JP2002247023A - Method for sharing session sharing key, method for certifying network terminal, network, terminal, and repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safety share a session sharing key K for secrecy/certification by a network terminal and an access point while suppressing delay up to the establishment of communication between the network terminal and the access point. SOLUTION: A disclosure key YA to be used for the generation of a session sharing key K is inserted into a packet transmission from a network terminal 8-1 to an access point 4-1 on the basis of a DHCP, a disclosure key YB to be used for the generation of the key K is inserted into a packet transmitted from the access point 4-1 to the terminal 8-1 on the basis of the DHCP, the access point 4-1 generates the key K on the basis of the key YA and the terminal 8-1 generates the key K on the basis of the key KB.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a session sharing key sharing method, a network terminal authentication method, a network terminal, and a relay device in a communication network system in which a network terminal and a relay device in the same data link layer are connected via a communication cable. About. In addition,
The inside of the same data link layer means a range within which communication can be performed without passing through a router.

[0002]

2. Description of the Related Art As a conventional communication system, Ethernet
t or IEEE802.3 CSMA / CD (Carrier Se
nse Multiple Access with Collision Detection) system and the like are known. In these communication systems, the procedure of key exchange used for authentication for starting communication is not particularly defined, and each network terminal can basically freely access the network.

[0003]

However, according to the above-mentioned technology, since the procedure for sharing the session sharing key for confidentiality and / or authentication between the network terminal side and the relay device side is not defined, the concealment procedure is not performed. and/
Alternatively, there has been a problem that the session sharing key for authentication cannot be safely shared by the network terminal side and the relay apparatus side. Further, according to the above-described technique, there is a problem that a risk of unauthorized access to the network is high because a procedure for key exchange used for authentication of a network terminal connected to the network is not particularly defined.

The present invention has been made in view of the above, and it is a first object of the present invention to allow a network terminal side and a relay apparatus side to safely share a secret and / or authentication session shared key. The present invention has been made in view of the above, and has a second object to reduce unauthorized access to a network.

[0005]

According to a first aspect of the present invention, there is provided a session sharing key sharing method, comprising: a network terminal for transmitting / receiving a packet and a relay device for relaying the packet via a communication cable. A session sharing key sharing method for sharing a session sharing key for confidentiality and / or authentication to the network terminal side and the relay device side when communicating with each other, wherein communication between the network terminal and the relay device is performed. A first insertion step of inserting first information used for generating the session shared key into a packet transmitted from the network terminal side to the relay device side based on a protocol executed when starting, The packet transmitted from the relay device side to the network terminal side based on the protocol includes the set A second insertion step of inserting second information used for generating a session shared key, and the relay device generates the session shared key based on the first information inserted in the first insertion step. And a second generation step of generating the session shared key on the network terminal side based on the second information inserted in the second insertion step.

According to the session sharing key sharing method of the present invention, in the first insertion step, the network terminal side receives the relay device from the network terminal based on a protocol executed when communication between the network terminal and the relay device is started. The first information used to generate the session shared key is inserted into the packet transmitted to the network side, and in the second insertion step, the packet transmitted from the relay apparatus side to the network terminal side based on this protocol is , Inserting the second information used for generating the session shared key, generating the session shared key based on the first information on the relay device side in the first generation step, and generating the session shared key on the network terminal side in the second generation step. A session shared key is generated based on the second information. As a result, information for generating a session shared key can be exchanged without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

According to a second aspect of the present invention, there is provided a session sharing key sharing method according to the first aspect, wherein the protocol is a protocol that associates a network layer address with a MAC address. .

[0008] In the session sharing key sharing method according to the second aspect, the session is shared between packets transmitted and received between the relay device and the network terminal based on a protocol for associating the network layer address with the MAC address. By inserting and exchanging information for generating a key, it is possible to exchange information for generating a session shared key without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

A third aspect of the present invention provides the session sharing key sharing method according to the first aspect, wherein the protocol is ARP.

In the session shared key sharing method according to the third aspect, information for generating a session shared key is inserted into a packet transmitted and received between the relay apparatus and the network terminal based on the ARP for exchange. By doing so, it is possible to exchange information for generating a session shared key without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

According to a fourth aspect of the present invention, in the session sharing key sharing method of the first aspect, the protocol is a protocol for allocating a network layer address to the network terminal.

According to the session sharing key sharing method of the present invention, a session sharing key is generated in a packet transmitted / received between the relay device and the network terminal based on a protocol for assigning a network layer address to the network terminal. By inserting and exchanging information for session sharing, it is possible to exchange information for generating a session shared key without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

According to a fifth aspect of the present invention, there is provided a session sharing key sharing method according to the first aspect, wherein the protocol is DHCP.

In the session shared key sharing method according to the fifth aspect, information for generating a session shared key is inserted into a packet transmitted and received between the relay apparatus and the network terminal based on DHCP to exchange the information. By,
Information for generating a session shared key can be exchanged without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

Further, in the network terminal authentication method according to the present invention, when a network terminal transmitting and receiving a packet and a relay device for relaying the packet communicate via a communication cable, the network terminal on the relay device side. A method of authenticating a network terminal, comprising: an encryption step of encrypting first information for generating a session shared key used for the authentication with a secret key; and starting communication between the network terminal and the relay device. A first insertion step of inserting the first information encrypted in the encryption step into a packet transmitted from the network terminal side to the relay apparatus side based on a protocol executed when The relay device encrypts the encrypted first information inserted in the first insertion step with the secret key. A decryption step of transmitting the decrypted information to a certificate authority that returns the information, and a decryption step of receiving the first information decrypted by the certificate authority, from the relay device side to the network terminal side based on the protocol A second packet used to generate the session shared key
A second insertion step of inserting the information of
A first generation step of generating the session shared key based on the first information decrypted in the decryption step, and a second information inserted in the second insertion step on the network terminal side. And a second generation step of generating the session shared key based on the second generation step.

In the network terminal authentication method according to the sixth aspect, in the encryption step, the first information for generating a session shared key used for authentication is encrypted with a secret key,
In the first insertion step, a packet transmitted from the network terminal to the relay apparatus based on a protocol executed when communication between the network terminal and the relay apparatus is started is encrypted in the encryption step. The first information is inserted, and in the decryption step, the encrypted first information is transmitted from the relay device to the certificate authority, and the first information decrypted by the certificate authority is received by the relay device. 2) inserting second information used for generating a session shared key into a packet transmitted from the relay apparatus to the network terminal based on this protocol in the inserting step; And generating a session shared key based on the second information inserted in the second inserting step in a second generating step. As a result, the network terminal side and the relay device side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

According to a seventh aspect of the present invention, there is provided the network terminal authentication method according to the sixth aspect, wherein the protocol is a protocol that associates a network layer address with a MAC address.

According to the network terminal authentication method of the present invention, a session shared key is added to a packet transmitted and received between the relay device and the network terminal based on a protocol for associating a network layer address with a MAC address. By inserting and exchanging information for generation, the session shared key for network terminal authentication can be exchanged between the network terminal and the relay device without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Can be safely shared.

According to a eighth aspect of the present invention, in the method of authenticating a network terminal according to the sixth aspect, the protocol is ARP.

In the network terminal authentication method of the present invention, information for generating a session shared key is exchanged by inserting information for generating a session shared key into a packet transmitted and received between the relay apparatus and the network terminal based on the ARP. Thus, the network terminal side and the relay apparatus side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay apparatus.

According to a ninth aspect of the present invention, in the network terminal authentication method of the sixth aspect, the protocol is a protocol for assigning a network layer address to the network terminal.

According to a ninth aspect of the present invention, a method for generating a session shared key for a packet transmitted and received between a relay device and a network terminal based on a protocol for assigning a network layer address to the network terminal. The session shared key for network terminal authentication can be secured to the network terminal and the relay device without increasing the number of packet exchanges when starting communication between the network terminal and the relay device by inserting and exchanging the information of the network terminal and the relay device. Can be shared.

According to a tenth aspect of the present invention, in the network terminal authentication method of the sixth aspect, the protocol is DHCP.

In the network terminal authentication method according to the tenth aspect, information for generating a session shared key is exchanged by inserting information for generating a session shared key into a packet transmitted and received between the relay apparatus and the network terminal based on DHCP. Accordingly, the network terminal side and the relay apparatus side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay apparatus.

According to an eleventh aspect of the present invention, in the network terminal authentication method according to any one of the sixth to tenth aspects, the first information and the second information are different. It is a public key of the Herman public key distribution method, and the session shared key is a shared key of the Diffie-Hellman public key distribution method.

In the network terminal authentication method according to the eleventh aspect, the session shared key is shared by the network terminal side and the relay apparatus side using the Diffie-Hellman type public key distribution method. Further, it can be appropriately protected.

According to a twelfth aspect of the present invention, in the network terminal authentication method according to any one of the sixth to eleventh aspects, the network terminal side further transmits to the relay apparatus side. A first hash value calculating step of calculating a hash value based on the data link layer payload of the packet to be performed and the data including the session shared key generated in the second generating step; a MAC header and the payload of the packet; A first CRC value calculating step of calculating a CRC value based on the data including the hash value calculated in the first hash value calculating step, and the CRC value calculated in the first CRC value calculating step is stored in the MAC header and The packet attached to the payload is transmitted from the network terminal to the relay device. And a hash value based on the payload transmitted in the packet transmitting step and the data including the session shared key generated in the first generating step. Calculating a second hash value, and calculating a CRC value based on the MAC header and the payload transmitted in the packet transmitting step and data including the hash value calculated in the second hash value calculating step. A second CRC value calculation step, and comparing the CRC value transmitted in the packet transmission step with the CRC value calculated in the second CRC value calculation step on the relay device side, thereby transmitting the network terminal to the packet. And an authentication step of performing authentication in units.

According to a twelfth aspect of the present invention, in the first hash value calculation step, the data link layer payload and the second generation step of the packet transmitted from the network terminal side to the relay apparatus side are performed. A hash value is calculated based on the data including the generated session shared key. In a first CRC value calculation step, a CRC value is calculated based on the data including the MAC header and the payload and the hash value calculated in the first hash value calculation step. In the packet transmitting step, a packet in which the CRC value calculated in the first CRC value calculating step is added to the MAC header and the payload is transmitted from the network terminal side to the relay apparatus side, and in the second hash value calculating step , The payload transmitted in the packet transmission step and the session generated in the first generation step A hash value is calculated based on the data including the shared key, and the second CRC value calculation step is based on the MAC header and the payload transmitted in the packet transmission step and the data including the hash value calculated in the second hash value calculation step. And calculate the CRC value, and in the authentication process,
By comparing the CRC value transmitted in the packet transmitting step with the CRC value calculated in the second CRC value calculating step, the relay apparatus authenticates the network terminal in packet units. As a result, it is possible to perform authentication on a packet basis without changing the format of the packet.

According to a thirteenth aspect of the present invention, there is provided a network terminal which communicates with a relay device for relaying a packet via a communication cable, based on a protocol executed when communication with the relay device is started. Insertion means for inserting, into a packet to be transmitted to the relay device side, first information used for generating a secret and / or authentication session shared key, and transmission from the relay device side based on the protocol Obtaining means for obtaining the second information for generating the session shared key included in the packet to be transmitted, and generating means for generating the session shared key based on the second information obtained by the obtaining means. Is what you do.

In the network terminal according to the thirteenth aspect, the insertion means includes a packet for concealment and a secret packet in a packet transmitted to the relay device based on a protocol executed when communication with the relay device is started. And / or inserts first information used for generating a session shared key for authentication, and obtains second information for generating a session shared key included in a packet transmitted from the relay device based on this protocol. And generating means for generating a session shared key based on the second information obtained by the obtaining means. As a result, information for generating a session shared key can be exchanged without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

According to a fourteenth aspect of the present invention, in the network terminal for communicating via a communication cable with a relay device for relaying a packet, a first terminal used for generating a session shared key for authentication of the network terminal is provided.
Encrypting means for encrypting the information with a secret key, and encrypting the packet to be transmitted to the relay device based on a protocol executed when communication with the relay device is started. An insertion unit that inserts the first information that has been converted, an obtaining unit that obtains the second information for generating the session shared key included in a packet transmitted from the relay device based on the protocol, Generating means for generating the session shared key based on the second information obtained by the obtaining means.

According to a fourteenth aspect of the present invention, the encrypting means encrypts the first information used for generating a session shared key for authentication of the network terminal with a secret key, and the inserting means encrypts the first information. The first information encrypted by the encryption unit is inserted into a packet transmitted to the relay device based on a protocol executed when communication with the device is started. Then, the second information for generating the session shared key included in the packet transmitted from the relay device side is obtained, and the generating unit generates the session shared key based on the second information obtained by the obtaining unit. As a result, the network terminal side and the relay device side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

A network terminal according to a fifteenth aspect of the present invention is the network terminal according to the fourteenth aspect, further comprising: a data link layer payload of a packet to be transmitted to the relay device side; Hash value calculating means for calculating a hash value based on data including a shared key;
CRC value calculation means for calculating a CRC value based on a C header, the payload, and data including the hash value calculated by the hash value calculation means;
Packet transmitting means for transmitting a packet in which the CRC value calculated by the C value calculating means is added to the MAC header and the payload to the relay device side.

In the network terminal according to the fifteenth aspect, the hash value calculating means calculates the hash value based on the payload of the packet to be transmitted to the relay device and the data including the session shared key generated by the generating means. The CRC value calculating means calculates the CRC value based on the data including the MAC header and the payload of the transmission packet and the hash value calculated by the hash value calculating means, and the packet transmitting means calculates the CRC value by the CRC value calculating means. The packet in which the CRC value is added to the MAC header and the payload is transmitted to the relay device side. As a result, it is possible to perform authentication on a packet basis without changing the format of the packet.

A relay device according to claim 16 communicates with a network terminal that transmits and receives a packet via a communication cable, and relays the packet.
First information included in a packet transmitted from the network terminal side based on a protocol executed when communication with the network terminal is started, and used for generating a secret and / or authentication session shared key Acquiring means for acquiring the second information used for generating the session shared key in a packet to be transmitted to the network terminal side based on the protocol; and Generating means for generating the session shared key based on the first information.

According to the relay device of the present invention, the acquisition means is included in a packet transmitted from the network terminal side based on a protocol executed when communication with the network terminal is started, and is used for concealment. And / or obtains first information used for generating a session shared key for authentication, and inserts the second information used for generating the session shared key into a packet transmitted to the network terminal based on this protocol. The generating unit generates a session shared key based on the first information acquired by the acquiring unit. As a result, information for generating a session shared key can be exchanged without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

A relay device according to claim 17 communicates with a network terminal for transmitting and receiving a packet via a communication cable and relays the packet.
A session shared key for authentication of the network terminal included in a packet transmitted from the network terminal based on a protocol executed when communication with the network terminal is started and encrypted by a secret key. Acquiring means for acquiring first information used for generation, and the encrypted first information acquired by the acquiring means,
Decryption means for decrypting the information encrypted by the secret key and transmitting the decrypted information to a certification authority that returns the information, and receiving the first information decrypted by the certification authority; Insertion means for inserting second information used for generating the session shared key into a packet to be transmitted to Means.

In the relay device according to the seventeenth aspect, the acquisition means may include a secret key included in a packet transmitted from the network terminal based on a protocol executed when communication with the network terminal is started. Obtains first information used for generating a session shared key for authentication of a network terminal, which is encrypted by the secret key, and decrypts the encrypted first information obtained by the obtaining means with the secret key. Decrypts the information encrypted by the certificate authority, transmits the decrypted information to the certificate authority, receives the first information decrypted by the certificate authority, and transmits the information to the network terminal based on the protocol by the insertion means. The second information used for generating the session shared key is inserted into the packet, and the generation unit generates the session shared key based on the first information received by the decryption unit. As a result, the network terminal side and the relay device side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device.

The relay device according to claim 18 is the relay device according to claim 17, further comprising: a data link layer payload of a packet received from the network terminal side; and the session shared key generated by the generation unit. Hash value calculating means for calculating a hash value based on data including: a MAC header and the payload of the packet; and a CRC based on data including the hash value calculated by the hash value calculating means.
CRC value calculating means for calculating a value, a CRC value of the packet received from the network terminal side and the CRC value
Authentication means for authenticating the network terminal in packet units by comparing the CRC value calculated by the value calculation means.

In the relay device according to the eighteenth aspect, the hash value calculating means may determine the hash value based on data including a data link layer payload of the packet received from the network terminal and the session shared key generated by the generating means. Is calculated by the CRC value calculating means based on the data including the MAC header and the payload of the packet and the hash value calculated by the hash value calculating means.
The C value is calculated, and the authentication unit authenticates the network terminal in units of packets by comparing the CRC value of the packet received from the network terminal with the CRC value calculated by the CRC value calculation unit. As a result, it is possible to perform authentication on a packet basis without changing the format of the packet.

[0041]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The present invention is not limited by the embodiment.

FIG. 1 is an explanatory diagram showing the configuration of a communication network system according to one embodiment of the present invention.
This communication network system includes a backbone network 43, a router 2 connecting the backbone network 43 and the Internet 1, and a wide area L
AN10-1 to 10-N1 and each wide area LAN 10-1
It comprises routers 3-1 to 3-N1 for connecting 10-N1 to the backbone network 43, respectively. Each wide area L
At least one access point such as a bridge or a router is connected to each of the ANs 10-1 to 10-N1. In this example, the access points 4-1 to 4-N2 are connected to the wide area LAN 10-1, and the wide area LAN 1
The access points 6-1 to 6-N3 are connected to 0-N1.

Each access point is connected to a network terminal via a communication cable to form a communication network. In this example, the access point 4-1 is connected to the network terminals 8-1 to 8-k1, and forms a communication network 41-1. The access point 4-N2 is connected to the network terminals 8-k2 to 8-N4.
To form a communication network 41-N2. The access point 6-1 is connected to the network terminals 9-1 to 9-k3, and
-1 is formed.

The access point 6-N3 is connected to the network terminals 9-k4 to 9-N5 to form a communication network 42-N3. Each network terminal can communicate with the Internet 1 or another network terminal via an access point. Also, each of the wide area LANs 10-1 to 10-N1 has an authentication server 5-1 to 5 to hold authentication data of a network terminal.
−N1 are respectively connected. Authentication server 5-1
5-N1 can perform reliable communication with each access point. Each of the authentication servers 5-1 to 5-N1 includes:
It holds authentication data for authenticating a network terminal belonging to its own wide area LAN. Here, the authentication data is a user ID and a secret key shared with the user.

That is, the secret key is shared between the certificate authority and the network terminal in advance. The key is information for encrypting and / or decrypting information. Further, a bridge may be used instead of the routers 2 and 3-1 to 3-N1. Also, each of the authentication servers 5-1 to 5
-N1 may not be directly connected to each of the wide area LANs 10-1 to 10-N1.
And the like, and may be connected to each of the wide area LANs 10-1 to 10-N1 via each of the routers 3-1 to 3-N1.

Next, the configuration of the network terminal will be described. FIG. 2 shows the network terminal 8-shown in FIG.
1 is a block diagram showing a schematic configuration of FIG. The network terminal 8-1 is based on a storage device 11 for holding information of a user ID and a secret key, a prime number p and a primitive root α used for a Diffie-Hellman type public key distribution method, and a Diffie-Hellman type public key distribution method. The prime number p and the primitive root α
Generate a public key Y _A was used to obtain the public key Y _B from the access point, and stores it in the storage unit 11 to calculate a session shared key K Diffie - Hellman calculation unit 13
And the public key Y generated by the Diffie-Hellman calculation unit 13
_And an encryption unit 15 for encrypting _A with a secret key.

Further, when starting communication with the access point, the network terminal 8-1 starts a DHCP (Dynami
c, a DHCP processing unit 16 for transmitting and receiving packets based on the Host Configuration Protocol, a data link layer payload of the packet to be transmitted, and a session shared key K.
And a MAC value based on data including a data link layer payload and a MAC address of a packet to be transmitted and a hash value calculated by the hash value calculating unit 12.
It includes a CRC value calculation unit 14 for calculating an RC value, a packet processing unit 17 for transmitting and receiving a MAC frame, and a network communication unit 18 for communicating with an access point via a communication cable.

The prime number p and the primitive root α are shared in advance by each network terminal and each access point. For example, "2" is used as the primitive root α, and the prime number p
768-bit or 1024-bit prime numbers are used.
The storage device 11 has a writable nonvolatile recording medium such as an EEPROM or a power-backed-up RAM,
The information of the ID, the secret key, the prime number p and the primitive root α is held. Diffie - Hellman calculation unit 13, the Diffie - based on Hellman type public key distribution method, [0, p-1] randomly selects an integer X _A between the prime p and primitive root stored in the storage device 11 generate a public key Y _a using information and integer X _a of alpha, a public key Y _B from the access point
Acquires, calculates the session shared key K by using the integer X _A and a public key Y _B, and stores in the storage device 11.

The encryption unit 15, Diffie - public key Y _A Hellman calculation unit 13 has generated and encrypted with the private key stored in the storage device 11. The DHCP processing unit 16
The predetermined packet, such as DHCP-DISCOVER or DHCP-REQUEST to be transmitted on the basis of the CP, a public key and the ID and the encryption unit 15 stored in the storage device 11 a public key Y _A (hereinafter encrypted, encrypted Y _A is E (Y
_A )) is inserted. This insertion is based on the MA
It may be performed on the C header part or on the data link layer payload part. Also, the DHCP processing unit 16
Obtains a predetermined packet such as DHCP-OFFER or DHCP-ACK transmitted from the access point based on DHCP, and obtains a public key Y _B included in the packet.
And outputs it to the Diffie-Hellman calculation unit 13.

The hash value calculator 12 calculates a hash value based on the data link layer payload of the packet to be transmitted and the data including the session shared key K held in the storage device 11. The CRC value calculator 14 calculates the CRC value based on the data link layer payload and the MAC address of the packet to be transmitted and the data including the hash value calculated by the hash value calculator 12. The packet processing unit 17 includes a data link layer payload and MA
C address and CR calculated by the CRC value calculator 14
A MAC frame is generated from the C value and transmitted, and a MAC frame from the access point is received.

The network communication unit 18 communicates with an access point via a communication cable. The network terminal 8-1 is a wide area LAN to which the own network terminal belongs.
The access point 10-1 can access the access points 4-1 to 4-N2 and the access point 6-1.
Access to other wide area LAN access points such as .about.6-N3 can be performed. In this case, the authentication server of the access destination other wide area LAN is used as the authentication server 5-1.
E (Y _A) and ID are transmitted to the authentication server 51 returns the public key Y _A decrypted. Each of the other network terminals has the same configuration as the network terminal 8-1.

Next, the access point will be described. FIG. 3 is a block diagram showing a schematic configuration of the access point 4-1 shown in FIG. Access point 4-
Reference numeral 1 denotes a LAN communication unit 21 for communicating with the wide area LAN 10-1, a storage device 22 for storing information of a prime number p, a primitive root α, an address of an authentication server and an address of a DHCP server, and a Diffie-Hellman type public key. _A public key YA is obtained from the network terminal based on the delivery method, a public key Y _B is generated using the prime number p and the primitive root α, a session shared key K is calculated and stored in the storage device 22. And a Hermann calculation unit 24.

The access point 4-1 is connected to the DHC
DH which detects a predetermined packet based on P and extracts and inserts a public key of the Diffie-Hellman type public key distribution method
The CP processing unit 23 calculates a hash value based on the data including the data link layer payload and the session shared key K of the packet from the network terminal, and includes the data link layer payload and the MAC address of the packet and the calculated hash value. CR based on data
A hash value / CRC value calculation unit 26 for calculating a C value;
A packet processing unit 25 that performs transmission / reception processing of an AC frame and performs authentication of each packet of a network terminal.
And a network communication unit 27 that communicates with a network terminal via a communication cable.

The LAN communication section 21 has a wide area LAN 10-1.
Communication with the The storage device 22 includes a hard disk and an R
It has a recording medium such as an AM and holds information on a prime number p, a primitive root α, an address of an authentication server, and an address of a DHCP server. Diffie - Hellman calculation unit 24, the Diffie - based on Hellman type public key distribution method, we obtain the public key Y _A of the network terminal, selects a random integer X _B between [0, p-1], The public key Y _{B is obtained} by using the prime number p, the primitive root α, and the integer X _B held in the storage device 22.
It generates, by calculating the session shared key K stored in the storage device 22 by using the integer X _B and a public key Y _A.

The DHCP processing unit 23 includes a packet processing unit 2
5 from the LAN communication unit 21 and the packet processing unit 2
Transfer to 5. Then, the DHCP processing unit 23 checks the packet to be transferred from the packet processing unit 25 to the LAN communication unit 21 and checks the packet including the information of E (Y _A ) and ID.
Detecting a predetermined packet based on HCP, extracts E (Y _A) and ID included in the packet, and requests the decoding by sending to the authentication server 51, decoding from the authentication server 5-1 receiving a public key Y _a that is.

The DHCP processing unit 23 checks a packet transferred from the LAN communication unit 21 to the packet processing unit 25, detects a predetermined packet based on DHCP, and adds the Diffie-Hellman calculation unit 24 to this packet. insert the calculated public key Y _B forwards the packet processing unit 25. The hash value / CRC value calculation unit 26 calculates a hash value based on the data link layer payload of the packet from the network terminal and the data held in the storage device 22 and including the session shared key K, and calculates the data link layer payload of the packet. Then, a CRC value is calculated based on the data including the MAC address and the calculated hash value.

The packet processing unit 25 performs MAC frame transmission / reception processing, and authenticates a network terminal for each packet by the built-in authentication unit 28. The authentication unit 28 compares the CRC value of the packet from the network terminal with the CRC value calculated by the hash value / CRC value calculation unit 26, and determines whether the access is legitimate or illegal based on whether or not they match. It is determined whether there is any access, and if the access is illegal, the packet is discarded. Alternatively, a packet retransmission request may be made in consideration of a data error due to communication disturbance. Network communication unit 27
Communicates with each network terminal via a communication cable.

Note that here, the authentication server 5-1 has the DH
Since the example which also serves as a CP server is shown, the storage device 22 includes:
The information on the address of the authentication server 5-1 and the information on the address of the DHCP server are collectively held. Also, the DHCP processing unit 23 transfers a predetermined packet based on DHCP addressed to the authentication server 5-1 as it is, and
Extracts E (Y _A ) and ID from this packet,
The public key Y _A decrypted with predetermined packet based on the DHCP may be sent to the access point 4-1.
Other access points have the same configuration as the access point 4-1.

Next, the authentication server will be described. FIG. 4 is a block diagram showing a schematic configuration of the authentication server 5-1 shown in FIG. The authentication server 5-1 has its own wide area LAN.
And a storage device 31 for holding information on the secret key and ID of the user and data for DHCP, and decrypting E (Y _A ) transmitted by the access point with a secret key corresponding to the ID transmitted by the access point. A decryption unit 32 for converting and returning the data, a DHCP processing unit 33 for performing a DHCP transmission / reception process, and a LAN communication unit 34 for performing communication with the wide area LAN 10-1.

The storage device 31 is a hard disk or RAM
And the like, and holds the information on the secret key and ID of each user belonging to the wide area LAN 10-1 and the data for DHCP. The decryption unit 32 decrypts E (Y _A ) transmitted by the access point with a secret key corresponding to the ID transmitted by the access point,
Reply to the sender's access point. Also, if the ID transmitted by the access point is another wide area LAN
If an ID requests the decoding by sending the ID and E (Y _A) to the authentication server of the other wide-area LAN.
Thus, decoding of E (Y _A), because the network terminal by encrypting the public key Y _A is performed by only the authentication servers belonging, it is not necessary to send and receive secret key itself.

The DHCP processing unit 33 has a DHCP-DIS
A packet such as COVER or DHCP-REQUEST is received, a packet such as DHCP-OFFER or DHCP-ACK is transmitted, and a DHCP process for dynamically assigning an IP address to a network terminal is performed. The LAN communication unit 34 performs communication with the wide area LAN 10-1. Here, the example in which the authentication server 5-1 also functions as the DHCP server has been described, but a DHCP server may be provided separately from the authentication server 5-1. In addition, each access point 4-1 to 4
-N2 may also serve as a DHCP server. in this case,
The DHCP processing unit 23 of each of the access points 4-1 to 4-N2 executes the DHCP processing executed by the authentication server 5-1. The other authentication servers 5-2 to 5-N1 have the same configuration as the authentication server 5-1.

The components of the network terminal, access point, and authentication server described above are functionally conceptual, and need not necessarily be physically configured as illustrated. For example, all or a part of the processing functions provided by each of these components may be replaced with a C (not shown).
It can be realized by a PU (Central Processing Unit) and a program interpreted and executed by the CPU. That is, the ROM (not shown) stores the OS (Operat
Instructing the CPU in cooperation with the
A computer program for performing various processes. Then, the CPU performs various processes according to the program. Further, all or a part of the processing functions provided by each of these components can be realized as hardware by wired logic.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 5 is an explanatory diagram showing a processing procedure of a session shared key generation process for generating a session shared key K prior to communication according to this embodiment. Here, a case where the network terminal 8-1 and the access point 4-1 generate the session shared key K will be described as an example. In this session shared key generation processing, first, the network terminal 8-1, and stores the determined integer X _A (S1). Next, the network terminal 8-1
Prime p, based on the primitive root α and integer X _A, and calculates the public key Y _A of the formula 1 (S2). Y _A = α ＾ (X _A ) mod (p) (Equation 1) where A mod (B) indicates a remainder obtained by dividing the integer A by the integer B, and A ＾ (B) indicates the remainder of A Indicates B-th power.

Next, the network terminal 8-1, the calculated public key Y _A encrypts the secret key to generate _{E (Y A) (S3)} , ID and E (Y _A) a DHCP-R
It is inserted into the EQUEST and transmitted to the access point 4-1 (S4). The access point 4-1 is a DHCP-
Upon receiving the REQUEST, this DHCP-REQU
The EST is transferred and this DHCP-REQUEST
The ID and E (Y _A ) included in ST are extracted, and this I
E sends D and E a (Y _A) to the authentication server 51
_A request for decryption of (Y _A ) is made (S5). Authentication server 5-
1 is DHCP-REQUEST and ID and E
When (Y _A) to receive and decode the E (Y _A) by the private key corresponding to the ID, and the public key Y _A decrypted, D
A reply is sent to the access point 4-1 together with the HCP-ACK (S6).

The access point 4-1 is connected to the DHCP-A
Upon receiving the CK and a public key Y _A, it determines the integer X _B (S7). Next, the access point 4-1, prime p, based on the primitive root α and integer X _B, calculates the public key Y _B represented by the formula 2 (S8). Y _B = α ＾ (X _B ) mod (p) (Equation 2) Next, the access point 4-1 sets the public key Y _B to DH
It is inserted into the CP-ACK and transmitted to the network terminal 8-1 (S9). The access point 4-1, based on the public key Y _A and integer X _B, and stores the calculated session shared key K of the formula 3 (S10).

K = Y _A ＾ (X _B ) mod (p) = α ＾ (X _A · X _B ) mod (p) (Equation 3) On the other hand, the network terminal 8-1 transmits the DHCP-ACK Upon receipt, and extracts the public key Y _B contained in DHCP-ACK. Then, the network terminal 8-1 on the basis of the public key Y _B and the integer X _A, and stores the calculated session shared key K of the formula 4 (S11). K = Y _B ＾ (X _A ) mod (p) = α ＾ (X _A · X _B ) mod (p) (Equation 4)

Here, when the access point 4-1 and the network terminal 8-1 can correctly share the session shared key K, the network terminal 8-1 and the authentication server 5
-1 share the secret key, the access point 4-1 communicates with the network terminal 8-
1 can be authenticated as a legitimate network terminal. Conversely, when the access point 4-1 and the network terminal 8-1 cannot correctly share the session shared key K, it is determined that the network terminal 8-1 and the authentication server 5-1 do not share the secret key. Therefore, the access point 4-1 is connected to the network terminal 8
-1 can be determined to be an unauthorized network terminal.

As described above, by exchanging the public keys Y _A and Y _B for generating the session shared key K with the DHCP, the session shared key K can be shared without increasing the number of packet exchanges. Communication can be performed efficiently. Also, the network terminal 8-1
When the communication according to (1) is started, it is possible to prevent an increase in the delay time until the communication is established. The session shared key K shared by the network terminal 8-1 and the access point 4-1 is
-1 can be used for various concealments and / or authentications.

Next, a case where the network terminal connects to an access point of a wide area LAN other than the wide area LAN to which the own network terminal belongs will be described. FIG. 6 is an explanatory diagram showing a processing procedure of a session shared key generation process when a network terminal connects to an access point of another wide area LAN according to this embodiment.
Here, a case where the network terminal 9-1 and the access point 4-1 generate the session shared key K will be described as an example. The same processes as those in the case where the network terminal is connected to the own wide area LAN are denoted by the same reference numerals as those in FIG. In this session shared key generation process, the authentication server 5-1 determines that the ID received in step S5 is not the ID of the own wide area LAN 10-1, and the authentication server 5-1 sends the ID to the authentication server 5-N1 of the wide area LAN 10-N1 corresponding to this ID. ,
By sending the ID and E (Y _A) requests the decoding of _{E (Y A) (S21)} .

The authentication server 5-N1 is connected to the authentication server 5-1.
ID and E (Y_A), This ID
E (Y_A) Decrypt and decrypt
Public key Y_AIs returned to the authentication server 5-1 (S2
2). The authentication server 5-1 receives a request from the authentication server 5-N1.
Public key Y_AAnd forward it to the access point 4-1.
You. Alternatively, the access point is sent from the authentication server 5-N1.
Public key Y addressed to To 4-1 _AMay be transmitted. like this
First, the network terminal 9-1 is connected to another wide area LAN 10-1.
When connecting to the access point 4-1 of
Secret to access point 4-1 and authentication server 5-1
Share session shared key K without knowing key
be able to. This method is used, for example, in a branch office LAN.
In addition, the network of the notebook PC etc. of the user from the head office
This is effective when connecting a terminal.

Next, the authentication processing of the network terminal at the access point after the DHCP or session shared key generation processing is completed will be described. In this authentication processing, a hash value is generated using the session shared key K, and authentication is performed on a packet basis by adding this hash value to the CRC value of the MAC frame. FIG.
Is the MAC of the network terminal according to this embodiment.
FIG. 9 is an explanatory diagram illustrating a processing procedure of a frame generation process. In the MAC frame generation processing, the network terminal first generates data including the data link layer payload of the transmission packet and the session shared key K (S3).
1).

In this example, data in which the data link layer payload is sandwiched by the session shared key K is created. However, the arrangement of the data link layer payload and the session shared key K is not particularly limited. The shared key K may be added, or the session shared key K may be sandwiched between data link layer payloads. Alternatively, only a part of the session shared key K and the data link layer payload may be used. Furthermore, this data contains M
An AC header may be included. Next, the network terminal calculates a hash value from the data generated in step S31 (S32).

Next, the network terminal generates data including the calculated hash value, the MAC header of the transmission packet, and the data link layer payload (S3).
3). The arrangement of the data is not particularly limited. Then, the network terminal calculates a CRC value of the data generated in step S33 (S34), and calculates this CRC value as M
It is used as the CRC value of the AC frame (S35).
Transmit the AC frame to the access point.

FIG. 8 is an explanatory diagram showing a processing procedure of authentication processing in packet units by the access point according to this embodiment. In this authentication processing, the access point firstly sets the data link layer payload and the session shared key K of the packet received from the network terminal.
Is generated in the same manner as the network terminal described above (S41). Next, the access point
A hash value is calculated from this data (S42). Next, the access point generates data including the calculated hash value and the MAC header and the data link layer payload of the received packet in the same manner as the network terminal described above (S43). ).

Then, the access point determines in step S
The CRC value of the data generated in 43 is calculated (S44),
This CRC value is compared with the CRC value of the received packet,
If they are the same, it is determined that the network terminal that transmitted this packet has the correct session shared key K, that is, that the network terminal has the correct secret key shared with the authentication server, and performs authentication. As described above, since the authentication can be performed for each packet without changing the packet format, the maximum transferable data length of the data link is not affected and the user is transparent.

This method can also be applied to a case where a packet is transmitted from an access point to a network terminal. That is, the access point may calculate the CRC value in the same manner as the above-described network terminal to generate a packet, and the network terminal may calculate the CRC value in the above-described access point in the same manner and perform authentication for each packet. . As a result, authentication can be performed for each packet on the network terminal side, and it can be determined whether the packet is from a third party impersonating the access point or a legitimate packet from the access point.

Next, a case where the session shared key K is used for secrecy will be described. FIG. 9 is an explanatory diagram for explaining the concealment process according to this embodiment. Here, communication between the network terminal 8-1 and the access point 4-1 will be described as an example. In this concealment process, the network terminal 8
When -1 transmits a data packet to the access point 4-1, it encrypts the data packet with the session shared key K of its own network terminal and transmits it. The access point 4-1 that has received the encrypted encrypted packet decrypts the encrypted packet with the session shared key K of the access point and transmits the decrypted packet to the destination.

When the access point 4-1 transmits a data packet to the network terminal 8-1, the access point 4-1 encrypts the data packet using the session shared key K of the access point and transmits the data packet. Network terminal 8-1 receiving the encrypted packet
Decrypts the encrypted packet using the session shared key K of the own network terminal.

As described above, according to this embodiment,
Insert the public key Y _A used for generating the session shared key K to the packet to be transmitted to the access point from the network terminal based on the DHCP, transmission to the network terminal from the access point based on the DHCP packet insert a public key Y _B used for generating the session shared key K to be, based on the public key Y _a at the access point generates a session shared key K, based on the public key Y _B at the network terminal side Generate a session shared key K.

As a result, the public keys Y _A and Y _B can be exchanged without increasing the number of packet exchanges when starting communication between the network terminal and the access point. It is possible to securely share the session sharing key K for confidentiality and / or authentication with the network terminal side and the access point side while suppressing a delay until the communication establishment. This method is particularly effective in communication using a physical layer, which makes it easy for an unauthorized third party to intercept and transmit communication. In this embodiment, DHCP has been described as an example, but ARP (Address Resolution Protocol) has been described.
For example, another protocol performed prior to the communication between the network terminal and the access point may be used. In this case, a processing unit that performs processing related to the protocol is provided instead of the above-described DHCP processing units. Further, a pair of a secret key and a public key may be used instead of the session shared key. In the above-described example, the prime number p is used, but a power of a prime number may be used. Furthermore, a Diffie-Hellman public key distribution method using elliptic encryption is also possible.

[0081]

As described above, according to the session sharing key sharing method of the present invention (claim 1), in the first inserting step,
Inserting first information used for generating a session shared key into a packet transmitted from the network terminal to the relay device based on a protocol executed when communication between the network terminal and the relay device is started, In a second insertion step, second information used for generating a session shared key is inserted into a packet transmitted from the relay apparatus side to the network terminal side based on this protocol, and in the first generation step, the relay apparatus The side generates a session shared key based on the first information, and in a second generation step, the network terminal generates a session shared key based on the second information.
Accordingly, since the information for generating the session shared key can be exchanged without increasing the number of packet exchanges when starting the communication between the network terminal and the relay device, the session shared key for concealment and / or authentication can be exchanged. Can be safely shared by the network terminal side and the relay apparatus side.

Further, the session sharing key sharing method of the present invention (claim 2) provides a method for transmitting and receiving packets between a relay device and a network terminal based on a protocol for associating a network layer address with a MAC address. By inserting and exchanging information for generating a session shared key, information for generating a session shared key can be exchanged without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Therefore, the session sharing key for confidentiality and / or authentication can be safely shared between the network terminal side and the relay apparatus side.

Further, the session shared key sharing method of the present invention (claim 3) inserts information for generating a session shared key into a packet transmitted and received between the relay apparatus side and the network terminal side based on ARP. By exchanging the information, the information for generating the session shared key can be exchanged without increasing the number of packet exchanges when starting the communication between the network terminal and the relay device. The session shared key can be safely shared between the network terminal and the relay device.

The session sharing key sharing method according to the present invention (claim 4) provides a method for sharing a session between packets transmitted and received between the relay device and the network terminal based on a protocol for assigning a network layer address to the network terminal. By inserting and exchanging information for generating a key, it is possible to exchange information for generating a session shared key without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. The session sharing key for confidentiality and / or authentication can be safely shared by the network terminal side and the relay apparatus side.

Further, the session shared key sharing method of the present invention (claim 5) inserts information for generating a session shared key into a packet transmitted and received between the relay apparatus side and the network terminal side based on DHCP. By exchanging the information, the information for generating the session shared key can be exchanged without increasing the number of packet exchanges when starting the communication between the network terminal and the relay device. The session shared key can be safely shared between the network terminal and the relay device.

Also, in the network terminal authentication method of the present invention (claim 6), in the encryption step, the first information for generating the session shared key used for authentication is encrypted with the secret key, and in the first insertion step. In a packet transmitted from the network terminal to the relay device based on a protocol executed when communication between the network terminal and the relay device is started, the first information encrypted in the encryption process is In the inserting and decrypting step, the encrypted first information is transmitted from the relay apparatus to the certificate authority, and the first information decrypted by the certificate authority is received by the relay apparatus, and in the second inserting step, The second information used to generate the session shared key is inserted into a packet transmitted from the relay device side to the network terminal side based on this protocol, and is decrypted in the decryption step in the first generation step. It generates a session shared key based on one of the information, in the second generation step, generating a session shared key based on the second information inserted in the second insertion step.
This allows the network terminal side and the relay device side to safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Unauthorized access to the network can be reduced.

A network terminal authentication method according to the present invention (Claim 7) provides a method for converting a session transmitted and received between a relay apparatus and a network terminal based on a protocol for associating a network layer address with a MAC address. By inserting and exchanging information for generating a shared key, a session shared key for network terminal authentication can be exchanged between the network terminal and the network terminal without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Since the device can safely share the information, unauthorized access to the network can be reduced.

Further, the network terminal authentication method of the present invention (claim 8) inserts information for generating a session shared key into a packet transmitted and received between the relay device side and the network terminal side based on ARP. By exchanging, the network terminal side and the relay apparatus side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay apparatus. Therefore, unauthorized access to the network can be reduced.

Further, the network terminal authentication method of the present invention (claim 9) provides a method for assigning a session shared key to a packet transmitted / received between a relay device and a network terminal based on a protocol for assigning a network layer address to the network terminal. By inserting and exchanging information for generation, a session shared key for network terminal authentication can be exchanged between the network terminal and the relay device without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Can be safely shared, so that unauthorized access to the network can be reduced.

Further, the network terminal authentication method of the present invention (claim 10) inserts information for generating a session shared key into a packet transmitted / received between the relay apparatus side and the network terminal side based on DHCP. By exchanging, the network terminal side and the relay device side can safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Therefore, unauthorized access to the network can be reduced.

Further, the network terminal authentication method of the present invention (Claim 11) uses the Diffie-Hellman public key distribution method to share the session shared key between the network terminal side and the relay device side. Can be more appropriately protected.

Also, in the network terminal authentication method of the present invention (claim 12), in the first hash value calculation step, the data link layer payload and the second generation of the packet transmitted from the network terminal to the relay device side are performed. Calculating a hash value based on the data including the session shared key generated in the step, and calculating a CRC value in the first CRC value calculating step based on the payload and the data including the hash value calculated in the first hash value calculating step Calculated in the packet transmission step, and the CRC calculated in the first CRC value calculation step.
A packet in which the value is added to the MAC header and the payload is transmitted from the network terminal side to the relay apparatus side,
In the second hash value calculation step, a hash value is calculated based on the MAC header and the payload transmitted in the packet transmission step and the data including the session shared key generated in the first generation step, and in the second CRC value calculation step, A CRC value is calculated based on the MAC header and the payload transmitted in the packet transmitting step and the data including the hash value calculated in the second hash value calculating step, and the CRC value transmitted in the packet transmitting step is calculated in the authentication step. 2nd C
By comparing the CRC value calculated in the RC value calculation step with the CRC value, the relay device authenticates the network terminal in packet units. As a result, authentication can be performed in packet units without changing the format of the packet, so that unauthorized access to the network can be reduced more appropriately.

[0093] Also, the network terminal of the present invention (claim 13) is characterized in that the insertion means conceals a packet to be transmitted to the relay device side based on a protocol executed when communication with the relay device is started. The first information used for generating a session shared key for use in authentication and / or authentication is inserted, and the obtaining means is configured to generate a second shared key for generating a session shared key included in a packet transmitted from the relay apparatus based on this protocol. And the generating means generates a session shared key based on the second information obtained by the obtaining means. Accordingly, since the information for generating the session shared key can be exchanged without increasing the number of packet exchanges when starting the communication between the network terminal and the relay device, the session shared key for concealment and / or authentication can be exchanged. Can be safely shared by the network terminal side and the relay apparatus side.

Further, in the network terminal of the present invention (claim 14), the encrypting means encrypts the first information used for generating the session shared key for authentication of the network terminal with a secret key, and the inserting means includes: Inserting the first information encrypted by the encryption unit into a packet to be transmitted to the relay device based on a protocol executed when communication with the relay device is started; , The second information for generating a session shared key included in the packet transmitted from the relay device side is acquired, and the generation unit generates the session shared key based on the second information acquired by the acquisition unit. . This allows the network terminal side and the relay device side to safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Unauthorized access to the network can be reduced.

In the network terminal according to the present invention, the hash value calculating means may determine whether the hash value is calculated based on the data including the payload of the packet to be transmitted to the relay device and the session shared key generated by the generating means. The CRC value calculation means calculates the MA of the transmission packet.
A CRC value is calculated based on the data including the C header, the payload, and the hash value calculated by the hash value calculation means, and the packet transmission means adds the CRC value calculated by the CRC value calculation means to the MAC header and the payload. It is transmitted to the relay device side. As a result, authentication can be performed in packet units without changing the format of the packet, so that unauthorized access to the network can be reduced more appropriately.

The relay device of the present invention (claim 16)
Is included in a packet transmitted from the network terminal side based on a protocol executed when the acquisition unit starts communication with the network terminal, and
Alternatively, first information used for generating a session shared key for authentication is obtained, and the inserting means adds second information used for generating a session shared key to a packet transmitted to the network terminal based on this protocol. And the generating unit generates a session shared key based on the first information acquired by the acquiring unit. Accordingly, since the information for generating the session shared key can be exchanged without increasing the number of packet exchanges when starting the communication between the network terminal and the relay device, the session shared key for concealment and / or authentication can be exchanged. Can be safely shared by the network terminal side and the relay apparatus side.

The relay device of the present invention (claim 17)
Is a session for network terminal authentication, which is included in a packet transmitted from the network terminal based on a protocol executed when the acquisition unit starts communication with the network terminal and is encrypted by a secret key. Authentication for acquiring first information used for generation of a shared key and for decrypting the encrypted first information acquired by the acquiring means by decrypting the information encrypted with the secret key and returning the encrypted first information Transmitting the certificate to the network terminal, receiving the first information decrypted by the certificate authority, and inserting the second information used for generating the session shared key into the packet transmitted to the network terminal side based on this protocol. The information is inserted, and the generation unit generates a session shared key based on the first information received by the decryption unit. This allows the network terminal side and the relay device side to safely share the session shared key for network terminal authentication without increasing the number of packet exchanges when starting communication between the network terminal and the relay device. Unauthorized access to the network can be reduced.

The relay device of the present invention (claim 18)
The hash value calculating means calculates a hash value based on the data link layer payload of the packet received from the network terminal side and the data including the session shared key generated by the generating means, and the CRC value calculating means calculates The CRC value is calculated based on the MAC header and the payload and the data including the hash value calculated by the hash value calculation means, and the authentication means calculates the CRC value of the packet received from the network terminal and the CRC value calculated by the CRC value calculation means. , The network terminal is authenticated in packet units. As a result, authentication can be performed in packet units without changing the format of the packet, so that unauthorized access to the network can be reduced more appropriately.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a communication network system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a network terminal shown in FIG.

FIG. 3 is a block diagram illustrating a schematic configuration of an access point illustrated in FIG. 1;

FIG. 4 is a block diagram illustrating a schematic configuration of the authentication server illustrated in FIG. 1;

FIG. 5 is an explanatory diagram of a procedure of a session shared key generation process according to the embodiment;

FIG. 6 is an explanatory diagram showing a procedure of a session shared key generation process when a network terminal connects to an access point of another wide area LAN according to the embodiment;

FIG. 7 is an explanatory diagram illustrating a processing procedure of a MAC frame generation process according to the embodiment;

FIG. 8 is an explanatory diagram illustrating a procedure of an authentication process according to the embodiment;

FIG. 9 is an explanatory diagram illustrating a concealment process according to the embodiment;

[Explanation of symbols]

1 Internet 2,3-1-3-N1 Router 4-1-4-N2,6-1-6-N3 Access Point 5-1-1-5-N1 Authentication Server 8-1-1-8-N4,9-1 9-N5 Network terminal 10-1 to 10-N1 Wide area LAN 11, 22, 31 Storage device 12 Hash value calculation unit 13, 24 Diffie-Hellman calculation unit 14 CRC value calculation unit 15 Encryption unit 16, 23, 33 DHCP processing Unit 17, 25 Packet processing unit 18, 27 Network communication unit 21, 34 LAN communication unit 26 Hash value / CRC value calculation unit 28 Authentication unit 32 Decryption unit 41-1 to 41-N2, 42-1 to 42-N3 Communication Network 43 Backbone Network

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 9/00 675D (72) Inventor Masataka Ota 2-12-1 Ookayama, Meguro-ku, Tokyo Tokyo Institute of Technology F term (reference) 5J104 AA16 EA04 EA24 JA03 MA03 NA02 NA05 PA07 5K030 GA15 HA08 HB11 HC01 HC14 HD03 HD06 HD09 JA11 JL07 JT03 KA04 LD19 MD04 5K033 AA08 CB01 CC04 DA06 DB18 DB20 EA07 EC01 EC03

Claims (18)

[Claims] When a network terminal that transmits and receives a packet and a relay device that relays the packet communicate via a communication cable, a session shared key for concealment and / or authentication is transmitted to the network terminal and the relay device. A session sharing key sharing method to be shared by the device side, wherein the network terminal side is transmitted to the relay device side based on a protocol executed when communication between the network terminal and the relay device is started. A first insertion step of inserting first information used for generating the session shared key into a packet transmitted from the relay device to the network terminal based on the protocol. A second insertion step of inserting second information used for generating a key; and A first generation step of generating the session shared key based on the first information inserted in the first insertion step; and the network terminal side, on the side of the second information inserted in the second insertion step, A second generation step of generating the session shared key based on the session shared key. 2. The session sharing key sharing method according to claim 1, wherein the protocol is a protocol that associates a network layer address with a MAC address. 3. The session sharing key sharing method according to claim 1, wherein the protocol is ARP. 4. The session sharing key sharing method according to claim 1, wherein the protocol is a protocol for assigning a network layer address to the network terminal. 5. The session sharing key sharing method according to claim 1, wherein the protocol is DHCP. 6. A network terminal authentication method for authenticating the network terminal on the relay device side when a network terminal transmitting and receiving a packet and a relay device relaying the packet communicate via a communication cable, An encryption step of encrypting, using a secret key, first information for generating a session shared key used for the authentication, based on a protocol executed when communication between the network terminal and the relay device is started. A first insertion step of inserting the first information encrypted in the encryption step into a packet transmitted from the network terminal side to the relay apparatus side; Transmitting the encrypted first information inserted in the step to a certificate authority that decrypts and returns the information encrypted by the secret key, A decryption step of receiving the decrypted first information by a certificate authority; and using the session shared key in a packet transmitted from the relay device to the network terminal based on the protocol. A second insertion step of inserting second information; a first generation step of generating the session shared key on the relay device side based on the first information decrypted in the decryption step; A second generation step of generating the session shared key on the network terminal side based on the second information inserted in the second insertion step. 7. The network terminal authentication method according to claim 6, wherein the protocol is a protocol that associates a network layer address with a MAC address. 8. The method according to claim 6, wherein the protocol is ARP. 9. The method according to claim 6, wherein the protocol is a protocol for assigning a network layer address to the network terminal. 10. The method according to claim 6, wherein the protocol is DHCP. 11. The first information and the second information are public keys of a Diffie-Hellman public key distribution method, and the session shared key is a share of a Diffie-Hellman public key distribution method. The key is a key.
The network terminal authentication method according to any one of the above. 12. A hash value based on a data link layer payload of a packet transmitted from the network terminal to the relay device and data including the session shared key generated in the second generation step. A first hash value calculating step of calculating a CRC value based on a MAC header and the payload of the packet and data including the hash value calculated in the first hash value calculating step.
A CRC value calculating step; a packet transmitting step of transmitting a packet obtained by adding the CRC value calculated in the first CRC value calculating step to the MAC header and the payload from the network terminal side to the relay apparatus side; A second hash value calculating step of calculating a hash value on the relay device side based on the payload transmitted in the packet transmitting step and the data including the session shared key generated in the first generating step; A second CRC value calculating step of calculating a CRC value based on the MAC header and the payload transmitted in the packet transmitting step and data including the hash value calculated in the second hash value calculating step; Calculating the CRC value transmitted in the packet transmitting step and the second CRC value An authentication step of authenticating the network terminal on a packet basis by comparing the CRC value calculated in the step with the network terminal, the network terminal according to any one of claims 6 to 11, comprising: Authentication method. 13. A network terminal that communicates with a relay device that relays a packet via a communication cable, wherein the packet is transmitted to the relay device based on a protocol executed when communication with the relay device is started. Insertion means for inserting, into a packet, first information used to generate a secret and / or authentication session shared key; and the session shared key included in a packet transmitted from the relay device based on the protocol. A network terminal comprising: an obtaining unit that obtains second information for generation; and a generating unit that generates the session shared key based on the second information obtained by the obtaining unit. 14. A network terminal that communicates with a relay device that relays a packet via a communication cable, wherein first information used to generate a session shared key for authentication of the network terminal is encrypted with a secret key. Means for inserting the first information encrypted by the encryption means into a packet to be transmitted to the relay device based on a protocol executed when communication with the relay device is started. Means for acquiring the second information for generating the session shared key included in the packet transmitted from the relay device side based on the protocol, and acquiring the second information acquired by the acquiring means Generating means for generating the session shared key based on the network terminal. 15. A hash value calculating unit that calculates a hash value based on a data link layer payload of a packet to be transmitted to the relay device and data including the session shared key generated by the generating unit. CRC value calculation means for calculating a CRC value based on the MAC header and the payload of the packet and data including the hash value calculated by the hash value calculation means; and calculating the CRC value calculated by the CRC value calculation means. M
The network terminal according to claim 14, further comprising: a packet transmitting unit configured to transmit a packet added to an AC header and the payload to the relay device side. 16. A relay device that communicates with a network terminal that transmits and receives packets via a communication cable and relays the packet, wherein the network terminal is based on a protocol executed when communication with the network terminal is started. Acquiring means for acquiring first information included in a packet transmitted from the side and used for generating a secret and / or authentication session shared key, and transmitting the first information to the network terminal based on the protocol Insertion means for inserting second information used for generating the session shared key into a packet, and generation means for generating the session shared key based on the first information acquired by the acquisition means. A relay device characterized by the above-mentioned. 17. A relay device for communicating via a communication cable with a network terminal transmitting and receiving a packet, and relaying the packet, wherein the network terminal is based on a protocol executed when communication with the network terminal is started. Acquiring means for acquiring first information used for generating a session shared key for authentication of the network terminal, which is included in a packet transmitted from the side and encrypted by a secret key; and Decryption means for transmitting the encrypted first information to a certification authority that decrypts and returns the information encrypted with the secret key, and receives the first information decrypted by the certification authority; Second information used for generating the session shared key in a packet transmitted to the network terminal based on the protocol. And a generating unit that generates the session shared key based on the first information received by the decrypting unit. 18. A hash value calculating means for calculating a hash value based on a data link layer payload of a packet received from the network terminal side and data including the session shared key generated by the generating means; CRC value calculating means for calculating a CRC value based on the MAC header, the payload, and data including the hash value calculated by the hash value calculating means; and C of the packet received from the network terminal.
The relay device according to claim 17, further comprising: authentication means for authenticating the network terminal in packet units by comparing an RC value with the CRC value calculated by the CRC value calculation means. .