Mobile communication system, mobile communication method, distribution server, radio line control station, and mobile station

The present invention is a mobile communication system, a mobile communication method, a distribution server, and a wireless device in which a wireless device is configured to transmit emergency information transmitted from a distribution server to a mobile station by using broadcast communication. Regarding line control stations and mobile stations.

Conventionally, emergency information such as earthquake information and tsunami information issued by government offices and local governments is transmitted to mobile stations using broadcast communications such as CBS (Cell Broadcast Service) and MBMS (Multimedia Broadcast / Multicast Service). A mobile communication system for transmitting emergency information is known.

Specifically, in such a mobile communication system for transmitting emergency information, the wireless line control station RNC is specified by using a traffic channel for broadcast communication such as CTCH (Common Traffic Channel) and MTCH (MBMS Traffic Channel). It is configured to transmit the above-mentioned emergency information received from terminals such as government offices and local governments via a distribution server to mobile stations located in the area.

<p num="0004"><nplcit num="1"><text>3GPP TS23.041</text></nplcit><nplcit num="2"><text>3GPP TS23.246</text></nplcit></p>

<p num="0005"> However, in the conventional mobile communication system for transmitting emergency information, the mobile station is not configured to authenticate the sender of the emergency information transmitted by using the broadcast communication, so that the mobile station is forged by an unauthorized radio base station. There is a problem that false alarms may occur due to the transmission of the emergency information, and the credibility of the sender of the emergency information may be lost, and the recipient may be confused.</p><p num="0006"> Therefore, the present invention has been made in view of the above-mentioned problems, and it is possible to prevent spoofing of the sender of the emergency information when the emergency information is transmitted to the mobile station by using the broadcast communication. It is an object of the present invention to provide a mobile communication system, a mobile communication method, a distribution server, a wireless line control station, and a mobile station.</p>

<p num="0007"> The first feature of the present invention is a mobile communication system in which a wireless device is configured to transmit notification information (emergency information) transmitted from a distribution server to a mobile station using broadcast communication. The distribution server includes a key transmission unit configured to transmit the public key of the distribution server to the mobile station, and the wireless device is the transmission from the distribution server. The mobile station includes a notification information transmitting unit configured to transmit the notification information to the mobile station, and the mobile station authenticates the validity of the notification information based on the electronic signature of the received notification information. The gist is to have a certification unit that is configured to do so.</p><p num="0008"> In the first feature of the present invention, the wireless device includes a wireless line control station and a wireless base station, and the notification information transmitting unit is provided in the wireless base station, and the notification of the wireless base station. The information transmission unit is configured to transmit the notification information using a channel for notifying a specific mobile station that there is incoming call information, and the key transmission unit of the distribution server is configured to transmit the notification information. The public key of the distribution server may be configured to be transmitted to the mobile station using a traffic channel for broadcast communication.</p><p num="0009"> In the first feature of the present invention, the wireless device includes a wireless line control station and a wireless base station, and the notification information transmission unit is provided in the wireless line control station of the wireless line control station. The notification information transmission unit is configured to transmit the notification information using a channel for notifying a specific mobile station that there is incoming call information, and the key transmission unit of the distribution server. May be configured to transmit the public key of the distribution server to the mobile station using a traffic channel for broadcast communication.</p><p num="0010"> In the first feature of the present invention, the distribution server uses an electronic signature generator configured to generate an electronic signature for the notification information and a traffic channel for broadcast communication to generate the electronic signature. It may include an electronic signature transmitter configured to transmit the signature to the mobile station.</p><p num="0011"> In the first feature of the present invention, the distribution server transmits an electronic signature generator configured to generate an electronic signature for the notification information and the generated electronic signature to the wireless line control station. The notification information transmission unit of the wireless line control station includes an electronic signature transmission unit configured to perform the above, and uses a channel for notifying a specific mobile station that there is incoming information. , The electronic signature may be configured to be transmitted to the mobile station together with the notification information.</p><p num="0012"> In the first feature of the present invention, the wireless line control station includes an electronic signature generator configured to generate an electronic signature for the received notification information, and the notification information of the wireless line control station. The transmitting unit is configured to transmit the electronic signature together with the notification information to the mobile station by using a channel for notifying the specific mobile station that there is incoming information. May be good.</p><p num="0013"> A second feature of the present invention is a mobile communication method in which a wireless device transmits notification information transmitted from a distribution server to a mobile station by using broadcast communication, and the distribution server is the same. A step of transmitting the public key of the distribution server to the mobile station, a step of the wireless device transmitting the notification information transmitted from the distribution server to the mobile station, and a step of receiving the notification information by the mobile station. The gist is to have a step of authenticating the validity of the notification information based on the electronic signature of the notification information.</p><p num="0014"> A third feature of the present invention is a distribution server configured to transmit notification information to a mobile station via a wireless device using broadcast communication, and the public key of the distribution server is used. A key transmitter configured to transmit to the mobile station, a notification information transmitter configured to transmit the notification information to the wireless device, and an electronic signature for the notification information. It is a gist to include an electronic signature generation unit configured to generate an electronic signature and an electronic signature transmission unit configured to transmit the generated electronic signature to the wireless device.</p><p num="0015"> A fourth feature of the present invention is a wireless line control station configured to transmit notification information transmitted from a distribution server to a mobile station using broadcast communication, and is a specific mobile. It is configured to transmit the notification information received from the distribution server and an electronic signature for the notification information to the mobile station by using a channel for notifying the station that there is incoming information. The gist is to have a notification information transmission unit.</p><p num="0016"> A fifth feature of the present invention is a wireless line control station configured to transmit notification information transmitted from a distribution server to a mobile station using broadcast communication, and the distribution server. From the distribution server using an electronic signature generator configured to generate an electronic signature for the notification information received from the distribution server and a channel for notifying a specific mobile station that there is incoming information. The gist is to include a notification information transmitting unit configured to transmit the received notification information and the generated electronic signature to the mobile station.</p><p num="0017"> A sixth feature of the present invention is a mobile station configured to receive notification information transmitted using broadcast communication, and said via a control channel for initiating the broadcast communication. The notification information receiving unit configured to receive the notification information, the authentication unit configured to authenticate the validity of the notification information based on the electronic signature of the received notification information, and the authentication. The gist is to include a notification information display unit configured to control the display method of the notification information based on the result.</p><p num="0018"> In the sixth feature of the present invention, the electronic signature receiving unit is configured to receive the electronic signature via the traffic channel for broadcast communication, and the display unit is provided via the control channel. After displaying the received notification information, if the authentication result is negative, it may be configured to display that the notification information is incorrect.</p><p num="0019"> In the sixth feature of the present invention, the electronic signature receiving unit is configured to receive the electronic signature via the control channel for initiating the broadcast communication, and the display unit is the authentication unit. If the result is negative, the notification information received via the control channel may not be displayed.</p>

<p num="0020"> As described above, according to the present invention, when transmitting emergency information to a mobile station using broadcast communication, a mobile communication system capable of preventing spoofing of the sender of the emergency information, mobile Communication methods, distribution servers, wireless line control stations and mobile stations can be provided.</p>

<figref num="1">It is an overall block diagram of the mobile communication system which concerns on 1st Embodiment of this invention.</figref><figref num="2">It is a functional block diagram of the distribution server which concerns on 1st Embodiment of this invention.</figref><figref num="3">It is a functional block diagram of the radio base station Node B which concerns on 1st Embodiment of this invention.</figref><figref num="4">It is a functional block diagram of the mobile station UE which concerns on 1st Embodiment of this invention.</figref><figref num="5">It is a figure which shows an example of the display screen in the mobile station UE which concerns on 1st Embodiment of this invention.</figref><figref num="6">It is a sequence diagram which shows the operation of transmitting emergency information in the mobile communication system which concerns on 1st Embodiment of this invention.</figref><figref num="7">It is a functional block diagram of the wireless line control station RNC which concerns on 2nd Embodiment of this invention.</figref><figref num="8">It is a sequence diagram which shows the operation of transmitting emergency information in the mobile communication system which concerns on 2nd Embodiment of this invention.</figref><figref num="9">It is a functional block diagram of the wireless line control station RNC which concerns on 3rd Embodiment of this invention.</figref><figref num="10">It is a figure which shows an example of the structure of PCCH or MCCH generated by the wireless line control station RNC which concerns on 3rd Embodiment of this invention.</figref><figref num="11">It is a sequence diagram which shows the operation of transmitting emergency information in the mobile communication system which concerns on 3rd Embodiment of this invention.</figref><figref num="12">It is a sequence diagram which shows the operation of transmitting emergency information in the mobile communication system which concerns on 4th Embodiment of this invention.</figref>

(Mobile communication system according to the first embodiment of the present invention) The configuration of the mobile communication system according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

In the mobile communication system according to the present embodiment, the wireless device (wireless line control station RNC or wireless base station Node B) is a type of notification information transmitted from the distribution server 10, "emergency information (by government offices, local governments, etc.)". Emitted earthquake information, tsunami information, etc.) is configured to be transmitted to the mobile station UE using broadcast communication (CBS, MBMS, etc.).

Specifically, as shown in FIG. 1, the mobile communication system according to the present embodiment includes a distribution server, a plurality of wireless line control stations RNC # 1 and # 2, and a plurality of wireless base stations Node B # 11, It is equipped with # 12 and a plurality of mobile stations UEs # 1 and # 2.

For convenience of explanation, in the example of FIG. 1, two wireless line control stations RNC, two wireless base stations Node B, and two mobile stations UE have been described. Needless to say, in the present invention, these devices are two. It is also applicable to the example when two or more are provided.

The distribution server 10 functions as a CBC (Cell Broadcast Center) or BM-SC, and receives earthquake information, tsunami information, etc. issued by government agencies, local governments, etc. when an event such as an earthquake or tsunami occurs. It is configured to receive emergency information and transmit such emergency information to a predetermined wireless line control station RNC.

Specifically, the distribution server 10 includes a key update unit 11, a key transmission unit 12, an emergency information reception unit 13, an electronic signature generation unit 14, an electronic signature transmission unit 15, and an emergency information transmission unit 16. It is equipped.

The key update unit 11 is configured to update the public key and the private key of the distribution server 10 at a predetermined timing. For example, the key update unit 11 may be configured to update the public key and the private key of the distribution server 10 each time the emergency information is distributed.

The key transmission unit 12 is configured to transmit the public key of the distribution server 10 to the mobile station UE.

Specifically, the key transmission unit 12 uses the CTCH (Common Traffic Channel) or MTCH (MBMS Traffic Channel), which is a traffic channel for CBS or MBMS (broadcast communication), to use the distribution server 10. The public key is configured to be sent to the mobile station UE.

The emergency information receiving unit 13 is configured to receive requests for distribution of emergency information such as earthquake information and tsunami information from government offices, local governments, and the like. Here, it is assumed that the delivery request includes the emergency information and the delivery area (paging area or MBMS service area) of the emergency information.

The electronic signature generation unit 14 uses the private key of the distribution server 10 to generate an electronic signature (that is, an electronic signature for proving the identity of the emergency information) for the emergency information received by the emergency information receiving unit 13. It is configured as follows.

The electronic signature transmission unit 15 uses the traffic channel CTCH or MTCH for CBS or MBMS (broadcast communication) to generate the above-mentioned electronic signature generated by the electronic signature generation unit 14. It is configured to transmit to the mobile station UE.

The emergency information transmitting unit 16 transmits the emergency information received by the emergency information receiving unit 13 to the wireless line control station RNC by SABP (Service Area Broadcast Protocol) defined by 3GPP TS25.419. It is configured.

As shown in FIG. 3, the radio base station Node B includes an emergency information receiving unit 21 and an emergency information transmitting unit 22.

The emergency information receiving unit 21 is configured to receive emergency information transmitted from the distribution server 10 via the wireless line control station RNC.

Specifically, the PCH receiving unit 31 is configured to receive "PCH" transmitted from the wireless line control station RNC.

The emergency information transmission unit 22 is configured to transmit the emergency information transmitted from the distribution server 10 to the mobile station UE.

Specifically, the emergency information transmission unit 22 has incoming information for a specific mobile station (mobile station belonging to a specific group) of "PICH (Paging Indication Channel)" or "MICH (MBMS Indication Channel)". It is configured to transmit the above-mentioned emergency information using a channel for notifying that.

As shown in FIG. 4, the mobile station UE has an emergency information receiving unit 31, an emergency information display unit 32, an electronic signature receiving unit 33, a public key receiving unit 34, a public key storage unit 35, and sender authentication. It is equipped with a part 36.

The emergency information receiving unit 31 is configured to receive the above-mentioned emergency information via the control channel "PICH" or "MICH" for initiating CBS or MBMS (broadcast communication).

The electronic signature receiving unit 33 is configured to receive the above-mentioned electronic signature via the traffic channel "CTCH" or "MTCH" for CBS or MBMS (broadcast communication).

The public key receiving unit 34 is configured to receive the public key of the distribution server 10 via the traffic channel "CTCH" or "MTCH" for CBS or MBMS (broadcast communication).

The public key storage unit 35 is configured to store the public key of the distribution server 10 received by the public key receiving unit 34.

The sender authentication unit 36 displays the emergency information display unit 32 based on the above-mentioned electronic signature received by the electronic signature receiving unit 33 and the public key of the distribution server 10 stored in the public key storage unit 35. It is configured to authenticate the validity of the emergency information provided (ie, to authenticate the identity of the source of the emergency information).

The emergency information display unit 32 is configured to display emergency information included in "PICH" or "MICH" received by the emergency information receiving unit 31.

Specifically, as shown in FIG. 5A, the emergency information display unit 32 may be configured to display simple information on the display screen, or receives simple information by an alarm or vibration. It may be configured to notify the fact.

Further, the emergency information display unit 32 is configured to control the display method of emergency information based on the authentication result by the sender authentication unit 36.

Specifically, when the emergency information display unit 32 displays the emergency information received via "PICH" or "MICH" and the above-mentioned authentication result is negative (that is, the distribution source of the emergency information). If the identity of the person is not recognized), as shown in Fig. 6 (b), it is configured to indicate that the above-mentioned emergency information was incorrect.

(Operation of the mobile communication system according to the first embodiment of the present invention) Hereinafter, the operation of the mobile communication system according to the present embodiment will be described with reference to FIG.

As shown in FIG. 6, in step S1000, the distribution server 10 transmits the public key of the distribution server 10 to the mobile station UE using the traffic channel CTCH or MTCH for CBS or MBMS. ..

Step In flop S1001, the distribution server 10, from the government and local governments, upon receiving the distribution request for the emergency information such as earthquake information or tsunami information, the radio network control station corresponding to the distribution area included in such distribution request Send emergency information to RNC.

In step S1002, the radio line control station RNC transmits the received emergency information to the radio base station Node B.

In step S1003, the radio base station Node B uses "PICH" or "MICH" to transmit the above-mentioned emergency information to the mobile station UE.

In step S1004, the mobile station UE displays the emergency information contained in the PICH or MICH transmitted from the radio base station Node B, as shown in FIG. 5 (a).

For example, the mobile station UE displays emergency information for notifying "earthquake occurrence" when "0101" is set in the lower 4 bits of the predetermined 12 bits in "PICH" or "MICH". If the lower 4 bits of the 12 bits are set to "1010", it may be configured to display emergency information for notifying the "flood occurrence".

In step S1005, a process for starting CBS or MBMS (broadcast communication) is performed.

In step S1006, after the above processing is completed, the distribution server 10 uses the public key of the distribution server 10 to generate an electronic signature for the above-mentioned emergency information, and traffic for CBS or MBMS (broadcast communication). The generated digital signature is transmitted to the mobile station UE using the channel "CTCH" or "MTCH".

In step S1007, the mobile station UE authenticates the validity of the emergency information displayed in step S1004 based on the received electronic signature and the public key of the distribution server 10 stored in the public key storage unit 35. ..

If the authentication result is negative, the mobile station UE indicates that the above emergency information was incorrect, as shown in FIG. 6 (b).

In step S1008, the distribution server 10 updates the public key and private key of the distribution server 10, and in step S1009, the distribution server 10 uses the traffic channel CTCH or MTCH for CBS or MBMS. Send the public key to the mobile station UE.

(Action / Effect of Mobile Communication System According to First Embodiment of the Present Invention) According to the mobile communication system according to the present embodiment, the mobile station UE is transmitted using "CTCH" or "MTCH" after displaying the emergency information transmitted using "PICH" or "MICH". Since the validity of the emergency information is authenticated by using the electronic signature of the emergency information, it is possible to shorten the arrival delay of the emergency information to the mobile station UE and prevent spoofing of the emergency information to the sender. ..

(Mobile communication system according to the second embodiment of the present invention) A mobile communication system according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. Hereinafter, the mobile communication system according to the present embodiment will be described focusing on the differences from the mobile communication system according to the first embodiment described above.

As shown in FIG. 7, the wireless line control station RNC includes an emergency information receiving unit 41 and an emergency information transmitting unit 42.

The emergency information receiving unit 41 is configured to receive the emergency information transmitted from the distribution server 10.

The emergency information transmission unit 42 is configured to transmit the emergency information transmitted from the distribution server 10 to the mobile station UE.

Specifically, the emergency information transmission unit 42 sets "PCCH (Paging Control Channel)" or "MICH (MBMS Control Channel)" (channel for notifying a specific mobile station that there is incoming information). It is configured to use and transmit the emergency information described above.

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

As shown in FIG. 8, in step S2000, the distribution server 10 transmits the public key of the distribution server 10 to the mobile station UE using the traffic channel CTCH or MTCH for CBS or MBMS. ..

In step S2001, when the distribution server 10 receives a distribution request for emergency information such as earthquake information and tsunami information from a government office or a local government, the wireless line control station RNC corresponding to the distribution area included in the distribution request. Send emergency information to.

In step S2002, the radio line control station RNC transmits the received emergency information to the mobile station UE using "PCCH" or "MCCH".

In step S2003, the mobile station UE displays the emergency information contained in the "PCCH" or "MCCH" transmitted from the wireless line control station RNC, as shown in FIG. 5 (a).

For example, the mobile station UE is configured to indicate that it has received emergency information inserted in the "payload section (240 bits) (see 3GPP TS 34.108)" in the "PCCH" or "MCCH". May be good.

The operation of steps S2004 to S2008 is the same as the operation of steps S1005 to S1009 described above.

According to the mobile communication system according to the present embodiment, the mobile station UE is transmitted using "CTCH" or "MTCH" after displaying the emergency information transmitted using "PCCH" or "MCCH". Since the validity of the emergency information is authenticated by using the electronic signature of the emergency information, it is possible to shorten the arrival delay of the emergency information to the mobile station UE and prevent spoofing of the emergency information to the sender. ..

(Mobile communication system according to the third embodiment of the present invention) A mobile communication system according to a third embodiment of the present invention will be described with reference to FIGS. 9 to 11. Hereinafter, the mobile communication system according to the present embodiment will be described focusing on the differences from the mobile communication system according to the first embodiment described above.

As shown in FIG. 9, the wireless line control station RNC includes an emergency information receiving unit 41, an emergency information transmitting unit 42A, a private key receiving unit 43, a secret key storage unit 44, and an electronic signature generating unit 45. doing.

The private key receiving unit 43 is configured to receive the private key of the distribution server 10 transmitted from the distribution server 10.

The private key storage unit 44 is configured to store the private key of the distribution server 10 received by the private key receiving unit 43.

The electronic signature generation unit 45 uses the emergency information received by the emergency information receiving unit 41 and the private key of the distribution server 10 stored in the private key storage unit 44 to generate an electronic signature for the emergency information. It is configured as follows.

The emergency information transmission unit 42A is configured to transmit the electronic signature generated by the electronic signature generation unit 45 to the mobile station UE together with the above-mentioned emergency information by using the PCCH or the MCCH. There is.

Specifically, as shown in FIG. 10A, the emergency information transmitting unit 42A has an arbitrary character string indicating emergency information with respect to the "payload unit (240 bits)" in the "PCCH" or "MCCH". And an electronic signature for the emergency information may be inserted.

Further, as shown in FIG. 10B, the emergency information transmitting unit 42A has a bit pattern corresponding to the emergency information (for example, described above) with respect to the payload unit (240 bits) in the PCCH or the MCCH. "0101", "1010", etc.) and the electronic signature for the emergency information may be inserted.

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

As shown in FIG. 11, in step S3000A, the distribution server 10 transmits the public key of the distribution server 10 to the mobile station UE using the traffic channel CTCH or MTCH for CBS or MBMS. ..

In step S3000B, the distribution server 10 transmits the private key of the distribution server 10 to the wireless line control station RNC.

In step S3001, when the distribution server 10 receives a distribution request for emergency information such as earthquake information and tsunami information from a government office or a local government, the wireless line control station RNC corresponding to the distribution area included in the distribution request. Send emergency information to.

In step S3002, the wireless line control station RNC uses the received emergency information and the private key of the distribution server 10 stored in the private key storage unit 44 to generate an electronic signature for the emergency information.

In step S3003, the radio line control station RNC transmits the received emergency information and the generated electronic signature to the mobile station UE using "PCCH" or "MCCH".

In step S3004, the mobile station UE authenticates the validity of the emergency information based on the received electronic signature and the public key of the distribution server 10 stored in the public key storage unit 35.

If the authentication result is positive, the mobile station UE displays the received emergency information. On the other hand, if the authentication result is negative, the mobile station UE determines that the above-mentioned emergency information is incorrect and does not display the emergency information.

For example, the mobile station UE displays emergency information for notifying "earthquake occurrence" when "0101" is set in the lower 4 bits of the predetermined 12 bits in "PCCH" or "MCCH". If the lower 4 bits of the 12 bits are set to "1010", it may be configured to display emergency information for notifying the "flood occurrence".

In step S3005, a process for starting CBS or MBMS (broadcast communication) is performed.

In step S3006, the distribution server 10 updates the public key and private key of the distribution server 10, and in step S3007, the distribution server 10 uses the traffic channel CTCH or MTCH for CBS or MBMS. The public key is transmitted to the mobile station UE, and in step S3008, the private key of the distribution server 10 is transmitted to the wireless line control station RNC.

(Mobile communication system according to the fourth embodiment of the present invention) A mobile communication system according to a third embodiment of the present invention will be described with reference to FIG. Hereinafter, the mobile communication system according to the present embodiment will be described focusing on the differences from the mobile communication system according to the first embodiment described above.

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

As shown in FIG. 12, in step S4000, the distribution server 10 transmits the public key of the distribution server 10 to the mobile station UE using the traffic channel CTCH or MTCH for CBS or MBMS. ..

In step S4001, the distribution server 10 receives a distribution request for emergency information such as earthquake information and tsunami information from government offices, local governments, etc., and the emergency information included in the received distribution request and the private key of the distribution server 10. Is used to generate an electronic signature for the emergency information.

In step S4002, the emergency information and the electronic signature for the emergency information are transmitted to the wireless line control station RNC corresponding to the distribution area included in the distribution request.

In step S4003, the radio line control station RNC transmits the received emergency information and the electronic signature to the mobile station UE using "PCCH" or "MCCH".

In step S4004, the mobile station UE authenticates the validity of the emergency information based on the received electronic signature and the public key of the distribution server 10 stored in the public key storage unit 35.

If the authentication result is positive, the mobile station UE displays the received emergency information. On the other hand, if the authentication result is negative, the mobile station UE determines that the above-mentioned emergency information is incorrect and does not display the emergency information.

For example, the mobile station UE displays emergency information for notifying "earthquake occurrence" when "0101" is set in the lower 4 bits of the predetermined 12 bits in "PCCH" or "MCCH". If the lower 4 bits of the 12 bits are set to "1010", it may be configured to display emergency information for notifying the "flood occurrence".

In step S4005, a process for starting CBS or MBMS (broadcast communication) is performed.

In step S4006, the distribution server 10 updates the public key and private key of the distribution server 10, and in step S4007, the distribution server 10 uses the traffic channel CTCH or MTCH for CBS or MBMS. Send the public key to the mobile station UE.

The entire contents of Japanese Patent Application No. 2006-169435 (filed on June 19, 2006) are incorporated in the specification of the present application by reference.

In addition, the entire contents of "3GPP TS23.041" and "3GPP TS23.246" are incorporated in the present specification by reference.

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

10 ... Delivery server 11 ... Key update department 12 ... Key transmitter 13, 21, 31, 41 ... Emergency information receiver 14, 45 ... Electronic signature generator 15 ... Digital signature transmitter 16, 22, 42, 42A ... Emergency information transmitter 32 ... Emergency information display 33 ... Electronic signature receiver 34 ... Public key receiver 35 ... Public key storage 36 ... Sender Authentication Department 43 ... Private key receiver 44 ... Private key storage