JP4316450B2 - Network relay device, network system, and encrypted communication method - Google Patents

Description

  The present invention relates to a network relay device, a network system, and an encrypted communication method capable of performing network communication having an advanced security function based on IPsec or the like.

  Recently, network communication having advanced security functions based on IPsec (IP Security Protocol) or the like has been realized (see, for example, Patent Document 1). By using such network communication, it is as if the communication counterparts such as CPE (Customer Premises Equipment, hereinafter referred to as user equipment) and network relay equipment (hereinafter, also referred to as router) are as safe as possible. VPN (Virtual Private Network) capable of communicating as if directly connected with the network.

  In such network communication using IPsec, an encryption tunnel based on IPsec is established and encrypted communication is performed. Therefore, authentication / encryption information based on a key management protocol such as ISAKMP (Internet Security Association & Key Management Protocol) is used. Exchange (IKE; Internet Key Exchange) is performed. This IKE includes a two-stage negotiation. First, the first-stage negotiation (hereinafter referred to as Phase-I) is executed, whereby the subsequent second-stage negotiation (hereinafter referred to as Phase). -II) is encrypted, and then Phase-II is executed, thereby completing the establishment of encrypted communication (encryption tunnel) by EPS (Encapsulating Security Payload).

At this time, an SA (Security Association) representing information such as an authentication / encryption algorithm and a key (KEY) for performing the encrypted communication is created at the time of each IKE negotiation, and both communication partners (user device, Stored in the memory of the network relay device).
JP 2004-104559 A

However, the above conventional technique has the following problems.
For example, after the encryption tunnel is constructed between the user apparatus and the network relay apparatus (that is, after the SA related to the encryption tunnel is created and stored), the user apparatus is restarted due to a failure or the like. The user apparatus makes an encryption tunnel construction request to the network relay apparatus again. At this time, the network relay apparatus determines that the re-requested cryptographic tunnel construction request is a new cryptographic tunnel construction request, and creates and stores an SA related to the new cryptographic tunnel. For this reason, the SA related to the encryption tunnel constructed before restarting is stored in the memory of the network relay device for a certain period of time, making it difficult to effectively use the memory resources in the network relay device. In particular, when many cryptographic tunnels are built at the same time and many SAs are created and stored, the more free space in the memory, the more crypto tunnels can be constructed. It is desired to reduce the impossible memory area.
An object of the present invention is to make it possible to use more encryption tunnels simultaneously and in parallel in a network relay device, a network system, and an encryption communication method for constructing an encryption tunnel based on IPsec and performing encrypted communication. is there.

In order to solve the above problems, the network relay device of the present invention is:
An encrypted tunnel is established with the user apparatus (for example, the user apparatus 10) and encrypted communication is performed. If data communication via the encrypted tunnel is not performed for a predetermined time, the setting of the encrypted tunnel is canceled. A network relay device (eg, router 20),
When device identification information (for example, KEY data shown in FIG. 4) for identifying the user device is notified from the user device during construction of the encryption tunnel, the device identification information is stored in a memory, and the encryption tunnel is stored. Identification information control means (for example, CP21) for erasing the device identification information from the memory (for example, SA2a) when the setting is released,
If a request for construction of a new cryptographic tunnel is made from the user device after construction of the cryptographic tunnel, the cryptographic tunnel is currently continued based on whether the device identification information is currently stored in the memory. A cryptographic tunnel construction control means for controlling to cancel the setting of the ongoing cryptographic tunnel and to start construction of the new cryptographic tunnel if the cryptographic tunnel is ongoing. For example, CP21)
A network relay device comprising:

In order to solve the above-mentioned problem, the network system of the present invention is
A network relay device that relays data communication performed between networks (for example, the router 20), and a user device that can perform data communication via the network relay device (for example, the user device 10), An encryption tunnel is established between the user device and the network relay device to perform encrypted communication with each other, and if the data communication via the encryption tunnel is not performed for a predetermined time, the setting of the encryption tunnel is canceled. A network system (eg, network system 100),
The user equipment is
An identification information notification means (for example, CP11) for notifying the network relay device of device identification information (for example, KEY data shown in FIG. 4) for identifying the own device during the construction of the encryption tunnel;
The network relay device is:
When the device identification information is notified, the device identification information is stored in a memory (for example, SA1a), and the device identification information is erased from the memory when the setting of the encryption tunnel is cancelled. (For example, CP21)
If a request for construction of a new cryptographic tunnel is made from the user device after construction of the cryptographic tunnel, the cryptographic tunnel is currently continued based on whether the device identification information is currently stored in the memory. A cryptographic tunnel construction control means for controlling to cancel the setting of the ongoing cryptographic tunnel and to start construction of the new cryptographic tunnel if the cryptographic tunnel is ongoing. For example, CP21)
A network system characterized by comprising:

In order to solve the above problem, the encrypted communication method of the present invention is:
An encryption tunnel is established between a network relay device (for example, the router 20) that relays data communication performed between networks and a user device (for example, the user device 10) that can perform data communication via the network relay device. An encrypted communication method for constructing and performing encrypted communication with each other, and canceling the setting of the encryption tunnel when data communication via the encryption tunnel is not performed for a predetermined time,
An identification information notification step of notifying device identification information for identifying the user device (for example, KEY data shown in FIG. 4) from the user device to the network relay device during construction of the encryption tunnel;
When the device identification information is notified to the network relay device, an information storage step of storing the device identification information in a memory (for example, SA2a) of the network relay device;
An information erasing step of erasing the device identification information from the memory when the setting of the encryption tunnel is canceled,
If a request for construction of a new cryptographic tunnel is made from the user device after construction of the cryptographic tunnel, the cryptographic tunnel is currently continued based on whether the device identification information is currently stored in the memory. And determining whether or not the encryption tunnel is ongoing, canceling the setting of the ongoing encryption tunnel and starting the construction of the new encryption tunnel. It is.

  According to the present invention, identification information unique to a user apparatus is stored in a network relay apparatus when an encryption tunnel is established. For this reason, after the encryption tunnel is established between the user device and the network relay device, before the encryption tunnel is terminated, the user device is restarted due to a failure or the like, and a new encryption tunnel establishment request is issued by the user. Even if the network relay device is changed from the device to the network relay device, the network relay device uses the currently unfinished cryptographic tunnel by the user device that has made this new cryptographic tunnel construction request based on the identification information. It can be easily confirmed. Since the authentication / encryption information related to the unfinished encryption tunnel can be deleted from the memory of the network relay device, it is possible to effectively use the memory resources of the network relay device. In particular, since the free memory capacity of the network relay device can be increased, many cryptographic tunnels can be constructed simultaneously and in parallel.

Hereinafter, a network system 100 to which the present invention is applied will be described with reference to the drawings.
In the network system 100, as shown in FIG. 1, a user apparatus (CPE) 10 and a router 20 as a network relay apparatus construct an encryption tunnel in the network N and can perform encrypted communication with each other via the encryption tunnel. Connected to. The network system 100 may have a configuration in which a plurality of user devices 10 are connected.

  As shown in FIG. 2A, the user apparatus 10 includes a CP (Central Processor) 11 and an NP (Network Processor) 12. The CP 11 includes an ISAKMP control daemon (daemon) 11a, a kernel (kernel) 11b, and a DB (DB). Data Base) 11c and SA (SA data base) 1a. The ISAKMP control daemon 11a and the kernel 11b may represent functions of a program executed by the CP 11, or may represent hardware functions.

  The ISAKMP control daemon 11a exchanges authentication / encryption information (Phase-I, II negotiation) with the router 20 based on the ISAKMP key management protocol in order to establish encrypted communication by IPsec. In particular, during Phase-I, the ISAKMP control daemon 11a uses the various peer information (for example, the address of the router 20) stored in the DB 11c to generate the ISAKMP packet D1 and the ISAKMP packet D3 shown in FIG. create.

  When creating the ISAKMP packet D1, the ISAKMP control daemon 11a creates an ID payload by adding unique KEY data for identifying the user device 10 such as a MAC address to the ID data of the user device 10. For example, the IP address “user@customer.com” related to the user apparatus 10 is recorded in several bytes of “Identification Data” included in the ID payload indicated by reference numeral D4 in FIG. 4, and the remaining several bytes are included in the remaining several bytes. KEY data (“00010203”) for identifying the user device 10 such as a MAC address is recorded.

  Further, the ISAKMP control daemon 11a stores the SAs created at the stages of Phase-I and II (referred to as Phase-I SA and Phase-II SA, respectively) in SA1a. Each SA includes ID data to which the KEY data is added.

  When transmitting a packet via the network N, the kernel 11b refers to SA1a to determine whether the Phase-I SA and Phase-II SA related to the transmission packet are already stored (created) in SA1a. If each SA is already stored in SA1a, the transmission packet is encrypted using each SA. If each SA related to the transmission packet is not stored in the SA 1a, a request for creating each SA is made to the ISAKMP control daemon 11a. At this time, the ISAKMP control daemon 11a performs Phase-I and II with the transmission destination of the packet to create each SA.

  The NP 12 includes an interface for transmitting and receiving packets via the network N.

  As shown in FIG. 2B, the router 20 includes CP21 and NP22. The CP21 includes an ISAKMP control daemon 21a, a kernel l21b, a DB 21c, and SA2a. The ISAKMP control daemon 21a and the kernel 21b may represent functions of a program executed by the CP 21, or may represent hardware functions.

  The ISAKMP control daemon 21a exchanges authentication / encryption information (Phase-I, II negotiation) with the user apparatus 10 based on the ISAKMP key management protocol in order to construct an encryption tunnel based on IPsec. In particular, during Phase-I, the ISAKMP control daemon 21a creates the ISAKMP packet D2 shown in FIG. 3 by using various peer information (for example, the address of the user device 10) stored in the DB 21c.

  Further, the ISAKMP control daemon 21a stores the SAs created at the stages of Phase-I and II (referred to as Phase-I SA and Phase-II SA, respectively) in SA2a. Each SA includes ID data to which the KEY data is added.

  When a packet is received via the network N, the kernel 21b refers to SA2a and determines whether the Phase-I SA and Phase-II SA related to the received packet are already stored (created) in SA2a. If the SA is already stored in the SA 2a, the received packet is decoded using each SA. If each SA related to the received packet is not stored in the SA 2a, a request for creating each SA is made to the ISAKMP control daemon 21a. At that time, the ISAKMP control daemon 21a performs Phase-I and II with the transmission source of the packet to create each SA.

  The kernel l21b cancels the setting of the encryption tunnel when the packet transmission from the user apparatus 10 is not performed for a predetermined time after the encryption tunnel is established or when the setting cancellation instruction of the encryption tunnel is received from the user apparatus 10. To do. In this case, the kernel l21b deletes the Phase-I SA and Phase-II SA related to the encryption tunnel from the SA 2a.

  The NP 22 includes an interface for transmitting and receiving packets via the network N.

  Next, the contents of Phase-I processing performed between the ISAKMP control daemon 11a of the user apparatus 10 and the ISAKMP control daemon 21a of the router 20 via the network N will be described.

  First, the ISAKMP control daemon 11a creates an ISAKMP packet D1, and transmits this ISAKMP packet D1 to the router 20 side via the NP12 (step S1). Here, the ISAKMP packet D1 includes an IP header (IP), a UDP header (UDP), an ISAKMP header (ISAKMP), an SA payload (SA), a key exchange payload (KE), a NANCE payload (Ni), and an ID payload (IDi). ) Is included.

  Next, when the ISAKMP packet D1 is received from the user apparatus 10 side, the ISAKMP control daemon 21a adds the HASH payload (HASHr) to the ISAKMP packet D1 to create the ISAKMP packet D2, and the ISAKMP packet D2 is transferred to the NP22. To the user device 10 (step S2). Here, the ISAKMP packet D2 includes an IP header (IP), a UDP header (UDP), an ISAKMP header (ISAKMP), an SA payload (SA), a key exchange payload (KE), a NANCE payload (Nr), an ID payload (IDr). ) And HASH payload (HASHr).

  When the ISAKMP packet D2 is received from the router 20 side, the ISAKMP control daemon 11a adds an encrypted HASH payload (HASH_i) to the IP header, UDP header, and ISAKMP header, and sends the ISAKMP packet D3. The ISAKMP packet D3 is created and transmitted to the router 20 (step S3). Here, the ISAKMP packet D3 includes an IP header (IP), a UDP header (UDP), an ISAKMP header (ISAKMP), and a HASH payload (HASHi).

  Next, a restart process when the user device 10 is restarted after the encryption tunnel is established between the user device 10 and the router 20 will be described with reference to FIG.

  First, once an encryption tunnel (referred to as a first encryption tunnel) is established between the user apparatus 10 and the router 20, the user apparatus 10 and the router 20 are respectively connected to the Phase− associated with the first encryption tunnel. I SA and Phase-II SA (referred to as first Phase-I and first Phase-II SA) are created and stored. Here, the IP address used in constructing the first encryption tunnel is referred to as a first IP address, and the ID payload (IDi) is referred to as a first ID payload.

  Thereafter, when the user device 10 is restarted due to a failure or the like, the ISAKMP control daemon 11a sets the user device 10 to a newly assigned IP address (referred to as a second IP address different from the first IP address). The unique KEY data (the same KEY data used for the first encryption tunnel) is further added to create a new second ID payload (IDi).

  Further, the ISAKMP control daemon 11a creates a new ISAKMP packet D1 including the second ID payload and transmits it to the router 20 side.

  Thereafter, when the ISAKMP control daemon 21a of the router 20 receives the newly created ISAKMP packet D1, the KEY data included in the second ID payload is stored in the SA 2a as the second Phase-I SA, Authentication of a packet received in the future is performed based on the second IP address included in the second ID payload (step S11).

  Thereafter, along with the completion of the creation of the second Phase-I SA, the negotiation of the Phase-I shown in FIG. 3 is terminated, and this second Phase-I SA is stored in each of the SA1a and SA2a of the user apparatus 10 and the router 20. (Step S12).

  Then, the ISAKMP control daemon 21a refers to SA2a to determine whether another Phase-I SA related to the second IP address (unrelated to the first encryption tunnel) is stored in SA2a. (Step S13).

  If another Phase-ISA related to the second IP address is stored in SA2a at Step S13 (Step S13; Yes), the other Phase-ISA is deleted and the process goes to Step S15. If the other Phase-ISA is not stored in SA2a (Step S13; No), the process proceeds to Step S15.

  Thereafter, the ISAKMP control daemon 21a determines whether or not another Phase-ISA related to the KEY data unique to the user device 10 is stored in the SA 2a (step S15).

  At this time, if the user apparatus 10 is restarted before the preset Phase-ISA lifetime ends, it is already created and stored when the first encryption tunnel is established (before the restart). Since Phase-I SA still remains in SA2a (step S15; Yes), ISAKMP control daemon 21a is created and stored before the restart, and Phase-I SA, Phase-II still remains in SA2a. SA is deleted (step S16), and the process proceeds to step S17.

  If no other Phase-ISA related to the KEY data is stored in SA2a at step S15 (step S15; No), the process proceeds to step S17.

  Then, the ISAKMP control daemon 21a performs Phase-II processing, and constructs a new encryption tunnel with the user device 10 (step S17).

  As described above, when the encryption tunnel is established, the KEY data specific to the user apparatus is stored in the SA 2a of the router 20 in association with the SA. For this reason, after the encryption tunnel is established between the user apparatus 10 and the router 20, before the encryption tunnel is terminated, the user apparatus 10 is restarted due to a failure or the like, and a new encryption tunnel establishment request is issued. Even in the case where the user device 10 makes the router 20, the router 20 uses the currently unfinished encryption tunnel by the user device 10 which has made this new encryption tunnel construction request based on the KEY data. It can be easily confirmed. Since the SA related to the unfinished encryption tunnel can be deleted from the SA 2a of the router 20, the memory resources of the router 20 can be effectively used. In particular, the free memory capacity of the router 20 can be increased, and more cryptographic tunnels can be constructed in parallel.

  Note that the description in this embodiment is not limited to the above description. The detailed configurations and detailed operations of the network system 100, the user device 10, and the router 20 in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

It is a figure which shows schematic structure of the network system to which this invention is applied. (A) is a functional block diagram of the user apparatus shown in FIG. 1, and (b) is a functional block diagram of the router shown in FIG. It is a figure which shows the detailed content and transmission / reception timing of an ISAKMP packet in Phase-I negotiation at the time of encryption tunnel construction. It is a figure which shows the content of the ID payload to which this invention is applied. It is a flowchart explaining the restart process of the user apparatus performed after the encryption tunnel construction to which this invention is applied.

Explanation of symbols

10 User device 100 Network system 11 CP
11a ISAKMP control daemon 11b kernel 11c DB
12 NP
1a SA
20 router 21 CP
21a ISAKMP control daemon 21b kernel 21c DB
22 NP
2a SA
D1, D2, D3 ISAKMP packet N network

Claims (3)

A network relay device that establishes an encryption tunnel with a user device and performs encrypted communication, and cancels the setting of the encryption tunnel when data communication via the encryption tunnel is not performed for a predetermined time,
When device identification information for identifying the user device is notified from the user device during construction of the encryption tunnel, the device identification information is stored in a memory, and the device is set when the encryption tunnel setting is released. Identification information control means for erasing identification information from the memory;
If a request for construction of a new cryptographic tunnel is made from the user device after construction of the cryptographic tunnel, the cryptographic tunnel is currently continued based on whether the device identification information is currently stored in the memory. A cryptographic tunnel construction control means for controlling whether to cancel the setting of the ongoing cryptographic tunnel and start construction of the new cryptographic tunnel if the cryptographic tunnel is ongoing. ,
A network relay device comprising: A network relay device that relays data communication performed between networks, and a user device capable of data communication via the network relay device, the encryption tunnel between the user device and the network relay device A network system that performs encrypted communication with each other and cancels the setting of the encryption tunnel when data communication via the encryption tunnel is not performed for a predetermined time,
The user equipment is
Identification information notifying means for notifying the network relay device of device identification information for identifying its own device during construction of the encryption tunnel,
The network relay device is:
When the device identification information is notified, the device identification information is stored in a memory, and the device identification information is erased from the memory when the setting of the encryption tunnel is canceled,
If a request for construction of a new cryptographic tunnel is made from the user device after construction of the cryptographic tunnel, the cryptographic tunnel is currently continued based on whether the device identification information is currently stored in the memory. A cryptographic tunnel construction control means for controlling whether to cancel the setting of the ongoing cryptographic tunnel and start construction of the new cryptographic tunnel if the cryptographic tunnel is ongoing. ,
A network system characterized by comprising: An encryption tunnel is established between a network relay device that relays data communication performed between networks and a user device that can perform data communication via the network relay device, and performs encrypted communication with each other. An encryption communication method for canceling the setting of the encryption tunnel when data communication through the tunnel is not performed for a predetermined time,
An identification information notifying step of notifying the network relay device of device identification information for identifying the user device during construction of the encryption tunnel;
When the device identification information is notified to the network relay device, an information storage step of storing the device identification information in a memory of the network relay device;
An information erasing step of erasing the device identification information from the memory when the setting of the encryption tunnel is canceled,
If a request for construction of a new cryptographic tunnel is made from the user device after construction of the cryptographic tunnel, the cryptographic tunnel is currently continued based on whether the device identification information is currently stored in the memory. And determining whether or not the encryption tunnel is ongoing, canceling the setting of the ongoing encryption tunnel and starting the construction of the new encryption tunnel. .

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