JP4031489B2 - Communication terminal and communication terminal control method - Google Patents

Description

  The present invention relates to a communication terminal and a communication terminal control method for communicating with a desired network or server via a plurality of networks.

  In recent years, opportunities to use communication terminals not only in the company but also in homes, shops, public facilities such as airports and stations have increased, and it has become easier to connect communication terminals to the corporate network via the Internet or the Internet. In order to connect, a technique is widely used in which a profile, which is information for connecting to a desired network via a network, is set in a communication terminal, and the communication terminal uses the profile to connect to the desired network.

  For example, in Patent Literature 1, a wireless digital camera analyzes a downloaded profile, and an authentication set up by an operator who provides a hot spot service area via an access point according to an authentication method specified in the analyzed profile. A technique for performing authentication processing unique to a hot spot with a server and connecting to a network is described.

Also, in Patent Document 2, an electronic device having a wireless function performs network settings using a predetermined profile, and communication means for performing communication connection according to the settings, and success or failure of communication connection between the communication means and an access point. When the connection is not successful, a technique is described in which the optimum profile for the current access point is selected from a plurality of profiles, and the communication means performs communication connection via the access point using the selected profile. Yes.
JP-A-2004-128886 (30th to 50th paragraphs, FIGS. 2 and 4) Japanese Unexamined Patent Publication No. 2004-94736 (paragraphs 50-52, FIG. 4)

  However, in the technology related to the communication terminal described above, it is necessary for the user to perform security management related to network connection restrictions and virus countermeasures, and the security management is left to the work of each individual user. There is a problem that it is difficult for a network administrator or a telecommunications carrier to thoroughly manage security.

  The present invention has been made in order to solve the conventional problems, and provides a communication terminal and a communication terminal control method capable of improving security related to the communication terminal and the network when connecting to the network using a profile. With the goal.

The communication terminal of the present invention uses the profile storage means for storing a profile configured by combining connection information for connecting to a desired network, and the desired network using the profile including policy information related to network connection. Connection means for connecting to the network, connection control means for controlling network connection in accordance with the policy information when the connection means tries to connect to the desired network, security confirmation means for confirming the security of the communication terminal, and communication terminal Updating means for updating a function having the above vulnerability, the policy information includes first information for confirming the security with a server, and second information for updating the function from the update server. And update all the functions for each line type specified in the profile. And a third information for determining whether to update a part of the functions or not to update all of the functions, and the connection control means, wherein the connection means When trying to connect to a desired network, connect to the server according to the first information included in the policy information, the security confirmation means confirms the security of the communication terminal through the server, the connection control means When the result confirmed by the security confirmation unit is abnormal, the update unit connects to the update server according to the second information included in the policy information, and the update unit includes the second information included in the policy information through the update server. The function is updated according to the information of 3, and the use of the protocol related to the function that is not updated is limited .

With this configuration, when connecting to a desired network, the network connection is controlled according to the policy information. Therefore, when connecting to the network using a profile, the communication terminal and the network are configured according to policy information that can be flexibly set. Such security can be enhanced.
Further, since the security of the communication terminal is confirmed when attempting to connect to a desired network, intrusion into the network can be prevented when the communication terminal is unauthorized.
Further, when the result of confirming the security is abnormal, the function having the vulnerability of the communication terminal is updated, so that the safety of the communication terminal can be ensured.
Further, since the update of the function having the vulnerability of the communication terminal is determined according to the line type specified in the profile, the function having the vulnerability can be appropriately updated.

  In the communication terminal of the present invention, the policy information includes restriction information for restricting connection to a specific network, and the connection control means includes a network indicated by the control information included in the policy information. It has the structure which restrict | limits connecting to.

  With this configuration, since connection to the network indicated by the restriction information included in the policy information is restricted, the communication terminal can be prevented from connecting to an unreliable network.

  In the communication terminal of the present invention, the profile is encrypted, and the connection means decrypts the encrypted profile and confirms whether or not the connection control means is valid. In some cases, the decrypted profile is used to connect to the desired network.

  The use of the information obtained by decrypting the profile is limited to the inside of the connection means, and the user cannot access the connection information of this network. Therefore, in order to realize a desired connection, the communication of the present invention is used. Use of the terminal is essential.

  Further, with this configuration, since the connection means for decrypting the profile confirms the validity of the connection control means, the network administrator who manages the profile forcibly causes the user to use the valid connection control means. Can do. As a result, it is possible to thoroughly implement security management that has been entrusted to the work of individual users. Furthermore, it is possible to force various functions on the communication terminal to the user by changing or adding an object whose validity is confirmed by the connection means.

The communication terminal control method of the present invention uses the profile storage means for storing a profile configured by combining connection information for connecting to a desired network, and the desired information using the profile including policy information relating to network connection. Connection means for connecting to the network, connection control means for controlling network connection according to the policy information when the connection means tries to connect to the desired network, security confirmation means for confirming the security of the communication terminal, Updating means for updating a function having a vulnerability of the communication terminal, the policy information includes first information for confirming the security with a server, and second information for updating the function from the update server. And all the above functions for each line type specified in the profile. A communication terminal control method in a communication terminal that includes updating, third information for determining whether to update some of the functions, or not to update all of the functions, The connection control means connects to the server according to first information included in the policy information when the connection means tries to connect to the desired network, and the security confirmation means connects the communication terminal through the server. The connection control means connects to the update server according to the second information included in the policy information when the result confirmed by the security confirmation means is abnormal, and the update means Update the function according to the third information included in the policy information through the update server, and the protocol related to the function that is not updated. It has a configuration that limits the use.

With this configuration, when connecting to a desired network, the network connection is controlled according to the policy information. Therefore, when connecting to the network using a profile, the communication terminal and the network are configured according to policy information that can be flexibly set Such security can be enhanced.
Further, since the security of the communication terminal is confirmed when attempting to connect to a desired network, intrusion into the network can be prevented when the communication terminal is unauthorized.
Further, when the result of confirming the security is abnormal, the function having the vulnerability of the communication terminal is updated, so that the safety of the communication terminal can be ensured.
Further, since the update of the function having the vulnerability of the communication terminal is determined according to the line type specified in the profile, the function having the vulnerability can be appropriately updated.

  In the communication terminal control method of the present invention, the policy information includes restriction information for restricting connection to a specific network, and the connection control means includes the restriction information included in the policy information. It has the structure which restrict | limits connecting to the network shown.

  With this configuration, since connection to the network indicated by the restriction information included in the policy information is restricted, the communication terminal can be prevented from connecting to an unreliable network.

  In the communication terminal control method of the present invention, the profile is encrypted, and the connection means decrypts the encrypted profile and confirms whether or not the connection control means is valid. Is valid, the decrypted profile is used to connect to the desired network.

  The use of the information obtained by decrypting the profile is limited to the inside of the connection means, and the user cannot access the connection information of this network. Therefore, in order to realize a desired connection, the communication of the present invention is used. Use of the terminal is essential.

  Further, with this configuration, since the connection means for decrypting the profile confirms the validity of the connection control means, the network administrator who manages the profile forcibly causes the user to use the valid connection control means. Can do. As a result, it is possible to thoroughly implement security management that has been entrusted to the work of individual users. Furthermore, it is possible to force various functions on the communication terminal to the user by changing or adding an object whose validity is confirmed by the connection means.

  As described above, the present invention provides a communication terminal and a communication terminal capable of enhancing security related to the network when connecting to a network using a profile.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a communication terminal and a communication terminal control method according to the present invention will be described in detail with reference to the drawings.

(First embodiment of the present invention)
FIG. 1 is a system configuration diagram of a communication system according to the first embodiment of the present invention. The communication system shown in FIG. 1 has a configuration including a communication terminal 10, a network 31 to a network 33, and a server 41 to a server 43.

  The communication terminal 10 can connect to a desired network using a profile for connecting to the network. More specifically, the communication terminal 10 connects to the network by connecting to an access point, gateway, firewall, or the like serving as the entrance of the network using connection information constituting a profile.

  The connection information is information relating to various protocols, and includes authentication information compliant with each protocol, setting information for each protocol, information relating to a connection procedure compliant with each protocol, and the like. Further, the connection information may be information for connecting to the server in the same manner as the network. Since the connection information is a component constituting the profile, the connection information is hereinafter referred to as a profile component.

  The communication terminal 10 may be a personal computer, a mobile phone, or a PDA (Personal Digital Assistant), and may be anything as long as it can communicate with a server via a network. The server is a file server, a Web server, a mail server, or the like, and the type of server is not limited.

  In the first embodiment of the present invention, the communication terminal 10 is connected to the network 31 as an access point. However, in another embodiment, another network may be connected as an access point. .

  In the first embodiment of the present invention, the server is connected only to the network 33 for convenience of explanation. However, in the present invention, the server may be connected to another network. Each network may be a LAN, a network managed by an ISP (Internet Service Provider), an intranet managed by a company, or the Internet.

  FIG. 2 is a block configuration diagram of the communication terminal according to the first embodiment of the present invention. The communication terminal 10 has hardware such as a CPU (Central Processing Unit), a memory, a communication interface, a screen, and an input unit for operating keys as shown in FIG. As shown in FIG. 2, the storage unit 11 includes a profile storage unit 11 including a memory, a connection unit 12, and a connection control unit 13.

  The connection unit 12 and the connection control unit 13 may be realized by a module of a program executed by the CPU. Specifically, the connection means 12 is realized by software for connecting to a desired network using a profile including policy information related to network connection, and the connection control means 13 is connected to the desired network. This is realized by software that controls network connection according to policy information when trying to connect, such as a personal firewall. Policy information will be described later.

  The profile storage unit 11 stores a profile configured by combining one or more profile parts. The profile is data created and provided by an ISP or a network administrator. An example of the profile is shown in FIG.

  The profile shown in FIG. 3A is composed of profile parts A to C.

  The profile component A is for connecting to the network 31, and has information for performing communication and authentication conforming to IEEE802.1x and EAP-TPS (PPP Extensible Authentication Protocol-Transport Layer Security).

  The profile part B is for connecting to the network 32 and has information relating to setting of an IP address and the like.

  The profile component C is policy information related to network connection, and has restriction information that restricts connection to the network 33, but here does not allow it. In addition, as an example of restricting the connection to the network 33, it is illustrated that connection to the network 33 is not permitted. However, the connection to the network 33 may be limited. Further, in the profile part C, it has been shown that the connection to the network is restricted. However, in addition to restricting the connection to the network, the general policy information represents a security policy related to security. .

  The profile shown in FIG. 3B is composed of profile parts A, B, D, E, and F.

  The profile part D is for connecting to the network 33 and has information for performing communication and authentication conforming to IPSec (SECurity architecture for the Internet Protocol).

  The profile component E is policy information relating to server connection, and has restriction information that restricts connection to the server 42 and the server 43, that is, does not allow it. The profile component F is used to log in to the server 41 that provides the WEB service, and includes a user name and a password thereof.

  Note that the profile shown in FIG. 3 may be concealed. For example, the profile creator provides a user who uses the communication terminal 10 with a profile encrypted with an encryption key or the like, and the user cannot confirm the contents of the profile. The concealed profile can be decrypted by the connecting means 12.

  The connection unit 12 decrypts the encrypted profile and confirms whether or not the connection control unit 13 is valid. If the confirmed result is valid, the connection unit 12 connects to a desired network using the profile. As a method of confirming the validity of the connection control means 13, for example, a method of exchanging confirmation of validity through a predetermined API (Application Programming Interface) provided by the connection control means 13 is used.

  The operation of the communication terminal according to the first embodiment of the present invention configured as described above will be described with reference to the drawings.

  FIG. 4 is a flowchart showing the operation of the communication terminal according to the first embodiment of the present invention.

  First, the user makes a connection request for connecting to a desired network or server while operating the input unit, and the connection unit 12 receives the connection request (S11). The connection unit 12 acquires a profile corresponding to the connection request from the profile storage unit 11 (S12). Here, the case where the acquired profile is the profile illustrated in FIG. 3A will be described below as a specific example.

  When the connection means 12 tries to connect to the network 32 using the profile shown in FIG. 3A, this profile is set in the connection control means 13 (S13), and the connection with the network 32 is tried. The connection control means 13 performs protocol processing related to the connection to the network up to the network 32 according to the set profile, and restricts the connection to the network 33 indicated by the profile part C which is a part of the profile (S14). .

  Specifically, the connection control unit 13 passes packets destined for the network 32 and filters (blocks) packets destined for the network 33. For this reason, even if the user attempts to connect to the network 33 in a state where the communication terminal 10 and the network 32 are connected, the user cannot connect.

  Thereafter, the connection unit 12 confirms whether or not the connection is terminated (S15), and the user makes a disconnection request for disconnecting from the desired network while operating the input unit, and the connection unit 12 disconnects. When the request is accepted, the profile is canceled for the connection control means 13 (S15).

  A case where the profile acquired in S12 is the profile shown in FIG. 3B will be described below as a specific example. In S13, when the connection unit 12 tries to connect to the network 32 using the profile shown in FIG. 3B, this profile is set in the connection control unit 13, and the connection with the server 41 is established via the network 33. Try.

  In S14, the connection control means 13 performs protocol processing related to connection to the network up to the server 41 according to the set profile, and connects to the server 42 and the server 43 indicated by the profile component E which is a part of the profile. Limit.

  For this reason, even if the user logs out from the server 41 and attempts to log in to the server 42 or the server 43 in a state where the communication terminal 10 and the server 41 are connected, the user cannot connect.

  Note that when there are a plurality of profiles corresponding to the connection request in S12, prioritization is performed in advance, and the above-described operations of S13 and S14 are performed until the connection is succeeded in order from the profile with the highest priority. It becomes.

  As described above, the communication terminal according to the first embodiment of the present invention controls the network connection according to the policy information when attempting to connect to a desired network, and therefore, when connecting to the network using a profile. In addition, security related to the communication terminal 10 and the network can be enhanced according to policy information that can be set flexibly.

  Further, since the connection to the network indicated by the restriction information included in the policy information is restricted, it is possible to prevent the communication terminal 10 from connecting to a network with low reliability.

(Second embodiment of the present invention)
FIG. 5 is a system configuration diagram of a communication system according to the second embodiment of the present invention. The communication system shown in FIG. 5 has a configuration including a communication terminal 20, a network 34 and a network 35, and a quarantine server 44, an authentication server 45, and an update server 46 connected to the network 34.

  As in the first embodiment of the present invention, the communication terminal 20 is connected to a desired network using a profile for connecting to the network. The profile includes policy information related to network connection, and the policy information is information for confirming the security of the communication terminal 20 with the quarantine server 44.

  In addition, in the policy information, the update server 46 determines whether to update this function according to information for updating the vulnerable function of the communication terminal 20 and the line type specified in the profile. Information to do.

  The communication terminal 20 may be a personal computer, a mobile phone, or a PDA (Personal Digital Assistant), and may be any device that can communicate with these servers via a network. The network 34 is, for example, an in-house LAN, and the network 35 is a network managed by an ISP (Internet Service Provider) or the Internet.

  FIG. 6 is a block configuration diagram of a communication terminal according to the second embodiment of the present invention. Similar to the communication terminal 10, the communication terminal 20 has hardware such as a CPU (Central Processing Unit), a memory, a communication interface, a screen, and an input unit for performing key operations, as shown in FIG. A profile storage unit 21 including a memory, a connection unit 12, a connection control unit 13, a security confirmation unit 24, and an update unit 25 are included.

  Of the components constituting the communication terminal according to the second embodiment of the present invention, the same components as those constituting the communication terminal according to the first embodiment of the present invention are the same. Reference numerals are assigned and explanations thereof are omitted.

  The connection unit 12, the connection control unit 13, the security confirmation unit 24, and the update unit 25 may be realized by a module of a program executed by the CPU. Specifically, the security confirmation unit 24 is realized by software for confirming the security of the communication terminal 20, for example, client software that performs virus checking, and the update unit 25 has a function having a vulnerability of the communication terminal 20. This is realized by software for updating.

  Further, the profile storage means 21 stores a profile configured by combining one or more profile parts as described in the first embodiment of the present invention. Note that this profile includes, for example, policy information followed by the communication terminal 20, and an example thereof is shown in FIG.

  The policy information shown in FIG. 7 includes rules for operations related to network connection. According to this policy information, the communication terminal 20 can connect only to the quarantine server 44 and the authentication server 45 before connecting to the network, authenticates to the authentication server 45, and is quarantined to the quarantine server 44. It will be. The policy information may be set to indicate that the communication terminal 20 cannot connect to all addresses before connecting to the network, or that the administrator cannot connect to addresses other than those considered necessary by the administrator. In addition, a server or the like to which the communication terminal 20 can be connected is limited from the start of connection to the completion of quarantine.

  Furthermore, if the quarantine result is normal, the communication terminal 20 can connect to a desired network according to the profile. Even if the quarantine result is normal, the networks that can be connected may be limited as shown in FIG. On the other hand, if the result of the quarantine is abnormal, the communication terminal 20 updates the function having the vulnerability of the communication terminal 20 through the update server 46.

  The operation of the communication terminal according to the second embodiment of the present invention configured as described above will be described with reference to the drawings.

  FIG. 8 is a flowchart showing the operation of the communication terminal according to the second embodiment of the present invention.

  First, the user makes a connection request for connecting to a desired network or server while operating the input unit, and the connection means 12 receives the connection request (FIG. 8A, S11). The connection unit 12 acquires a profile corresponding to the connection request from the profile storage unit 21 (S12). In the operation of the communication terminal according to the second embodiment of the present invention, an operation example in which the desired network is the network 35 and the network 35 is connected will be described.

  When the connection means 12 tries to connect to the network 35 using the acquired profile, this profile is set in the connection control means 13 (S13), and the connection with the network 35 is tried. At this time, it is assumed that the profile acquired by the connection unit 12 includes the policy information shown in FIG.

  The connection control means 13 performs control for confirming security according to the policy information shown in FIG. 7 included in the set profile (S24). In general, the operation in S24 is not limited to the policy information shown in FIG. 7, but is performed according to policy information created by a network administrator or the like.

  Here, the operation according to the policy information shown in FIG. 7 will be described. First, the connection control means 13 connects to the network 34 according to the connection information set in the profile, and then sends authentication information set in the profile to the authentication server 45 to request authentication, If the result is normal, quarantine is further requested to the quarantine server 44 (FIG. 8B, S31). Note that the quarantine is to check the version of a virus information file used in virus check software, check the version of the operating system and application software, and the like.

  When checking for the presence or absence of a virus, the security confirmation unit 24 performs a virus check in cooperation with the quarantine server 44. Note that before connection to the network and during authentication or quarantine, the servers and networks that can be connected are limited according to the policy information shown in FIG.

  The connection control means 13 determines whether or not the quarantine result is normal (S32), and if it is normal, the connection control means 13 connects to the network 35 according to the profile (S33). Note that the connection control means 13 limits the networks that can be connected as shown in FIG. 7 even if the quarantine result is normal.

  If the result of the quarantine is not normal, the updating unit 25 updates the function having the vulnerability of the communication terminal 20 through the update server 46 (S34). In the flowchart shown in FIG. 8, the process is terminated after S34 is processed. However, in another embodiment of the present invention, the operation of S33 is performed after S34 is processed to connect to the network 35. It may be.

  Further, the policy information shown in FIG. 7 includes a part of the vulnerable functions of the communication terminal 20 that updates all the vulnerable functions of the communication terminal 20 for each line type specified in the profile. Information for determining whether to update the function or not to update all the functions having the vulnerability of the communication terminal 20 may be included. This determination information is information indicating whether or not a function having vulnerability is updated for each line bandwidth of the line type specified in the profile.

  For example, when a broadband line such as IEEE802.11g is used for policy information in the profile, all functions having a vulnerability of the communication terminal 20 are updated, and when a relatively broadband line such as IEEE802.11b is used, the communication terminal Among the 20 vulnerabilities, a function that can be improved by downloading a relatively small patch, for example, a function that only updates the security of a specific application and requires a large patch, such as an operating system vulnerability In the case where a line having a narrow communication band such as PHS is used, judgment information indicating that the function having the vulnerability of the communication terminal 20 is not updated is included. Update according to the judgment information.

  Further, when updating according to the determination information, the updating unit 25 restricts the use of a protocol related to a function that is not updated. In the above-described example, when a line such as IEEE802.11b is used, since functions other than those having vulnerability of specific application software are not updated, use of application software that is not updated or protocol related to operating system vulnerability is not used. Restrict.

  Note that when there are a plurality of profiles corresponding to the connection request in S12, prioritization is performed in advance, and the above-described operations of S13 and S24 are performed until the connection is succeeded in order from the profile with the highest priority. It becomes.

  By the way, after the operation according to the policy information shown in FIG. 7 is finished, the connection means 12 confirms whether or not the connection is finished (FIG. 8A, S15), and the user moves the input unit. A disconnection request for disconnecting from a desired network is made while operating, and when the connection unit 12 accepts the disconnection request, the connection unit 13 cancels the profile (S16).

  If the usage environment of the communication terminal 20 is a line with a narrow communication band such as PHS and is not updated, when updating, the user moves to a place with a line with a wide communication band. Alternatively, the function having the vulnerability of the communication terminal 20 may be updated using a profile when using a line with a wide communication band, such as using a line with a wide communication band.

  As described above, the communication terminal according to the second embodiment of the present invention confirms the security of the communication terminal when attempting to connect to a desired network, and therefore the communication terminal 20 is illegal. Intrusion into the network can be prevented.

  Further, when the result of confirming the security is abnormal, the function having the vulnerability of the communication terminal 20 is updated, so that the safety of the communication terminal 20 can be ensured. In addition, since the update of the function having the vulnerability of the communication terminal 20 is determined according to the line type specified in the profile, the function having the vulnerability can be appropriately updated.

  As described above, the communication terminal according to the embodiment of the present invention has an effect that security related to the communication terminal and the network can be increased when connecting to the network using the profile, and the communication terminal is connected via the plurality of networks. It is useful as a personal computer, mobile phone, PDA or the like for communicating with a desired network or server.

1 is a system configuration diagram of a communication system according to a first embodiment of the present invention. The block block diagram of the communication terminal which concerns on the 1st Embodiment of this invention. The figure which shows an example of the profile which concerns on embodiment of this invention. The flowchart which shows operation | movement of the communication terminal which concerns on the 1st Embodiment of this invention. The system block diagram of the communication system which concerns on the 2nd Embodiment of this invention. The block block diagram of the communication terminal which concerns on the 2nd Embodiment of this invention. The figure which shows an example of the policy information which concerns on embodiment of this invention. The flowchart which shows operation | movement of the communication terminal which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20 Communication terminal 11, 21 Profile storage means 12 Connection means 13 Connection control means 24 Security confirmation means 25 Update means 31, 32, 33, 34, 35 Network 41, 42, 43 Server 44 Quarantine server 45 Authentication server 46 Update server

Claims (6)

Profile storage means for storing a profile configured by combining connection information for connecting to a desired network;
Connection means for connecting to the desired network using the profile including policy information relating to network connection;
Connection control means for controlling network connection according to the policy information when the connection means tries to connect to the desired network ;
Security confirmation means for confirming the security of the communication terminal;
Updating means for updating a function having a vulnerability of the communication terminal,
The policy information includes first information for confirming the security with a server, second information for updating the function from an update server, and the function for each line type specified in the profile. Third information for determining whether to update all, to update some of the functions, or not to update all of the functions,
The connection control means connects to the server according to first information included in the policy information when the connection means tries to connect to the desired network,
The security confirmation means confirms the security of the communication terminal through the server,
The connection control means connects to the update server according to the second information included in the policy information when the result confirmed by the security confirmation means is abnormal,
The update means updates the function according to third information included in the policy information through the update server, and restricts use of a protocol related to a function that is not updated . The policy information includes restriction information for restricting connection to a specific network,
The communication terminal according to claim 1, wherein the connection control unit restricts connection to a network indicated by restriction information included in the policy information. The profile is encrypted,
The connection means decrypts the encrypted profile, confirms whether or not the connection control means is valid, and if the confirmed result is valid, connects to the desired network using the decrypted profile. The communication terminal according to claim 1 or 2. Profile storage means for storing a profile configured by combining connection information for connecting to a desired network; connection means for connecting to the desired network using the profile including policy information related to network connection; A connection control means for controlling network connection according to the policy information when the connection means tries to connect to the desired network, a security confirmation means for confirming the security of the communication terminal, and a function having a vulnerability of the communication terminal. Updating means for updating, and the policy information is designated by the profile, first information for confirming the security with the server, second information for updating the function from the update server, and the profile. Update all of the above functions for each line type. Update function, or a third information for determining not to update all the functions, a communication terminal control method in a communication terminal is included,
The connection control means connects to the server according to first information included in the policy information when the connection means tries to connect to the desired network,
The security confirmation means confirms the security of the communication terminal through the server,
The connection control means connects to the update server according to the second information included in the policy information when the result confirmed by the security confirmation means is abnormal,
The update means updates the function according to third information included in the policy information through the update server, and restricts use of a protocol related to a function that is not updated . The policy information includes restriction information for restricting connection to a specific network,
5. The communication terminal control method according to claim 4, wherein the connection control means restricts connection to a network indicated by restriction information included in the policy information. The profile is encrypted,
The connection means decrypts the encrypted profile, confirms whether or not the connection control means is valid, and if the confirmed result is valid, connects to the desired network using the decrypted profile. 6. The communication terminal control method according to claim 4 or 5, wherein:

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