JP4526079B2 - Multi-hop communication system, mobile terminal thereof, route control server, and route establishment method - Google Patents

Description

  The present invention relates to a multihop communication system and a mobile terminal thereof, a route control server, and a route establishment method, and more particularly to a multihop communication system capable of providing multihop communication excellent in communication safety on an ad hoc network and the mobile terminal thereof. The present invention relates to a route control server and a route establishment method.

  In addition to a method in which a mobile terminal communicates via a wireless base station, such as a mobile phone network or a wireless LAN, there is a method in which terminals directly exchange data. For example, this is supported by a communication mode called “ad hoc mode” in a wireless LAN. In ad hoc mode, terminals communicate with each other on a one-to-one basis, but by further expanding this and using ad hoc routing technology, not only the other party but also the other party Multi-hop communication has been proposed that enables communication by using a mobile terminal located at a relay terminal as a relay terminal, and is disclosed in Patent Document 1, for example.

  On the other hand, in a wireless network constructed ad hoc, there are not always only terminals that operate correctly. In some cases, a malicious third party may exist and perform various attacks. In ad hoc routing technology, data packets sent from a terminal go through multiple relay terminals. In conventional ad hoc routing technology, even if there is a person who acts fraudulently on the relay terminal, know that Is difficult.

  Further, in the conventional routing technique, it is necessary for end terminals (transmission terminal and destination terminal) that communicate with each other to register a unique address that can uniquely identify a partner terminal for a transmission packet. For this reason, the end terminal which is performing communication is known to the entire relay node, and communication anonymity is significantly lost.

For such a technical problem, Patent Document 1 discloses a technique for establishing a communication path while ensuring anonymity and confidentiality when a terminal performs ad hoc communication. According to Patent Document 1, when all terminals can be connected to a wide area network (infrastructure network) and communication between terminals (ad hoc communication) is possible, a relay terminal (actual communication) is established on the established communication path. (Except for the two terminals at both ends) that cannot see the contents of the communication or even specify the end terminal.
Japanese Patent Application No. 2003-420753

  In the above-described conventional technology, all terminals functioning as relay stations exist within the infrastructure network and must be able to communicate with the “route control server (RM)” installed in the infrastructure network. Therefore, secure ad hoc communication via terminals located outside the infrastructure network cannot be realized.

  An object of the present invention is to solve the above-described problems of the prior art and to perform secure multi-hop communication if at least one of a plurality of terminals functioning as relay stations on an ad hoc network is located within an infrastructure network. An object of the present invention is to provide a multi-hop communication system that can be realized, a mobile terminal thereof, a route control server, and a route establishment method.

In order to achieve the above object, the present invention includes a plurality of mobile terminals (S, T, X) and a route control server, and transmits a route request message (RREQ) transmitted from the transmitting terminal S to another mobile terminal X. Of the multi-hop communication system in which the other mobile terminal X relays the route response message (RREP) transmitted by the destination terminal T in response to the RREQ to the transmission terminal S to establish a route. The route establishment method is characterized by the following measures.
(1) Procedure for transmitting terminal S to store session ID and unique key KCs in association with each other
(2) The sending terminal S further floods the RREQ in which the encrypted source address IPs and destination address IPt, the session ID, and the encrypted unique key KCs are registered.
(3) Procedure for determining whether or not the mobile terminal X that has received the RREQ can communicate with the routing server
(4) A procedure in which the mobile terminal X capable of communicating with the routing server transmits an anonymous address assignment request message (FWREQ) including the encrypted addresses IPs and IPt to the routing server
(5) The routing control server decrypts the encrypted addresses IPs and IPt, and re-encrypts with an encryption key that cannot be decrypted except by the destination terminal T.
(6) The routing control server further sends back an anonymous address assignment response message (FWREP) including the re-encrypted addresses IPs and IPt and anonymous addresses FWs and FWt to the mobile terminal X.
(7) Procedure for the mobile terminal X to store the unique key KCx in association with the session ID registered in the RREQ
(8) The mobile terminal X further floods the RREQ to which the addresses IPs and IPt are re-encrypted and the encrypted unique key KCx and the anonymous addresses FWs and FWt are added.
(9) The destination terminal T that has received the flooded RREQ from the mobile terminal X decrypts the re-encrypted addresses IPs and IPt and the unique keys KCs and KCx.
(10) The destination terminal T further generates a plurality of hop information that is registered with the anonymous addresses FWs and FWt and encrypted with the unique keys KCs and KCx.
(11) The destination terminal T further floods the RREP including the received RREQ session ID and a plurality of hop information encrypted with the unique keys KCs and KCx.
(12) The procedure in which the mobile terminal X that has received the RREP extracts the unique key associated with the session ID registered in the RREP
(13) A procedure for registering the hop information when the mobile terminal X can further decrypt any of the plurality of hop information registered in the RREP with the extracted encryption key.
(14) Flooding RREP with registered hop information
(15) A procedure in which the transmitting terminal S that has received the flooded RREP from the mobile terminal X extracts a unique key associated with the session ID registered in the RREP
(16) A procedure for registering the hop information when the transmitting terminal S is further able to decrypt any of a plurality of hop information registered in the RREP with the encryption key

According to the present invention, the following effects are achieved.
(1) Since the transmission source address and destination address of RREQ and RREP are encrypted, a route can be established without specifying end terminals (transmission terminal S and destination terminal T) by the relay terminal.
(2) Each RREQ and RREP message transmission at each relay terminal is performed by broadcast without specifying the destination address as a dummy address [0.0.0.0], and the source is also included in each message. Since no information that can easily specify the destination or the destination is included, a route can be established without specifying the hop source or destination of RREQ or RREP to each relay terminal.
(3) Since data communication on the established route is performed using anonymous addresses (FWs, FWt), communication can be performed without specifying an end terminal as a relay terminal.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration example of an ad hoc network to which a route establishing method of the present invention is applied. A wireless access point AP, a route control server RM connected to the wireless access point AP via a network, and A plurality of mobile terminals (S, A, B,... T) are the main components.

In this embodiment, only the mobile terminals A and B are located within the communication area of the wireless access point AP, that is, within the infrastructure network, the mobile terminals S, C, and T are located outside the infrastructure network, and the mobile terminal S transmits A case where the mobile terminal T behaves as a terminal and the mobile terminal T behaves as a destination terminal will be described as an example. In the present embodiment, communication data is concealed using a public key / private key pair and a shared key, so that the routing server RM and each of the mobile terminals S, A, B, C, T are shown in FIG. Various encryption keys are managed as shown in the list.
(a) First public key KRMp:
Issued by the routing server RM and held in all mobile terminals.
(b) First secret key KRMs:
This key is paired with the first public key KRMp and is held only by the server RM.
(c) First shared key KRM_x:
The key is shared by the mobile terminal X and the server RM, and is registered in advance in the server RM by each mobile terminal X.
(d) Second public key Kxp:
This is a key unique to each mobile terminal X and is held by the routing server RM.
(e) Second secret key Kxs:
It is a key that is paired with each of the second public keys Kxp, and is held by each mobile terminal X.
(f) Second shared key KCx:
It is generated in each mobile terminal X when flooding the RREQ and is used to confirm the validity of the RREP received thereafter.
(g) Session key SK:
It is generated at the destination terminal T when a route is established, registered in the RREP, and notified to each relay terminal. Since the session key SK is shared by all the relay terminals, it can be used even after the route is established.

  3 and 4 are flowcharts showing a route establishment procedure executed by each mobile terminal at the time of route establishment, and FIG. 5 is a flowchart showing a route establishment procedure executed by the route control server RM at the time of route establishment. FIG. 6 is a sequence diagram when establishing a route.

  In the terminal S, a route table is searched in response to a route establishment instruction with the terminal T as a destination, and it is confirmed whether or not the route to the terminal T is already registered. Here, the description will be continued assuming that the route to terminal T is not registered in the route table and it is determined that a new route search is necessary. In the transmitting terminal S, a route request message (RREQ) having the final destination as the terminal T is generated.

  FIG. 7 is a diagram showing an example of a format of a signaling message transmitted / received between the mobile terminals and between each mobile terminal and the routing server RM, and includes a basic header and a signaling unit. In the basic header, parameters such as a Type value indicating a message type (RREQ, RREP, FWREQ, FWREP, etc.), a length Len of a signaling unit, and a flag value are registered.

  FIG. 8 is a diagram illustrating a basic format of RREQ, which is stored in the signaling unit and transmitted. The RREQ includes an IP address “IPs” of the transmission terminal S, an IP address “IPt” of the destination terminal T, an “address ID” uniquely corresponding to an anonymous address FWs and FWt described later, and a unique correspondence with each session “ "Session ID" and its candidate value "Session ID candidate", Sequence number "seq", Hop limit number "hop limit", "Public key", Message identifier (hash code) "sig", Number of hops to date " Fields of “hop”, “previous hop order ID” to be described later, and hop information “hop info” are secured.

  The IP addresses “IPs” and “IPt” of the transmission terminal S and the destination terminal T are encrypted with the first public key KRMp at the transmission terminal S and registered in the RREQ. In the “session ID candidate”, a random value is registered in the transmission terminal S. In the “session ID”, the initial value “0” is registered in the transmission terminal S. In the “public key”, the first public key “KRMp” is registered when transmitted from the transmission terminal S. The message identifier “sig” is a unique signature for each terminal, with the IP address IPs, IPt encrypted data, address ID, session ID candidate, session ID, seq, hop limit, and public key (KRMp) as signature ranges. One shared key KRM_x (KRM_s in the case of the transmitting terminal S) is generated by calculation of a keyed hash function such as HMAC-MD5 using the encryption key.

  In the “hop info”, the IP address “IPx”, “previous hop order ID”, “own hop order ID”, “FW value”, “second shared key KCx” of each mobile terminal X, anonymous as will be described later The fields of address pair “FWs”, “FWt” and check value “check” are reserved. The anonymous addresses “FWs”, “FWt”, and “check” are parameters that are provided later from the routing server RM, and are all “0” when flooded from the transmission terminal S.

  The “previous hop order ID” is one of identifiers representing the pop order of messages, and is an ordinal number given to the RREQ by the previous mobile terminal that hopped the message to itself. The “own hop order ID” is an ordinal number assigned to the RREQ by itself, and is a value larger than the “previous hop order ID”. In the RREQ transmitted from the transmission terminal S, “0” is registered in both “previous hop order ID” and “own hop order ID”. The “hop info” is encrypted with the first public key KRMp and stored in the RREQ.

  In the RREQ, a dummy address (for example, [0.0.0.0]) is registered in the source address of the IP header, and a broadcast address (for example, [255.255.255.255]) is registered in the destination address and flooded on the network. The

  When the mobile terminal A receives the RREQ flooded from the transmission terminal S in step S1 of FIG. 3, in step S2, the “address ID” registered in the RREQ is referred to. The address ID of the RREQ received at the terminal A is still “0”, which means that the validity of the RREQ has not yet been verified by the server RM. This also means that the address information (IP address “IPs”, “IPt”) of the RREQ is still encrypted with the first public key KRMp and can be decrypted only by the routing server RM. Then, the process proceeds to step S5 without attempting to decipher it.

  If the address ID is other than “0”, the RREQ address information is re-encrypted by the server RM with the first shared key KRM_t that can be decrypted if the destination terminal T. Therefore, it progresses to step S3. In step S3, the address information of the RREQ is decrypted with the first shared key KRM_x unique to each terminal, and the decryption is tried. In step S4, it is determined whether or not the destination of the RREQ is itself based on whether or not the decoding is successful. If it cannot be decoded, it is determined that the destination of the received RREQ is other than itself, and the process proceeds to step S5.

  In step S5, it is determined whether or not it is within the infrastructure network. If it is terminal A, it is determined that it is within the range and the process proceeds to step S6. In step S6, a FW address request message (FWREQ) for requesting anonymous addresses FWs and FWt to the server RM is generated and transmitted to the server RM in step S7.

  FIG. 9 is a diagram showing an example of the basic format of the FWREQ, which has the same format as the RREQ, and includes parameters within the RREQ signature range, message identifiers “sig”, “Hop Info”, and the like. Is registered and sent as it is.

  Proceeding to FIG. 5, when the server RM receives the FWREQ in step S51, the server RM proceeds to step S52 and refers to the “address ID” stored in the FWREQ. In the case of FWREQ sent from terminal A, the “address ID” is “0”, which is the first FWREQ received for the same RREQ, and this means that anonymous addresses FWs, FWt and session IDs are not assigned. The process proceeds to step S53.

  In step S53, the address information encrypted with the first public key KRMp is decrypted with the first secret key KRMs, and the IP address “IPs” of the transmission terminal S and the IP address “IPt” of the destination terminal T are extracted. . In step S54, calculation of a keyed hash function such as HMAC-MD5 is performed on the signature range data using the first shared key KRM_s shared by the server RM with the transmission terminal S as an encryption key, and the calculation result and the FWREQ are calculated. The registered message identifier “sig” is compared. If the two match and the validity of the FWREQ is confirmed, the process proceeds to step S55, where each of the IP addresses “IPs” and “IPt” is the first shared key KRM_t that the server RM shares with the destination terminal T. It is encrypted again.

  In step S56, “Hop Info” encrypted with the first public key KRMp is decrypted with the first secret key KRMs, and further encrypted with the second public key Ktp unique to the destination terminal T. In step S57, it is determined whether or not the value of “session ID candidate” registered in FWREQ has already been assigned to another session. If not assigned, the process proceeds to step S58, and the value of the session ID candidate is registered as it is as a session ID. If the value of the session ID candidate is already assigned to another session, the process proceeds to step S59, and an unassigned ID is registered as a session ID.

  In step S60, an FW address response message (FWREP) is generated. FIG. 10 is a diagram showing an example of the basic format of FWREP. Compared to the received FWREQ (FIG. 9), the public key is changed from the first public key KRMp to the second public key Ktp unique to the destination terminal T. And the encryption key of the address information is changed from the first public key KRMp to the first shared key KRM_t of the destination terminal T, and the message identifier “sig” is a keyed hash with the first shared key KRM_t of the destination terminal T as the encryption key The calculation result of the function has been changed.

  In step S61, unassigned anonymous addresses FWs and FWt are assigned to the pairs of IP addresses “IPs” and “IPt” of the transmission terminal S and the destination terminal T, and are registered in the table together with check values (random numbers). . In step S62, the entry number of the table (or a value that can be converted to that value on a one-to-one basis) is registered as an “address ID”, and is registered in FWREP along with the FWs, FWt, and check values. In step S63, the FWREP is transmitted to terminal A.

  If the address ID of the received FWREQ is other than “0” in step S52, the process proceeds to step S64, and a pair of anonymous addresses FWs and FWt is extracted from the table based on the value. In step S65, the registered anonymous addresses FWs and FWt are compared with the extracted anonymous addresses FWs and FWt and Hop info of FWREQ. If the two match, the process proceeds to step S63 and FWREP is transmitted.

  On the other hand, if the two do not match, some fraud has been performed, so in step S66 FWREQ is discarded and FWREP is not transmitted. Even if the anonymous address FWs and FWt are already registered in FWREQ even though the address ID is determined to be “0” in step S52, some fraud has been performed, so the FWREQ is discarded and FWREP Is not sent.

  Returning to FIG. 3, after transmitting the FWREQ, the terminal A proceeds to step S10 upon receiving the FWREP in step S8, and tries to decrypt the address information with its own first shared key KRM_a. In step S11, it is determined again whether or not the RREQ is addressed to the own terminal based on whether or not the decoding is successful. The address information of FWREP cannot be decrypted by the terminal A because it is re-encrypted with the first shared key KRM_t unique to the destination terminal T by the routing control server RM in the step S55. Accordingly, here again, it is determined that the destination of the RREQ is other than itself and the process proceeds to step S12. Note that after the FWREQ is transmitted in the step S7, a predetermined time elapses before the FWREP is received in the step S8, and if a timeout is detected in the step S9, the process proceeds to the step S12.

  In step S12, a random value larger than the previous hop order ID registered in the received RREQ is generated as the own hop order ID. Then, anonymous addresses FWs, FWt, own hop order ID and previous hop order ID assigned by the routing server RM and additionally registered in FWREP, and the second shared key KCx (generated by terminal X as a random value) Etc. are written in Hop Info, and this is multiple-encrypted using the public key Ktp registered in the FWREP, and the RREQ is updated by rewriting the previous hop order ID to the own hop order ID.

  In this embodiment, after transmitting FWREQ in step S7, the process waits until FWREP is received in step S8. However, after transmitting FWREQ in step S7, the process is terminated for the time being, and the subsequent FWREQ is changed. You may make it transfer to said step S10 with a reception.

  FIG. 11 is a diagram schematically representing the multiple encryption structure of the Hop Info, which is generated by the terminal A into the Hop Info re-encrypted with the second public key Ktp in the path control server RM. Hop Info is added and collectively encrypted with the second public key Ktp.

  In step S13, the updated RREQ is flooded. In step S14, the session ID candidate, the session ID, the self-hop order ID, the seq, the check value, and the second shared key KCx registered in the FWREP are temporarily registered in their own transfer list in association with each other. The However, anonymous addresses FWs and FWt are not registered. The lifetime related to these temporary registrations is shorter than the lifetime when official registration is performed.

  FIG. 12 is a diagram showing an example of the RREQ flooded from the terminal A. Compared with the RREQ flooded from the transmission terminal S, the encryption key of the address information is unique to the destination terminal T from the KRMp. The key is changed to KRM_t, and the public key is also changed from KRMp to the second public key Ktp unique to the destination terminal T.

  Returning to FIG. 3, the terminal B that has received the RREQ from the terminal A determines that the address ID is other than “0” in step S2. If the address ID is other than “0”, the process proceeds to step S3, where the address information registered in the RREQ is decrypted with its own first shared key KRM_b to attempt decryption. In step S4, it is determined whether or not the destination of the RREQ is itself based on whether or not the decoding is successful.

  If the destination of the RREQ is the terminal B, the address information can be decrypted by the routing server RM because the server RM is re-encrypted with the first shared key KRM_b shared with the terminal B. However, since the address information of RREQ received by the terminal B is encrypted with the first shared key KRM_t of the destination terminal T, it cannot be decrypted. Accordingly, here, it is determined that a destination other than itself is the destination, and the process proceeds to step S5. Thereafter, as in the case of terminal A, transmission of FWREQ (S7), reception of FWREP (S8), update of RREQ (S12), flooding of RREQ (S13), update of transfer list (S14), etc. are executed. Is done.

  Further, since the terminal C that has received the RREQ from the terminal B is determined not to be a destination terminal in step S4, it is determined to be out of service in step S5, and therefore the process proceeds to step S12 without transmitting FWREQ to the server RM. RREQ update (S12), RREQ flooding (S13), transfer list update (S14), and the like are executed.

  Note that the out-of-service terminal immediately processes the received RREQ without communicating with the routing server RM. At that time, “0” is registered in FWs, FWt, and check of Hop Info, and only the number of hops is updated in others, and the public key registered in the RREQ (if any of the terminals in the previous stage is a range terminal) For example, the second public key Ktp of the destination terminal T and the first public key KRMp, if any of the preceding terminals are out-of-service terminals, are flooded.

  On the other hand, when the destination terminal T receives the RREQ in step S1, the destination terminal T proceeds from step S2 to step S3 and tries to decode it. If this RREQ relays a terminal in the range even once, the address information is re-encrypted with the first shared key KRM_t unique to itself in the server RM, and if it is the terminal T, it is correctly decrypted and decrypted. Therefore, the process proceeds from step S4 to step S21. In step S21, it is determined whether or not the destination IP address IPt obtained by the decryption matches its own IP address. If the two match, it is determined that the destination of the RREQ is itself, and the process proceeds to step S22.

  Even if the RREQ received at the destination terminal T has never relayed a terminal within the range, if the destination terminal T is a terminal within the range, the process proceeds to step S6 and subsequent steps, and FWREQ is sent to the server RM in the same manner as described above. (Step S7) and FWREP is received (step S8), the address information is re-encrypted with the first shared key KRM_t in the FWREP, and the address information can be decrypted and decrypted in step S11. Therefore, it can progress to step S22.

  In step S22, a keyed hash function of the signature range is calculated using the first shared key KRM_t as an encryption key, and the calculation result is compared with the message identifier “sig” registered in RREQ. When a plurality of RREQs are received through a plurality of routes, other than the RREQ currently being processed (validation is being confirmed) are temporarily stored as Pending RREQ in the queue. When the validity of the RREQ is confirmed, the process proceeds to step S23, and all the multiplexed Hop Info are decrypted one after another using the second secret key Kts. In step S24, Hop Info is verified.

  At this time, Hop Info generated in the terminal in the range includes FWs, FWt, and check values, but if those values are different among multiple Hop Info, some sort of fraud is being done. The RREQ is discarded because it is considered. If all FWs, FWt, and check values match, the continuity of the previous hop order ID and own hop order ID registered in each Hop Info, and whether each hop order ID increases in hop order The validity is determined based on the above. If there is no problem in determining the legitimacy of the route, the process proceeds to step S25 and the route information is registered. In step S26, a route establishment response (RREP) message is generated and flooded in step S27. Even in this RREP, a dummy address (for example, [0.0.0.0]) is registered as the source address of the IP header, and a broadcast address (for example, [255.255.255.255]) is registered as the destination address.

  FIG. 13 is a diagram showing an example of the format of the RREP. The seq, session ID, and session ID candidate are the same as the received RREQ. The Hop Info of each relay terminal stored in the Hop Info of the received RREQ after being multi-encrypted is separately encrypted and concatenated with the second shared key KCx registered in each Hop Info. Each Hop Info concatenation permutation is random. If a suitable number of dummy Hop Infos are inserted, it is difficult for a third party to know the number of Hops. In each Hop Info, the session key SK is common to all Hop Info in the RREP, and is randomly generated by the destination terminal T when the RREP is transmitted.

  In the Hop Info for the transmitting terminal S, as shown in an example in FIG. 14, together with an encryption key used at the time of data communication (for example, an AES encryption key if AES encryption is used), all relay terminals (the RREQ Own address IPx, own hop order ID, and second shared key KCx are added as relay address information. The destination terminal T generates an encryption key (AES) for data communication. The flag is for transmitting various types of information to the transmitting terminal S, and here includes information for transmitting whether each relay terminal is within or outside the service area.

  When terminal C receives the flooded RREP from the destination terminal T in step S15 in FIG. 3, the process proceeds to step S31 in FIG. 4, and the transfer list is searched using the session ID registered in this RREP as a search key. Is done. In step S32, the second shared key KCx associated with the session ID is extracted.

  If the session ID is “0” when the RREQ is received first, the session ID candidate is registered in the transfer list. Searches again with the session ID candidates registered in RREP. When the search by the session ID or the session ID candidate is successful, the value of the session ID of RREQ is written in the transfer list, and the value of the session ID candidate is updated to “0”. If both searches fail, the RREP is discarded.

  In step S33, all Hop Info registered in RREP is decrypted using the extracted second shared key KCx. In step S34, it is determined whether or not the decrypted valid data is included in all the decrypted data. If valid data cannot be obtained, there is a possibility that some kind of fraud including tampering has been performed, so the process proceeds to step S41, and the current RREP is discarded.

  If there is Hop Info from which valid data is obtained, the process proceeds to step S35, and it is determined whether or not the RREP destination is itself. If it is the terminal C, it is determined that the destination is other than itself, so the process proceeds to step S36, and the contents are written in the transfer list. However, the lifetime for this registration is shorter than that for official registration.

  In step S37, it is determined whether or not it is within the range, and if it is within the range, the process proceeds to step S38 and the range flag F1 is set. In step S39, all data other than the own hop order ID is deleted or rewritten to dummy data from its own Hop Info (FIG. 13) from which the valid data is obtained, and then re-used using the session key SK. Encrypted. In step S40, the RREP including the re-encrypted Hop Info is flooded. At this time, a dummy address is registered as the source address of the IP header, and a broadcast address is registered as the destination address.

  The above procedure is executed at each relay terminal, and if no fraud is detected at all the relay terminals, the RREP reaches the transmitting terminal S. When the transmitting terminal S receives the RREP, it is determined whether or not the destination of the RREP is itself.

  If it is determined in step S35 that it is the destination, the process proceeds to step S42, and the session key SK is extracted. In step S43, all Hop Info is decrypted using the session key SK. In step S44, the own hop order ID of each mobile terminal registered in each Hop Info is extracted. In step S45, all the relay address information (local hop order ID) registered in the RREP is extracted. In step S46, the local hop order ID of each mobile terminal is compared with all the relay address information. If the two match completely, the anonymous addresses FWs, FWt, session ID, etc. are registered in the transfer list in step S47. In step S48, it is registered in the route information table. In step S49, a route establishment completion notification (RCMP) is transmitted to the destination terminal T.

  In the RCMP, the FWt and FWs are set in the destination address and the source address, and transmitted to the destination terminal T using the data encryption key AES notified in the RREP. When the destination terminal T receives the RCMP, the pending RREQ is discarded and the route table is determined. Accordingly, the destination terminal T can transmit data from that point.

  In the above-described embodiment, it has been described that the FWREQ is transmitted to the routing control server RM when the mobile terminal that has received the RREQ is within range, but if the transmission terminal S is within range, the transmission terminal S also Similarly, FWREQ is transmitted.

It is a figure of the ad hoc network to which the route establishment method of the present invention is applied. It is the figure which showed the list | wrist of the encryption key managed by a route control server and each mobile terminal. It is the flowchart (the 1) which showed the route establishment procedure performed with each mobile terminal at the time of route establishment. It is the flowchart (the 2) which showed the route establishment procedure performed with each mobile terminal at the time of route establishment. 6 is a flowchart showing a route establishment procedure performed by the route control server RM when a route is established. It is a sequence diagram at the time of route establishment. It is the figure which showed an example of the format of a signaling message. It is the figure which showed the basic format of RREQ. It is the figure which showed an example of the basic format of FWREQ. It is the figure which showed an example of the basic format of FWREP. It is the figure which expressed the multiple encryption structure of Hop Info typically. FIG. 3 is a diagram showing an example of RREQ flooded from mobile terminal A in FIG. 1. It is the figure which showed an example of the format of RREP. FIG. 4 is a diagram illustrating a structure of Hop Info for a transmission terminal S.

Explanation of symbols

S, A, B, C, T ... Mobile terminal
RM: Routing server
AP: Wireless access point

Claims (13)

Including a plurality of mobile terminals (S, T, X) and a route control server, the other mobile terminal X relays the route request message (RREQ) transmitted from the transmission terminal S to the destination terminal T, and the destination terminal T In the route establishment method of the multihop communication system in which the other mobile terminal X relays the route response message (RREP) transmitted in response to RREQ to the transmission terminal S to establish the route,
A procedure in which the transmission terminal S stores the session ID and the unique key KCs in association with each other,
The sending terminal S further floods the encrypted source address IPs and destination address IPt, the session ID, and the registered RREQ of the encrypted unique key KCs;
A procedure for determining whether or not the mobile terminal X that has received the RREQ can communicate with the routing server;
A procedure for transmitting an anonymous address assignment request message (FWREQ) including the encrypted addresses IPs and IPt to the route control server by the mobile terminal X capable of communicating with the route control server;
The routing server decrypts the encrypted addresses IPs, IPt, and re-encrypts it with an encryption key that cannot be decrypted except by the destination terminal T;
The routing server further returns an anonymous address assignment response message (FWREP) including the re-encrypted address IPs, IPt and anonymous address FWs, FWt to the mobile terminal X;
A procedure in which the mobile terminal X stores a unique key KCx in association with a session ID registered in the RREQ;
The mobile terminal X further floods the RREQ to which the addresses IPs and IPt are re-encrypted and the encrypted unique key KCx and the anonymous addresses FWs and FWt are added,
The destination terminal T that has received the RREQ flooded from the mobile terminal X decrypts the re-encrypted addresses IPs, IPt and the encrypted unique keys KCs, KCx;
The destination terminal T further encrypts hop information including at least the anonymous addresses FWs and FWt with the unique keys KCs and KCx of each terminal, and generates a plurality of encrypted hop information with different encryption keys. Procedure and
The destination terminal T further floods the RREP including the received RREQ session ID and the plurality of encrypted hop information;
The mobile terminal X that has received the RREP extracts a unique key KCx associated with a session ID registered in the RREP;
When the mobile terminal X can further decrypt any one of a plurality of hop information registered in the RREP with the extracted encryption key KCx, a procedure for registering the hop information in its own table;
The mobile terminal X further floods the RREP in which the decrypted hop information was registered, and
The transmitting terminal S that has received the RREP flooded from the mobile terminal X extracts the unique key KCs associated with the session ID registered in the RREP,
A step of registering the hop information in its own table when the transmitting terminal S can further decrypt any of the plurality of hop information registered in the RREP with the encryption key KCs. A path establishment method for a multi-hop communication system. The other mobile terminal X that has received the RREQ flooded from the mobile terminal X,
A procedure for determining whether or not communication with the route control server is possible;
A procedure for transmitting the FWREQ to the routing server if it can communicate with the routing server;
Receiving FWREP from the routing server;
A procedure for storing the unique key KCx in association with the session ID registered in the RREQ;
The multi-hop communication system according to claim 1, further comprising: a procedure for re-encrypting the addresses IPs and IPt and flooding the encrypted unique key KCx and the RREQ to which the anonymous addresses FWs and FWt are added. Route establishment method.   The route establishment method for a multi-hop communication system according to claim 1 or 2, further comprising a procedure in which the mobile terminal X that cannot communicate with the route control server floods the received RREQ. Including a plurality of mobile terminals (S, T, X) and a route control server, the other mobile terminal X relays the route request message (RREQ) transmitted from the transmission terminal S to the destination terminal T, and the destination terminal T In the route establishment method of the multihop communication system in which the other mobile terminal X relays the route response message (RREP) transmitted in response to RREQ to the transmission terminal S to establish the route,
Each mobile terminal X
A first public key KRMp common to all mobile terminals;
A second secret key Kxs unique to each mobile terminal;
Each mobile terminal possesses a first shared key KRM_x shared with the route server,
The routing server is
A first secret key KRMs paired with the first public key KRMp;
A second public key Kxp paired with each of the second secret keys Kxs;
Possessing a first shared key KRM_x shared with each mobile terminal;
(1) The sending terminal S is
A procedure for generating address information by encrypting its own address IPs and the address IPt of the destination terminal T with the first public key KRMp;
A procedure for generating a second shared key KCs unique to itself;
The procedure to set the candidate value of session ID,
Generating hop information including at least its own address IPs and the second shared key KCs;
Encrypting the hop information with the first public key KRMp;
Broadcasting at least the RREQ in which the address information, the session ID candidate and the encrypted hop information are registered;
(2) The terminal X receiving the RREQ
A procedure for determining whether or not the destination of the RREQ is based on whether or not the address information can be decrypted with the first shared key KRM_x of the address information;
A procedure for determining whether or not a communication range with the routing control server;
A procedure for generating a second shared key KCx unique to itself;
Anonymous address request message (FWREQ) in which at least the address information registered in the RREQ, the session ID candidate, and the encrypted hop information are registered when the destination of the RREQ is other than itself and within the communication range Sending to the routing server;
When the destination of the RREQ is other than itself and out of the communication range, the first public key includes at least the hop information including the address IPx and the second shared key KCx together with the hop information registered in the received RREQ. A procedure for multiple encryption with KRMp or the second public key Ktp;
Broadcasting an RREQ including the session ID candidate and multiple encrypted hop information;
Storing the session ID candidate and the second shared key KCx in association with each other,
(3) The routing server that received the FWREQ
A procedure for determining whether or not it is the first FWREQ for the same RREQ;
If it is the first FWREQ, the address information is decrypted with the first secret key KRMs and re-encrypted with the shared key KRM_t) of the destination terminal T;
A step of decrypting the hop information registered in the first FWREQ with the first secret key KRMs and re-encrypting with the second public key Ktp of the destination terminal T;
A procedure for assigning anonymous addresses FWs and FWt to the decrypted addresses IPs and IPt,
To select an unassigned session ID,
Transmitting an anonymous address response message (FWREP) including the session ID, anonymous addresses FWs, FWt and the second public key Ktp of the destination terminal T to the terminals in the area,
(4) The terminal X receiving the FWREP
A procedure for extracting the session ID, anonymous addresses FWs, FWt and second public key Ktp of the destination terminal T registered in FWREP;
The hop information including its own address IPx, its own second shared key KCx and the anonymous addresses FWs, FWt is multiplexed with the second public key Ktp of the destination terminal T together with the hop information registered in the RREQ. And the steps to
Broadcasting the RREQ including the session ID, the session ID candidate, the second public key Ktp of the destination terminal T and the multiplex information of the multiplex encryption;
Storing the session ID and the second shared key KCx in association with each other,
(5) The destination terminal T that has received the RREQ
A procedure for determining whether or not the destination of the RREQ is based on whether or not the address information registered in the RREQ can be decrypted with the first shared key KRM_t);
A procedure for decrypting the hop information of each terminal whose destination is registered in its own RREQ with its own second secret key Kts,
A procedure for storing the addresses IPs, IPt and anonymous addresses FWs, FWt registered in the hop information in association with each other;
Re-encrypting the hop information of each terminal with the second shared key KCx registered in the hop information,
Broadcasting the RREP including the session ID, the session ID candidate and all the re-encrypted pop information,
(6) The terminal X receiving the RREP
A procedure for extracting a second shared key KCx associated with a session ID or a session ID candidate registered in RREP;
A procedure for determining the presence or absence of hop information that can be decrypted with the second shared key KCx;
The procedure for extracting anonymous addresses FWs, FWt registered in the hop information that could be decoded,
A procedure for registering the anonymous addresses FWs and FWt in the routing table;
Broadcast the received RREP, and
(7) The transmitting terminal S that has received the RREP
A procedure for extracting a second shared key KCs associated with a session ID or a session ID candidate registered in RREP;
A procedure for determining whether or not it is a destination based on the presence or absence of hop information that can be decrypted with the second shared key KCs and the decrypted hop information;
And a procedure for extracting anonymous addresses FWs and FWt registered in the hop information. The transmitting terminal S is
A procedure of generating a message identifier (sig) by performing a one-way operation with a first shared key KRM_s on a predetermined signature range of RREQ including the encrypted address information;
Registering the message identifier (sig) in the RREQ,
The terminal X that has received the RREQ
Registering the message identifier (sig) and signature range registered in the RREQ with the FWREQ,
The routing server that received the FWREQ
Verifying the validity of the FWREQ based on a message identifier (sig);
A procedure for updating the message identifier (sig) by performing a one-way operation with the first shared key KRM_t) of the destination terminal T within the predetermined signature range;
Registering the updated message identifier (sig) with the FWREP;
The terminal X that has received the FWREP
The procedure to extract the message identifier (sig) registered in FWREP,
Registering the extracted message identifier (sig) in the RREQ to be broadcast,
The destination terminal T that has received the RREQ is
5. The route establishment method for a multi-hop communication system according to claim 4, further comprising a procedure for verifying validity of the RREQ based on a message identifier (sig). The destination terminal T that has received the RREQ is
Session key SK), and
A procedure for adding the session key SK) to the hop information of each terminal;
Including the procedure of adding the own addresses of all terminals as a relay address group to the hop information of the transmitting terminal S,
The terminal X that has received the RREP
Re-encrypting the hop information that could be decrypted with its own second shared key KCx with the session key SK) registered in the hop information,
Broadcast RREP with its own hop information updated to the re-encrypted hop information,
The transmitting terminal S that has received the RREP
A procedure for extracting the session key SK) and the relay address group registered in the hop information that can be decrypted with the second shared key KCs of itself;
A procedure for decrypting all hop information with the extracted session key SK);
6. The method for verifying the validity of the RREP based on whether or not the own address of each terminal registered in each hop information matches the relay address group, The route establishment method of the described multihop communication system. The transmitting terminal S is
A procedure for setting an initial value to an order ID representing the own hop order and registering this in the RREQ as a previous stage ID,
The terminal X that has received the RREQ
A procedure for setting a self-stage ID having a value larger than the previous stage ID registered in the RREQ;
A procedure for updating and registering the preceding stage ID and the own stage ID in the hop information,
Updating the previous stage ID value registered in the RREQ to the own stage ID value,
The destination terminal T that has received the RREQ is
6. The path establishment method for a multi-hop communication system according to claim 4, further comprising a procedure for verifying the validity of the hop order based on the previous-stage ID and the own-stage ID registered in each hop information.   The route establishment method for a multi-hop communication system according to any one of claims 4 to 7, wherein a dummy address is registered as a source address of the RREQ and RREP. In a multi-hop network including a plurality of terminals and a route control server, a mobile terminal that transmits a route request (RREQ) to a destination terminal and establishes a multi-hop route based on RREP returned from the destination terminal in response to the request. And having a transmission terminal function, a relay terminal function, and a destination terminal function,
The transmitting terminal function is
Means for storing a first public key KRMp common to all terminals;
Means for storing a second secret key Kxs unique to each terminal;
Means for storing a first shared key KRM_x shared with the route server;
Means for encrypting its own address IPs and the address IPt of the destination terminal T with the first public key KRMp to generate address information;
Means for generating a second shared key KCs unique to itself;
Means for setting session ID candidates;
Means for generating hop information including its own address IPs and the second shared key KCs;
Means for encrypting the hop information with a first public key KRMp;
Means for broadcasting the registered RREQ of the address information, the session ID candidate and the encrypted hop information;
Means for receiving a RREP returned in response to the RREP;
Means for extracting a second shared key KCs associated with a session ID or a session ID candidate registered in the RREP;
Means for determining whether or not it is a destination based on the presence or absence of hop information that can be decrypted with the second shared key KCs and the decrypted hop information;
And a means for extracting anonymous addresses FWs and FWt registered in the hop information. The mobile terminal further comprises:
Means for determining the destination of the RREQ based on whether or not the address information of the received RREQ can be decrypted with its own first shared key KRM_x;
Means for decrypting the hop information of each terminal whose destination is registered in its own RREQ with its own second secret key Kts;
Means for encrypting hop information of each terminal with the second shared key KCx registered in each hop information;
The mobile terminal of the multi-hop communication system according to claim 9, further comprising: means for broadcasting RREP including all the encrypted pop information. The relay terminal function of the mobile terminal is
Means for determining whether or not the destination of the RREQ is based on whether or not the address information registered in the received RREQ can be decrypted with the first shared key KRM_x of the own RREQ;
Means for determining whether or not a communication area with the route control server;
A procedure for generating a second shared key KCx unique to itself;
Anonymous address request message (FWREQ) in which at least the address information registered in the RREQ, the session ID candidate, and the encrypted hop information are registered when the destination of the RREQ is other than itself and within the communication range Means for transmitting to the routing server;
When the destination of the RREQ is other than itself and out of the communication range, the first and first hop information including at least the address IPx and the second shared key KCx together with the hop information registered in the received RREQ. Means for preferentially multiplex encryption with the second public key of the two public keys KRMp or Ktp;
Means for broadcasting an RREQ including the session ID candidate and multiple encrypted hop information;
Means for extracting the session ID, anonymous addresses FWs, FWt and second public key Ktp of the destination terminal T registered in the received FWREP;
The hop information including its own address IPx, its own second shared key KCx and the anonymous addresses FWs and FWt is multiplexed with the second public key Ktp of the destination terminal T together with the hop information registered in the RREQ. Means,
Means for broadcasting the RREQ including the session ID, the session ID candidate, the second public key Ktp of the destination terminal T, and the multiplex information of the hops encrypted,
The mobile terminal of the multihop communication system according to claim 9, further comprising means for storing the session ID or the session ID candidate and the second shared key KCx in association with each other. The destination terminal function unit of the mobile terminal is
Means for determining whether or not the address of the RREQ is itself based on whether or not the address information registered in the received RREQ can be decrypted with the first shared key KRM_t of the own;
Means for decrypting the hop information of each terminal whose destination is registered in its own RREQ with its own second secret key Kts;
Means for storing the addresses IPs, IPt and anonymous addresses FWs, FWt registered in the hop information in association with each other;
Means for re-encrypting the hop information of each terminal with the second shared key KCx registered in each hop information;
The mobile terminal of the multi-hop communication system according to claim 9, further comprising: means for broadcasting an RREP including the session ID, the session ID candidate, and all the re-encrypted pop information. Including a plurality of mobile terminals (S, T, X) and a route control server, the other mobile terminal X relays the route request message (RREQ) transmitted from the transmission terminal S to the destination terminal T, and the destination terminal T The other mobile terminal X relays the route response message (RREP) transmitted in response to the RREQ to the transmitting terminal S to establish a route, the source address IPs and the destination address IPt of the RREQ, and each movement relayed In the routing server of the multi-hop communication system in which the hop information for identifying the terminal X is encrypted ,
A first secret key KRMs paired with a first public key KRMp common to all mobile terminals, a second public key Kxp paired with a second secret key Kxs unique to each mobile terminal, and each mobile terminal Means for storing the first shared key KRM_x to be shared;
Except for the transmitting terminal S, each mobile terminal T, X in the communication area including the destination terminal transmits when receiving the RREQ, and transmits the source address IPs, destination address IPt encrypted with the first public key KRMp, and Means for receiving an anonymous address assignment request message (FWREQ) including hop information;
Means for determining whether the first FWREQ with respect to said received FWREQ is identical RREQ transmitted from the transmitting terminal S,
If the first FWREQ, the encrypted source address IPs and destination addresses IPt decoded by the first secret key KRMs, it means for re-encrypted with the first shared key KRM_t of the destination terminal T,
It decodes the hop information registered in the first FWREQ in the first secret key KRMs, means for re-encrypted with the second public key Ktp of the destination terminal T,
Means for assigning anonymous addresses FWs and FWt to the decrypted addresses IPs and IPt,
Means to select an unassigned session ID;
An anonymous address response message (FWREP) including the re-encrypted source address IPs and destination address IPt, session ID, anonymous addresses FWs and FWt, and the second public key Ktp of the destination terminal T is sent to the FWREQ in the communication area. And a means for transmitting to the mobile terminal that has transmitted the path control server of the multi-hop communication system.

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