobile communication system in the present embodiment, it is assumed that the predetermined public key Pk held in the mobile station UE is not updated.

  In this case, when the mobile station UE receives a new “counter cs”, the mobile station UE updates the “counter cs” held by the mobile station UE with the new “counter cs”.

  Secondly, with reference to FIG. 4, an operation of transmitting a “Warning message” in the mobile communication system according to the present embodiment will be described.

  As illustrated in FIG. 4, in step S2001, the cell broadcast entity CBE transmits “Emergency Broadcast Request” to the cell broadcast center CBC.

  Here, “Emergency Broadcast Request” includes “Warning message”, “Counter cw”, “Signature”, and the like.

  The “Signature” is a digital signature generated based on the “Warning message” and the “Counter cw”.

  In step S2002, the cell notification center CBC transmits “Write-Replace Warning Request” to the mobility management node MME.

  Here, “Write-Replace Warning Request” includes “Warning message”, “Counter cw”, “Signature”, and the like.

  In step S2003, the mobility management node MME transmits “Write-Replace Warning Confirm” to the cell broadcast center CBC.

  In step S2004, the cell broadcast center CBC transmits “Emergency Broadcast Response” to the cell broadcast entity CBE.

  In step S2005, the mobility management node MME transmits “Write-Replace Warning Request” to the radio base station eNB.

  Here, “Write-Replace Warning Request” includes “Warning message”, “Counter cw”, “Signature”, and the like.

  In step S2006, the radio base station eNB transmits broadcast information to the mobile station UE.

  Here, the notification information includes “Warning message”, “Counter cw”, “Signature”, and the like.

  3rdly, with reference to FIG. 5, the operation | movement when the mobile station UE receives the alerting | reporting information containing "Warning message" in the mobile communication system which concerns on this embodiment is demonstrated.

  As illustrated in FIG. 5, when the mobile station UE receives broadcast information including “Warning message”, “Counter cw”, “Signature”, and the like in step S101, the mobile station UE stores the predetermined information held by itself in step S102. Using the public key Pk, a verification process for the “Signature” is performed.

  If the verification process is successful in step S103, the operation proceeds to step S104. If the verification process fails, the operation proceeds to step S106.

  In step S104, the mobile station UE compares the “Counter cw” with the “counter cs” held by itself.

  If it is determined that “Counter cw” is ahead of “counter cs”, the operation proceeds to step S105. If it is determined that “Counter cw” is not ahead of “counter cs”, Operation proceeds to step S106.

  In step S105, the mobile station UE displays such “Warning message”.

  On the other hand, in step S106, the mobile station UE does not display such “Warning message”.

  According to the mobile communication system according to the present embodiment, in the PWS, the mobile station UE does not need to update the public key Pk for verifying the validity of the “Warning message” for each “Warning message”. Even when a “Warning message” having a different content is transmitted, the “Warning message” can be appropriately received.

  As a result, it is not necessary to perform a key update procedure for all mobile stations UE every time a “Warning message” is transmitted, and thus an increase in network load can be avoided.

  Also, according to the mobile communication system according to the present embodiment, every time the above-mentioned “Warning message” is transmitted, the counter corresponding to the public key Pk for verifying the validity of the “Warning message” (that is, “Counter” Since “cw” is updated, a security effect equivalent to “a new key is used for each“ Warning message ””, which is a premise in the existing PWS, can be realized.

(Modification 1)
Hereinafter, the mobile communication system according to the first modification of the present invention will be described by focusing on the differences from the mobile communication system according to the first embodiment described above.

  In the mobile communication system according to the first modification, the network updates the mobile station via the broadcast information at a predetermined timing in order to update the predetermined public key Pk and “counter cs” held in the mobile station UE. A new predetermined public key Pk can be notified to the UE together with a new “counter cs”.

  In the broadcast information, a new “counter cs” may be given a digital signature.

  In such a case, the mobile station UE receives a new “counter cs” and a new predetermined public key Pk (that is, the broadcast information includes both the new “counter cs” and the new predetermined public key Pk). In this case, the “counter cs” and the predetermined public key Pk held by itself are updated with the new “counter cs” and the new predetermined public key Pk.

  Note that the network transmits the “Counter cw” and the predetermined public key Pk at a predetermined timing, that is, at timings other than the attach process and the position registration process (for example, when the transmission of a series of “Warning messages” is completed). You may be comprised so that it can do.

  Here, the network may be configured to simultaneously transmit “Counter cw” and the predetermined public key Pk, or to transmit only one of “Counter cw” and the predetermined public key Pk. It may be configured.

  The characteristics of the present embodiment described above may be expressed as follows.

  A first feature of the present embodiment is a mobile communication method, in which the radio base station eNB sends a “Warning message (warning information)” and a “Counter cw (counter)” to the mobile station UE. The step of notifying the “Signature (digital signature)” generated based on the “Warning message” and “Counter cw”, and the mobile station UE uses the predetermined public key Pk to verify the “Signature” (Verification) ) And comparing the received “Counter cw” with the held “counter cs” and the case where the mobile station UE has succeeded in the above-described verification process, and the received “Counter cw” Is the same as the “counter cs” or “ and a step of displaying the received “Warning message” when it is determined that the process is ahead of “counter cs”.

  In the first feature of the present embodiment, the mobile station UE may further include a step of receiving and holding “counter cs” and a predetermined public key Pk in the attach process or the position registration process.

  In the first feature of the present embodiment, the network (wireless base station eNB) further has a step of updating only “counter cs” held by the mobile station UE using broadcast information at a predetermined timing. May be.

  In the first feature of the present embodiment, the network (radio base station eNB) updates “counter cs” and a predetermined public key Pk held by the mobile station UE using broadcast information at a predetermined timing. You may have a process further.

  In the first feature of the present embodiment, when the mobile station UE receives the broadcast information described above, the mobile station UE updates the held “counter cs” and updates the held public key Pk. Alternatively, the verification process for “Signature” may be used subsequently.

  In the first feature of the present embodiment, the mobile station UE may update the predetermined public key Pk and “counter cs” held when the broadcast information is received.

  The second feature of the present embodiment is the mobile station UE, which is generated from the radio base station eNB based on the “Warning message” and “Counter cw” together with the “Warning message” and “Counter cw”. Using the receiving unit 11 configured to receive “Signature” and a predetermined public key Pk, the “Signature” is verified, and the received “Counter cw” is held. The verification unit 12 configured to compare “counter cs” and the received “Counter cw” when the verification process is successful and the received “Counter cw” is the same as the “counter cs” or “ If it is determined that it is ahead of "counter cs" And summarized in that and a display unit 13 configured to display the signal "Warning message".

  In the second feature of the present embodiment, the verification unit 12 may be configured to receive and hold “counter cs” and a predetermined public key Pk in the attach process or the position registration process.

  In the second feature of the present embodiment, the verification unit 12 updates the held “counter cs” according to the broadcast information received from the radio base station eNB, and holds the held public key Pk. May be configured to continue to be used for the verification process without being updated.

  In the second feature of the present embodiment, the verification unit 12 is configured to update a predetermined public key Pk and “counter cs” that are held in accordance with broadcast information received from the radio base station eNB. May be.

  Note that the operations of the mobile station UE, the radio base station eNB, and the mobility management node MME described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be a combination of both. May be implemented.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the mobile station UE, the radio base station eNB, or the mobility management node MME. Further, the storage medium and the processor may be provided as a discrete component in the mobile station UE, the radio base station eNB, or the mobility management node MME.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

UE ... mobile station 10 ... transmission unit 11 ... reception unit 12 ... verification unit 13 ... display unit

Claims (10)

The wireless base station notifying the mobile station of the warning information and the counter together with the warning information and the digital signature generated based on the counter;
The mobile station performs a verification process on the digital signature using a predetermined public key, and compares the received counter with a held counter;
When the mobile station has succeeded in the verification process, and when the received counter determines that the received counter is the same as or more advanced than the held counter, the received warning information is displayed. And a mobile communication method.   The mobile communication method according to claim 1, further comprising a step of the mobile station receiving and holding the counter and the predetermined public key in an attach process or a location registration process.   The mobile communication method according to claim 1, further comprising the step of updating only the counter using broadcast information at a predetermined timing.   The mobile communication method according to claim 1, further comprising the step of updating the predetermined public key and the counter using broadcast information at a predetermined timing.   The mobile station updates the held counter when the broadcast information is received, and continues to use the predetermined public key for the verification process without updating the counter. Item 4. The mobile communication method according to Item 3.   The mobile communication method according to claim 4, wherein the mobile station updates the predetermined public key and the counter held when the broadcast information is received. A receiver configured to receive the warning information and a digital signature generated based on the counter, together with the warning information and the counter, from the radio base station;
A verification unit configured to perform a verification process on the digital signature using a predetermined public key, and to compare the received counter with a held counter;
The received warning information is displayed when the verification process is successful and when it is determined that the received counter is the same as or more advanced than the held counter. And a display unit.   The mobile station according to claim 7, wherein the verification unit is configured to receive and hold the counter and the predetermined public key in an attach process or a location registration process.   The verification unit updates the held counter according to the broadcast information received from the radio base station, and continues to use the held public key for the verification process without updating the predetermined public key. The mobile station according to claim 7, wherein the mobile station is configured as follows.   The said verification part is comprised so that the said predetermined | prescribed public key and the said counter which are hold | maintained may be updated according to the alerting | reporting information received from the said wireless base station. Mobile station.

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