JP2006041726A - Shared key replacing system, shared key replacing method and method program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of replacing a shared key which can realize a key replacement rapidly and safely even by a device, such as a network home electric appliance, etc. in which calculating resources and memory resources, etc. are limited. <P>SOLUTION: An external device 1 transmits a message based on an existing key replacement protocol, such as an IKE, etc. to a device 2 in a house through an HGW 3 before a cipher communication with the device 2 in the house. When the message for replacing a key is received from the external device 1, the HGW 3 performs a key replacing process with the external device 1 by proxy of the device 2 in the house. The HGW 3 distributes the shared key replaced from the external device 1 to the device 2 in the house. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shared key exchange system, a shared key exchange method, and a method program, and more particularly, exchanges encryption / authentication keys between communication devices that transmit and receive highly confidential data via a network. The present invention also relates to a shared key exchange system for sharing, a shared key exchange method, and a method program.

  With the spread of the Internet in recent years, services via networks such as e-mail and electronic commerce have increased, and so-called “net home appliances” that can be connected to the network in the home are also increasing. This home appliance extends to white goods such as an air conditioner and a microwave oven, and a service for controlling the air conditioner from outside the house and downloading a cooking program for the microwave oven from a server has been proposed. However, with the spread of this network, problems such as malicious third parties tampering with or stealing electronic data on the network (unauthorized viewing) and impersonating others to receive services are emerging. ing. For this reason, network security measures have become important.

  As an effort to realize a security function on a network, protocols using encryption technology and authentication technology are variously standardized or put into practical use. For example, there is IPsec (IP Security Protocol) as a protocol that defines the security function at the IP packet level. IPsec is a protocol standardized by the Internet Engineering Task Force (IETF), and its contents are defined by the IETF specification “RFC2401” (Non-patent Document 1) and the like. In this IPsec, by encrypting the IP packet itself, it is possible to protect communication contents from a thief and prevent secret leakage. Other security protocols include security functions at the transport layer level, such as SSL (Secure Socket Layer) used in WEB and the like, and TLS (Transport Layer Security), which is the successor to SSL. The contents are defined by the IETF specification “RFC2246” (Non-patent Document 2) and the like.

For example, when transmitting / receiving encrypted data between devices using a protocol such as IPsec, prior to data transmission / reception, “device authentication” for confirming whether the communication partner device is valid ”, And a procedure of “key exchange” in which a key used for encryption (hereinafter referred to as a shared key) is exchanged between both devices.
As a procedure for “device authentication”, an authentication method using a digital signature using a public key encryption method, which is used to prevent threats such as impersonation by an unauthorized user, is known. In addition, as a “key exchange” procedure, the user can manually set a shared key (secret key), but it is necessary to set a shared key on a device at a remote location without being known by others. The procedure is complicated. Further, if one shared key is continuously used for a long time, the possibility that the third party can decrypt the shared key increases. Therefore, it is necessary to update the shared key as necessary. For this reason, it is preferable to automatically and safely perform the processes such as generation, distribution, and update necessary for sharing the shared key between devices, and various methods have been proposed for this. .

  For example, as a method for exchanging one shared key between two devices, there is a Diffie-Hellman key exchange method as a widely used basic technology. This Diffie-Hellman key exchange method (hereinafter referred to as DH method) is also used in the IKE (Internet Key Exchange) standardized as the IPsec key exchange protocol (including the device authentication procedure) described above. It has been. The outline of this IKE is disclosed in IETF specification “RFC2407” (Non-patent Document 2) and the like. In SSL and TLS, a protocol called Handshake is defined as a key exchange protocol used as a standard.

  By the way, “device authentication” and “key exchange” performed in the IKE and SSL / TLS-Handshake protocols generally require high-load processing. For example, “device authentication” using a digital signature and “key exchange” using a DH method require multiple-length exponentiation, and a general-purpose PC may require several seconds of processing time. Therefore, a device equipped with a low-performance CPU such as an Internet home appliance requires a lot of time for processing of “device authentication” and “key exchange” (hereinafter, these processes are collectively referred to as “shared key exchange”). . For this reason, there has been a problem that the encryption communication cannot be started immediately or the operation of other applications is hindered because the CPU is occupied only for the shared key exchange for a long time.

Therefore, conventionally, as one of countermeasures against such a problem, a shared key exchange method in which a part of processing of shared key exchange performed by a device such as an Internet home appliance is substituted for another device has been disclosed (for example, a patent) Literature 1 and Patent literature 2).
The conventional shared key exchange method disclosed in Patent Document 1 will be described below as the shared key exchange method of the first conventional example. FIG. 25 is a diagram for explaining the shared key exchange method of the first conventional example. In FIG. 25, an out-of-home device A and an in-home device B are two devices that perform encrypted communication between them. The HGW performs a generation process of a key AB used for encryption communication performed between the out-of-home device A and the in-home device B. First, it is assumed that secure communication paths using the key HA and the key HB are established in advance between the HGW-external device A and the HGW-home device B (steps S1001 and S1002).
When the out-of-home device A starts encrypted communication with the in-home device B, the out-of-home device A issues an access request to the HGW (step S1003). The HGW that has received the access request from the outside device A confirms whether or not the home device B can be accessed (step S1004). The in-home device B determines whether or not access is possible, and returns a notification indicating that access is possible (OK) or access is impossible (NG) to the HGW (step S1005). When receiving access permission, the HGW generates a key AB for encryption communication between the out-of-home device A and the in-home device B (step S1006), and uses the secure communication path prepared in advance and the out-of-home device A and The key AB is distributed to the home device B (steps S1007 and S1008). As a result, the out-of-home device A and the in-home device B are in a state where encryption communication using the key AB can be performed (step S1009).

Next, a conventional shared key exchange method disclosed in Patent Document 2 will be described below as a shared key exchange method of a second conventional example. FIG. 26 is a diagram for explaining a shared key exchange method of the second conventional example. In FIG. 26, an out-of-home device A and an in-home device B are two communication devices that perform encrypted communication between them. The key exchange proxy server performs generation processing and device authentication processing of a key AB used for encryption communication performed by the out-of-home device A and the in-home device B. Note that the out-of-home device A and the in-home device B send and receive messages in accordance with IKE, which is an existing key exchange protocol.
IKE-compliant messages include six messages called IKE Phase 1 (IKE MM first message to sixth message), three messages called IKE Phase 2 (IKE QM first message to third message), and the like. is there. Each time the in-home device B receives an IKE message (IKE MM first, third, fifth message) from the out-of-home device A, it sends various request messages (start request, key generation request, authentication request, etc.) to the key exchange proxy server. And sends a part of the processing determined by IKE to the key exchange proxy server. Specifically, the in-home device B requests the key exchange proxy server for high-load processing in IKE such as “key exchange processing by DH method” and “device authentication processing by digital signature”. The key exchange proxy server performs the requested processing and returns a response message to the home device B. The in-home device B constructs an IKE message based on the content of the response message received from the key exchange proxy server, and transmits it to the out-of-home device A as an IKE response message.

As described above, according to the shared key exchange method of the first conventional example or the second conventional example, it is possible to reduce the processing load of the in-home device B by substituting a part of the key exchange processing to another device. it can. As a result, even in a home device (for example, an Internet home appliance) equipped with a small number of computing resources (low performance CPU), the shared key can be safely shared with the opposite device without any problem.
JP 2002-271309 A Japanese Patent Laid-Open No. 2003-179592 Standard Specification “RFC2401”, IETF, [Search January 7, 2004], Internet <URL: http://www.ietf.org/rfc/rfc2401.txt> Standard Specification “RFC2246”, IETF, [Search January 7, 2004], Internet <URL: http://www.ietf.org/rfc/rfc2246.txt> Standard Specification “RFC2407”, IETF, [Search January 7, 2004], Internet <URL: http://www.ietf.org/rfc/rfc2407.txt>

  However, since the shared key exchange method of the first conventional example uses a unique protocol to request the HGW to generate a shared key, it is compatible with general-purpose key exchange protocols such as IKE and HandShake. There is no sex. For this reason, when performing encrypted communication by IPsec between the out-of-home device A and the in-home device B, the standard key exchange protocol IKE cannot be used. That is, in the shared key exchange method of the first conventional example, it is necessary to incorporate a unique key exchange protocol for the three devices, namely, the out-of-home device A, the in-home device B, and the HGW. Therefore, there is a problem that an original protocol must be incorporated even in the out-of-home device A that can use a general-purpose protocol (such as IKE) without any restriction on processing capability or memory.

  In the shared key exchange method of the second conventional example, since a general-purpose key exchange protocol is used between the outside device A and the inside device B, it is necessary to incorporate a unique key exchange protocol into the outside device A. There is no. However, the processing performed on behalf of the key exchange proxy server is part of the processing required for IKE (key generation, device authentication), and IKE message processing and management of SA (security association) are still performed by the home device B. Must be executed. Originally, it is known that the IKE protocol is complicated. For example, only the interpretation of the IKE message and the processing for managing the SA require a program size of about 100 kilobytes to several hundred kilobytes. Accordingly, there has been a problem that the shared key exchange method of the second conventional example cannot be adopted for devices such as Internet home appliances with limited calculation resources and memory resources.

  Therefore, an object of the present invention is to enable high-speed and secure key exchange while maintaining compatibility with existing key exchange protocols even when using devices with limited computational resources and memory resources. A shared key exchange system, a shared key exchange method, and a method program therefor are provided.

In the present invention, a first communication device in a home network and a second communication device in another network are connected via a gateway, and between the first communication device and the second communication device. The present invention is directed to a shared key exchange system for exchanging keys for performing encryption processing on transmitted and received packets.
And in order to achieve the said objective, in the shared key exchange system of this invention, a 1st communication apparatus and a gateway are provided with the following structures. The first communication device includes a storage unit that stores a shared key shared with the second communication device distributed from the gateway, and a second communication device that uses the shared key stored in the storage unit. And a cryptographic communication unit that performs cryptographic communication between the two. The gateway selects a packet to be used for exchanging the shared key from the packets transmitted by the first and second communication devices, and changes the forwarding destination of the selected packet to the gateway itself by the filtering unit. Based on the changed packet, a key exchange agent that performs a process of generating a shared key shared with the second communication device, and a shared key generated by the key exchange agent is used as the first communication device. And a key distribution unit to distribute to

  In order to achieve the above object, in the shared key exchange system of the present invention, the home network is connected to the gateway and the first communication device, and is connected to the second communication device via the gateway. It is also possible to provide three communication devices. In this case, the first communication device uses a storage unit that stores a shared key shared with the second communication device distributed from the third communication device, and a shared key stored in the storage unit. And an encryption communication unit that performs encryption communication with the second communication device. The gateway includes a filtering unit that selects a packet used for exchanging the shared key from packets transmitted by the first and second communication devices, changes a transfer destination of the selected packet, and relays the packet to the third communication device. . The third communication device is generated by a key exchange proxy unit that performs processing for generating a shared key shared with the second communication device based on the packet relayed by the filtering unit, and a key exchange proxy unit. And a key distribution unit that distributes the shared key to the first communication device.

  In order to achieve the above object, in the shared key exchange system of the present invention, the first communication device and the third communication device may have the following configurations. The first communication device uses a storage unit that stores a shared key shared with the second communication device distributed from the third communication device, and a second key using the shared key stored in the storage unit. Select the packet to be used for exchanging the shared key from the packets transmitted by the encryption communication unit and the second communication device, and perform the encryption communication with the communication device, and change the transfer destination of the selected packet. And a filtering unit relaying to the third communication device. The third communication device is generated by a key exchange proxy unit that performs processing for generating a shared key shared with the second communication device based on the packet relayed by the filtering unit, and a key exchange proxy unit. And a key distribution unit that distributes the shared key to the first communication device. In this case, the gateway functions as a router.

  In order to achieve the above object, in the shared key exchange system of the present invention, the first communication device and the third communication device may have the following configurations. The first communication device uses a storage unit that stores a shared key shared with the second communication device distributed from the third communication device, and a second shared key stored in the storage unit. An encryption communication unit that performs encryption communication with the other communication device. The third communication device selects a packet to be used for exchanging the shared key from the packets transmitted by the first and second communication devices, and changes the transfer destination of the selected packet to the third communication device itself And a key exchange agent that performs processing for generating a shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering unit, and a sharing that is generated by the key exchange agent A key distribution unit that distributes the key to the first communication device. In this case, the gateway functions as a router.

  Here, the filtering unit selects a packet transmitted from the second communication device based on a predetermined key exchange protocol as a packet used for exchanging the shared key.

  Further, the encryption communication unit can transmit the plaintext packet toward the second communication device when the shared key is not stored in the storage unit. In this case, the filtering unit selects a plaintext packet as a packet used for exchanging the shared key.

  Further, the key exchange agent unit sets the address of the first communication device as a packet transmission source when transmitting a packet to the second communication device in the process of generating the shared key.

  Preferably, the predetermined key exchange protocol is IKE. The predetermined key exchange protocol may be SSL / TLS-Handshake.

  The third communication device may be a communication card or adapter connected to the first communication device. The home network can further include a fourth communication device. In this case, the third communication device may be a communication card or an adapter connected to the fourth communication device.

Further, the present invention connects a first communication device in a home network and a second communication device in another network, and is transmitted / received between the first communication device and the second communication device. It is also directed to a gateway device that exchanges a shared key for performing encryption processing on a packet to be encrypted.
In order to achieve the above object, the gateway device of the present invention selects a packet used for exchanging the shared key from the packets transmitted by the first and second communication devices, and sets the transfer destination of the selected packet as the gateway A filtering unit that changes to the device itself, a key exchange agent unit that performs processing for generating a shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering unit, and a key exchange A key distribution unit that distributes the shared key generated by the proxy unit to the first communication device.

In the present invention, a first communication device in a home network and a second communication device in another network are connected via a gateway, and the first communication device and the second communication device are connected to each other. It is also directed to a shared key exchange method for exchanging keys for performing encryption processing on packets transmitted and received between them.
And in order to achieve the said objective, in the shared key exchange method of this invention, a 1st communication apparatus and a gateway are provided with the following steps. The first communication device includes an encryption communication step of performing encrypted communication with the second communication device using a shared key shared with the second communication device distributed from the gateway. The gateway selects a packet used for exchanging the shared key from the packets transmitted by the first and second communication devices, and changes the forwarding destination of the selected packet to the gateway itself, and the forwarding destination is determined by the filtering step. Based on the changed packet, a key exchange agent step for performing a process of generating a shared key shared with the second communication device, and the shared key generated by the key exchange agent step is used as the first communication device. And a key distribution step of distributing to the network.

  In order to achieve the above object, in the shared key exchange method of the present invention, the first communication device, the third communication device, and the gateway may include the following steps. Here, the third communication device exists in the home network, is connected to the gateway and the first communication device, and is connected to the second communication device via the gateway. The first communication device performs an encryption communication step of performing encrypted communication with the second communication device using a shared key shared with the second communication device distributed from the third communication device. Prepare. The gateway includes a filtering step of selecting a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, changing a transfer destination of the selected packet, and relaying the packet to the third communication device. . The third communication device is generated by a key exchange agent step and a key exchange agent step that perform a process of generating a shared key shared with the second communication device based on the packet relayed by the filtering step. And a key distribution step of distributing the shared key to the first communication device.

  In order to achieve the above object, in the shared key exchange method of the present invention, the first communication device and the third communication device may include the following steps. An encryption communication step in which the first communication device performs encrypted communication with the second communication device using a shared key shared with the second communication device distributed from the third communication device; An encryption communication step and a filtering step of selecting a packet to be used for exchanging the shared key from the packets transmitted by the second communication device, changing the transfer destination of the selected packet, and relaying it to the third communication device. . The third communication device is generated by a key exchange agent step and a key exchange agent step that perform a process of generating a shared key shared with the second communication device based on the packet relayed by the filtering step. And a key distribution step of distributing the shared key to the first communication device.

  In order to achieve the above object, in the shared key exchange method of the present invention, the first communication device and the third communication device may include the following steps. The first communication device performs an encryption communication step of performing encrypted communication with the second communication device using a shared key shared with the second communication device distributed from the third communication device. Prepare. A filtering step in which the third communication device selects a packet to be used for exchanging the shared key from the packets transmitted by the first and second communication devices, and changes the transfer destination of the selected packet to the third communication device itself. And a key exchange proxy step for generating a shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering step, and a sharing generated by the key exchange proxy step A key distribution step of distributing the key to the first communication device.

In the present invention, a first communication device in a home network and a second communication device in another network are connected via a gateway, and the first communication device and the second communication device are connected to each other. It is also directed to a program for causing a first communication device and a gateway to implement a method for exchanging keys for performing encryption processing on packets transmitted and received between them.
And in order to achieve the said objective, the program of this invention makes a 1st communication apparatus and a gateway perform the following steps. That is, the first communication device is caused to execute an encryption communication step for performing encryption communication with the second communication device using a shared key shared with the second communication device distributed from the gateway. . In addition, a packet used for exchanging the shared key is selected from the packets transmitted by the first and second communication devices to the gateway, and the forwarding step of the selected packet is changed to the gateway itself. Based on the packet whose destination has been changed, a key exchange proxy step for generating a shared key shared with the second communication device, and a shared key generated by the key exchange proxy step And a key distribution step for distributing to the communication device.

In the present invention, a first communication device in a home network and a second communication device in another network are connected via a gateway, and the first communication device and the second communication device are connected to each other. The present invention is also directed to a program for causing a first communication device, a gateway, and a third communication device in a home network to exchange a key for performing encryption processing on packets transmitted and received between them. Yes.
And in order to achieve the said objective, the program of this invention may make a 1st communication apparatus, a 3rd communication apparatus, and a gateway perform the following steps. That is, cryptographic communication for performing cryptographic communication with the second communication device using the shared key shared with the second communication device distributed from the third communication device to the first communication device. Make the step execute. Also, a filtering step of selecting a packet to be used for exchanging the shared key from the packets transmitted by the first and second communication devices to the gateway, changing the transfer destination of the selected packet, and relaying it to the third communication device Is executed. In addition, a key exchange agent step that performs a process of generating a shared key shared with the second communication device based on the packet relayed by the filtering step to the third communication device, and a key exchange agent step And a key distribution step of distributing the generated shared key to the first communication device.

  Moreover, in order to achieve the said objective, the program of this invention may make a 1st communication apparatus, a 3rd communication apparatus, and a gateway perform the following steps. That is, cryptographic communication for performing cryptographic communication with the second communication device using the shared key shared with the second communication device distributed from the third communication device to the first communication device. A filtering step of selecting a packet to be used for exchanging the shared key from the packets transmitted by the encryption communication step and the second communication device, changing the transfer destination of the selected packet and relaying it to the third communication device; Is executed. In addition, a key exchange agent step that performs a process of generating a shared key shared with the second communication device based on the packet relayed by the filtering step to the third communication device, and a key exchange agent step And a key distribution step of distributing the generated shared key to the first communication device.

  Moreover, in order to achieve the said objective, the program of this invention may make a 1st communication apparatus, a 3rd communication apparatus, and a gateway perform the following steps. That is, cryptographic communication for performing cryptographic communication with the second communication device using the shared key shared with the second communication device distributed from the third communication device to the first communication device. Let the step execute. Further, the third communication device selects a packet to be used for exchanging the shared key from the packets transmitted by the first and second communication devices, and changes the transfer destination of the selected packet to the third communication device itself. Generated by a filtering step, a key exchange agent step for performing a process of generating a shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering step, and a key exchange agent step And a key distribution step of distributing the shared key to the first communication device.

As described above, according to the present invention, key exchange processing with a high load and a large program size can be delegated to the HGW. As a result, a shared key can be exchanged at high speed and safely even in a home device such as an internet home appliance with limited computing resources and memory resources. In addition, the HGW performs key exchange processing on behalf of a home device based on a general-purpose key exchange protocol. As a result, the out-of-home device does not need to be aware of the key exchange protocol used by the in-home device, and can exchange the shared key using a general-purpose key exchange protocol.
Further, according to the present invention, the key exchange process can be delegated to a communication device different from the HGW. In this way, by connecting a communication device that performs key exchange processing as a communication card or adapter to a device in the home network, a function for performing key exchange processing can be added to the device in the home network.

(First embodiment)
FIG. 1 is a diagram showing an example of a network configuration to which a shared key exchange method according to the first embodiment of the present invention is applied. In FIG. 1, a network to which the shared key exchange method according to the first embodiment is applied includes an out-of-home device 1, an in-home device 2, an HGW 3, and a public network 4. The home device 2 and the HGW 3 constitute a home network 5. In a network to which this shared key exchange method is applied, the in-home device 2 is connected to the out-of-home device 1 via the public network 4 represented by the HGW 3 and the Internet. The home device 2 is a device that is assumed to be an internet home appliance installed in the home network 5.

  In FIG. 1, the out-of-home device 1 performs key exchange processing based on the IKE protocol with the HGW 3 and encrypted communication based on the IPsec protocol with the in-home device 2. The HGW 3 performs transfer destination sorting (filtering processing) according to the type of received packet, and key exchange processing (key exchange proxy processing) with the external device 1 on behalf of the in-home device 2. Further, the HGW 3 distributes the shared key exchanged by the key exchange proxy process to the home device 2. The in-home device 2 performs encrypted communication based on the IPsec protocol with the out-of-home device 1 using the shared key distributed by the HGW 3.

Next, specific configurations of the out-of-home device 1, the in-home device 2, and the HGW 3 in which the shared key exchange method according to the first embodiment of the present invention is implemented will be described with reference to FIGS.
[Configuration of outside device 1]
FIG. 2 is a block diagram illustrating a configuration example of the out-of-home device 1 according to the first embodiment. 2, the out-of-home device 1 includes a storage unit 101, an information setting unit 102, a communication application 103, an IPsec encryption communication unit 104, a key exchange unit 105, a communication protocol processing unit 106, and a WAN I / F 107.

The storage unit 101 stores information necessary for the outside device 1 to execute the shared key exchange method according to the first embodiment. FIG. 3 is a diagram illustrating an example of information stored in the storage unit 101 of the external device 1. In FIG. 3, the storage unit 101 stores an IPsec shared key DB and an IPsec policy DB.
The IPsec shared key DB is a database for setting a shared key necessary for encrypted communication based on the IPsec protocol. In the IPsec shared key DB, in addition to the shared key, an encryption algorithm corresponding to each shared key and a packet type (selector) to be encrypted can be set.
The IPsec policy DB is a database that sets a security policy to be applied to a packet transmitted / received by the outside device 1. The security policy set here is whether the received packet is discarded, transmitted in plain text, whether IPsec encryption is applied, what algorithm is used if IPsec encryption is applied, etc. Is defined for each packet type. In the present embodiment, the IPsec policy DB stored in the out-of-home device 1 is set with “Encrypt all communication between the out-of-home device 1 and the in-home device 2 with IPsec” as the policy 1. It shall be (see FIG. 3).
The storage unit 101 can also store other information. For example, the other information includes information necessary for mutual authentication with the opposite device (information used for a pre-shared key and a digital signature), various parameter information used for transmission / reception of the IKE message, and the like.

  The information setting unit 102 sets information stored in the storage unit 101. The communication application 103 is an application such as a WEB browser, and transmits / receives data to / from the opposite device (home device 2).

The IPsec encryption communication unit 104 performs encryption communication by IPsec with the opposite device. Specifically, the IPsec encryption communication unit 104 refers to information stored in the storage unit 101 (for example, a shared key stored in the IPsec common key DB or a policy stored in the IPsec policy DB). Then, processing such as packet encryption and decryption is performed.
The key exchange unit 105 exchanges a shared key based on the IKE protocol with an opposite device that performs encrypted communication. The communication protocol processing unit 106 performs processing related to a communication protocol such as an IP layer or a TCP layer on a packet to be transmitted / received. The WAN I / F 107 connects the communication protocol processing unit 106 and the public network 4.

[Configuration of home device 2]
FIG. 4 is a block diagram illustrating a configuration example of the home device 2 according to the first embodiment. 4, the home device 2 includes a storage unit 201, a communication application 203, an IPsec encryption communication unit 204, a distribution key setting unit 205, a communication protocol processing unit 206, and a LAN I / F 207.

  Similar to the storage unit 101 (see FIG. 2) of the out-of-home device 1, the storage unit 201 stores information necessary for the home device 2 to execute the shared key exchange method according to the first embodiment. FIG. 5 is a diagram illustrating an example of information stored in the storage unit 201 of the home device 2. In FIG. 5, the storage unit 201 stores an IPsec shared key DB. The IPsec shared key DB is the same as the IPsec shared key DB (see FIG. 3) stored in the outside device 1.

The IPsec encryption communication unit 204 performs encryption communication with the opposite device by IPsec. Note that the IPsec encryption communication unit 204 of the home device 2 does not encrypt the packet to be transmitted when the shared key is not stored in the IPsec shared key DB.
The distribution key setting unit 205 sets the shared key distributed from the HGW 3 in the storage unit 201 (IPsec shared key DB). The LAN I / F 207 connects the communication protocol processing unit 206 and the HGW 3. The communication application 203 and the communication protocol processing unit 206 have the same configuration as that of the outside device 1 (see FIG. 2).

[Configuration of HGW3]
FIG. 6 is a block diagram illustrating a configuration example of the HGW 3 according to the first embodiment. In FIG. 6, the HGW 3 includes a storage unit 301, an information setting unit 302, a key exchange proxy unit 305, a key distribution unit 307, a packet filter 308, a communication protocol processing unit 316, a WNAI / F 317, a communication protocol processing unit 326, and a LAN I / O. F327 is provided.

  In FIG. 6, the storage unit 301 stores information necessary for the HGW 3 to execute the shared key exchange method according to the first embodiment. FIG. 7 is a diagram illustrating an example of information stored in the storage unit 301 of the HGW 3. In FIG. 7, the storage unit 301 stores an IPsec shared key DB, an IPsec policy DB, and a packet filter DB. Here, the IPsec shared key DB is the same as the IPsec shared key DB (see FIG. 3) stored in the outside device 1. In the IPsec policy DB, a security policy applied to the in-home device 2 and a security policy applied to the HGW 3 are set. That is, the HGW 3 is acting as a security policy manager for the home device 2. In this embodiment, it is assumed that “policy 2” shown below is set as the security policy applied to the in-home device 2 and “policy 3” is set as the security policy applied to the HGW 3 in the IPsec policy DB. (See FIG. 7).

Security policy-Policy applied to in-house device 2 Policy 2: "Encrypt all communication between out-of-home device 1 and in-home device 2 with IPsec"
-Policy applied to HGW3 Policy 3: "Discard all plaintext packets received from outside the home"
(Excluding packets that match other policies)

  The packet filter DB is a database for setting packet filter rules for distributing received packets. The packet filter rule is created by the information setting unit 302 based on the security policy registered in the IPsec policy DB. FIG. 8 is a diagram illustrating a specific example of packet filter rules set in the packet filter DB according to the first embodiment.

  The information setting unit 302 further sets a packet filter rule in the packet filter DB, as compared with the information setting unit 102 (see FIG. 2) included in the external device 1. Specifically, the information setting unit 302 can set a packet filter rule based on the policies (policy 2 and policy 3) registered in the IPsec policy DB. For example, from the policy 2 (all communication between the out-of-home device 1 and the home device 2 is encrypted with IPsec), the information setting unit 302 changes the rules 1 to 5 of the packet filter shown below to the policy 3 (home All the plaintext packets received from outside are discarded), and then the packet filter rules shown below are set (see FIG. 8).

Rules for packet filter (Rule 1) Source = in-home device 2, destination = out-of-home device 1, packet = IPsec encrypted packet 54 received, processing: relay packet directly to out-of-home device 1 (Rule 2) Source = Out-of-home device 1, transmission destination = in-home device 2, packet = reception of IPsec encrypted packet 54, processing: relay packet directly to in-home device 2 (rule 3) transmission source = in-home device 2, transmission destination = out-of-home device 1, Packet = Reception of plaintext packet 56, Processing: Transfer to packet exchange agent 305 as a packet to be processed in HGW 3 (Rule 4) Source = external device 1, transmission destination = internal device 2, packet = IKE key exchange packet 52 Reception, processing: Transfer to the key exchange agent 305 as a packet to be processed in the HGW 3 (Rule 5) Source = home device 2, destination = HGW3, packet = Distribution packet 58 reception and processing: Transfer to key distribution unit 307 as a packet to be processed in HGW 3 (Others) Source = any external device (including external device 1), destination = device in home network 5 (Including home device 2), packet = packets other than the above rules (for example, plaintext packet 59) received, processed: packet discarded

  The key exchange agent unit 305 notifies the key distribution unit 307 that a new shared key has been generated as compared with the key exchange unit 105 (see FIG. 2) provided in the external device 1. The key distribution unit 307 distributes the shared key generated by the key exchange agent unit 305 to the home device 1. The packet filter 308 relays, forwards, or discards packets received from the public network 4 or the home network 5 based on the packet filter rules.

  The communication protocol processing unit 316, the WAN / IF 317, the communication protocol processing unit 326, and the LAN / IF are the same as the configuration of the out-of-home device 1 (see FIG. 2) or the in-home device 2 (see FIG. 4). That is, in the HGW 3, the LAN I / F 327 and the communication protocol processing unit 326 process transmission / reception packets with the in-home device 2, and the WAN I / F 317 and the communication protocol processing unit 316 process transmission / reception packets with the outside device 1. .

  Next, the shared key exchange method according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a processing sequence diagram for explaining a shared key exchange method when encrypted communication is started from the outside device 1 in the first embodiment. FIG. 10 is a processing sequence diagram for explaining a shared key exchange method when encrypted communication is started from the home device 2 in the first embodiment. FIG. 11 is a diagram for explaining the details of the filtering process performed by the HGW 3. 9 and 10, the address of the outside device 1 is IPa, the address of the home device 2 is IPb, and the address of the HGW 3 is IPh. In the present embodiment, it is assumed that the global address (IPb) is assigned not only to the out-of-home device 1 and the HGW 3 but also to the in-home device 2 in the home network 5.

First, a shared key exchange method (FIG. 9) when starting encrypted communication from the outside device 1 will be described.
[Pre-processing]
With reference to FIG. 9, description will be given from pre-processing (steps S10, S30, S31 and securing of a secure communication path between HGW 3 and home device 2) before starting communication. In the out-of-home device 1 and the HGW 3, it is assumed that a security policy is set in advance in each IPsec policy DB (steps S10 and S30). Note that the security policies set here are the above-described policies 1 to 3. That is, policy 1 (see FIG. 3) is set in the IPsec policy DB of the out-of-home device 1, and policies 2 and 3 (see FIG. 7) are set in the IPsec policy DB of the HGW 3.
In the HGW 3, the packet filter rules generated by the information setting unit 302 are registered in the IPsec policy DB based on the security policies (policies 2 and 3) (step S31). The packet filter rules registered here are the rules 1 to 6 described above.
In addition, it is assumed that a secure communication path is secured in advance between the HGW 3 and the home device 2. For example, in this secure communication path, an appropriate key is set offline on the HGW 3 and the home device 2 using input means such as a keyboard, a remote controller, and a portable storage medium. Data transmitted / received between the terminals may be secured by encrypting the data with the key.

[Processing at the outside device 1]
After the pre-processing is completed, in the outside device 1 (see FIG. 2), the communication application 103 sends the plaintext packet 51 to the IPsec encryption communication unit 104 when starting communication with the opposite device (in-home device 2). (Step S11). When receiving the plaintext packet 51 from the communication application 103, the IPsec encryption communication unit 104 searches the IPsec policy DB of the storage unit 101 for a security policy corresponding to the received packet (step S12). Here, the IPsec encryption communication unit 104 determines to encrypt the received plaintext packet in accordance with the policy (policy 1) stored in the IPsec policy DB, and stores a shared key for encrypting the plaintext packet 51. A search is made from the IPsec shared key DB 101 (step S13).

If the shared key does not exist, the IPsec cryptographic communication unit 104 requests the key exchange unit 105 to generate a shared key. Upon receiving the request from the IPsec encryption communication unit 104, the key exchange unit 105 performs key exchange processing based on the IKE protocol with the opposite device (home device 2) (step S14). At this time, the opposite device that is actually performing the key exchange process with the outside device 1 is the HGW 3. However, the in-home device 1 transmits the key exchange packet 52 in which the address (IPb) of the in-home device 2 is set as the transmission destination, and the IKE key exchange packet in which the address (IPb) of the in-home device 2 is set as the transmission source. Since 53 is received, the presence of HGW 3 is not conscious. Since this key exchange process is a process based on the existing IKE protocol, a detailed description thereof will be omitted. When the key exchange with the opposite device is successful, the key exchange unit 105 registers the exchanged shared key (shared key Kab) in the IPsec shared key DB of the storage unit 101 (step S15).
On the other hand, if the shared key exists, the IPsec encryption communication unit 104 encrypts the plaintext packet 51 with the shared key, and transmits the IPsec encrypted packet to the home device 2 via the communication protocol processing unit 106 and the WAN I / F 107. 54 is transmitted (step S40).

[Processing at HGW3]
In the HGW 3 (see FIG. 6), the packet filter 308 includes an IKE key exchange packet 52 in which an address addressed to the in-home device 2 is set as the transmission destination from the out-of-home device 1 via the WAN I / F 317 and the communication protocol processing unit 316. Receive. The packet filter 308 transfers the received IKE key exchange packet 52 to the key exchange proxy unit 305 according to the above-described packet filter rule (rule 4). Details of the filtering process (FIG. 11) performed by the packet filter 308 will be described later.

  The key exchange agent 305 that has received the IKE key exchange packet 52 performs key exchange processing with the opposite device (external device 1) on behalf of the in-home device 2 (step S32). At this time, the key exchange proxy unit 305 transmits the IKE key exchange packet 53 and the like to the outside device 1 if necessary. At the time of transmission, in the IKE key exchange packet 53, the IP address (IPb) of the home device 2 is set as the transmission source.

  When the key exchange with the opposite device is successful, the key exchange agent unit 305 registers the exchanged shared key (shared key Kab) in the IPsec shared key DB of the storage unit 301 and makes a new shared with the key distribution unit 307. Notify that a key has been generated. Upon receiving the notification, the key distribution unit 307 reads the IPsec shared key DB, and transmits the newly generated shared key Kab to the home device 2 as the key distribution packet 57 (step S33). Distribution of the shared key Kab to the home device 2 is performed by a secure communication path prepared in advance.

  Next, when the packet filter 308 receives a response message (key distribution packet 58) from the home device 2 for the distribution of the shared key Kab, the packet filter 308 transfers the response message to the key distribution unit 307 according to the packet filter rule (rule 5) described above. To do. The key distribution unit 307 that has received the key distribution packet 58 confirms that the home device 1 has received the shared key. It is assumed that the procedure for distributing the shared key follows a predetermined procedure. For example, as a predetermined procedure, the response message (key distribution packet 58) may not be transmitted / received. The key distribution unit 307 may retransmit the key distribution packet 57 when the response message cannot be received.

[Processing at home device 2]
In the home appliance 2 (see FIG. 4), the distribution key setting unit 205 receives the key distribution packet 57 from the HGW 3 via the LAN I / F 207 and the communication protocol processing unit 206. When the shared key is distributed by the key distribution packet 57, the distribution key setting unit 205 registers the distributed key in the IPsec shared key DB of the storage unit 201 (step S23).

  As described above, after the shared key Kab is registered in the IPsec shared key DB of the out-of-home device 1 and the in-home device 2, the out-of-home device 1 and the in-home device 2 use the shared key Kab to encrypt using IPsec. Communication can be performed (step S40).

Secondly, a shared key exchange method (FIG. 10) when encryption communication is started from the home device 2 will be described.
[Pre-processing]
Referring to FIG. 10, pre-processing before starting communication (steps S 10, S 30, S 31 and securing of a secure communication path between HGW 3 and home device 2) is performed when cryptographic communication is started from outside device 1. This is the same as the shared key exchange method (FIG. 9).

[Processing at home device 2]
After completion of the pre-processing, when the communication application 203 starts communication with the opposite device (external device 1) in the home device 2 (see FIG. 4), the plaintext packet 55 is sent to the IPsec encryption communication unit 204. Send (step S20). When receiving the plaintext packet 55 from the communication application 203, the IPsec encryption communication unit 204 searches the IPsec policy DB of the storage unit 201 for a shared key for encrypting the received plaintext packet (step S21).

If the shared key does not exist, the IPsec encryption communication unit 204 transmits the unencrypted plaintext packet 56 to the address (IPa) of the external device 1 via the communication protocol processing unit 206 and the LAN / IF 207 ( Step S22). Note that the IPsec encryption communication unit 204 can request the HGW 3 to generate a key using some method instead of transmitting the plaintext packet 56. For example, the IPsec encryption communication unit 204 may transmit a key generation request packet to the HGW 3 using the same communication path as the key distribution packet 58. Subsequent processing (step S23) in the in-home device 2 is the same as the shared key exchange method (see FIG. 9) in the case of starting encrypted communication from the out-of-home device 1.
On the other hand, if the shared key exists, the IPsec encryption communication unit 204 encrypts the plaintext packet 55 with the shared key, and encrypts the IPsec packet to the outside device 1 via the communication protocol processing unit 206 and the WAN I / F 207. The packet 54 is transmitted (step S40).

[Processing at HGW3]
In the HGW 3 (see FIG. 6), the packet filter 308 receives the plaintext packet 56 from the home device 2 via the WAN I / F 317 and the communication protocol processing unit 316. The packet filter 308 transfers the plaintext packet 56 to the key exchange proxy unit 305 in accordance with the packet filter rule (rule 3) described above. The key exchange agent unit 305 that has received the plaintext packet 56 performs key exchange processing with the opposite device (external device 1) on behalf of the in-home device 2 (step S32). The key exchange processing (step 32) performed by the key exchange proxy unit 305 and the subsequent processing are the same as those in the shared key exchange method (see FIG. 9) in the case of starting encrypted communication from the outside device 1.

[Processing at the outside device 1]
In the external device 1 (see FIG. 2), the key exchange unit 105 receives the IKE key exchange packet 53 from the HGW 3 via the WAN / IF 107 and the communication protocol processing unit 106. Upon receiving the IKE key exchange packet 53, the key exchange unit 105 performs key exchange processing with the opposite device (external device 1) (step S14). The key exchange processing (step 14) performed by the key exchange proxy unit 305 and the subsequent processing are the same as those in the shared key exchange method (see FIG. 9) when the encrypted communication is started from the outside device 1.

  As described above, after the shared key Kab is registered in the IPsec shared key DB of the out-of-home device 1 and the in-home device 2, the out-of-home device 1 and the in-home device 2 use the shared key Kab to encrypt using IPsec. Communication can be performed (step S40).

Next, details of filtering processing performed by the packet filter 308 will be described. In FIG. 11, when a packet filter 308 (see FIG. 6) receives a packet from the out-of-home device 1 or the in-home device 2, it applies the filtering rule (see FIG. 8) set in the packet filter DB of the storage unit 301. Then, the received packets are sorted (step S311).
The packet filter 308 applies rule 1 or rule 2 to the IPsec encrypted packet 54 received from the out-of-home device 1 or the in-home device 2 and relays it directly to the opposite device (step S312). Further, the rule 3 is applied to the plaintext packet 56 received from the in-home device 2, and the rule 4 is applied to the IKE key exchange packet 52 received from the out-of-home device 1, so that the key exchange proxy unit Transfer to 305 (step S313). Further, the rule 5 is applied to the key distribution packet 58 received from the home device 2 and transferred to the key distribution unit 307 (step S314). For other packets (for example, plaintext packet 59 received from outside device 1), the rules are applied to discard the packet (step S315).

  The shared key exchanging method of the present invention is not limited to home appliances 2 as home appliances 2 but can be applied to communication devices in which the CPU and memory resources that can be mounted are limited. In the home network 5, a plurality of home devices 2 can be installed. In that case, the HGW 3 may perform key exchange processing for a plurality of in-home devices 2.

  In the common key exchange method of the present invention, the case where IPsec is used as the encryption communication protocol has been described. However, an encryption communication protocol such as SSL or TLS may be used. Moreover, although the case where IKE was used as a shared key exchange protocol was demonstrated, you may use another shared key exchange protocol. For example, a shared key exchange protocol such as SSL / TLS-Handshake can be used instead of IKE.

  Furthermore, although the case where a global address that can be directly specified from an external device (external device 1) is set as the address of the home device 2 has been described, a private address that is valid only within the home network 5 may be set. it can. In this case, for example, the HGW 3 can relay communication between the out-of-home device 1 and the in-home device 2 by using a NAT (Network Address Translation) mechanism.

As described above, according to the shared key exchange method according to the first embodiment of the present invention, key exchange processing with a high load and a large program size can be delegated to the HGW 3. As a result, the shared key can be exchanged at high speed and safely even in the home appliance 2 such as an Internet home appliance with limited calculation resources, memory resources, and the like.
Further, the HGW 3 performs the key exchange process on the basis of a general-purpose key exchange protocol as if the home device 2 did. As a result, the out-of-home device 1 does not need to be aware of the key exchange protocol used by the in-home device 2, and can exchange the shared key using a general-purpose key exchange protocol.

(Second Embodiment)
FIG. 12 is a diagram illustrating an example of a network configuration to which the shared key exchange method according to the second embodiment of the present invention is applied. Note that, in the second embodiment, the same equipment and configuration as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In FIG. 12, the network to which the shared key exchange method according to the second embodiment is applied is further home compared to the network to which the shared key exchange method according to the first embodiment is applied (see FIG. 1). A communication device 6 is provided in the network 5. The communication device 6 performs key exchange processing with the outside device 1 on behalf of the inside device 2. Therefore, in the second embodiment, the HGW 32 does not perform key exchange processing.

Next, specific configurations of the out-of-home device 1, the in-home device 2, and the HGW 32 in which the shared key exchange method according to the second embodiment of the present invention is implemented will be described with reference to FIGS.
The configurations of the out-of-home device 1 and the in-home device 2 are the same as the out-of-home device 1 (see FIG. 2) and the in-home device 2 (see FIG. 4) of the first embodiment.
[Configuration of HGW32]
FIG. 13 is a block diagram illustrating a configuration example of the HGW 32 according to the second embodiment. In FIG. 13, the HGW 32 does not include the key exchange proxy unit 305 and the key distribution unit 307 as compared with the HGW 3 (see FIG. 6) according to the first embodiment. Further, the storage unit 321 does not store the IPsec shared key DB as compared to the storage unit 301 of the first embodiment (see FIG. 14). This is because the HGW 32 does not perform key exchange processing. The information setting unit 322 creates a packet filter rule based on a policy registered in the IPsec policy DB, as with the information setting unit 302 of the first embodiment, but the rule to be created is the first embodiment. (See FIG. 8). FIG. 15 is a diagram illustrating a specific example of packet filter rules set in the packet filter DB according to the second embodiment. In FIG. 15, rules 3 to 5 are different from those of the first embodiment. In the second embodiment, the plaintext packet 56 received from the in-home device 2 according to the rule 3 is sent to the communication device 6, and the IKE key exchange packet 52 received from the outside device 1 according to the rule 4 is sent to the communication device 6. 5 relays the IKE key exchange packet 53 received from the in-home device 2 (communication device 6) to the out-of-home device 1.

[Configuration of communication device 6]
FIG. 16 is a block diagram illustrating a configuration example of the communication device 6 according to the second embodiment. 16, the communication device 6 includes a storage unit 601, an information setting unit 602, a key exchange proxy unit 605, a key distribution unit 607, a communication protocol processing unit 616, and a LAN I / F 617. The storage unit 601 stores the IPsec shared key DB (see FIG. 17). The information setting unit 602, the key exchange proxy unit 605, the key distribution unit 607, the communication protocol processing unit 616, and the LAN I / F 617 are the same as those provided in the HGW 3 (see FIG. 6) according to the first embodiment.

  Next, a shared key exchange method according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 18 is a processing sequence diagram for explaining a shared key exchange method when encrypted communication is started from the outside device 1 in the second embodiment. FIG. 19 is a processing sequence diagram for explaining a shared key exchange method when encrypted communication is started from the home device 2 in the second embodiment. 18 and 19, the address of the communication device 6 is assumed to be a global address IPs.

First, a shared key exchange method (FIG. 18) when starting encrypted communication from the outside device 1 will be described.
[Pre-processing]
Referring to FIG. 18, in the second embodiment, a secure communication path is secured between communication device 6 and home device 2 instead of between HGW 3 and home device 1. Other processes (steps S10, S30, and S31) are the same as those in the first embodiment (see FIG. 9). It is assumed that the communication device 6 and the home device 2 are directly connected by a wired cable such as a LAN cable, a wireless communication path such as a wireless LAN or an infrared ray.

[Processing at the outside device 1]
Processing in the outside device 1 is the same as that in the first embodiment.

[Processing by HGW32]
In the HGW 32 (see FIG. 13), the packet filter 308 performs a filtering process on the received packet in accordance with the above-described packet filter rules (see FIG. 15).
For example, the packet filter 308 relays the IKE key exchange packet 52 addressed to the in-home device 2 received from the outside device 1 via the WAN I / F 317 and the communication protocol processing unit 316 to the communication device 6 based on the rule 4. . Further, the packet filter 308 relays the IKE key exchange packet 53 received from the communication device 6 to the outside device 1 based on the rule 5. Depending on the configuration of the home network, if the destination of the IKE key exchange packet 52 received from the external device 1 is transferred as it is, the home device 2 receives the packet and the packet arrives at the communication device 6 There may not be. In order to prevent this, the packet filter 308 changes the destination (IP address or MAC address) of the IKE key exchange packet 52 to that of the communication device 6 or encapsulates the IKE key exchange packet 52 to Processing such as forwarding after adding a header indicating the destination may be performed.

[Processing in the communication device 6]
In the communication device 6 (see FIG. 16), the key exchange agent 605 performs key exchange processing with the opposite device (external device 1) on behalf of the in-home device 2 (step S60). The key exchange agent 605 sets the address (IPb) of the in-home device 2 as the source address when transmitting the IKE key exchange packet 53 to the out-of-home device 1.
In addition, when the key exchange agent unit 605 succeeds in exchanging the key with the opposite device, the key exchange agent unit 605 registers the exchanged shared key (shared key Kab) in the IPsec shared key DB of the storage unit 601 and stores it in the key distribution unit 607. Notify that a new shared key has been generated. Upon receiving the notification, the key distribution unit 607 reads the IPsec shared key DB, and transmits the newly generated shared key Kab to the in-home device 2 as the key distribution packet 57 (step S61).

[Processing at home device 2]
The processing in the household device 2 is the same as that in the first embodiment.

Secondly, a shared key exchange method (FIG. 19) in the case of starting encrypted communication from the home device 2 will be described.
[Pre-processing]
Referring to FIG. 19, pre-processing before starting communication (steps S10, S30, S31 and securing a secure communication path between communication device 6 and in-home device 2) starts encryption communication from out-of-home device 1. This is the same as the shared key exchange method in the case (see FIG. 18).
[Processing at home device 2]
The processing in the household device 2 is the same as that in the first embodiment (see FIG. 10).
[Processing by HGW32]
In the HGW 32 (see FIG. 13), the packet filter 308 relays the plaintext packet 56 received from the home device 2 via the LAN I / F 327 and the communication protocol processing unit 326 to the communication device 6 according to the rule 3 of the packet filter described above. To do.

[Processing in the communication device 6]
In the communication device 6 (see FIG. 16), when receiving the plaintext packet 56 from the HGW 3, the key exchange agent unit 605 performs key exchange processing with the opposite device (external device 1) on behalf of the in-home device 2. It performs (step S60). The key exchange processing performed by the key exchange proxy unit 605 (step 60 and subsequent processing is the same as the shared key exchange method (see FIG. 18) in the case of starting encrypted communication from the outside device 1).

  In the second embodiment, the example in which the communication device 6 directly distributes the key distribution packet 57 to the home device 2 has been described. However, the key distribution packet 57 is relayed to the home device 2 by relaying the HGW 32. The packet 57 may be distributed. In this case, the packet filter DB stored in the HGW 32 further adds rules 6 to 7 for the key distribution packet. FIG. 20 is a diagram illustrating a specific example of a packet filter rule for adding a rule for a key distribution packet. In FIG. 20, the HGW 32 relays the key distribution packet 57 received from the communication device 6 according to the rule 6 to the home device 2, and relays the key distribution packet 58 received from the home device 2 according to the rule 7 to the communication device 6. .

  In the second embodiment, the filtering process performed by the HGW 32 may be executed by the home device 2 or the communication device 6. FIG. 21 is a diagram illustrating an example of a network configuration to which a shared key exchange method is applied when filtering processing is executed by the home device 2. In FIG. 21, the key exchange packet transmitted from the outside device 1 is filtered by the in-home device 2 and then transferred to the communication device 6. FIG. 22 is a diagram illustrating an example of a network configuration to which a shared key exchange method is applied when filtering processing is executed by the communication device 6. In FIG. 22, the key exchange packet transmitted from the external device 1 is filtered by the communication device 6 and transferred to the key exchange proxy process.

  The communication device 6 may be connected to the home device 2 as a communication card or an adapter. FIG. 23 is a diagram illustrating an example of a network configuration to which the shared key exchange method is applied when the communication device 6 is connected to the home device 2 as a communication card. In FIG. 23, the communication device 6 that is a communication card is connected (attached) to the home device 2, so that the above-described key exchange proxy processing and filtering processing functions can be added to the home device 2.

  Furthermore, the communication device 6 is connected to a communication device other than the home device 2 that performs encryption communication as a communication card or an adapter, so that the above-described key exchange proxy processing and filtering processing are added to the other device. can do. FIG. 24 is a diagram illustrating an example of a network configuration to which the shared key exchange method is applied when the communication device 6 is connected to a communication device different from the home device 2 as an adapter. In FIG. 24, the communication device 6 which is an adapter can be added to the communication device 7 by being connected to the communication device 7 so that the functions of the key exchange proxy processing and filtering processing described above can be added.

  As described above, in the shared key exchange method according to the second embodiment of the present invention, the shared key exchange according to the first embodiment is performed by substituting the communication device 6 different from the HGW 32 for the key exchange processing. The same effect as the method can be obtained. Further, by connecting the communication device 6 acting as a key exchange process as a communication card or adapter to a device within the home network, a function for acting as a key exchange process can be added to the device within the home network.

  The shared key exchanging method described above is realized by CPU interpreting and executing predetermined program data stored in a storage device (ROM, RAM, hard disk, etc.) that can execute the processing procedure described above. In this case, the program data may be introduced into the storage device via the storage medium, or may be directly executed from the storage medium. The storage medium refers to a semiconductor memory such as a ROM, a RAM, or a flash memory, a magnetic disk memory such as a flexible disk or a hard disk, an optical disk memory such as a CR-ROM, a DVD, or a BD, and a memory card. The storage medium is a concept including a communication medium such as a telephone line or a conveyance path.

In addition, the functional blocks of the encryption communication unit, packet filter, key exchange agent unit, and key distribution unit constituting the home device, HGW, or communication device of the present invention are typically integrated circuits such as LSI (integration degree). It is realized as an IC, a system LSI, a super LSI, an ultra LSI, or the like due to a difference. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. Also, an FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of the circuit cells inside the LSI may be used.
Furthermore, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. There is a possibility of adaptation of biotechnology.

  The shared key exchanging method of the present invention is useful when a device such as an Internet home appliance having a small processing capacity and a small amount of memory is exchanged with an external device.

The figure which shows an example of the network structure to which the shared key exchange method in the 1st Embodiment of this invention is applied. The block diagram which shows the structural example of the outdoor equipment 1 which concerns on 1st Embodiment. The figure which shows an example of the information which the memory | storage part 101 of the outdoor equipment 1 memorize | stores. The block diagram which shows the structural example of the household equipment 2 which concerns on 1st Embodiment. The figure which shows an example of the information which the memory | storage part 201 of the household appliance 2 memorize | stores The block diagram which shows the structural example of HGW3 which concerns on 1st Embodiment. The figure which shows an example of the information which the memory | storage part 301 of HGW3 memorize | stores. The figure which shows the specific example of the rule of the packet filter set to packet filter DB in 1st Embodiment. FIG. 3 is a process sequence diagram for explaining a shared key exchange method when encrypted communication is started from the outside device 1 in the first embodiment. Processing sequence diagram for explaining a shared key exchange method in the case of starting encrypted communication from the home device 2 in the first embodiment Processing sequence diagram explaining details of filtering processing performed by HGW 3 The figure which shows an example of the network configuration to which the shared key exchange method which concerns on the 2nd Embodiment of this invention is applied. The block diagram which shows the structural example of HGW32 which concerns on 2nd Embodiment. The figure which shows an example of the information which the memory | storage part 321 of HGW32 memorize | stores. The figure which shows the specific example of the rule of the packet filter set to packet filter DB of 2nd Embodiment The block diagram which shows the structural example of the communication apparatus 6 which concerns on 2nd Embodiment. The figure which shows an example of the information which the memory | storage part 621 of the communication apparatus 6 memorize | stores. Processing sequence diagram for explaining a shared key exchange method in the case of starting encrypted communication from the outside device 1 in the second embodiment A processing sequence diagram for explaining a shared key exchange method when encrypted communication is started from the home device 2 in the second embodiment The figure which shows the specific example of the rule of the packet filter which adds the rule with respect to the packet for key distribution The figure which shows an example of the network structure to which the shared key exchange method at the time of performing filtering processing by the household equipment 2 is applied The figure which shows an example of the network structure to which the shared key exchange method at the time of performing the filtering process by the communication apparatus 6 is applied The figure which shows an example of the network structure to which the shared key exchange method at the time of connecting the communication apparatus 6 to the household apparatus 2 as a communication card is applied. The figure which shows an example of the network structure to which the shared key exchange method at the time of connecting the communication apparatus 6 to the communication apparatus different from the household apparatus 2 as an adapter is applied The figure explaining the shared key exchange method of the 1st prior art example The figure explaining the shared key exchange method of the 2nd prior art example

Explanation of symbols

1 Out-of-home equipment 2 In-home equipment 3, 32 HGW
4 Public network 5 Home network 51, 55, 56, 59 Plain text packet 52, 53 IKE key exchange packet 54 IPsec encrypted packet 57, 58 Key distribution packet 101, 201, 301 Storage unit 102, 202, 302 Information setting unit 103, 203 Communication application 104, 204 IPsec encryption communication unit 105, 305 Key exchange unit 106, 206, 316, 326 Communication protocol processing unit 107, 317 WAN / IF
207, 327 LAN / IF
307 Key distribution unit 308 Packet filter

Claims (20)

A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange system for exchanging a key for performing encryption processing on a packet,
The first communication device is:
A storage unit for storing a shared key shared with the second communication device distributed from the gateway;
An encryption communication unit that performs encryption communication with the second communication device using the shared key stored in the storage unit;
The gateway is
A filtering unit that selects a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, and changes a transfer destination of the selected packet to the gateway itself;
A key exchange proxy unit that performs processing to generate the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering unit;
A shared key exchange system comprising: a key distribution unit that distributes the shared key generated by the key exchange agent unit to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange system for exchanging a key for performing encryption processing on a packet,
In the home network, there is a third communication device connected to the gateway and the first communication device, and connected to the second communication device via the gateway,
The first communication device is:
A storage unit for storing a shared key shared with the second communication device distributed from the third communication device;
An encryption communication unit that performs encryption communication with the second communication device using the shared key stored in the storage unit;
The gateway is
A filtering unit that selects a packet used for exchanging the shared key from packets transmitted by the first and second communication devices, changes a transfer destination of the selected packet, and relays the packet to the third communication device With
The third communication device is:
A key exchange agent that performs processing for generating the shared key shared with the second communication device based on the packet relayed by the filtering unit;
A shared key exchange system comprising: a key distribution unit that distributes the shared key generated by the key exchange agent unit to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange system for exchanging a key for performing encryption processing on a packet,
In the home network, there is a third communication device connected to the gateway and the first communication device, and connected to the second communication device via the gateway,
The first communication device is:
A storage unit for storing a shared key shared with the second communication device distributed from the third communication device;
An encryption communication unit that performs encrypted communication with the second communication device using the shared key stored in the storage unit;
The packet used for exchanging the shared key is selected from the packets transmitted by the encryption communication unit and the second communication device, and the transfer destination of the selected packet is changed and relayed to the third communication device. A filtering unit,
The third communication device is:
A key exchange agent that performs processing for generating the shared key shared with the second communication device based on the packet relayed by the filtering unit;
A shared key exchange system comprising: a key distribution unit that distributes the shared key generated by the key exchange agent unit to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange system for exchanging keys for performing encryption processing on
In the home network, there is a third communication device connected to the gateway and the first communication device, and connected to the second communication device via the gateway,
The first communication device is:
A storage unit for storing a shared key shared with the second communication device distributed from the third communication device;
An encryption communication unit that performs encryption communication with the second communication device using the shared key stored in the storage unit;
The third communication device is:
A filtering unit that selects a packet used for exchanging the shared key from packets transmitted by the first and second communication devices, and changes a transfer destination of the selected packet to the third communication device itself;
A key exchange proxy unit that performs processing to generate the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering unit;
A shared key exchange system comprising: a key distribution unit that distributes the shared key generated by the key exchange agent unit to the first communication device.   The filtering unit selects a packet transmitted from the second communication device based on a predetermined key exchange protocol as a packet used for exchanging the shared key. Or 5. The shared key exchange system according to any one of 4 above. The encryption communication unit transmits a plaintext packet to the second communication device when the shared key is not stored in the storage unit;
6. The shared key exchange system according to claim 1, wherein the filtering unit selects the plaintext packet as a packet used for exchanging the shared key.   In the process of generating the shared key, the key exchange agent unit sets the address of the first communication device as a transmission source of the packet when transmitting the packet toward the second communication device. The shared key exchange system according to claim 1, characterized in that:   6. The common key exchange system according to claim 5, wherein the predetermined key exchange protocol is IKE.   6. The shared key exchange system according to claim 5, wherein the predetermined key exchange protocol is SSL / TLS-Handshake.   5. The shared key exchange system according to claim 2, wherein the third communication device is a communication card or an adapter connected to the first communication device. The home network further includes a fourth communication device,
5. The shared key exchange system according to claim 2, wherein the third communication device is a communication card or an adapter connected to the fourth communication device. The first communication device in the home network is connected to the second communication device in another network, and the packets transmitted and received between the first communication device and the second communication device are encrypted. A gateway device for exchanging a shared key for performing an encryption process,
A filtering unit that selects a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, and changes a transfer destination of the selected packet to the gateway device itself;
A key exchange proxy unit that performs processing to generate the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering unit;
A gateway device comprising: a key distribution unit that distributes the shared key generated by the key exchange agent unit to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange method for exchanging a key for performing encryption processing on a packet,
The first communication device is:
An encryption communication step of performing encryption communication with the second communication device using a shared key shared with the second communication device distributed from the gateway;
The gateway is
A filtering step of selecting a packet used for exchanging the shared key from packets transmitted by the first and second communication devices, and changing a forwarding destination of the selected packet to the gateway itself;
A key exchange proxy step of performing a process of generating the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering step;
A shared key exchange method comprising: a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange method for exchanging a key for performing encryption processing on a packet,
In the home network, there is a third communication device connected to the gateway and the first communication device, and connected to the second communication device via the gateway,
The first communication device is:
Using a shared key shared with the second communication device distributed from the third communication device, comprising an encryption communication step of performing encrypted communication with the second communication device;
The gateway is
Filtering that selects a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, changes a transfer destination of the selected packet, and relays the packet to the third communication device With steps,
The third communication device is:
A key exchange agent step of performing a process of generating the shared key shared with the second communication device based on the packet relayed by the filtering step;
A shared key exchange method comprising: a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange method for exchanging a key for performing encryption processing on a packet,
In the home network, there is a third communication device connected to the gateway and the first communication device, and connected to the second communication device via the gateway,
The first communication device is:
An encryption communication step of performing encrypted communication with the second communication device using a shared key shared with the second communication device distributed from the third communication device;
The packet used for exchanging the shared key is selected from the packets transmitted by the encryption communication step and the second communication device, and the transfer destination of the selected packet is changed and relayed to the third communication device. A filtering step,
The third communication device is:
A key exchange agent step of performing a process of generating the shared key shared with the second communication device based on the packet relayed by the filtering step;
A shared key exchange method comprising: a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A shared key exchange method for exchanging a key for performing encryption processing on a packet,
In the home network, there is a third communication device connected to the gateway and the first communication device, and connected to the second communication device via the gateway,
The first communication device is:
Using a shared key shared with the second communication device distributed from the third communication device, comprising an encryption communication step of performing encrypted communication with the second communication device;
The third communication device is:
A filtering step of selecting a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, and changing a transfer destination of the selected packet to the third communication device itself;
A key exchange proxy step of performing a process of generating the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering step;
A shared key exchange method comprising: a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A program for causing the first communication device and the gateway to implement a method for exchanging a key for performing encryption processing on a packet,
In the first communication device,
Using a shared key shared with the second communication device distributed from the gateway, executing an encryption communication step of performing encrypted communication with the second communication device;
To the gateway,
A filtering step of selecting a packet used for exchanging the shared key from packets transmitted by the first and second communication devices, and changing a forwarding destination of the selected packet to the gateway itself;
A key exchange proxy step of performing a process of generating the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering step;
A program for executing a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A program for causing a first communication device, a gateway, and a third communication device in the home network to exchange a method for exchanging a key for performing encryption processing on a packet,
In the first communication device,
Using a shared key shared with the second communication device distributed from the third communication device to execute an encryption communication step of performing encrypted communication with the second communication device;
To the gateway,
Filtering that selects a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, changes a transfer destination of the selected packet, and relays the packet to the third communication device Let the steps run,
In the third communication device,
A key exchange agent step of performing a process of generating the shared key shared with the second communication device based on the packet relayed by the filtering step;
A program for executing a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A program for causing the first communication device and a third communication device in the home network to exchange a method for exchanging a key for performing encryption processing on the packet,
In the first communication device,
An encryption communication step of performing encrypted communication with the second communication device using a shared key shared with the second communication device distributed from the third communication device;
The packet used for exchanging the shared key is selected from the packets transmitted by the encryption communication step and the second communication device, and the transfer destination of the selected packet is changed and relayed to the third communication device. Filtering step and
In the third communication device,
A key exchange agent step of performing a process of generating the shared key shared with the second communication device based on the packet relayed by the filtering step;
A program for executing a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device. A first communication device in the home network and a second communication device in another network are connected via a gateway, and are transmitted and received between the first communication device and the second communication device. A program for causing the first communication device and a third communication device in the home network to exchange a method for exchanging a key for performing encryption processing on the packet,
In the first communication device,
Using a shared key shared with the second communication device distributed from the third communication device to execute an encryption communication step of performing encrypted communication with the second communication device;
In the third communication device,
A filtering step of selecting a packet to be used for exchanging the shared key from packets transmitted by the first and second communication devices, and changing a transfer destination of the selected packet to the third communication device itself;
A key exchange proxy step of performing a process of generating the shared key shared with the second communication device based on the packet whose transfer destination has been changed by the filtering step;
A program for executing a key distribution step of distributing the shared key generated by the key exchange agent step to the first communication device.

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