JP4706317B2 - COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND COMMUNICATION TERMINAL - Google Patents

Description

  The present invention relates to a communication system, a communication method, and a communication terminal.

  With the spread of the Internet, the increase in the volume of data that can be transmitted and received on the Internet, and the speeding up of transmission and reception, various services based on the Internet protocol (hereinafter referred to as IP) have begun to be provided. One example is Voice Over IP (hereinafter referred to as VoIP) that implements a voice call via an IP communication network.

  In recent years, not only personal computers (hereinafter referred to as PCs) but also various devices such as televisions, game devices, car navigation devices, mobile phones, and information home appliances are connected to the Internet and are based on IP. Can receive service.

  When receiving the service, the user who receives the service is generally required to prove that the user is a valid user from the service provider side. That is, in order for the service providing side to authenticate whether or not the user can receive the service provision, the user is required to provide data used for authentication to the service providing side. The data used for this authentication is usually a user name and password registered in advance on a service server or the like. When the user transmits a user name and password from the communication terminal, which is the device connected to the Internet, to the server, the server authenticates the user.

  The above authentication method is generally adopted in VoIP as well. Specifically, Session Initiation Protocol (hereinafter referred to as SIP) is used in VoIP, but an SIP server that communicates with a communication terminal according to SIP is usually based on a user password transmitted from the communication terminal. SIP client authentication is performed.

  However, in the above authentication method, since the password is transmitted from the communication terminal to the server, there is a possibility that the password may be leaked in the middle of the transmission path, and there is a problem that the security is low. In addition, in the environment where various devices can be used as communication terminals as described above, if it is necessary to transmit a password in order to receive service provision, the user must input the password on a device that does not have an input device. As a result, there is a problem that the device cannot receive service. In addition, there is a problem that it is inconvenient for the user to input a password or the like every time in order to receive provision of services.

  Therefore, the present invention has been made in view of such problems, and an object of the present invention is to provide a highly secure and simple user-friendly communication system for realizing a voice call over an IP communication network. The method is to authenticate the user.

  In order to solve the above problems, according to an aspect of the present invention, a communication method is provided in which a communication terminal and a server transmit and receive audio data via an IP communication network. The communication method includes a module connection step in which a mobile module storing user identification information and a user secret key is connected to a communication terminal; and the communication terminal transmits a communication start request including the user identification information to a server. Start request step: The server that receives the start request generates challenge data, encrypts the challenge data with the user's public key identified by the user identification information included in the start request, and includes the encrypted challenge data An authentication data transmission request step for transmitting an authentication data transmission request to the communication terminal; the communication terminal receiving the authentication data transmission request provides the encrypted challenge data to the portable module, A decryption step for decrypting the challenge data with the secret key; and the communication terminal decrypts the challenge data. A calculation step for obtaining a hash value of the challenge data; an encryption step in which the communication terminal provides the hash value to the portable module, and the portable module causes the hash value to be encrypted with the user's private key; A data transmission step of transmitting the encrypted hash value to the server; the server receiving the hash value decrypts the hash value with the user's public key, and the validity of the decrypted hash value is determined based on the challenge data A legitimacy judgment step for judging; and a communication start step for the server to start communication with the communication terminal when the decrypted hash value is legitimate as a result of the legitimacy judgment.

  According to the above invention, the data transmitted and received for authentication between the communication terminal and the server is challenge data generated by the server, and the server determines whether the communication terminal can use the user's private key. Authenticate by Therefore, it is not necessary to transmit the user's password from the communication terminal to the server, and there is no risk of password leakage. Therefore, authentication can be performed safely. In addition, the user does not need to enter a password to have the server authenticate himself. In addition, the user's private key required for authentication is stored in the mobile module, and data recombination with the private key is performed in the mobile module. Therefore, there is a low possibility that the secret key is leaked outside the portable module. As a result, in the communication system, the user can be authenticated by a method that is highly secure and easy for the user.

  The communication method further includes: a disconnection detecting step in which the communication terminal detects that the connection with the mobile module is disconnected; and when the disconnection with the mobile module is detected in the disconnection detection step, the communication terminal A disconnect notification step of transmitting a notification to the server; and a communication end step in which the server that has received the disconnect notification ends the communication with the communication terminal. According to this configuration, when the connection with the portable module is disconnected and authentication using the secret key in the portable module cannot be continued, the communication is terminated.

  In the disconnect notification step, the notification transmitted from the communication terminal to the server may include a hash value of the challenge data. In this case, in the communication end step, the server sets the validity of the hash value to the challenge data. Based on the determination, if the hash value is valid, the communication with the communication terminal may be terminated.

  In the authentication data transmission request step, the server may generate an electronic signature using its own private key and transmit the electronic signature together with the authentication data transmission request to the communication terminal. It may further include a server validity determination step that determines the validity of the electronic signature using the public key, and proceeds to the decryption step if the electronic signature is valid as a result of the determination. According to this configuration, the communication terminal can authenticate the validity of the server.

  In order to solve the above problems, according to another aspect of the present invention, a communication system is provided in which a communication terminal and a server transmit and receive audio data via an IP communication network. The communication system includes a user information storage unit that stores user identification information and a user secret key, and a data processing unit that rearranges data using the user secret key, and includes a portable module that can be connected to a communication terminal. The communication terminal in this system includes a module control unit that performs data processing of the portable module and recombines data to be transmitted to the server and encrypts the data; and a transmission unit that transmits the encrypted data to the server. The server in the communication system includes: a user certificate storage unit that stores a certificate including user identification information and a user public key; a reception unit that receives encrypted data from a communication terminal; and a reception unit that receives the encrypted data. A user validity judgment unit that decrypts the data with the user's public key and judges the validity of the decrypted data; whether or not communication with the communication terminal is permitted based on the judgment result of the legitimacy by the user validity judgment unit; A communication control unit for determining;

  According to the above invention, the server performs authentication based on whether or not the communication terminal can use the user's private key based on the user's public key. The user's private key required for authentication is stored in the mobile module, and data recombination with the private key is performed in the mobile module. Therefore, there is a low possibility that the secret key is leaked outside the portable module. As a result, in the communication system, the user can be authenticated by a method that is highly secure and easy for the user.

  In the communication system, the server may further include a transmission data creation unit that encrypts data to be transmitted to the communication terminal with the user's public key. In this case, the module control of the communication terminal performs data processing of the portable module. The data received from the server may be rearranged and decrypted. According to such a configuration, only the communication terminal that can use the user's private key can decrypt the data transmitted from the server to the communication terminal. Therefore, even if data leaks in the transmission path, the possibility of being decrypted by a third party is low.

  In the communication system, the server may further include a server information storage unit that stores its own secret key, and a transmission data creation unit that encrypts data to be transmitted to the communication terminal using its own secret key. In this case, the communication terminal has a server information acquisition unit that acquires the public key of the server and a server validity determination that decrypts the data received from the server with the server public key and determines the validity of the decrypted data. A communication control unit that determines whether or not to allow communication with the server based on a result of determination of validity by the server validity determination unit. According to such a configuration, the communication terminal can authenticate the legitimacy of the server, and safer communication can be performed.

  In order to solve the above problems, according to another aspect of the present invention, a communication terminal is provided that transmits and receives audio data to and from a server via an IP communication network. The communication terminal can be connected to a portable module provided with a user information storage unit for storing user identification information and a user secret key, and a data processing unit for rearranging data using the user secret key. A module control unit configured to recombine and encrypt the data to be transmitted to the server; and a transmission unit configured to transmit the encrypted data to the server. The server transmits the data transmitted to the server. It is decrypted with the user's public key, and whether to permit communication with the server is determined based on the validity of the decrypted data.

  According to the above invention, the server performs authentication based on whether or not the communication terminal can use the user's private key based on the user's public key. The user's private key required for authentication is stored in the mobile module, and data recombination with the private key is performed in the mobile module. Therefore, there is a low possibility that the secret key is leaked outside the portable module. As a result, in the communication system, the user can be authenticated by a method that is highly secure and easy for the user.

  The communication terminal may further include a receiving unit that receives data encrypted with the user's public key from the server. In this case, the module control unit receives the data from the server as a data processing unit of the portable module. The data may be rearranged and decrypted.

  The communication terminal includes a receiving unit that receives data encrypted with the server's private key from the server; a server information acquisition unit that acquires the server's public key; and the data received by the receiving unit is decrypted with the server's public key And a server validity judgment unit that judges the validity of the decrypted data; and a communication control unit that decides whether or not to allow communication with the server based on a result of judgment of validity by the server validity judgment unit; You may prepare.

  Further, user authentication data for authenticating a user who is permitted to use the mobile module may be stored in the user information storage unit of the mobile module. In this case, the user authentication data is input to the user and input. A user authentication unit that determines whether or not to use the mobile module based on the user authentication data and the user authentication data stored in the mobile module may be further provided. According to such a configuration, abuse of the mobile module by a third party can be prevented.

  In addition, the module control unit may detect that the connection with the portable module is disconnected. In this case, the transmission unit may detect that the connection with the portable module is detected by the module control unit. A notification may be sent to the server.

  In order to solve the above problems, according to another aspect of the present invention, there is provided a computer program that causes a computer to function as the communication terminal. The computer program is stored in a storage unit included in the computer, and is read and executed by a CPU included in the computer, thereby causing the computer to function as the communication terminal. A computer-readable recording medium on which a computer program is recorded is also provided. The recording medium is, for example, a magnetic disk or an optical disk.

  As described above, according to the present invention, in a communication system that realizes a voice call via an IP communication network, user authentication can be performed by a method that is highly secure and that is simple for the user.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  Hereinafter, the communication system according to the present invention will be described by applying it to a communication system including a SIP client and a SIP server in VoIP that realizes a voice call via an IP communication network. The SIP client and the SIP server perform communication by starting, changing, and ending a session according to the extended SIP as described below. In this embodiment, SIP is extended so that a SIP client and a SIP server can authenticate each other using a public key infrastructure (hereinafter referred to as PKI).

  First, based on FIG. 1, the whole structure of the communication system 100 concerning this embodiment is demonstrated. The communication system 100 mainly includes a PKI token 102, communication terminals 104a, 104b, 104c,... (Hereinafter simply referred to as communication terminal 104), a communication network 106, and a server 108.

  The PKI token 102 is an example of a portable module and is configured to be connectable to the communication terminal 104. For example, the PKI token 102 is issued from the service providing side to a user registered in the VoIP service provided by the communication system 100, and stores data that allows the service providing side to authenticate the user. If the user connects the PKI token 102 to the communication terminal 104, the user can be provided with the service by the communication terminal 104 after receiving authentication from the service providing side via the communication terminal 104 using the data in the PKI token 102. The detailed configuration of the data for authenticating the user and the PKI token 102 will be described later with reference to FIG. The PKI token 102 is desirably large and heavy enough to be easily carried by the user. Examples of the PKI token 102 include devices, IC cards, and mobile phones that can be connected to the communication terminal 104 via a Universal Serial Bus (hereinafter referred to as USB). Further, the connection between the PKI token 102 and the communication terminal 104 may be either a wired connection or a wireless connection.

  The communication terminal 104 is an SIP client that is connected to the server 108 via the communication network 106 and communicates with the server 108 according to the expanded SIP. When the PKI token 102 is connected, the communication terminal 104 becomes a medium for the user who is the owner of the PKI token 102 to receive service. As shown in the figure, the communication terminal 104 includes a PC (104a), a telephone (104b), a mobile phone (104c), a TV, a game machine, a PDA (Personal Digital Assistant), a car navigation device, an information appliance, Etc. can be illustrated.

  The server 108 is a SIP server that is connected to the communication terminal 104 via the communication network 106 and communicates with the communication terminal 106 according to the expanded SIP. The server 108 is, for example, a server device owned by a service provider that provides a VoIP service using the communication system 100. The server 108 stores data for authenticating a user registered in the service. Authenticate.

  The communication network 106 is an IP communication network that connects the communication device 104 and the server 108 so that they can communicate with each other, and may be wired or wireless.

  According to the communication system 100 configured as described above, the user can connect the portable PKI token 102 to the communication device 104 a, 104 b, or 104 c and receive the VoIP service using the communication device 104.

  The overall configuration of the communication system 100 has been described above. Next, the configuration of the PKI token 102 will be described.

  First, the hardware configuration of the PKI token 102 will be described. The PKI token 102 includes a CPU (Central Processing Unit), storage means, connection means, and the like. The CPU performs overall control of the PKI token 102. Further, the CPU reads out each piece of information stored in the storage means and performs processing based on the information, thereby executing data encryption / decryption processing, which will be described later. The storage means includes an external storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a hard disk. The connection means realizes a wired or wireless connection with another computer. Note that the hardware configuration of the PKI token 102 is not limited to the above example, and any configuration may be used as long as it can store a secret key, which will be described later, and can execute a data rearrangement process using the secret key.

  Next, the functional configuration of the PKI token 102 will be described with reference to FIG. As shown in FIG. 2, the PKI token 102 mainly includes a data processing unit 112, a user information storage unit 114, a server certificate storage unit 116, and the like.

  The user information storage unit 114 stores data for the server 108 to authenticate the user. Specifically, the user information storage unit 114 includes storage means, and stores user identification information and a user secret key. The user identification information is a user ID, a user name, etc. for uniquely identifying the user in the server 108. The user's private key is a key for encrypting or decrypting data. Encryption is the recombination of data using an encryption key in order to prevent the decryption and use of the data by a third party. Decrypting means recombining data that has been encrypted and cannot be decrypted using a decryption key to obtain original decryptable data. The encryption key and the decryption key are predetermined rules used for rearranging digital information.

  In this embodiment, a public key cryptosystem that uses different keys for encryption and decryption is adopted as the encryption scheme. That is, the data encrypted with the secret key stored in the user information storage unit 114 can be decrypted only with the public key corresponding to the secret key. In addition, data encrypted with the corresponding public key can be decrypted only by the secret key stored in the user information storage unit 114. In the public key cryptosystem, the secret key must be kept secret. Therefore, the user's private key stored in the user information storage unit 114 is protected so that it cannot be read from the outside of the PKI token 102. This protection can be implemented by restricting access to the private key only to the data processing unit 112 inside the PKI token and prohibiting access to the private key from the outside of the PKI token 102. .

  The user information storage unit 114 also stores data for authenticating a user who is permitted to use the PKI token 102. If anyone can use the PKI token 102, for example, when the user drops the PKI token 102, a third party who picks up the PKI token 102 can impersonate the user and receive a service. Therefore, it is preferable to perform user authentication when using the PKI token 102. For this purpose, the user information storage unit 114 stores, for example, a password preset by the user. In addition, in order to perform biometric authentication, information on physical features such as a user's fingerprint, iris, voiceprint, and face may be stored.

  In addition, the user information storage unit 114 may store user setting data and user private data. The user setting data is, for example, VoIP service information used by the user, the address of the server 108 that is the connection destination, and the like. The communication terminal 104 can obtain information on the server 108 to be connected by reading the setting data from the connected PKI token 102. The user's private data is, for example, information on a partner with whom the user makes a voice call via the server 108 using the VoIP service. The communication terminal 104 may read the user's private data from the connected PKI token 102 and display the information on a display device included in the communication terminal 104.

  The server certificate storage unit 116 includes storage means and stores the certificate of the server 108. The certificate of the server 108 includes the public key of the server 108 and the electronic signature of the certificate authority that issued the certificate.

  The data processing unit 112 includes a CPU, and has a function of rearranging data using the user's secret key. Specifically, the data processing unit 112 acquires data from the communication terminal 104 based on an instruction from the connected communication terminal 104, and uses the acquired data using the secret key stored in the user information storage unit 114. Recombine and encrypt or decrypt. Then, the encrypted or decrypted data is provided to the communication terminal 104.

  The configuration of the PKI token 102 has been described above. Next, the configuration of the communication terminal 104 will be described.

  First, the hardware configuration of the communication terminal 104 will be described. The communication terminal 104 includes a CPU (Central Processing Unit), storage means, input means, output means, connection means, communication means, and the like. The CPU performs overall control of the communication terminal 104. In addition, the CPU acquires information input from the input unit, reads out each piece of information stored in the storage unit, and performs processing based on the information to perform communication with the server 108. For each process. The storage means includes an external storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a hard disk. Examples of input means include a keyboard, mouse, and telephone number buttons. The output means can be exemplified by a display device such as a display. The communication means is connected to other computers such as the server 108 via a communication network, and transmits / receives information to / from other computers. The connection means realizes a wired or wireless connection with the PKI token 102. Note that the hardware configuration of the communication terminal 104 is not limited to the above example, and any configuration that can execute each process for performing communication with the server 108 may be used.

  Next, the functional configuration of the communication terminal 104 will be described with reference to FIG. The communication terminal 104 includes a reception unit 122, a transmission unit 124, a communication control unit 126, a transmission data creation unit 128, a PKI token control unit 130, a user authentication unit 132, a server information acquisition unit 134, a server validator It mainly includes a sex determination unit 136 and the like.

  The receiving unit 122 has a function of receiving data transmitted from the server 108. Specifically, the receiving unit 122 includes a communication unit, and receives data transmitted from the server 108 when the communication terminal 104 communicates with the server 108. The data received from the server 108 includes a data request for the server 108 to authenticate a user who intends to receive a service provided by the communication terminal 104 and data for verifying the validity of the server 108. The data request for authenticating the user includes data encrypted with the user's public key held by the server 108. The data for proving the validity of the server 108 is data encrypted with the secret key of the server 108. Hereinafter, the data encrypted with the private key of the server 108 is also referred to as a server electronic signature.

  The transmission unit 124 has a function of transmitting data to the server 108. Specifically, the transmission unit 124 includes a communication unit, and transmits data to be transmitted to the server 108 when the communication terminal 104 communicates with the server 108. The data transmitted to the server 108 includes data for certifying the validity of the user who intends to receive the service provided by the communication terminal 104. The data for certifying the validity of the user is data encrypted with the user's private key stored in the connected PKI token 102. Hereinafter, the data encrypted with the user's private key is also referred to as the user's electronic signature.

  The transmission data creation unit 128 creates data to be transmitted to the server 108. Specifically, the transmission data creation unit 128 includes a CPU and storage means, and creates data in a format according to the expanded SIP. The data created by the transmission data creation unit 128 includes the above-described data for proving the validity of the user who intends to receive the service provided by the communication terminal 104.

  The PKI token control unit 130 is an example of a module control unit and has a function of controlling the PKI token 102. Specifically, the PKI token control unit 130 includes a CPU and connection means, and detects the connection of the PKI token 102 and the disconnection of the connection with the PKI token 102. Further, the PKI token control unit 130 provides the data to be transmitted to the server 108 to the data processing unit 112 of the PKI token 102 and encrypts it with the user's private key, and obtains the encrypted data from the data processing unit 112. To do. Also, the PKI token control unit 130 provides the data received from the server 108 to the data processing unit 112 of the PKI token 102, decrypts it with the user's private key, and acquires the decrypted data from the data processing unit 112. To do.

  The server information acquisition unit 134 has a function of acquiring information on the server 108. Specifically, the server information acquisition unit 134 includes a CPU, and acquires the certificate of the server 108 with which the communication terminal 104 communicates from the server certificate storage unit 116 of the connected PKI token 102. .

  The server validity determination unit 136 has a function of determining the validity of the server 108 with which the communication terminal 104 communicates. Specifically, the server validity determination unit 136 includes a CPU, and includes a reception unit 122. Is decrypted with the server public key included in the certificate acquired by the server information acquisition unit 134 to determine whether the electronic signature is valid.

  The communication control unit 126 has a function of controlling communication with the server 108. Specifically, the communication control unit 126 includes a CPU, and determines whether to permit communication with the server 108 based on the determination result of the server validity determination unit 136. If the server validity determination unit 136 determines that the electronic signature received from the server 108 is valid, the communication control unit 126 permits communication with the server 108, while the server validity determination unit If it is determined by 136 that the electronic signature received from the server 108 is not valid, the server 108 is likely to be an unauthorized server operated by a third party pretending to be the service provider. . Therefore, the communication control unit 126 does not allow the communication terminal 104 to communicate with the server, and the communication terminal 104 does not perform communication.

  The user authentication unit 132 has a function of authenticating a user who uses the connected PKI token 102. Specifically, the user authentication unit 132 includes a CPU, input means, and output means. The user authentication section 132 prompts the user to input a password via the output means, and receives the password input by the user via the input means. User verification is performed by checking the above password stored in the PKI token 102. When the user authentication unit 132 succeeds in the user authentication, the user authentication unit 132 permits the use of the connected PKI token 102 and causes the PKI token control unit 130 to continue the control of the PKI token 102. On the other hand, if the user authentication fails, the use of the connected PKI token 102 is not permitted, an error message is displayed on the output means, and subsequent processing of the PKI token 102 by the communication device 104 is prohibited.

  The configuration of the communication terminal 104 has been described above. Next, the configuration of the server 108 will be described.

  First, the hardware configuration of the server 108 will be described. The server 108 includes a CPU (Central Processing Unit), storage means, communication means, and the like. The CPU performs overall control of the server 108. In addition, the CPU executes each process for performing communication with the communication terminal 104 by reading each information stored in the storage unit and performing a process based on the information. The storage means includes an external storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a hard disk. The communication means is connected to another computer such as the communication terminal 104 via a communication network, and transmits / receives information to / from the other computer. Note that the hardware configuration of the server 108 is not limited to the above example, and any configuration that can execute each process for performing communication with the communication terminal 104 is acceptable.

  Next, the functional configuration of the server 108 will be described with reference to FIG. The server 108 includes a reception unit 142, a transmission unit 144, a communication control unit 146, a transmission data creation unit 148, a user validity judgment unit 150, a user certificate storage unit 152, a server information storage unit 154, and the like. Prepare mainly.

  The receiving unit 142 has a function of receiving data transmitted from the communication terminal 104. Specifically, the reception unit 142 includes a communication unit, and receives data transmitted from the communication terminal 104 when the server 108 communicates with the communication terminal 104. The data received from the communication terminal 104 includes data for certifying the validity of the user who intends to receive the service provided by the communication terminal 104. The data for proving the validity of the user is the above-described electronic signature of the user.

  The transmission unit 144 has a function of transmitting data to the communication device 104. Specifically, the transmission unit 144 includes a communication unit, and transmits data to be transmitted to the communication terminal 104 when the server 108 communicates with the communication terminal 104. The data transmitted to the communication terminal 104 includes a request for transmitting data for authenticating the user by the server 108 to the communication terminal 104 and data for proving the validity of the server 108. As described above, the data request for authenticating the user includes data encrypted with the user's public key held by the server 108. The data for proving the validity of the server 108 is the above-described electronic signature of the server.

  The transmission data creation unit 148 creates data to be transmitted to the communication terminal 104. Specifically, the transmission data creation unit 148 includes a CPU and storage means, and creates data in a format according to the expanded SIP. The data created by the transmission data creation unit 148 includes the above-described data request for authenticating the user and the electronic signature of the server.

  The user certificate storage unit 152 has a function of storing a user certificate. Specifically, the user certificate storage unit 152 includes storage means, and stores a plurality of user certificates registered in the VoIP service provided by the server 108 in association with identification information of each user. To do. The certificate includes the user's public key and the electronic signature of the certificate authority that issued the certificate. The public key of the user included in the certificate corresponds to the private key of each user stored in the PKI token 102.

  The server information storage unit 154 stores information on the server 108. Specifically, the server information storage unit 154 includes storage means and stores the secret key of the server 108. The private key of the server 108 corresponds to the public key included in the server certificate stored in the PKI token 102.

  The user validity judgment unit 150 has a function of judging the legitimacy of a user who receives a service provided by the communication terminal 104 with which the server 108 communicates. Specifically, the user validity determination unit 150 includes a CPU, and the user's public key stored in the user certificate storage unit 152 is the user's electronic signature received by the reception unit 142 from the communication terminal 104. It is judged whether or not the electronic signature is valid by decrypting with the above.

  The communication control unit 146 has a function of controlling communication with the communication device 104. Specifically, the communication control unit 146 includes a CPU, and determines whether to allow communication with the communication terminal 104 based on the determination result of the user validity determination unit 150. If the user validity determination unit 150 determines that the user's electronic signature received from the communication terminal 104 is valid, the communication control unit 150 permits communication with the communication terminal 104. When the validity determination unit 150 determines that the electronic signature of the user received from the communication terminal 104 is not valid, the valid PKI token 102 is not connected to the communication terminal 104, and the third There is a high possibility that the person is improperly trying to receive the service through the communication terminal 104. Therefore, the communication control unit 150 does not allow the server 108 to communicate with the communication terminal 104, and the server 108 does not communicate.

  The configuration of the server 108 has been described above. Next, the flow of communication processing between the communication terminal 104 and the server 108 will be described with reference to FIG.

First, the PKI token 102 is connected to the communication terminal 104 (S102). Next, the communication terminal 104 transmits a request to the server 108 (S104). This request is a request to start communication and does not include authentication data for the server 108 to authenticate the user. The server 108 receives the request from the communication terminal 104 and transmits a response (S106). This response is a notification of an error that authentication data is not included, and includes a request for authentication data.
In response to the error response from the server 108, the communication terminal 104 transmits the request again (S108). This request includes the electronic signature of the user as authentication data for authenticating the user who wants to receive the service by the communication terminal 104. In response to the request including the authentication data, the server 108 transmits a positive response (S110). With this positive response, a session is established between the communication terminal 104 and the server 108, and communication is started.

  After an arbitrary time has elapsed, the communication terminal 104 transmits a request to the server 108 (S112). This request is, for example, a request for transmitting audio data, and includes authentication data similar to the authentication data transmitted to the server 108 in S108. In response to the request, the server 108 determines whether the session established in S110 is valid. When the session is invalidated due to a timeout or the like, the server 108 transmits an error response to the communication terminal 104 (S114). This error response includes a request for new authentication data. Upon receiving the error response, the communication terminal 104 transmits the request again (S116). This request is a request to start communication and includes new authentication data. The server 108 receives the request including the new authentication data and transmits a positive response (S118). With this positive response, a new session is established between the communication terminal 104 and the server 108, and communication is started.

  When the connection with the PKI token 102 is disconnected, the communication terminal 104 detects the disconnection (S120). When the disconnection is detected, the communication terminal 104 transmits a request to the server 108 (S122). This request is a notification of disconnection detection and requests termination of communication. Also, this request does not include authentication data. Since the user's electronic signature is generated by the PKI token 102 in which the user's private key is stored, the communication terminal 104 cannot obtain the user's electronic signature after the connection with the PKI token 102 is disconnected. Because. In response to the request to end communication, the server 108 transmits a positive response (S124). With this positive response, communication between the communication terminal 104 and the server 108 ends, and the session ends.

  The response that the server 108 transmits to the communication terminal 104 in S106 and the like, and the request that the communication terminal 104 transmits to the server 108 in S108 and the like are data in a format according to the SIP expanded in the present embodiment. Here, each data will be described with reference to FIG. 10 and FIG.

  FIG. 10 shows data included in the response that the server 108 transmits to the communication terminal 104. This data is obtained by changing a part of the WWW-Authenticate response header defined in RFC2617. Hereinafter, this data is referred to as an authentication response header. Hereinafter, the changed part will be mainly described.

  The pki-challenge 202 is data used by the server 108 for user authentication. Specifically, at least a session key is generated as an example of challenge data by the server 108, and data (session-key-enc) obtained by encrypting the generated session key with the user's public key is included. A session key, which is an example of challenge data, is an arbitrary value for identifying a session that is generated by the server 108 when a communication start request is received from the communication terminal 104. The session key may be, for example, the date and time (Western calendar + date + time) when the server 108 receives the request. Further, the server 108 may encrypt not only the session key but also other values such as a nonce value.

  qop-valu 204 indicates the type of authentication supported by the server 108. s-sign indicates an authentication method using an electronic signature. s-auth and s-auth-final indicate a hash value authentication method. The authentication by s-auth-final is performed when the communication terminal 104 cannot continue the authentication method using the electronic signature while the server 108 is communicating with the communication terminal 104 using the authentication method using the electronic signature. Is done to end.

  The session-key-enc 206 is as described above.

  The session-key-signature 208 is an electronic signature obtained by encrypting a session key with the secret key of the server 108 and is data for proving the validity of the server 108.

  FIG. 11 shows data included in the request transmitted from the communication terminal 104 to the server 108. This data is obtained by changing a part of the Authorization request header defined in RFC2617. Hereinafter, this data is referred to as an authentication request header. The authentication data is included in the authentication request header. Hereinafter, the changed part will be mainly described.

  The pki-response 302 is authentication data for causing the server 108 to authenticate the user. Specifically, the data encrypted from the user's public key received from the server 108 is decrypted with the user's private key, and the hash value obtained by applying a predetermined hash function to the decrypted data is stored in the user's secret key. Data (response) encrypted with the private key is included. In addition to the session key, the hash function is applied to the user name (username) together with the session key, and the server 108 authenticates the user with the data obtained by encrypting the hash value obtained therefrom with the user's private key. It is good also as data for.

  The message-qop 304 is the quality of protection given to the data by the communication terminal 102 and designates the authentication method to be performed by the server 108. Any value included in the above-described qop-valu 204 is specified in message-qop 304.

  The response 306 is as described above.

  Next, a detailed flow of processing performed by the communication terminal 104 and the server 108 in the communication system 100 will be described with reference to FIGS.

  FIG. 6 shows a processing flow of the communication terminal 104 from when the PKI token 102 is connected to the communication terminal 104 until the communication terminal 104 establishes a session with the server 108. First, the user connects the PKI token 102 to the communication terminal 104 in the standby state (S202) (S204). The communication terminal 104 detects the connection of the PKI token 102 and reads user information from the connected PKI token 102 (S206). The user information read here is information for identifying a user such as a user name or a user ID. Next, the communication terminal 104 displays the read user information on the display device, and displays a message prompting input of user authentication data (S208). When the user inputs, for example, a password as user authentication data (S210), the communication terminal 104 performs user authentication by comparing with the password stored in the PKI token 102 (S212).

  If the user authentication is successful, the communication terminal 104 reads the setting data for the user from the PKI token 102 and executes the setting (S214). For example, as described above, the address of the server 108 to be connected is read as setting data, and preparations for communication with the server 108 are made. Further, the communication terminal 104 reads the user's private data from the PKI token 102 and executes the setting (S216). For example, as described above, information on the other party of the call (phone book including the name of the other party) is read as personal data of the user and displayed on the display device. Subsequently, the communication terminal 104 tries to establish a session with the server 108 (S218). Detailed processing of S218 will be described later with reference to FIG. If the session is successfully established (S220), the communication terminal 108 becomes online and can communicate with the server 108 (S222). If the communication terminal 104 is in an online state, the user can make a voice call from the communication terminal 104 via the server 108 with the other user who uses the other communication terminal.

  If the user authentication fails in S212, the communication terminal 104 determines whether the number of authentication attempts exceeds the set value (S224). If it exceeds, the use of the PKI token 102 is prohibited. The process ends, and the establishment of the session with the server 108 fails (S230). On the other hand, if the set value is not exceeded in S224, a warning that the passwords are different and a message prompting the user to re-enter the password are displayed (S228), and the user waits for input of the password.

  FIG. 7 shows a flow of processing in which the communication terminal 104 terminates communication with the server 108 when the connection with the PKI token 102 is disconnected in the communication terminal 104 in the online state. First, the connection with the PKI token 102 is disconnected, for example, by the user pulling out the PKI token 102 from the communication terminal 104 (S302). The communication terminal 104 detects the disconnection and ends the session being executed with the server 108 (S304). Specifically, as described above, the communication terminal 104 transmits a communication end request to the server 108 to end the session with the server 108. The communication terminal 104 determines whether the session is successfully terminated (S306), and displays an error message if the session is unsuccessful (S308). Then, regardless of whether the session is successfully terminated or failed, the communication terminal 104 deletes the user information and the session information from the storage unit of the communication terminal 104 (S310). Then, the communication terminal 104 returns to the standby state (S312).

  8A to 8C show the flow of processing performed when the server 108 receives a request from the communication terminal 104. First, the communication terminal 104 transmits a request (S402), and the server 108 receives the request (S404). Then, the server 108 determines whether an authentication request header is included in the received request (S406). Specifically, for example, it is determined whether the data described with reference to FIG. 11 is included. The case where the authentication request header is included in the request is a situation where the server 108 has already established a session with the communication terminal 104 and started communication, and the request does not include the authentication request header. Is a situation where the server 108 has not yet established a session with the communication terminal 104 and the request received from the communication terminal 104 is a request to start communication.

  As a result of the determination, if the authentication request header is included, the server 108 determines whether the value of “nonce” in the authentication request header is valid (S408). The case where the value of “nonce” is valid is a situation where the established session is valid, and the case where the value of “nonce” is invalid is a situation where the established session is invalid. As a result of the determination, if it is valid, the server 108 determines whether the value of “qop” in the authentication request header is “s-auth-final”. The case where the value of “qop” is “s-auth-final” is a situation in which the request received from the communication terminal 104 is a request for termination of communication due to disconnection of the connection with the PKI token 102. is there. As a result of the determination, if the value of “qop” is not “s-auth-final”, it is determined whether the session key is valid (S412). When the session key is valid, the established session is valid, and when the session key is invalid, the established session is invalidated due to a timeout or the like.

  If the session key is valid, the server 108 creates data for authentication (S414 in FIG. 8B). Specifically, for example, the session key of the session being established is read from the storage means stored in advance, and the hash function set in “algorithm” included in the authentication request header is applied to the session key. Find the hash value. Next, the server 108 determines whether the value of “qop” included in the authentication request header is “s-sign” (S416).

  If the value of “qop” is “s-sign”, the server 108 authenticates the user's electronic signature, which is authentication data included in the authentication request header (S418). Specifically, the hash value of the session key encrypted with the user's private key included in the authentication request header is decrypted with the user's public key stored in the user certificate storage unit 152 and decrypted. It is determined whether the data matches the data created in S414. On the other hand, if the value of “qop” is not “s-sign” in S416, it is determined whether the hash value of the session key included in the authentication request header matches the hash value created in S414 (S420).

  If the authentication is successful as a result of the authentication in S418 or S420 (S422), the server 108 transmits a positive response to the communication terminal 104 (S424) and waits for the next request from the communication terminal 104.

  If the authentication request header is not included in the request in S406, the value of “nonce” is invalid in S408, the session key is invalid in S412, and if the authentication fails in S422, the server 108 A “nonce” value or session key is generated (S426 in FIG. 8C), and the generated “nonce” value and session key are stored in storage means (eg, RAM). This is performed for the server 108 to establish a new session with the communication terminal 104. Then, the server 108 generates an error message (S428) and transmits an error response to the communication terminal 104 (S430). Specifically, an authentication response header that is the data described with reference to FIG. 10 is generated using the session key generated in S426, and a response including the authentication response header is transmitted to the communication terminal 104.

  9A to 9C show the flow of processing performed when the communication terminal 104 transmits a request to the server 108. First, in the communication terminal 104, an event that the communication terminal 104 should send a request to the server 108 occurs (S502). The event includes, for example, an instruction to establish a new session by the user (S504), a timeout of the established session (S506), a change of the session being established (S508), and an error response sent by the server (S510). is there. S510 is related to S430 in FIG. 8C.

  When an event occurs, the communication terminal 104 determines whether the event is an error response from the server (that is, S510) (S512). The case of an error response from the server is a case where transmission of an authentication request header is requested from the server, and a case where a response including an authentication response header is transmitted from the server. In that case, the communication terminal 104 determines whether the electronic signature of the server is included in the authentication response header in the response received from the server (S518 in FIG. 9B). If there is an electronic signature, the communication terminal 104 authenticates the electronic signature using the server public key included in the server certificate stored in the connected PKI token 102 (S520). It is determined whether or not the authentication is successful (S522). If the authentication fails (S530), the communication with the server is terminated. On the other hand, if the authentication is successful in S522, the session key (challenge data) encrypted with the user's public key included in the authentication response header received from the server is used as the user's private key included in the PKI token 102. (S524). Note that this decryption processing is performed by the data processing unit 112 in the PKI token 102 as described above. The communication terminal 102 determines whether or not the decryption is successful (S526). If the communication terminal 102 fails, the communication terminal 102 ends the communication with the server 108. On the other hand, if the decryption is successful in S526, other data for preparing an authentication request header to be transmitted to the server 108 is prepared (S528). Specifically, data other than the session key such as “username” is generated in order to create the data in FIG. 11 described above.

  Then, the communication terminal 104 determines whether the PKI token 102 is connected (S532 in FIG. 9C). If not connected, generate an authentication request header in "s-auth-final" mode. Specifically, a hash value obtained by applying a predetermined hash function to the session key or the like is included in the authentication request header, and the value of “qop” described above is set to “s-auth-final”. On the other hand, if the PKI token 102 is connected in S532, it is determined whether to use an electronic signature (S534). Specifically, for example, if the setting data for a user stored in the PKI token 102 includes data for setting whether to use an electronic signature, the communication terminal 104 refers to the data. Thus, it is possible to determine whether or not to use an electronic signature. In this case, whether to use the electronic signature can be selected by the service provider or the user. Alternatively, when “s-sign” is not included in “qop-valu” in the authentication response header received from the server 108, that is, when a conventional SIP server that does not support the extended SIP is the communication partner, The communication terminal 104 can select not to use an electronic signature.

  If an electronic signature is used in S534, an authentication request header is generated in the “s-sign” mode (S536). Specifically, the communication terminal 104 obtains a hash value by applying a predetermined hash function to the session key or the like, provides the hash value to the data processing unit 112 in the PKI token 102, and encrypts it with the user's private key. Execute the conversion. Then, the communication terminal 104 includes the encrypted hash value (authentication data) in the authentication request header, and sets the above-described “qop” value to “s-sign”. On the other hand, if the electronic signature is not used in S534, an authentication request header is generated in the “s-auth” mode (S538). Specifically, a hash value obtained by applying a predetermined hash function to the session key or the like is included in the authentication request header, and the above-described “qop” value is set to “s-auth”. Then, the communication terminal 104 generates a request including the authentication request header generated in S536, S538, or S540 (S544), and transmits the request to the server 108 (S546).

  If the event is not reception of an error response from the server in S512, the communication terminal 104 determines whether the event is for establishment of a new session (that is, S504) (S514). If so, the process proceeds to S542 in FIG. 9C, and the communication terminal 104 generates a communication start request that does not include the authentication request header, and transmits the request to the server (S546).

  On the other hand, if the request is not for establishing a new session in S514 (that is, S506 or S508), the communication terminal 104 retrieves data necessary for creating an authentication request header to be included in the request transmitted to the server 108. (S516). The data necessary for creating the authentication request header is a session key used in a session that has been established or before the timeout, and is stored in the RAM of the communication terminal 104, for example. Then, the communication terminal 104 performs the processing from S532 onward using the retrieved session key or the like, generates a request, and transmits it to the server 108.

  The detailed processing flow performed by the communication terminal 104 and the server 108 in the communication system 100 has been described above.

  According to the communication system 100 according to the present embodiment, mutual authentication between the communication terminal 104 and the server 108 is performed by PKI. Therefore, since the user's password is not transmitted from the communication terminal 104 to the server 108, the password is not leaked in the middle of the transmission path, and the authentication can be performed safely. Further, since the user's private key is included in the PKI token 102 and restricted so that the private key cannot be accessed from the outside, the user can safely store the private key. Further, since the user who can use the PKI token 102 is authenticated by the communication terminal 104, the abuse of the PKI token 102 can be prevented. In addition, user setting data and user private data are stored in the PKI token, and these data are read and set by the communication terminal 104 connected to the PKI token 102. There is no need to make various settings. Further, any of the plurality of communication terminals 104 can be a communication terminal suitable for the user who owns the PKI token 102 by simply connecting the PKI token 102. Therefore, since the user can use the communication terminal 104 simply by connecting the PKI token 102 to the communication terminal 104, it is convenient for the user.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

It is explanatory drawing which shows the whole structure of the communication system concerning embodiment of this invention. It is a block diagram which shows the structure of the PKI token in the same embodiment. It is a block diagram which shows the structure of the communication terminal in the embodiment. It is a block diagram which shows the structure of the server in the embodiment. It is a flowchart which shows the whole flow of communication in the embodiment. It is a flowchart which shows the flow of a process of the communication terminal in the embodiment. It is a flowchart which shows the flow of a process of the communication terminal in the embodiment. It is a flowchart which shows the flow of a process of the server in the embodiment. It is a flowchart which shows the flow of a process of the server in the embodiment. It is a flowchart which shows the flow of a process of the server in the embodiment. It is a flowchart which shows the flow of a process of the communication terminal in the embodiment. It is a flowchart which shows the flow of a process of the communication terminal in the embodiment. It is a flowchart which shows the flow of a process of the communication terminal in the embodiment. It is explanatory drawing which shows the example of data of the authentication response header in the embodiment. It is explanatory drawing which shows the example of data of the authentication request header in the embodiment

Explanation of symbols

100 communication system 102 PKI token 104 communication terminal 106 communication network 108 server 112 data processing unit 114 user information storage unit 116 server certificate storage unit 122, 142 reception unit 124, 144 transmission unit 126, 146 communication control unit 128, 148 transmission data Creation unit 130 PKI token control unit 132 User authentication unit 134 Server information acquisition unit 136 Server validity judgment unit 150 User validity judgment unit 152 User certificate storage unit 154 Server information storage unit

Claims (12)

In a communication method in which a communication terminal and a server transmit and receive audio data via an IP communication network;
A module connection step in which a portable module storing user identification information and the user's private key is connected to the communication terminal;
A start request step in which the communication terminal transmits a communication start request including the identification information of the user to the server;
The server that has received the start request generates challenge data, encrypts the challenge data with the user's public key identified by the user identification information included in the start request, and includes the encrypted challenge data , An authentication data transmission request step of transmitting an authentication data transmission request to the communication terminal;
A decryption step in which the communication terminal that has received the authentication data transmission request provides the encrypted challenge data to the portable module, and causes the portable module to decrypt the challenge data with the user's private key. When;
A calculation step in which the communication terminal obtains a hash value of the decrypted challenge data;
An encryption step in which the communication terminal provides the hash value to the mobile module and causes the mobile module to encrypt the hash value with the user's private key;
A data transmission step in which the communication terminal transmits the encrypted hash value to the server;
A validity determination step in which the server that has received the hash value decrypts the hash value with the public key of the user and determines the validity of the decrypted hash value based on the challenge data;
A communication start step in which the server starts communication with the communication terminal when the decrypted hash value is valid as a result of the validity determination;
A communication method comprising: A disconnection detecting step for detecting that the communication terminal is disconnected from the portable module;
A disconnect notification step in which the communication terminal transmits a notification to the server when disconnection with the portable module is detected in the disconnect detection step;
A communication ending step in which the server receiving the disconnection notification ends communication with the communication terminal;
The communication method according to claim 1, further comprising: after the communication start step. In the disconnect notification step, the notification transmitted from the communication terminal to the server includes a hash value of the challenge data,
In the communication end step, the server determines the validity of the hash value based on the challenge data, and ends the communication with the communication terminal when the hash value is a valid value as a result of the determination. The communication method according to claim 2, wherein the communication method is characterized. In the authentication data transmission request step, the server generates an electronic signature with its own private key and transmits the electronic signature to the communication terminal together with the authentication data transmission request;
The communication terminal further includes a server validity determination step that determines the validity of the electronic signature using the public key of the server, and proceeds to the decryption step if the electronic signature is valid as a result of the determination. The communication method according to claim 1, wherein: In a communication system in which a communication terminal and a server transmit and receive audio data via an IP communication network;
A user information storage unit for storing user identification information and the user's private key, and a data processing unit for rearranging data using the user's private key, comprising a portable module connectable to the communication terminal,
The communication terminal is
A module control unit that performs the data processing unit of the portable module to recombine and encrypt data to be transmitted to the server;
A transmission unit for transmitting the encrypted data to the server;
The server
A user certificate storage unit for storing a certificate including the identification information of the user and the public key of the user;
A receiving unit for receiving the encrypted data from the communication terminal;
A user validity determination unit that decrypts the data received by the reception unit with the public key of the user and determines the validity of the decrypted data;
A communication control unit that determines whether or not to allow communication with the communication terminal based on a result of determination of validity by the user validity determination unit;
A communication system comprising: The server includes a transmission data creation unit that encrypts data to be transmitted to the communication terminal with the public key of the user,
6. The communication system according to claim 5, wherein the module control of the communication terminal causes the data processing unit of the portable module to recombine and decode data received from the server. The server includes a server information storage unit that stores its own secret key;
A transmission data creation unit that encrypts data to be transmitted to the communication terminal with the own private key,
The communication terminal includes a server information acquisition unit that acquires a public key of the server;
A server validity determination unit that decrypts the data received from the server with the public key of the server and determines the validity of the decrypted data;
A communication control unit that determines whether or not communication with the server is permitted based on a determination result of validity by the server validity determination unit;
The communication system according to claim 5, further comprising: In a communication terminal that transmits / receives voice data to / from a server via an IP communication network;
It can be connected to a portable module provided with a user information storage unit that stores user identification information and the user's private key, and a data processing unit that rearranges data using the user's private key,
A module control unit that performs the data processing unit of the portable module to recombine and encrypt data to be transmitted to the server;
A transmission unit for transmitting the encrypted data to the server;
Data transmitted to the server is decrypted by the server using the public key of the user, and whether or not communication with the server is permitted is determined based on the validity of the decrypted data. Terminal. A receiving unit for receiving data encrypted with the public key of the user from the server;
9. The communication terminal according to claim 8, wherein the module control unit causes the data processing unit of the portable module to rearrange and decode data received from the server. A receiving unit for receiving data encrypted with the secret key of the server from the server;
A server information acquisition unit for acquiring a public key of the server;
A server validity determination unit that decrypts the data received by the reception unit with the public key of the server and determines the validity of the decrypted data;
A communication control unit that determines whether or not communication with the server is permitted based on a determination result of validity by the server validity determination unit;
The communication terminal according to claim 8, further comprising: The user information storage unit of the mobile module stores user authentication data for authenticating a user who is permitted to use the mobile module,
A user authentication unit that allows the user to input the user authentication data, and determines whether or not to use the mobile module based on the input user authentication data and the user authentication data stored in the mobile module; The communication terminal according to claim 8, further comprising: The module control unit detects that the connection with the portable module is disconnected;
The communication terminal according to claim 8, wherein the transmission unit transmits a notification to the server when disconnection of the connection with the portable module is detected by the module control unit.

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