JP2006099515A - Communication method, client, and server - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent confusion caused due to connection to an unauthorized server by a new client/server newly trying connection to a network. <P>SOLUTION: In this communication method for allowing a client to connect to any of a plurality of working servers connected to the network, each of a plurality of working servers is provided with a process for generating a function notification document notifying a function of the working server, a process for adding a signature to the function notification document and transmitting it to the client, a process for allowing the client to determine validity of the received function notification document based on the signature, and a process for allowing the client to decide the working server at a connection destination based on the function of the working server notified by the function notification document from the working servers, from which the valid function notification is received. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a communication method for a client to connect to any of a plurality of active servers connected to a network, a communication method for a new server to participate in a network to which a plurality of active servers are connected, The present invention relates to a client and a server that realize such a communication method.

In recent years, attention has been focused on home networks, and each company is focusing on the development of home networks.

In such a home network, it is necessary to collect various information and control various devices connected to the home network. For this purpose, a system in which all clients connected to the home network are connected to only one active server is effective.
JP 2002-77143 A

In the conventional system as described above, when a new client or new server appears on the home network, it is necessary to select which operating server the new client or new server is connected to. At the time of such selection, a function notification document (subscribe document) for notifying the function of the active server is transmitted from the active server.

However, in the conventional communication system, when the function notification document is forged by a malicious third party, the client tries to connect to an unauthorized server, which causes confusion in the home network. There was a problem.

Therefore, the present invention has been made in view of the above points, and it is possible to avoid confusion caused by a new client or new server attempting to connect to a network connecting to an unauthorized server. An object is to provide a simple communication method, a client, and a server.

A first feature of the present invention is a communication method for a client to connect to any of a plurality of active servers connected to a network, wherein each of the plurality of active servers has a function of the active server. Generating a function notification document that notifies the function notification, a step in which each of the plurality of active servers adds a signature to the function notification document and transmits the signature to the client, and the client adds the signature to the signature. And determining the validity of the received function notification document based on the function of the active server notified by the function notification document from among the active servers from which the client has received the valid function notification document. And a step of determining a connection destination operating server.

According to this invention, the new client judges the validity of the function notification document (subscribe document) received from the active server, and determines the connection-destination active server from the active servers that received the valid function notification document. Therefore, it is possible to prevent a new client from connecting to an unauthorized server.

Further, according to this invention, since the new client determines the operation server to be connected based on the function of the operation server notified by the function notification document, the new client is optimal for realizing an optimal network configuration. A connection can be established with any active server.

In the first aspect of the present invention, the active server generates the signature using a common key between the active server and the client that can be generated using the secret key of the active server and the public key of the client, The client may be configured to determine the validity of the function notification document by using the common key that can be generated using the private key of the client and the public key of the operation server.

The second feature of the present invention is a communication method for a new server to participate in a network to which a plurality of active servers are connected, wherein the new server notifies the function of the new server. Generating a notification document, the new server adding a signature to the function notification document and transmitting the signature to the active server, and the active server receiving the signature based on the signature Determining the validity of the function notification document, and if the active server determines that the received function notification document is valid, based on the function of the new server notified by the function notification document, A connection between the operational server and the client,
And a step of determining whether or not to switch to a connection between the new server and the client.

According to this invention, the active server connects the connection between the client and the active server and the connection between the client and the new server based on the function of the new server notified by the function notification document (subscribe document). Therefore, it is possible to realize an optimal network configuration.

In the second aspect of the present invention, the new server generates the signature by using a common key between the new server that can be generated using a secret key of the new server and a public key of the active server. The operation server may be configured to determine the validity of the function notification document using the common key that can be generated using the secret key of the operation server and the public key of the new server.

A third feature of the present invention is a client configured to be connectable to any one of a plurality of active servers connected to a network, and the function of the active server is provided from each of the plurality of active servers. A function notification document receiving unit for receiving the function notification document to be notified, a determination unit for determining the validity of the received function notification document based on a signature added to the received function notification document, and a valid function The gist of the present invention is to include a connection destination determination unit that determines a connection destination active server based on the function of the active server notified by the function notification document from the active servers that have received the notification document.

In the third aspect of the present invention, the connection destination determination unit refers to the function notification document to determine an operation server having the largest number of functions as the connection destination operation server. Also good.

In the third aspect of the present invention, the connection destination determination unit refers to the function notification document and has the largest number of connections with clients (an operation server with the largest number of HCSPC connections).
May be determined as the operation server of the connection destination.

In the third feature of the present invention, the connection destination determination unit refers to the function notification document and selects an operation server identified by an identifier having the smallest value (an operation server having the smallest HCS identifier) as the connection destination. May be determined as the active server.

A fourth feature of the present invention is a function notification document receiving unit that is a server connected to a network and receives a function notification document that notifies the function of the new server from a new server that desires connection to the network. And, based on the signature added to the received function notification document, a legitimacy determination unit that determines the legitimacy of the function notification document, and if the received function notification document is determined to be valid, A determination unit that determines whether or not to switch the connection between the server and the client to the connection between the new server and the client based on the function notified by the notification document; The gist.

In the fourth aspect of the present invention, when the determination unit refers to the function notification document transmitted from the new server and the number of functions of the new server is greater than the number of functions of the server,
It may be determined to switch the connection.

In the fourth aspect of the present invention, the determination unit refers to the function notification document transmitted from the new server, and the number of connections with the client in the new server is greater than the number of connections with the client in the server. If so, it may be determined to switch the connection.

In the fourth aspect of the present invention, an identifier for identifying the server by which the determination unit refers to the function notification document transmitted from the new server and the value of the identifier (HCS identifier) identifying the new server is If the value is smaller than the value of (HCS identifier), it may be determined to switch the connection.

As described above, according to the present invention, a communication method and a client capable of avoiding confusion caused by a new client or new server attempting to connect to a network connecting to an unauthorized server. And a server can be provided.

(Configuration of communication system according to first embodiment of the present invention)
A configuration of a communication system according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the communication system according to the present embodiment, as shown in FIG. 1, a new client or a new server is configured to connect (participate) to a network (for example, a home network) to which a plurality of operation servers are connected. Yes.

As shown in FIG. 2, the client 10 in the communication system according to the present embodiment has a timer management unit 101, a timer handler unit 102, and an activation processing unit 103 as main functions.
A random number generation unit 104, a connection destination determination unit 105, a key information storage unit 106, and a signature calculation unit 1.
07, signature comparison unit 108, subscribe storage unit 109, connection server information storage unit 1
10, the advertisement generation unit 111, the device information storage unit 112, the key information acquisition unit 113, the signature acquisition unit 114, the subscribe processing unit 115, and the UDP unicast reception unit 11.
6 and a UDP multicast transmission unit 117.

The timer management unit 101 sets a timer in response to a request from the advertisement generation unit 111, thereby subscribing to wait for reception of a subscribe document (function notification document that notifies the function of the active server) from the active server. It manages live document reception waiting time.

When the waiting time for receiving a subscribe document managed by the timer management unit 101 has elapsed, the timer handler unit 102 sends the client 1 to the connection destination determination unit 105.
A request is made to determine a working server of 0 connection destination.

The activation processing unit 103 performs necessary activation processing when the client 10 is activated. For example, the activation processing unit 103 requests the random number generation unit 104 to generate a random number of the client 10 necessary for calculating the signature, and requests the advertisement generation unit 111 to generate an advertisement document.

The random number generation unit 104 generates a random number for the client 10 in response to a request from the activation processing unit 103. Hereinafter, the random number of the client 10 is expressed as “random number 10”.

In response to a request from the timer handler unit 102, the connection destination determination unit 105 determines a connection destination operation server from among the operation servers that have received a valid subscribe document.

Specifically, the connection destination determination unit 105 determines a connection destination active server based on the function of the operation server notified by the subscribe document stored in the subscribe storage unit 109.

Here, the subscribe document is a function (“features =”) that the active server has.
) And the number of connections with the client (HCSPC (Home Control Service)
e Protocol) the number of connections (“connected =”)) and an identifier (HCSPC identifier (“hcsps:”)) identifying the function of the active server (see FIG. 6)
.

For example, the connection destination determination unit 105 may be configured to determine the operation server having the largest number of functions as the connection destination operation server.

Further, the connection destination determination unit 105 may be configured to determine the server having the largest number of HCSPC connections as the connection destination operation server when there are a plurality of operation servers having the same number of functions.

Further, the connection destination determination unit 105 has the same number of functions and there are a plurality of operation servers having the same number of HCSPC connections, the operation server (H
When the identifier of the CSPC is a character literal), it may be configured to be determined as a connection destination active server.

For example, the HCSPC identifier # 1 is “hcsps: // PtPvXYJSQSqwTJpP
GjwOg ”and the HCSPC identifier # 2 is“ hcsps: 78AFYZ / eQ1az ”
In the case of “6o2JrRMrw”, the value when the first character “/” of the HCSPC identifier # 1 is a character literal is “# x2F”, and when the first character “7” of the HCSPC identifier # 2 is a character literal Since the value of “# x37” is determined, it is determined that the HCSPC identifier # 1 is smaller.

The key information storage unit 106 includes a public key of the client 10, a secret key of the client 10,
The random number of the client 10 generated by the random number generation unit 104 is stored.

The signature calculation unit 107 receives from the operation server using the public key and random number of the active server acquired by the key information acquisition unit 113 and the secret key and random number of the client 10 stored in the key information storage unit 106. The signature for judging the validity of the subscribed signed document is calculated. A specific signature calculation method will be described later.

The signature comparison unit 108 includes the signature calculated by the signature calculation unit 108 and the signature acquisition unit 114.
Is compared with the signature obtained by the above, and the validity of the signed subscribed document received from the active server is determined.

If it is determined that the signed subscribed document is a valid document,
The signature comparison unit 108 requests the subscribe storage unit 109 to store the subscribed signed document.

On the other hand, if it is determined that the signed subscribed document is not a valid document,
The signature comparison unit 108 discards the signed subscribe document.

The subscribe storage unit 109 stores signed subscribe documents received from a plurality of operation servers in response to a request from the signature comparison unit 108. The subscribe storage unit 109 provides the stored signed document with the signature to the connection destination determination unit 105 as necessary.

The connection server information storage unit 110 stores information related to the connection destination operating server determined by the connection destination determination unit 105 (for example, an identifier of the connection destination operation server).

The advertisement generation unit 111 generates an advertisement document in response to a request from the activation processing unit 103. Here, the advertisement document is generated by adding the public key and random number of the client 10 stored in the key information storage unit 106 to the device information stored in the device information storage unit 112 (see FIG. 15). .

In addition, after generating the advertisement document, the advertisement generation unit 111 requests the UDP multicast transmission unit 117 to transmit the advertisement document by UDP multicast and starts the timer management unit 101 for the subscription document reception waiting time. To ask.

The device information storage unit 112 stores device information of the client 10 (for example, information indicating the function of the client 10). The device information storage unit 112 provides the stored device information to the advertisement generation unit 111 as necessary.

The key information acquisition unit 113 acquires the public key and random number (key information) of the active server from the subscribed signed document analyzed by the subscribe processing unit 115. The key information acquisition unit 113 transmits the acquired key information to the signature calculation unit 107.

The signature acquisition unit 114 acquires a signature from the subscribed signed document analyzed by the subscribe processing unit 115. The signature acquisition unit 114 transmits the acquired signature to the signature comparison unit 108.

The subscribe processing unit 115 analyzes the subscribed signed document received from the active server via the UDP unicast receiving unit 116, and transmits the public key and random number (key information) of the active server to the key information acquiring unit 113. The signature is transmitted to the signature acquisition unit 114, and the subscribed document itself is transmitted to the subscribe storage unit 109.

The UDP unicast receiving unit 116 receives a signed subscribe document transmitted from each of a plurality of active servers by UDP unicast and transmits it to the subscribe processing unit 115.

The UDP multicast transmission unit 117 transmits an advertisement document by UDP multicast in response to a request from the advertisement generation unit 111.

As shown in FIG. 3, the server 20 in the communication system according to the present embodiment includes, as main functions, an activation processing unit 201, a random number generation unit 202, a key information storage unit 203, an authentication information generation unit 204, UDP unicast transmission unit 205, UDP multicast transmission unit 206, subscribe generation unit 207, server information storage unit 208, signature calculation unit 209, key information acquisition unit 210, signature comparison unit 211, and signature acquisition Unit 212, new server information acquisition unit 213, received document processing unit 214, UDP unicast reception unit 215, UDP multicast reception unit 216, connection server selection unit 217, redirect generation unit 218, connection management unit 219 and a TCP server 220.

The activation processing unit 201 performs necessary activation processing when the server 20 is activated. For example, the activation processing unit 201 requests the random number generation unit 202 to generate a random number of the server 20 necessary for calculating the signature, and the subscribe generation unit 20 to generate a subscribe document.
Ask 7

The random number generation unit 202 generates a random number for the server 20 in response to a request from the activation processing unit 201. The random number generation unit 202 uses the generated random number of the server 20 as the key information storage unit 203.
To store.

The key information storage unit 203 includes a public key of the server 20, a secret key of the server 20, and a random number generation unit 2
The random number of the server 20 generated by 02 is stored.

The authentication information generation unit 204 generates authentication information including the public key and random number of the server 20 in response to a request from the received document processing unit 214 that has received a subscribe document from a new server. The authentication information generation unit 204 requests the UDP unicast transmission unit 205 to transmit the generated authentication information to the new server by UDP unicast.

The UDP unicast transmission unit 205 includes a subscribe generation unit 207 and an authentication information generation unit 2.
In response to a request from 04, a signed subscribe document and authentication information are transmitted to a new server or a new client by UDP unicast.

The UDP multicast transmission unit 206 transmits a subscribe document (unsigned subscribe document) by UDP multicast in response to a request from the subscribe generation unit 207.

The subscribe generation unit 207 generates a subscribe document in response to a request from the activation processing unit 201 or the received document processing unit 214.

When receiving the request from the activation processing unit 201, the subscribe generation unit 207, based on the server information (for example, information indicating the function of the server 20) acquired from the server information storage unit 208, subscribe document (unsigned subscribe). Live document), and requests the UDP multicast transmission unit 206 to transmit the subscribe document by UDP multicast.

When receiving a request from the received document processing unit 214, the subscribe generation unit 207 receives the server information acquired from the server information storage unit 208, the public key, random number, and signature of the server 20 acquired from the key information storage unit 203. A subscribe document (subscribe document with signature) is generated based on the signature acquired from the calculation unit 209, and the UDP unicast is sent to the UDP unicast transmission unit 205 by using the UDP unicast, and the subscribe document is operated by an operating server or a new client. Ask to send to.

The server information storage unit 208 stores server information indicating the function of the server 20.

In response to a request from the key information acquisition unit 210, the signature calculation unit 209 includes a public key and a random number of a communication partner (new server, new client, or active server) acquired by the key information acquisition unit 210, and a key information storage unit. The signature is calculated using the secret key and random number of the server 20 stored in 203. A specific signature calculation method will be described later.

In addition, the signature calculation unit 209 provides a signature generated using the public key and random number of the new client or the active server and the secret key and random number of the server 20 to the subscribe generation unit 207.

On the other hand, the signature calculation unit 209 provides a signature generated by using the public key and random number of the new server and the secret key and random number of the server 20 to the signature comparison unit 211.

The key information acquisition unit 210 acquires the public key and random number of the communication partner (new server, new client, or active server) from the received document processing unit 214, and requests the signature calculation unit 209 to calculate the signature. It is.

In response to a request from the signature acquisition unit 212, the signature comparison unit 211 compares the signature calculated by the signature calculation unit 209 with the signature acquired by the signature acquisition unit 212 and adds the signature received from the new server. This is to determine the validity of the subscribed document.

If it is determined that the received subscribed signed document is a legitimate document, the signature comparison unit 211 connects the connection between the server 20 and the client 10 to the connection server selection unit 217, and the new server and client. Request to determine whether or not to switch to the connection with the terminal 10.

When it is determined that the received signed subscribe document is not a valid document, the signature comparison unit 211 discards the signed subscribe document.

The signature acquisition unit 212 acquires the signature added to the signed subscribe document from the received document processing unit 214. The signature acquisition unit 212 requests the signature comparison unit 211 to compare the acquired signature with the signature calculated by the signature calculation unit 209.

The new server information acquisition unit 213 acquires information about the new server (for example, information indicating the function of the new server) from the received document processing unit 214. The new server information acquisition unit 213 transmits information about the new server to the connection server selection unit 217 as necessary.

The received document processing unit 214 performs a predetermined process on the documents (subscribe document, advertised document, authentication information, etc.) received by the UDP unicast receiving unit 215 and the UDP multicast receiving unit 216.

The received document processing unit 214 obtains the number of connected clients from the connection management unit 219. When one or more clients are not connected, the subscribed document transmitted from the new server by the UDP multicast is used. Discard (unsigned subscribe document).

When the received document processing unit 214 receives an advertised document transmitted by UDP multicast from a new client, the received document processing unit 214 acquires a public key and a random number of the new client included in the received advertised document, and obtains a key information acquiring unit 210. By requesting to calculate the signature.

When the received document processing unit 214 receives a non-signed subscribe document from the new server, the received document processing unit 214 requests the authentication information generation unit 204 to generate authentication information.

In addition, when the received document processing unit 214 receives a signed subscribe document from the new server, the received document processing unit 214 acquires the public key and random number of the new server included in the received signed subscribe document to obtain the key information acquisition unit. Requests to calculate a signature by sending to 210. The received document processing unit 214 transmits the signature included in the received subscribed signed document to the signature acquisition unit 212.

The UDP unicast receiving unit 215 receives a document (subscription document with signature, authentication information, etc.) transmitted by UDP unicast from a server or a client via a network, and transmits it to the received document processing unit 214. is there.

The UDP multicast receiving unit 216 receives a document (such as an unsigned subscribe document or an advertised document) transmitted from a server or client via a network via a network and transmits the received document to the received document processing unit 214.

In response to a request from the signature comparison unit 211, the connection server selection unit 217 stores information on the new server acquired from the new server information acquisition unit 213 (function of the new server notified by the subscribe document) and server information storage The server information (function of the server 20) stored in the unit 208 is compared to determine whether to switch the connection between the server 20 and the client 10 to the connection between the new server and the client 10 To do.

When the connection server selection unit 217 determines that the new server is more sophisticated than the active server, the connection server selection unit 217 requests the redirect generation unit 218 to generate a redirect document for switching the connection described above. To do.

For example, when the number of new server functions (“features =”) is greater than the number of functions of the server 20, the connection server selection unit 217 determines to switch the connection.

In addition, when the number of functions of the new server and the number of functions of the server 20 are the same, the connection server selection unit 217 determines that the number of HCSPC connections in the new server (number of connections with clients in the new server: “connected =”) When the number of HCSPC connections in the server 20 is greater than the number of connections with clients in the server 20, it may be determined to switch the above-described connection.

In addition, the connection server selection unit 217 determines the HCSPC identifier in the new server when the number of functions of the new server is the same as the number of functions of the server 20 and the number of HCSPC connections of the new server is the same as the number of HCSPC connections of the server 20. The value of (identifier identifying a new server) is Server 2
0 is smaller than the value of the HCSPC identifier (identifier for identifying the server 20) at 0 (H
If the CSPC identifier is a character literal), it may be determined to switch the above connection.

In response to the request from the connection server selection unit 217, the redirect generation unit 218 receives the server 2
A redirect document to be transmitted to the client 10 connected to the client 0 is generated, and the TCP server 220 is requested to transmit the redirect document.

The connection management unit 219 manages the connection state with the client of the server 20. The connection management unit 219 provides the connection state to the received document processing unit 214 and the connection server selection unit 217 as necessary.

The TCP server 220 transmits / receives a document to / from the connected client 10.
(Communication method according to the first embodiment of the present invention)
First, referring to FIG. 4 to FIG. 12, in the communication system according to the first embodiment of the present invention, the new server B selects an active server A from a plurality of active servers connected to the network. The operation of selecting and connecting will be described.

As shown in FIG. 4, in step S1001, the new server B is activated. Here, the operation of the new server B in step S1001 will be described in detail with reference to FIG.

As shown in FIG. 5, in step S1001a, the activation processing unit 201 requests the random number generation unit 202 to generate the random number B of the new server B, and sends the subscribe generation unit 207 to generate a subscribe document. Ask.

In step S1001b, the random number generation unit 202 generates a random number B of the new server B. In step S1001c, the subscribe generation unit 207 determines that the server information storage unit 2
A subscribe document (unsigned subscribe document) is generated based on the server information acquired from 08, and the UDP multicast transmission unit 206 is requested to transmit the subscribe document by UDP multicast. FIG. 6 shows an example of the subscribe document generated here.

Next, as shown in FIG. 4, in step S1002, the UDP multicast transmission unit 206 of the new server B transmits the generated subscribe document by UDP multicast.

In step S1003, the active server A receives the subscribe document. Here, the operation of the active server A in step S1003 will be described in detail with reference to FIG.

As shown in FIG. 7, in step S1003a, the received document processing unit 214 refers to the number of connected clients acquired from the connection management unit 219 and determines whether or not there are connected clients.

If it is determined that there is no connected client, in step S1003e, the received document processing unit 214 discards the subscribed document.

On the other hand, if it is determined that there is a connected client, the received document processing unit 214
The authentication information generation unit 204 is requested to generate authentication information. In response to this, the authentication information generation unit 204 performs the key information storage unit 2 in steps S1003b and S1003c.
03, the random number A and public key A of the active server A are acquired, and authentication information is generated based on the acquired random number A and public key A of the active server A in step S1003d.

FIG. 8 shows an example of the authentication information generated here. In FIG. 8, “vectoro”
“r =” corresponds to the public key A of the active server A, and “value =” corresponds to the random number A of the active server A.

Next, as shown in FIG. 4, in step S1004, the UDP unicast transmission unit 205 of the active server A sends the authentication information including the random number A and the public key A of the active server A to the new server A by UDP unicast. Send to.

In step S1005, the new server B receives the authentication information. here,
With reference to FIG. 9, the operation of the new server B in step S1005 will be described in detail.

As shown in FIG. 9, in step S1005a, the signature calculation unit 209 requested to calculate the signature by the received document processing unit 214 uses the public information of the active server A from the authentication information received by the UDP unicast reception unit 215. A and random number A are acquired.

In step S1005b, the signature calculation unit 209 acquires the secret key B and random number B of the new server B from the key information storage unit 203.

In step S1005c, the signature calculation unit 209 verifies the verification key (using the active server A and the new server B with the public key A and the random number A of the active server A and the secret key B and the random number B of the new server B). The signature is calculated using a common key. For example, the verification key is calculated as follows.

For example, the secret key of the active server A is “s _A ”, the secret key of the new server B is “s _B ”, the public key of the active server A is “v _A ”, and the public key of the new server B is “v”. _B ”, the verification key calculated by the active server A is“ K _AB ”, and the verification key calculated by the new server B is“ K _BA ”.

Here, when “v _A ” and “v _B ” are arbitrary elements belonging to the same set, a function that satisfies “K _AB = K _BA ” in (Expression 1) to (Expression 4) described later is expressed as “f: It is defined as “a function for creating a secret key” and “F: a function for creating a verification key”.

In such a case, the signature calculation unit 209 can calculate the verification key by the following (Expression 1) to (Expression 4).
s _A = f (v _A ) (Formula 1)
s _B = f (v _B ) (Expression 2)
K _AB = F (s _A , v _B ) (Equation 3)
K _BA = F (s _B , v _A ) (Formula 4)
The active server A and the new server B have previously performed calculations according to (Equation 1) and (Equation 2), respectively, and store the calculation results as secret keys “s _A ” and “s _B ”, respectively. It shall be.

In such a case, the signature calculation unit 209 of the active server A uses the public key “v _A ” of the active server A.
And the verification key “K _AB ” calculated using the private key “s _A ” and the public key “v _B ” of the new server B
”Is a verification key“ calculated by the signature calculation unit 209 of the new server B using the public key “v _B ” of the new server B, the secret key “s _B ”, and the public key “v _A ” of the active server A. It becomes the same value as “K _BA ”.

Then, the signature calculation unit 209 calculates the signature by inputting the calculated verification key, the random number A of the active server A, and the random number B of the new server B into the hash function.

In step S <b> 1005 d, the subscribe generation unit 207 requested to generate a subscribe document by the received document processing unit 214 releases the server information acquired from the server information storage unit 208 and the new server B acquired from the key information storage unit 203. Generate a signed subscribe document based on the key B and the random number B and the signature acquired from the signature calculation unit 209, and UD
The P unicast transmission unit 205 is requested to transmit the subscribed signed document to the active server A by UDP unicast.

FIG. 10 shows an example of a signed subscribe document generated here. FIG.
“Vector =” corresponds to the public key B of the new server B, and “value =”
Corresponds to the random number B of the new server B, and “signature =” corresponds to the signature.

Next, as shown in FIG. 4, in step S1006, the UDP unicast transmission unit 205 of the new server B operates the signed subscribe document including the public key B and the random number B of the new server B by UDP unicast. Send to server A.

In step S1007, the active server A receives the signed subscribe document. Here, the operation of the active server A in step S1007 will be described in detail with reference to FIG.

As shown in FIG. 11, in step S1007a, the received document processing unit 214 acquires the public key B and random number B of the new server B included in the received subscribed signed document and sends them to the key information acquisition unit 210. Request to calculate the signature by sending. The received document processing unit 214 transmits the signature included in the received subscribed signed document to the signature acquisition unit 212.

In step S1007b, the signature calculation unit 209 obtains the secret key A and the random number A of the active server A from the key information storage unit 203.

In step S1007c, the signature calculation unit 209 uses the public key B and random number B of the new server B and the secret key A and random number A of the active server A in the same manner as in step S1005 described above. The signature is calculated using (a common key between the active server A and the new server B).

In step S1007d, the signature comparison unit 211 determines whether the signature acquired by the signature acquisition unit 212 matches the signature calculated by the signature calculation unit 209.

If it is determined that the two do not match, in step S1007g, the signature comparison unit 211
Discards the received signed subscribe document.

On the other hand, if it is determined that the two match, in step S1007e, the connection destination server selection unit 217 determines whether or not the new server B has a higher function than the active server A.

When it is determined that the function is high, in step S1007f, the redirect generation unit 218 transmits to the client 10 connected to the server 20 in response to a request from the connection server selection unit 217. Generate redirect document for. Note that FIG.
Shows an example of the redirect document generated here.

Next, as illustrated in FIG. 4, the TCP server 220 of the active server A transmits a redirect document to the client 10, thereby connecting the active server A and the client 10 to the new server B and the client. Switch to the connection with 10.

Second, referring to FIG. 13 to FIG. 18, in the communication system according to the first embodiment of the present invention, the new client C operates server # 1 from a plurality of operating servers connected to the network. The operation of selecting and connecting will be described.

As shown in FIG. 13, in step S2001, the new client C is activated. Here, the operation of the new client C in step S2001 will be described in detail with reference to FIG.

As shown in FIG. 14, in step S2001a, the activation processing unit 103 requests the random number generation unit 104 to generate a random number C for the new client C, and requests the advertisement generation unit 111 to generate an advertisement document. .

In step S2001b, the random number generation unit 104 generates a random number C for the new client C. In step S2001c, the advertisement generation unit 111 adds the device information stored in the device information storage unit 112 to the key information storage unit 106. An advertisement document is generated by adding the public key C and random number C of the new client C stored therein. FIG. 15 shows an example of the advertised document generated here.

In step S2110d, the timer management unit 101 starts a subscribe document reception waiting time for waiting for reception of a subscribe document from the active server # 1 by setting a timer.

Next, as shown in FIG. 13, in step S2002, the UD of the new client C
The P multicast transmission unit 117 transmits an advertisement document including the public key C and the random number C of the new client C by UDP multicast.

In steps S2003 and S2005, the active servers # 1 and # 2 respectively
The above advertisement document is received. Since the operation of the active server # 1 in step S2003 and the operation of the active server # 2 in step S2005 are the same, the operation of the active server # 1 in step S2003 will be described in detail with reference to FIG.

As shown in FIG. 16, in step S2003a, the signature calculation unit 209 requested to calculate the signature by the received document processing unit 214 uses the public key of the new client C from the advertised document received by the UDP unicast reception unit 215. C and random number C are acquired.

In step S2003b, the signature calculation unit 209 acquires the secret key # 1 and the random number # 1 of the active server # 1 from the key information storage unit 203.

In step S2003c, the signature calculation unit 209 uses the same method as in step S1005c described above to public key C and random number C of the new client C and secret key # 1 of the active server # 1.
The signature is calculated using a verification key (a common key between the new client C and the active server # 1) generated using the random number # 1.

In step S2003d, the subscribe generation unit 207 requested to generate a subscribe document by the received document processing unit 214 receives the server information acquired from the server information storage unit 208 and the active server # 1 acquired from the key information storage unit 203. Public key # 1 and random number # 1
And a signed subscription document based on the signature obtained from the signature calculation unit 209, and sends the signed subscription document to the new client C by UDP unicast to the UDP unicast transmission unit 205. To ask. FIG. 17 shows an example of a signed subscribe document generated here.

Next, as shown in FIG. 13, in step S2004, the UDP unicast transmission unit 205 of the active server # 1 converts the signed subscribe document including the public key # 1 and the random number # 1 of the active server # 1 into the UDP. Transmit to the new client C by unicast.

Similarly, in step S2006, the UDP unicast transmission unit 205 of the active server # 2 creates a signed document including the public key # 2 and the random number # 2 of the active server # 2 as a new client by UDP unicast. Sent to C.

In step S2007, the new client C receives such a signed subscribe document. Here, referring to FIG. 18, step S2007 of the new client C
The operation will be described in detail.

As shown in FIG. 18, in step S1007a, the UDP unicast receiving unit 11
6 confirms whether or not a signed subscribe document has been received. If received, this action
In step S2007b, if not received, the operation proceeds to step S2007e.

In step S2007b, the subscribe processing unit 115 acquires the public key # 1 and the random number # 1 of the active server # 1 included in the received subscribe document with a book name, and transmits them to the key information acquisition unit 113, thereby signing. Ask to calculate. In addition, the subscribe processing unit 115 transmits the signature included in the received subscribed signed document to the signature acquisition unit 114.

In step S2007c, the signature calculation unit 107 acquires the secret key C and random number C of the new client C from the key information storage unit 106.

In step S2007d, the signature calculation unit 107 uses the public key # 1 and the random number # 1 of the active server # 1 and the secret key C of the new client C in the same manner as in step S1005 described above.
The signature is calculated using a verification key (a common key between the new client C and the active server # 1) generated using the random number C and the random number C.

In step S2007e, the signature comparison unit 108 determines whether or not the signature acquired by the signature acquisition unit 114 matches the signature calculated by the signature calculation unit 107.

When it is determined that the two match, in step S2007f, the signature comparison unit 108 determines that the received signed subscribe document is a legitimate document and stores it in the subscribe storage unit 109.

On the other hand, if it is determined that the two do not match, the signature comparison unit 108 proceeds to step S2007g without saving the received signed document with signature.

In step S2007g, the timer handler unit 102 executes the timer management unit 101.
It is determined whether or not the subscription document reception waiting time managed by the elapses.

If it is determined that it has not elapsed, the operation returns to step S2007a and waits for reception of a further subscribe document (for example, a signed document from the active server # 2). On the other hand, if it is determined that the time has elapsed, the operation proceeds to step S2007h.

In step S2007h, the connection destination determination unit 105 includes the subscribe storage unit 109.
Referring to the subscribed document stored in the
Determine as the connection destination server.

Next, as shown in FIG. 13, connection processing is started between the new client C and the active server # 1.

1 is an overall configuration diagram of a communication system according to a first embodiment of the present invention. It is a functional block diagram of the client in the communication system which concerns on the 1st Embodiment of this invention. It is a functional block diagram of the server in the communication system which concerns on the 1st Embodiment of this invention. It is a sequence diagram which shows operation | movement when a new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of step S1001 when a new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the subscription transmitted when a new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of step S1003 when a new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the authentication information transmitted when the new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of step S1005 when a new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the subscribe with a signature transmitted when the new server appears in the communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of step S1007 when a new server appears in the communication system which concerns on the 1st Embodiment of this invention. In the communication system which concerns on the 1st Embodiment of this invention, it is a figure which shows an example of the redirect transmitted when a new server appears. It is a sequence diagram which shows operation | movement when the new client appears in the communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of step S2001 when the new client appears in the communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the UDP advertisement transmitted when a new client appears in the communication system according to the first embodiment of the present invention. It is a flowchart which shows operation | movement of step S2003 when a new client appears in the communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the advertisement with a signature transmitted when a new client appears in the communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of step S2007 when the new client appears in the communication system which concerns on the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Client, 101 ... Timer management part, 102 ... Timer handler part, 103 ...
Activation processing unit, 104 ... random number generation unit, 105 ... connection destination determination unit, 106 ... key information storage unit, 10
DESCRIPTION OF SYMBOLS 7 ... Signature calculation part, 108 ... Signature comparison part, 109 ... Subscribe preservation | save part, 110 ... Connection server information storage part, 111 ... Advertisement production | generation part, 112 ... Equipment information storage part, 113 ... Key information acquisition part, 114 ... Signature Acquisition unit 115 ... Subscribe processing unit 116 ... UDP unicast reception unit 117 ... UDP multicast transmission unit 20 ... Server 201 ... Startup processing unit 202 ... Random number generation unit 203 ... Key information storage unit 204 ... Authentication information generation unit, 205... U
DP unicast transmission unit, 206 ... UDP multicast transmission unit, 207 ... subscribe generation unit, 208 ... server information storage unit, 209 ... signature calculation unit, 210 ... key information acquisition unit, 2
DESCRIPTION OF SYMBOLS 11 ... Signature comparison part, 212 ... Signature acquisition part, 213 ... New server information acquisition part, 214 ... Received document processing part, 215 ... UDP unicast reception part, 216 ... UDP multicast reception part, 217 ... Connection server selection part, 218 ... redirect generation unit, 219 ... connection management unit, 22
0 ... TCP server

Claims (12)

A communication method for a client to connect to one of a plurality of active servers connected to a network,
Each of the plurality of active servers generating a function notification document for notifying the function of the active server;
Each of the plurality of operation servers adding a signature to the function notification document and transmitting the signature to the client;
The client determining the validity of the received function notification document based on the signature;
The client includes a step of determining a connection-destination active server from the active servers that have received a valid function notification document based on the function of the operation server notified by the function notification document. Communication method. The operating server generates the signature using a common key between the client that can be generated using the secret key of the operating server and the public key of the client,
The communication according to claim 1, wherein the client determines the validity of the function notification document by using the common key that can be generated by using the secret key of the client and the public key of the operation server. Method. A communication method for a new server to participate in a network to which a plurality of active servers are connected,
The new server generating a function notification document for notifying the function of the new server;
The new server adds a signature to the function notification document and transmits the signature to the active server;
The operation server determines the validity of the received function notification document based on the signature;
When the active server determines that the received function notification document is valid, the connection between the active server and the client is determined based on the function of the new server notified by the function notification document. And determining whether to switch to a connection between the new server and the client. The new server generates the signature using a common key between the new server that can be generated using the secret key of the new server and the public key of the active server,
The operation server determines the validity of the function notification document by using the common key that can be generated by using the secret key of the operation server and the public key of the new server.
The communication method described in 1. A client configured to be connectable to one of a plurality of active servers connected to the network,
A function notification document receiver for receiving a function notification document for notifying the function of the active server from each of the plurality of active servers;
A determination unit that determines the validity of the received function notification document based on a signature attached to the received function notification document;
A connection destination determination unit that determines a connection destination active server based on the function of the active server notified by the function notification document from the active servers that have received the valid function notification document. And the client. The said connection destination determination part determines the working server which has the most number of functions as the said working server of the connection destination with reference to the said function notification document. Client. 6. The client according to claim 5, wherein the connection destination determination unit determines an operation server having the largest number of connections with the client as the connection destination operation server with reference to the function notification document. 6. The client according to claim 5, wherein the connection destination determination unit determines an operation server identified by an identifier having the smallest value as the connection destination operation server with reference to the function notification document. . A server connected to the network,
A function notification document receiving unit that receives a function notification document that notifies the function of the new server from a new server that desires connection to the network;
A legitimacy determination unit that determines the legitimacy of the function notification document based on the signature added to the received function notification document;
When it is determined that the received function notification document is valid, a connection between the server and the client is established between the new server and the client based on the function notified by the function notification document. A server comprising: a determination unit that determines whether or not to switch to a connection. The determination unit refers to the function notification document transmitted from the new server, and determines to switch the connection when the number of functions of the new server is larger than the number of functions of the server. 10. A server according to claim 9, characterized in that The determination unit refers to the function notification document transmitted from the new server, and switches the connection when the number of connections with the client in the new server is greater than the number of connections with the client in the server. The server according to claim 9, wherein a determination is made. The determination unit refers to the function notification document transmitted from the new server, and switches the connection when an identifier value for identifying the new server is smaller than an identifier value for identifying the server. The server according to claim 9, wherein a determination is made.

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