JP2005229436A - Session management apparatus, method, and program for constructing encrypted communication channel between terminals - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily construct a secure data channel between terminals by performing signalling safely. <P>SOLUTION: A session management apparatus equipped with a means for performing connection to a first apparatus and a second apparatus via networks has a means for performing mutual authentication between itself and the first apparatus, establishing a first encrypted communication channel between the session management apparatus and the first apparatus, and holding a name of the first apparatus making it to correspond to identification information for the first encrypted communication channel; a means for establishing a second encrypted communication channel based on mutual authentication between the session management apparatus and the second apparatus; a means for receiving a message comprising the name of the first apparatus via the first encrypted communication channel from the first apparatus, and judging whether or not the name of the first apparatus comprised in the message is correct, by comparing the name of the first apparatus comprised in the message with the name of the first apparatus held being made to correspond to the identification information for the first encrypted communication channel; and a means for sending that message to the second apparatus via the second encrypted communication channel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for constructing a secure data channel between two terminals on a network.

  In the prior art, in order to construct a data channel between two terminals on an IP network and perform so-called peer-to-peer communication, from name registration to DNS, setting of FW etc. to ensure security Operations such as management and certificate acquisition are required. In addition, in order to perform peer-to-peer communication between multiple terminals with mutual authentication and encryption, obtain certificates for all these terminals, or manage IDs and passwords for all terminals. is required.

  Further, as a conventional technique, there is a technique for establishing a data channel between two terminals by performing signaling based on SIP. In order to enable both terminals to perform signaling while trusting each other in such a conventional technique. For example, a complicated procedure of exchanging certificates and key information in advance between both terminals is necessary.

As described above, the conventional technology cannot easily establish a secure data channel.
JP 2002-208921 A

  The present invention has been made in view of the above points, and an object of the present invention is to provide a technique for easily constructing a secure data channel between terminals by performing signaling safely.

  The above-described problem is a session management apparatus including means for connecting the first apparatus and the second apparatus via a network, and performs mutual authentication with the first apparatus, and the session management apparatus and the second apparatus Means for establishing a first encrypted communication channel with one apparatus and holding the name of the first apparatus and identification information of the first encrypted communication channel in association with each other; a session management apparatus; Means for establishing a second encrypted communication channel based on mutual authentication with the two devices, and a message including the name of the first device from the first device via the first encrypted communication channel. By comparing the name of the first device included in the message with the name of the first device held in association with the identification information of the first encrypted communication channel. The name of the first device included is Means for determining whether poetry not be solved by the session management apparatus characterized by comprising a means for transmitting the message to the second device via the second encrypted communication channel.

  According to the present invention, a terminal can be prevented from spoofing a name, and a message can be transferred safely. Thereby, a signaling message can be transferred safely, and a secure data channel can be easily constructed between terminals by including key information for communication between terminals in the signaling message.

  If it is determined that the name of the first device included in the message is not correct, an error message may be transmitted to the first terminal.

  In addition, the above-described problem is a session management apparatus including means for connecting the first apparatus and the second apparatus via a network, performing mutual authentication with the first apparatus, and the session management apparatus Means for establishing a first encrypted communication channel between the session management device and the first device, and means for establishing a second encrypted communication channel based on mutual authentication between the session management device and the second device; Means for receiving from the first device a message including a header indicating the reliability of the path between the first device and the session management device via the first encrypted communication channel, the session management device, and the second Means for adding to the message a header indicating the reliability of the path to the second device and transmitting the message to the second device via the second encrypted communication channel. management It can be solved by location.

  According to the present invention, since the header indicating the reliability of the route is included in the message, the second device that has received the message can check the reliability of the route by checking the header, resulting in the reliability of the message. Can be confirmed. Therefore, the signaling message can be transferred safely.

  The header indicating the reliability of the route included in the message includes the address of the device with the header. When the message is received, the header includes the address included in the header and the address of the device that transmitted the message. You may make it determine the correctness of the said header by comparing.

  According to the present invention, it is possible to easily construct a secure data channel between terminals by performing signaling safely while preventing name misrepresentation and ensuring the reliability of a route.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the outline of the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, a session management server 3 is installed between a terminal 1 and a terminal 2, and a data channel is established between the terminal 1 and the session management server 3 and the terminal 2 between the terminal 1 and the terminal 2. Signaling (signaling procedure) is executed, and after data channel construction, data communication is performed only between terminals without going through the session management server 3.

  In signaling, first, exchange of encryption key information is performed for establishing a secure signaling channel for performing encrypted communication such as IPsec between the terminal 1 and the session management server 3 and between the session management server 3 and the terminal 2. Mutual authentication is performed. Then, name registration to the session management server is established via the secure signaling channel established between the terminal 1 and the session management server 3 and between the session management server 3 and the terminal 2, and the secure data channel is established between the terminal 1 and the terminal 2. Signaling for is performed.

  Mutual communication between the session management server 3 and the terminal 1 and between the session management server 3 and the terminal 2 by signaling in establishing a secure signaling channel between the terminal 1 and the session management server 3 and between the session management server 3 and the terminal 2. Since a trust relationship based on authentication is established, a trust relationship is also established between the terminal 1 and the terminal 2. That is, a trust chain model via the session management server 3 is constructed by the mutual authentication. Therefore, a simple key information exchange procedure can be used in signaling for establishing a secure data channel between the terminal 1 and the terminal 2.

  Next, a communication sequence between the terminal 1 -session management server 3 -terminal 2 will be described with reference to FIG.

  The sequence shown in FIG. 2 is based on a system configuration in which the terminal 1, the session management server 3, and the terminal 2 are connected to an IP network such as the Internet.

  Each terminal includes a signaling function for performing signaling with the session management server 3, a function for performing data communication via a secure data channel, and an application for providing a desired service using the data communication. Yes.

  The session management server also has a signaling function for performing signaling with each terminal, a connection policy control function for controlling connection permission between terminals, an authentication function for authenticating each terminal, a terminal name to an IP address And a database for storing IDs and passwords used for authentication, a database for storing names and IP addresses in association with each other, and the like. Further, a function equivalent to general DNS can be provided as a name resolution function.

  As shown in FIG. 2, in constructing a secure data channel between the terminal 1 and the terminal 2, first, a secure signaling channel is constructed between the terminal 1 and the session management server 3 and between the terminal 2 and the session management server 3, respectively. , Do name registration.

  That is, key information (information for generating a cryptographic key) used for encryption communication such as IPsec is exchanged between the terminal 1 and the session management server 3 (step 1). Thereafter, mutual authentication is performed by encrypting information including its own ID and password and transmitting it to the other party (step 2). After authentication, a secure signaling channel is established, and the terminal 1 registers the name and IP address with the session management server 3 using the channel (step 3). A similar sequence is executed between the terminal 2 that is the communication partner of the terminal 1 and the session management server 3, and the name and IP address of the terminal 2 are registered in the session management server 3 (steps 4, 5, and 6).

  Thereafter, a connection request from the terminal 1 to the terminal 2 is transmitted via the secure signaling channel (step 7). The connection request includes the name of the terminal 2 and key information for encryption communication (information for generating the encryption key). The session management server 3 that has received the connection request checks that the terminal 1 is not lying with respect to the connection request from the terminal 1 (caller spoofing check), and further uses the connection policy control function to connect the terminal 1 and the terminal. 2 is checked (step 8), and if permitted, the IP address of the terminal 2 is obtained from the name of the terminal 2 by referring to the database using the name resolution function (step 9). ), And transfer the connection request to the terminal 2 via the secure signaling channel (step 10). At this time, the IP address of the terminal 1 is also transmitted to the terminal 2. If the connection between the terminal 1 and the terminal 2 is not permitted, the connection request for the terminal 1 is rejected. At this time, information regarding the terminal 2 is not transmitted to the terminal 1 at all. The sender spoofing check will be described in more detail later.

  The terminal 2 that has received the connection request transmits a response message including key information for encryption communication to the session management server 3 via the secure signaling channel as a response to the connection request (step 11). A response message is sent to the terminal 1 (step 12). At this time, the IP address of the terminal 2 is also transmitted to the terminal 1.

  With this procedure, encrypted communication between the terminal 1 and the terminal 2 becomes possible. That is, a secure data channel is established and desired data communication is performed.

  The fact that the secure signaling channel has been established through steps 1, 2, 4, and 5 means that the terminal-session management server has successfully authenticated each other and a trust relationship has been established. Since such a relationship is established between the terminal 1 and the session management server 3 and between the terminal 2 and the session management server 3, the terminal 1 and the terminal 2 are also mutually reliable. From step 7 onward, it is possible to use a procedure that is simpler than the key exchange procedure used in general encrypted communication.

  As means for realizing the above sequence, it is possible to use a protocol that is an extension of SIP (session initiation protocol). That is, the session management server 3 is caused to function as a SIP proxy server, and information exchanged in the above procedure is included in the SIP message.

  In this case, a REGISTER message can be used for establishing a secure signaling channel and registering a name, and an INVITE message can be used for establishing a secure data channel between terminal 1 and terminal 2.

  A sequence example in the case of using SIP is shown in FIG.

  The example shown in FIG. 3 is an example when signaling is performed via a plurality of session management servers connected by a secure channel. A plurality of session management servers connected by a secure channel may be referred to as a session management device. In the sequence configuration shown in FIG. 3, the IP address of the terminal 1 is 2001: 1234 :: 10, the IP address of the session management server A is 2001: 6789 :: 5060, and the IP address of the session management server B is 2001: abcd :: 5060, the IP address of the terminal 2 is 2001: cdef :: 10.

  An ID and a password are distributed in advance between each terminal and the session management server, and each of the terminal and the session management server stores the other party's ID and password in its own storage device. The session management server A and the session management server B communicate via a secure channel such as TLS.

  First, the terminals 1 and 2 use the REGISTER message to establish a secure channel with the session management server and register a name (conforming to SIP) to the session management servers A and B (step 21). (Corresponding to steps 1 to 6 in FIG. 2). The procedure of this part will be described later in detail.

  Subsequently, the terminal 1 uses the INVITE message describing the key information for encryption communication (information for generating the secret shared key in the example in the figure) as an SDP parameter as a connection request to the terminal 2, and the terminal 1 and the session management server A is transmitted via a secure signaling channel between A (step 22). Session management server A transfers the INVITE message to session management server B via a secure channel between session management servers A and B (step 23).

  The INVITE message from the terminal 1 includes a Route-Security header. When the Route-Security header is added, the device that has received the INVITE message asks whether the route from the address indicated by the Route-Security header: [address] to the device is secure (for example, Whether the encryption is performed by IPsec) is checked, and if it is secure, the Route-Security header is left as it is and the message is transferred. When it is necessary to check whether the route is secure at the transfer destination, a message with a Route-Security header: [your address] is transferred to the transfer destination. The response message has the Route-Security header added so far, and it can be seen that the message has been transferred via a secure route. In other words, the Route-Security header provides a mechanism for ensuring the safety of the route. Various forms of the Route-Security header will be described in detail later.

  Session management server B transmits an INVITE message to terminal 2 via a secure signaling channel between terminal 2 and session management server B (step 24). The session management server A and the session management server B perform name resolution for the terminal 2.

  The terminal 2 that has received the INVITE message transmits a response message including key information for encrypted communication as an SDP parameter to the terminal 1 (step 25). Then, the response message is carried in the opposite direction on the same route as the INVITE message, and is transmitted to the terminal 1 (steps 26 and 27).

  Thereafter, an acknowledgment (ACK) message is transmitted from the terminal 1 to the terminal 2 (steps 28 to 30), and encrypted communication (for example, communication by IPsec) between the terminal 1 and the terminal 2 becomes possible.

  The sequence of the REGISTER message in step 21 in FIG. 3 is, for example, as shown in FIG.

  In this case, first, a REGISTER message including key information for encryption communication (IPsec or the like) is transmitted from the terminal to the session management server (step 211). As a response, the session management server returns a response message including the key information for encryption communication to the terminal (step 212). Subsequently, the terminal transmits a REGISTER message including authentication information for authenticating the terminal by the session management server (step 213). In response, the session management server transmits a response message including authentication information necessary for the terminal to authenticate the session management server to the terminal (step 214). After mutual authentication is obtained, encrypted communication using the secure signaling channel becomes possible.

  Thereafter, since the packet is encrypted and transmitted / received via the secure signaling channel, name registration is performed by a normal REGISTER message sequence (steps 215 and 216).

  In the above sequence, it is assumed that other information necessary for encrypted communication such as IPsec is appropriately transmitted and received. Note that the authentication information may be information including an ID, a password, or the like, or a certificate (X.509 certificate or the like). Further, authentication information (certificate) may be included in a message used for exchanging key information for encryption communication.

(Identification spoofing monitoring, route reliability confirmation)
Now, as explained so far, mutual authentication is established between the terminal and the session management server, so that a mutual trust relationship can be established between each terminal and the session management server. A secure data channel can be easily established between terminals using a simple signaling procedure. Furthermore, in the present embodiment, in the sequence shown in FIG. 3, in order to perform signaling by the INVITE message in the secure data channel construction more securely, identity spoofing monitoring (caller spoofing check) by the session management server, and route Route-Security header is added to notify that it is safe.

  Here, the Route-Security header will be described. As described above, the Route-Security header is a header added by the terminal (SIP UA) and each session management server (SIP proxy) when transmitting a request message such as an INVITE message, and at least its own Includes IP address. The Route-Security header is added when notifying the transmission destination that the route (also referred to as a link) used for transmitting the request message is secure. Further, it may be added when the security of the link to which the request message is to be transmitted is higher than a predetermined level.

  A parameter of “security level” corresponding to the security function of the link used to transmit the request message to the next node may be added to the Route-Security header. For example, depending on the level of authentication (identity confirmation), authentication, integrity guarantee (guaranteed that the packet has not been tampered with), confidentiality (encryption of packet contents), etc., 0 to Three parameters can be added. A node that has received a message with a security level can determine whether or not the Route-Security header is correctly added by comparing the IP address of the Route-Security header with the IP address of the preceding node, and the Route Whether or not the parameter is valid can be determined based on whether or not the security level indicated in the -Security header matches the security level of the link that received the message. If the IP address of the Route-Security header does not match the IP address of the previous stage, it is determined that the Route-Security header has not been added in the previous stage, and the IP address of the previous stage is used. A Route-Security header without “security level” may be added. Thereby, the receiving terminal can know that there is a link to which the Route-Security header is not added.

  A terminal (SIP UA) that has received a request message via one or a plurality of session management servers refers to the Route-Security header added to the message, for example, so that the Route-Security header is included in the route. When there is a link that has not been added, it can be determined that there is a possibility that the route is not secure enough. If a Route-Security header having a parameter with a low security level is included, it can be determined that a link with a low security level has been passed. If it is determined that the reliability is not sufficient, for example, an error response can be returned.

  When a request message is transferred to a terminal through a secure signaling channel based on a series of mutual authentications, each node checks whether or not the preceding node has correctly added a Route-Security header (for example, Just check the IP address). That is, a terminal that receives a request message to which a series of Route-Security headers are added trusts the safety of the route only by checking the Route-Security header added by the preceding node. In this case, for example, when each node detects that the correct Route-Security header is not added in the previous stage, processing such as returning an error to the transmission source is performed. The examples shown in FIGS. 5, 6, and 7 described later show this case.

  Now, the terminal that receives the request message includes the Route-Security header included in the received request message in the response message as it is while maintaining the order. The response message is transferred to the transmission source terminal through the same route as the request message. However, in each session management server that passes through the response message, for example, the IP address included in the Route-Security header assigned by itself is used as its own IP address. By comparing, the message can be checked.

  The request message source terminal that received the response message with the Route-Security header added as it is can check the reliability of the message by checking a series of Route-Security headers in the same way as the terminal that received the request message. For example, the session can be canceled when it is determined that the reliability is low.

  Note that when the request message is transferred to the terminal via a secure signaling channel based on a series of mutual authentications, it is only necessary to check the Route-Security header including its own address.

  Next, in order to explain the identity spoofing monitoring by the session management server and the use example of the Route-Security header, the processing of steps 22 to 27 in the sequence shown in FIG. 3 will be described in more detail.

  FIG. 5 shows the sequence. 6 and 7 are diagrams for explaining the sequence shown in FIG. In the following description, it is assumed that the secure signaling channel has been established between the terminal 1 and the session management server A, and between the terminal 2 and the session management server B, and the name and address have been registered in the session management server (see FIG. 5 steps 51-54).

  First, as shown in FIG. 6A, an INVITE message is transmitted to the session management server A (step 55). In the INVITE message, the Route-Security header including the IP address of the terminal 1, the name of the connection destination (terminal 2) (To line, user-b@xyz.com), and the name of the transmission source (terminal 1) (From Line, user-a@abc.com).

  As shown in FIG. 6B, the session management server A that has received the INVITE message checks whether the name of the terminal 1 in the From line is correct (whether it is not spoofed). Here, the session management server A holds the name, IP address, port number, and information (for example, IPsec SA) for identifying the secure signaling channel connection between the terminal 1 and the session management server A in association with each other. . Therefore, the session management server A can grasp the name of the sender of the INVITE message from the connection, the IP address of the sender, etc. that received the INVITE message, and the name and the name in the From line of the received INVITE message. In comparison, if they match, it can be determined that there is no misrepresentation. Similarly, the IP address included in the Route-Security header and the IP address corresponding to the connection can be compared to determine whether the Route-Security header is correctly added. Here, when the From line or the Route-Security header is not correct, for example, the transfer of the INVITE message can be stopped and an error message can be returned to the transmission source.

  In addition, since the secure signaling channel is provided after the mutual authentication is performed between the terminal 1 and the session management server A, the session management server A transmits the INVITE message received from the terminal 1 from the terminal 1. You can trust it. Therefore, by checking the name in the From line, it is possible to check whether or not the terminal 1 is not impersonating.

  Next, the session management server A transfers the INVITE message to which the Route-Security header including its own IP address is added to the session management server B (step 56). Session management server A and session management server B are also connected by a secure channel in the same way as between terminal 1 and session management server A, and session management server B is sent from session management server A via that channel. It is determined that the INVITE message is certainly sent from the session management server A. Then, the session management server B checks whether the Route-Security header is correctly added by checking the IP address and the like of the Route-Security header added in the session management server A.

  Subsequently, as shown in FIG. 7A, the session management server B transfers an INVITE message to which the Route-Security header including its own IP address is added to the terminal 2 (step 57). The terminal 2 can confirm the reliability of the route through which the INVITE message has been transferred by checking the Route-Security header.

  The terminal 2 that has received the INVITE message transmits a response message including the Route-Security header, the To line, and the From line as it is to the transmission source along the path opposite to the path through which the INVITE message has been transferred. Therefore, first, the response message is transmitted to the session management server B (step 58).

  The session management server B that has received the response message from the terminal 2 checks the message forgery by determining whether or not the IP address of the first Route-Security header matches its own IP address, for example. Then, the response message is transferred from the session management server B to the session management server A (step 59).

  The session management server A performs a check by determining whether or not the IP address of the second Route-Security header matches its own IP address. Then, the response message is transferred to the terminal 1 that is the source of the INVITE message (step 60), and the terminal 1 determines whether or not the IP address of the third Route-Security header matches its own IP address. To check the validity of the message. The terminal 1 can also confirm the reliability of the route by confirming a series of Route-Security headers. Here, for example, when it is determined that a route with low reliability is passed, it is possible to perform a process of canceling the subsequent session.

  Next, functional blocks of each device when SIP is used as a signaling protocol will be described with reference to FIG.

  The session management server includes an SIP proxy that performs a process for transferring a call (message), an SIP registrar that performs SIP name registration, an authentication module that authenticates each terminal using an ID, a password, or a certificate, IPsec And an encryption module for performing encrypted communication.

  In addition, each terminal has a function unit that performs communication on the secure data channel, a SIP function unit that performs message communication based on SIP including transmission / reception of INVITE messages and issuance of REGISTER messages, IDs, passwords, certificates, etc. It has an authentication module for authenticating the session management server, and an encryption module for performing encrypted communication such as IPsec.

  The functions of the above session management server and each terminal are realized by a program, and each means of the session management device and terminal in the present invention is realized by a program, the session management device, and hardware of the terminal. It is what. The terminal is a computer such as a general PC including a CPU, a memory, a hard disk, and the like, a mobile device, and the like, and the functions of the terminal of the present embodiment can be realized by installing the program in the computer. The terminal may be a digital home appliance. The session management server is a computer such as a server, and includes a CPU, a memory, a hard disk, and the like. The function of the session management server of the present embodiment can be realized by installing the above program on the server.

  As described above, the configuration as in the present embodiment provides the following effects.

  First, since the name and the IP address are registered by the REGISTER message every time the terminal address is changed, the terminal side can use so-called dynamic IP address assignment. In addition, since the session management server performs name resolution, name registration in an open DNS, which was necessary in the past, becomes unnecessary. In addition, since a secure channel is established between each terminal and the session management server and signaling is performed, FW management on the terminal side becomes unnecessary. Further, since the session management server manages the ID and password of each terminal, it is not necessary to manage a large number of IDs and passwords on the terminal side. In addition, because the session management server connection policy control function does not even allow name resolution for the partner terminal that does not permit connection, the existence of the terminal itself is not known, and the terminal is illegally accessed. No fear of receiving. Furthermore, since the port number necessary for the secure data channel is transmitted by signaling via the secure signaling channel, the port number is not known to the outside if the signaling is not normally completed. Further, since only light signaling passes through the intermediate server (session management server) and actual data communication is performed between terminals in a peer-to-peer manner, the load on the intermediate server is not excessive.

  Further, in the prior art, in order to perform peer-to-peer communication that is mutually authenticated and encrypted between a large number of terminals, the certificates of all the terminals are obtained, or the IDs of all the terminals, Although it is necessary to manage passwords, according to the present invention, no prior security setting is required between members.

  Further, in the prior art, even if data channel encryption is not required, there was only a method using PKI as a means for ensuring the authenticity of the calling party number, but according to the present invention, service setting (SIP ID / password setting can prevent calling number spoofing / falsification.

  Furthermore, by confirming the contents of the From line in the INVITE message, it becomes possible to confirm whether or not the sender of the INVITE message has misrepresented the name, and the reliability can be further improved. Furthermore, by using the Route-Security header, it is possible to confirm the safety of the route and further improve the reliability. If it is assumed that the person who connects to the SIP server does not necessarily pass through a secure channel, by performing name spoofing confirmation and route safety confirmation by the Route-Security header, Communication with security can be realized.

  In addition, by using the mechanism using the spoofing confirmation and Route-Security header described in the embodiment, secure communication between terminals can be performed even through other networks.

  Although the mechanism of using spoof confirmation and the Route-Security header has been described by taking the INVITE message as an example, it is not limited to the INVITE message and can be applied to various message transfers.

  The present invention is not limited to the above-described embodiments, and various modifications and applications can be made within the scope of the claims.

It is a figure for demonstrating the outline | summary of embodiment of this invention. It is a sequence diagram of communication between the terminal 1-session management server 3-terminal 2. It is a figure which shows a sequence in detail. It is a figure which shows the sequence of a REGISTER message. It is a sequence chart for explaining identity spoofing monitoring and a Route-Security header. It is a figure for demonstrating the sequence of FIG. It is a figure for demonstrating the sequence of FIG. It is a functional block diagram of each apparatus in the case of using SIP as a signaling protocol.

Explanation of symbols

1, 2 Terminal 3, A, B Session management server

Claims (14)

A session management device comprising means for connecting to a first device and a second device via a network,
Mutual authentication is performed with the first device, a first encrypted communication channel is established between the session management device and the first device, and the name of the first device and the first encrypted communication channel are established. Means for holding the identification information in association with each other,
Means for establishing a second encrypted communication channel based on mutual authentication between the session management device and the second device;
A message including the name of the first device is received from the first device via the first encrypted communication channel, and the name of the first device and the first encrypted communication channel included in the message are received. Means for determining whether or not the name of the first device included in the message is correct by comparing the name of the first device held in association with the identification information of
Means for transmitting the message to the second device via the second encrypted communication channel.   The session management device according to claim 1, wherein an error message is transmitted to the first device when it is determined that the name of the first device included in the message is not correct. A session management device comprising means for connecting to a first device and a second device via a network,
Means for performing mutual authentication with the first device and establishing a first encrypted communication channel between the session management device and the first device;
Means for establishing a second encrypted communication channel based on mutual authentication between the session management device and the second device;
Means for receiving, from the first device, a message including a header indicating the reliability of the path between the first device and the session management device via the first encrypted communication channel;
Means for adding a header indicating the reliability of the path between the session management device and the second device to the message and transmitting the message to the second device via the second encrypted communication channel. A session management device.   The header indicating the reliability of the route included in the message includes the address of the device with the header, and when the message is received, the address included in the header and the source device that transmitted the message The session management apparatus according to claim 3, wherein the validity of the header is determined by comparing the address.   The session management apparatus according to claim 1, wherein the message is a message based on SIP. A method for transferring a message between a first device, a session management device, and a second device connected to a network, comprising:
Mutual authentication is performed between the session management device and the first device, and a first encrypted communication channel is established between the session management device and the first device. Holding the name and identification information of the first encrypted communication channel in association with each other;
Establishing a second encrypted communication channel based on mutual authentication between the session management device and the second device;
The first device sending a message including the name of the first device to the session management device via the first encrypted communication channel;
The session management device compares the name of the first device included in the message with the name of the first device held in association with the identification information of the first encrypted communication channel, thereby Determining whether the name of the first device included in the message is correct;
Transmitting the message to a second device via a second encrypted communication channel.   The method according to claim 6, wherein the session management device transmits an error message to the first device when determining that the name of the first device included in the message is not correct. A method for transferring a message between a first device, a session management device, and a second device connected to a network, comprising:
Performing mutual authentication between the session management device and the first device and establishing a first encrypted communication channel between the session management device and the first device;
Establishing a second encrypted communication channel based on mutual authentication between the session management device and the second device;
The first device transmitting a message including a header indicating the reliability of the path between the first device and the session management device to the session management device via the first encrypted communication channel;
The session management device transmitting the message to which the header indicating the reliability of the path between the session management device and the second device is added to the second device via the second encrypted communication channel; A method characterized by comprising.   The method according to claim 8, wherein the second device refers to a header indicating a reliability of a route attached to the message and determines whether or not the message is reliable.   The second apparatus transmits a response message including a series of headers identical to a series of headers indicating reliability of a path attached to a message received by the second apparatus to the session management apparatus. The method described in 1.   The header indicating the reliability of the route included in the message includes the address of the device to which the header is attached, and the device receiving the message receives the address included in the header and the source of the transmission source that transmitted the message. The method according to claim 8, wherein the validity of the header is determined by comparing the address of the device.   The method according to any one of claims 6 to 11, wherein the message is a SIP based message. A program for causing a computer to function as a session management device that transmits and receives messages between a first device and a second device connected to a network, the computer comprising:
Mutual authentication is performed with the first device, the first encrypted communication channel is established with the first device, the name of the first device and the identification information of the first encrypted communication channel, Means for holding the information in association with each other,
Means for establishing a second encrypted communication channel based on mutual authentication with a second device;
A message including the name of the first device is received from the first device via the first encrypted communication channel, and the name of the first device and the first encrypted communication channel included in the message are received. Means for determining whether the name of the first device included in the message is correct by comparing the name of the first device held in association with the identification information of
A program for causing the message to function as a means for transmitting the message to the second device via the second encrypted communication channel. A program for causing a computer to function as a session management device that transmits and receives messages between a first device and a second device connected to a network, the computer comprising:
Means for performing mutual authentication with the first device and establishing a first encrypted communication channel with the first device;
Means for establishing a second encrypted communication channel based on mutual authentication with a second device;
Means for receiving, from the first device, a message including a header indicating the reliability of the path between the first device and the session management device via the first encrypted communication channel;
A program for adding a header indicating the reliability of a path to and from a second device to the message and functioning as a means for transmitting the message to the second device via a second encrypted communication channel.

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