JP2012010254A - Communication device, communication method and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease an encryption processing amount in an encryption communication and ensure a preferable security.SOLUTION: A communication device 100 comprises: encryption means 116 encrypting a predetermined region determined according to a kind of data in packets in order to communicate with a counter device 200 via a network; transmission means 118 transmitting the packets to the counter device; and notification means 115 and 118 notifying the counter device of positional information of the predetermined region in the packets to be encrypted.

Description

  The present invention relates to a communication apparatus, a communication method, and a communication system that perform encrypted communication.

  As mobile communication systems, next-generation standards such as LTE (Long Tern Evolution), SAE (System Architecture Evolution), and ECN (Evolved Core Network) are currently known. In many of the next generation standards, it is considered that an IP network is used as a connection line between network devices. In a communication system using an IP network, it is required not only to communicate data with a relatively small amount of data as in the past, but also to communicate large volumes of data with a small delay, such as voice and moving images. There is a case. On the other hand, safety of communication data is also required at the same time. For example, in an IP network communication system, application of a technique called IPsec (IP security Protocol) that enables automatic communication encryption independently of an application on the communication system is being studied.

International Publication No. 2006/35501 Pamphlet JP-T-2007-513539

  However, when data encryption and transmission / reception are performed sequentially, the amount of processing in the network device increases, and processing may be delayed during data communication. Such processing delay may lead to a decrease in transmission efficiency in the IP network, and it is conceivable that the decrease in efficiency becomes remarkable particularly when large-capacity data such as music and moving images is communicated.

  The above-described prior art documents disclose a partial encryption unit for data transmitted and received in a secret communication system that conceals communication between a base station and a mobile device for a radio network control device in a CDMA system. However, according to such a method, in payload communication to which IPsec is applied, all packets are encrypted in the same manner as in the past, and thus the above-described processing delay problem cannot be completely solved.

  The present invention has been made in view of the above-described problems, and in a communication system using an IP network, it is possible to improve transmission efficiency by reducing processing delay without reducing the security of encrypted communication. An object is to provide a communication device, a communication method, and a communication system.

  In order to solve the above-described problem, a first communication device disclosed is a communication device that performs packet communication with an opposite device via a network, and includes an encryption unit, a transmission unit, and a notification unit. Prepare. The encryption unit partially performs encryption processing on a predetermined area in the packet transmitted from the transmission unit. The predetermined area is determined according to, for example, the type of data included in the packet. The transmission means transmits the partially encrypted packet to the opposite device. The notifying means notifies the opposite device of position information indicating an encrypted portion (that is, a predetermined area) in the packet.

  A first communication system is a communication system that transmits and receives packets via a network, and is provided with the above-described communication device and a decoding unit that decodes a received packet according to notified position information. Device.

  The first communication method includes an encryption step, a transmission step, and a notification step. In the encryption process, an operation similar to the operation performed by the encryption means described above is performed. In the transmission step, an operation similar to the operation performed by the transmission means described above is performed. In the notification step, an operation similar to the operation performed by the notification means described above is performed.

  In order to solve the above-described problem, a second communication device disclosed is a communication device that performs communication with a counter device via a network, and includes a construction unit, a division unit, a first encryption unit, , Second encryption means, and transmission means. The constructing means constructs a plurality of encrypted tunnels including a first encrypted tunnel and a second encrypted tunnel using different encryption algorithms with the opposite device. The dividing unit divides a packet to be transmitted to the opposite device into a plurality of fragments according to, for example, the type of data for each internal data field. The first encryption means encrypts some of the plurality of fragments using an encryption algorithm corresponding to the first encryption tunnel. The second encryption means encrypts fragments other than some of the fragments using an encryption algorithm corresponding to the second encryption tunnel. The transmission means transmits a part of the fragment, a part of the fragment via the first encryption tunnel, and transmits a fragment other than the part of the fragment via the second encryption tunnel.

  The second communication system is a communication system that transmits and receives packets via a network, and includes the communication device described above and a counter device. The opposite apparatus uses the first decryption means for decrypting the partial fragment using the encryption algorithm corresponding to the first encryption tunnel and the encryption algorithm corresponding to the second encryption tunnel. And a counter device including second decoding means for decoding.

  The second communication method includes a construction step, a division step, a first encryption step, a second encryption step, and a transmission step. In the construction process, an operation similar to the operation performed by the construction means described above is performed. In the dividing step, an operation similar to the operation performed by the dividing means described above is performed. In the first encryption step, an operation similar to the operation performed by the first encryption means described above is performed. In the second encryption step, an operation similar to the operation performed by the second encryption means described above is performed. In the transmission step, an operation similar to the operation performed by the transmission means described above is performed.

  According to the above-described configuration, partial encryption is performed on a predetermined area, which is a partial area in the packet, for each packet transmitted from the communication apparatus to the opposite apparatus. On the other hand, encryption is not performed for areas other than the predetermined area.

  Alternatively, for each packet transmitted from the communication device to the opposite device, a part of the fragment obtained by dividing the packet is encrypted using an encryption algorithm different from that for other fragments. For other fragment portions, it is preferable to apply an encryption algorithm having a relatively low encryption strength and a small amount of encryption processing. For this reason, the amount of data to be encrypted is reduced and the amount of processing for encryption processing is reduced compared to the case where all packets are transmitted after being encrypted or the same encryption algorithm is applied to all packets. Can be realized.

It is an image figure of communication via SA (Security Association) in IPsec communication. It is a figure which shows the structural example of the communication system in IPsec communication. It is a figure which shows the hardware constitutions of a communication apparatus. It is a block diagram which shows the structure of the function part in the network processor of a communication apparatus. It is a figure which shows the example of the encryption of the packet in IPsec communication. It is a sequence diagram which shows the flow of a process of 1st Embodiment of an encryption communication process. It is a sequence diagram which shows the flow of a process of 2nd Embodiment of an encryption communication process. It is a sequence diagram which shows the flow of a process of 3rd Embodiment of an encryption communication process. It is a block diagram which shows the aspect of the IPsec communication between the communication apparatus and opposing apparatus in a modification. It is a block diagram which shows the structure of the function part which performs SPD search and SA search. It is a sequence diagram which shows the flow of the encryption communication process of a modification. It is a flowchart which shows the flow of the encryption communication process of a modification. It is a figure which shows the flow of the packet transmission in a modification.

(1) About IPsec Communication With reference to FIG. 1, SA (Security Association) using an encryption key in IPsec communication will be described. FIG. 1 is a schematic diagram illustrating a state where encrypted communication is performed in a state where an SA, which is an IP tunnel using IPsec, is provided between the communication device NodeA and the communication device NodeB.

  As shown in FIG. 1, the packet transmitted from the communication device NodeA is transmitted to the communication device NodeB via the SA provided between the communication device NodeA and the communication device NodeB. The encryption key for using the SA is appropriately updated by the rekey process, and new SAs corresponding to the updated encryption key are sequentially used. The communication device NodeA and the communication device NodeB are, for example, an eNB 100 and a security gateway (security GW) GW 200 described later.

  As shown in FIG. 1, the communication device NodeA and the communication device NodeB provided with the SA include an SPI (Security Parameter Index), a sequence number (Sequence Number), and the like in the payload data. The SPI is an identification number for identifying the SA, and is information that makes it possible to identify the old and new SA before and after the encryption key is updated. The sequence number is an identification number for identifying a data packet transmitted using SA.

  The IPsec communication technique as shown in FIG. 1 is used in a wireless network system such as LTE (Long Term Evolution), for example.

  FIG. 2 is a block diagram illustrating a configuration of the communication system 1 including the disclosed communication device and the opposite device. As shown in FIG. 2, the communication system 1 includes an eNB 100 (eNodeB: evolved NodeB), a router, a security GW 200, and a serving gateway (serving GW) 300, which are base stations for wireless communication. The radio base station eNB100 transmits and receives user packets to and from a mobile terminal (UE: User Equipment) via an antenna.

  In the LTE wireless network, for example, a public IP network or the like may be used between the eNB 100 and a counterpart device such as a serving GW or an MME (Mobility Managing Entity). For this reason, in order to establish safe communication, it is preferable to use IPsec communication. In the example of FIG. 2, an IPsec SA is provided between the eNB 100 and the security GW 200 or between the eNBs 100 (see dotted lines). In the example of FIG. 2, IPsec encrypts a packet signal between the eNB 100 and the security GW 200 indicated by the dotted line part or between the two eNBs 100.

(2) Configuration Example With reference to FIG. 3, a communication device according to the disclosure and a modified example of encrypted communication performed by the communication device will be described. FIG. 3 illustrates a hardware configuration of the eNB 100 that is an example of a communication device. The eNB 100 includes an L2 switch 101, a communication interface (PHY) 102 for Ethernet (registered trademark), a receiver 103, a translator 104, a network processor 105, a network processor memory 106, a memory 107, and a memory controller 108. A CPU (Central Processing Unit) 109 and a PCI interface 110.

  Of the above-described configuration, the L2 switch 101 is a bridge for performing data transmission on the Ethernet (registered trademark), and exchanges transmission data and reception data with the PHY 102. The receiver 103 is a device that controls an interface for data reception in the PHY 102, and the translator 104 is a device that controls an interface for data transmission in the PHY 102. The network processor 105 terminates IPsec and various protocols used in communication with the security GW 200 that is an example of the opposite apparatus, and controls data transmission / reception via the receiver 103 and the translator 104. The CPU 109 is a host processor that controls the operation of the entire eNB 100. Data transmitted and received by the network processor 105 is exchanged with an external processing device via the PCI interface 110 under the control of the memory controller 108 and the CPU 109.

  Note that the security GW 200 as an example of the disclosed opposite device may have a configuration similar to that of a known security GW device, for example, in a portion not particularly described, or may be the same configuration as the eNB 100 described above.

  With reference to FIG. 4, a configuration of a functional unit that performs encrypted communication of data using the IPsec protocol in the network processor 105 of the eNB 100 will be described.

  The network processor 105 of the eNB 100 includes functional units described below in order to perform encrypted communication of data. Note that each functional unit described below is divided and shown for convenience regarding the functions of the network processor 105, and is not limited to a mode in which each functional unit actually exists as an independent entity. It may be a function in a section or software. The following configuration may be a configuration common to the transmission side and the reception side of encrypted communication. For example, a network processor included in the security GW 200 may have the same function unit.

  The reception processing unit 111 receives a transmission packet from the receiver 103 via the L2 switch 101 and the PHY 102. Further, the packet is fragmented to a predetermined data length.

  Based on the SPD information and the corresponding SA information, the key exchange processing unit 112 exchanges an encryption key with the security GW 200 using the IKE protocol to establish the SA.

  The SPD search processing unit 113 specifies selector information for determining a packet to be encrypted and an encryption algorithm based on information such as an identification flag and an IP header attached to an input packet (same as a fragmented packet). Search and assign information.

  The SA search processing unit 114 searches for the SA assigned to the packet based on the SPD identifier attached to the input packet, and adds the SA identifier.

  The encrypted position extracting unit 115 determines a part to be encrypted in the packet according to the encrypted position information defined in SA, the data type of the packet, or preset position information, and the encrypted part. Get position information such as offset and data size.

  The encryption processing unit 116 is a functional unit that encrypts a packet to be transmitted by IPsec communication, and encrypts the packet by using an encryption algorithm defined in SA. The encryption processing unit 116 selectively encrypts the portion specified in the position information notified from the encrypted position extraction unit 115.

  The decryption processing unit 117 is a functional unit that decrypts a packet received from the transmission side, and decrypts the received packet using an encryption algorithm defined in SA. The decryption processing unit 117 selectively performs decryption on the part specified in the position information notified from the transmission side or the encrypted position extraction unit 115.

  The transmission processing unit 118 transmits the packet encrypted by the encryption processing unit 116 to the security GW 200 on the receiving side via the SA.

  An example of packet encryption by the encryption processing unit 116 will be described with reference to FIG. The encryption part when encrypting the packet A having the original IP header, UDP header, and payload data will be described. When the packet A is encrypted, the ESP header B and the ESP trailer C are added to the packet A. The ESP trailer C includes data fields such as padding data, padding length, and next header. According to the conventional encryption processing, the entire range including the packet A and the ESP trailer C is designated as the portion D to be encrypted, and encryption is performed. Furthermore, a new IP header E for transmitting the encrypted packet via the SA and authentication data F as an authentication trailer are added.

On the other hand, in the encryption process in the disclosed communication system, when the packet A is encrypted, the part G selected according to the data type is encrypted in the part D to be encrypted. In other words, the part other than the part G selected according to the data type in the part D to be encrypted may not be encrypted.
(3) Encrypted Location Notification Processing First to third embodiments of encrypted location notification processing in IPsec communication performed between the eNB 100 and the security GW 200 will be described below.

  As described above, in the payload data in the packet transmitted from the eNB 100 to the security GW 200, the encrypted part and the non-encrypted part are mixed. However, in order to decrypt and reassemble data in which these encrypted parts and non-encrypted parts are mixed, at least the position of the encrypted part in the original data must be shared between the transmitting side and the receiving side. . For example, the transmission side and the reception side of the encrypted communication can appropriately share the position information of the encrypted part by positioning the encrypted part by negotiation. In addition, sharing of the position information of the encrypted portion can also be realized by the transmission side that has partially encrypted notifying the reception side of the position information of the encrypted portion.

(3-1) 1st Embodiment With reference to FIG. 6, 1st Embodiment of the notification process of the encryption position in IPsec communication performed between eNB100 and security GW200 is described. FIG. 6 is a diagram illustrating an encryption key exchange processing sequence for SA establishment performed between the eNB 100 and the security GW 200, taking IKE (Internet Key Exchange) as an example.

  In the first embodiment, an SA for data communication (Child SA) is established between the eNB 100 and the security GW 200. In order to construct the SA, an IKE_SA, which is an SA that encrypts the negotiation, is established between the eNB 100 and the security GW 200 in order to negotiate key exchange using the IKE protocol.

  Specifically, first, the eNB 100 that is the transmission side of the IPsec communication sends an IKE_SA_INIT request that is a message for exchanging IKE_SA information and a parameter for generating an encryption key to the security GW 200 that is the reception side. Send. This message includes IKE_SA parameters to be established and encryption key generation parameters. Similarly, the security GW 200 that has received the IKE_SA_INIT request transmits to the eNB 100 an IKE_SA_INIT response that is a message including the SA parameters and the encryption key generation parameters.

  Subsequently, the eNB 100 transmits an IKE_AUTH_ request, which is a message for requesting authentication to the security GW 200, including a parameter for establishing the SA. The security GW 200 transmits an IKE_AUTH_response including a parameter for establishing an SA as a response to the authentication.

  At this time, the parameters for establishing the SA include the position information for specifying the encrypted part of the packet together with the parameter for generating the encryption key, and positioning of the encrypted part between the eNB 100 and the security GW 200. Is done. For example, the key exchange processing unit 112 of the eNB 100 illustrated in FIG. 4 specifies position information for specifying an encrypted part such as an area including control data in a packet as a parameter for establishing an SA with respect to the security GW 200. The encrypted part is positioned by adding and communicating. Thus, the key exchange processing unit 112 of the eNB 100 has a function as a notification unit in the first embodiment.

  In addition, as described above with respect to CREATE_CHILD_SA performed when IKE_SA or Child SA is rekeyed, the parameters for establishing the SA include the position information for specifying the encrypted portion of the packet together with the parameters for generating the encryption key. It is. By using such position information, the encrypted part is positioned between the eNB 100 and the security GW 200.

  The eNB 100 establishes an SA with the security GW 200 using parameters for establishing the SA. After establishing the SA, the eNB 100 transmits, to the security GW 200, a packet in which payload data is partially encrypted as shown in FIG. The security GW 200 that has received the packet specifies the position of the encrypted portion in the packet based on the position information determined by positioning, and restores the original data by performing decryption.

  As described above, in the encrypted communication according to the first embodiment, the position of the encrypted part is shared between the eNB 100 and the security GW 200 during the negotiation after the IKE_SA is established. In the position information, for example, the start position of each encrypted portion and the data size from the start position are described on the ISAKMP message, and the encrypted position information is reflected for each SA when the SA is generated. Based on the position information, the eNB 100 and the security GW 200 recognize the start position and data size for performing encryption at the time of packet transmission and decryption at the time of reception, and perform partial encryption and decryption processing. .

  According to the encrypted communication of the first embodiment, the selected portion is selectively encrypted with respect to the packet transmitted / received by the encrypted communication. For this reason, the amount of processing can be reduced as compared with the case where all parts of the packet are encrypted, and the packet throughput can be increased. In particular, in multitasking in which a plurality of packets are communicated simultaneously, the data waiting time can be shortened, and the system processing can be significantly speeded up.

  In the first embodiment, for example, control data is encrypted and user data is communicated while being unencrypted. Control data refers to data that is important in using other data such as a UDP header and a GTPU header, and user data refers to data that can be used by using control data such as compressed data. is there. For this reason, control data that is relatively important for the use of data can be secured appropriately from unauthorized use of data because high security can be secured by authentication and encryption of SA. It becomes possible. On the other hand, since the user data portion is also protected by SA authentication, security can be ensured. In addition, the encryption algorithm normally used in IPsec can be suitably employ | adopted for the encryption algorithm used in each SA.

(3-2) Second Embodiment With reference to FIG. 7, a second embodiment of the encryption position notification process in IPsec communication performed between the eNB 100 and the security GW 200 will be described. FIG. 7 is a diagram illustrating an aspect of encrypted communication performed between the eNB 100 and the security GW 200 and a configuration of an ESP packet transmitted and received in the encrypted communication.

  In the second embodiment, an encrypted portion is included in the payload portion of the ESP packet communicated between the eNB 100 and the security GW 200 via the SA, and location information indicating the encrypted portion is added to the ESP packet. Is done.

  FIG. 7B is a diagram showing the configuration of the ESP packet. As shown in FIG. 7B, the ESP packet includes data fields of SPI (Security Parameters Index), SN (Sequence Number), payload data, padding data, and authentication data (Authentication Data).

  The SPI is a data field that includes information indicating the SA used for communication of the ESP packet. The SN is, for example, a continuous identification number assigned individually to each ESP packet for performing window control and preventing packet replay and the like. The payload data is a variable-length data field including control data and user data. The padding data is an adjustment data field for adjusting the payload data to the data size required by the encryption algorithm. After the padding data, a padding length field indicating the data size of the fixed-size padding data and a next header field indicating the data type included in the payload data are provided. The authentication data includes information called ICV (Integrity Check Value) used for detecting packet tampering.

  As shown in FIG. 7B, the payload data of the ESP packet is partially encrypted in the communication in the second embodiment. For example, the encryption processing unit 116 of the eNB 100 illustrated in FIG. 4 performs encryption of the encrypted part in the payload data extracted by the encryption position extraction unit 115. Further, at this time, for example, the encryption processing unit 116 performs encryption by adding position information indicating the start position and data size of the encrypted portion in the payload data to the padding data of the ESP packet.

  After receiving the ESP packet transmitted from the eNB 100, the security GW 200 detects the encrypted part by reading the position information added to the padding data. As described above, the encryption processing unit 116 of the eNB 100 has a function as a notification unit in the second embodiment.

  As described above, according to the encrypted communication of the second embodiment described above, similarly to the first embodiment, the amount of processing for encryption can be reduced by partial encryption of communication data. It is possible to increase the packet throughput.

  According to the encrypted communication of the second embodiment, since it is possible to specify an encrypted part for each ESP packet, there is an advantage that higher security can be ensured. In the ESP packet of the second embodiment, the configuration may be such that the location information of the encrypted part in the payload data is stored in a portion other than the padding data, and this configuration also has the same effect as the above configuration. Can be obtained. Since padding data is authenticated by SA, it is possible to protect against unauthorized acquisition of encrypted position information.

(3-3) Third Embodiment A third embodiment of encryption position notification processing in IPsec communication performed between the eNB 100 and the security GW 200 will be described with reference to FIG. FIG. 8 is a diagram illustrating an aspect of encrypted communication performed between the eNB 100 and the security GW 200 and a configuration of an ESP packet transmitted and received in the encrypted communication.

  In the third embodiment, before performing encrypted communication via the SA between the eNB 100 and the security GW 200, the position information of the encrypted part in the ESP packet is determined and shared between the two. . At the time of encrypted communication, the transmitting side encrypts and transmits, for example, a specific part of the ESP packet based on the position information, and the receiving side decrypts the data part based on the position information and acquires original data.

  As described above, according to the encrypted communication of the third embodiment described above, as in the first embodiment, the amount of processing for encryption can be reduced by partial encryption of communication data. It is possible to increase the packet throughput.

  In the third embodiment, since the eNB 100 and the security GW 200 that perform encrypted communication store the encrypted part in, for example, a memory, it is not necessary to notify the encrypted part again during the encrypted communication. For this reason, additional processing such as exchanging position information in negotiation after establishment of SA by the IKE protocol for encryption key exchange described in the first embodiment and including position information in the padding data described in the second embodiment For example, the encrypted communication according to the third embodiment can be realized by the same interface as that of the conventional encrypted communication.

  In the example described above, the configuration and processing for data transmission from the eNB 100 to the security GW 200 are described. However, the same configuration and processing may be applied to data transmission from the security GW 200 to the eNB 100. . In addition, as illustrated in FIG. 2, the above-described configuration and processing may be applied also in data transmission / reception between the eNB 100 and another eNB.

(4) Modified Example A modified example of the communication system for performing the encrypted communication process and an example of the operation according to the modified example will be described below.

(4-1) Device Configuration Example Functional units inside each configuration of the network processor 105, the security GW 250, and the serving GW 350 that transmit data by the eNB 150 using the IPsec protocol will be described with reference to FIG. Note that the hardware configuration of the eNB 150 may be the same as the hardware configuration of the eNB 100 described above, and each unit may be described using the same number. The configuration of the security GW 250 may be the same as that of the security GW 200 described above.

  The network processor 105 of the eNB 150 includes each functional unit described below in order to perform encrypted data communication. Note that each functional unit described below is divided and shown for convenience regarding the functions of the network processor 105, and is not limited to a mode in which each functional unit actually exists as an independent entity. It may be a function in a section or software.

  The reception processing unit 151 is an interface in the network processor 105 that receives transmission data from the receiver 103 and inputs the transmission data to the analysis processing unit 152 for each packet.

  The analysis processing unit 152 analyzes each data field included in the packet input from the reception processing unit 151, and uses the data such as a UDP header and a GTPU header for each data field, for example, relatively important. Discriminating between high control data and other relatively less important user data. For each data field in the packet, the analysis processing unit 152 adds an identification flag indicating the type of data based on the determination result and start position information of each data, and inputs the data to the fragment processing unit 153.

  The fragment processing unit 153 divides an input packet into fragments having a predetermined size, adds an IP header to each fragment, and inputs the fragment to the data determination unit 154.

  The data determination unit 154 is, for each piece of input fragment data, each piece of user data having relatively low importance or control data having relatively high importance for using the user data. Judgment is made. The data determination unit 154 adds an identification flag corresponding to the determination result to the fragment and inputs the fragment to the SPD search processing unit 155.

  The SPD search processing unit 155 searches for and assigns selector information for determining a packet to be encrypted and SPD information for specifying an encryption algorithm based on information such as an identification flag and an IP header attached to an input fragment. For example, the SPD search processing unit 155 performs the above-described search by referring to an SPD database or the like stored in the network processor memory 106. Further, the SPD search processing unit 155 notifies the SA search processing unit 156 and the key exchange processing unit 157 of the SPD identifier indicating the SPD information related to the search result.

  The SA search processing unit 156 searches for the SA assigned to each fragment based on the SPD identifier attached to the input fragment, and adds the SA identifier. For example, the SA search processing unit 156 performs the above-described search by referring to an SA database or the like stored in the network processor memory 106. Each SA is designated with a specific encryption algorithm, an encryption key for performing encrypted communication with the security GW 250 using the encryption algorithm, and an SPI parameter.

  Specific configurations of the SPD search processing unit 155 and the SA search processing unit 156 will be described with reference to FIG. FIG. 10A is an image diagram of functional units that perform a search operation in the SPD search processing unit 155 and the SA search processing unit 156. In FIG. 10A, the SPD search processing unit 155 and the SA search processing unit 156 have a joint functional configuration, and an SPD database 162 in which SPD information is stored, an SA database 163 in which SA information is stored, and a selector. 161.

  For example, in the examples shown in FIG. 9 and FIG. 10, SA1, which is a SA that specifies a normal encryption algorithm such as AES or KASUMI, which has a relatively high encryption strength, and a NULL encryption algorithm that has a relatively low encryption strength are specified. SA2 which is SA can be used. For this reason, the SPD database 162 shown in FIG. 10B stores two pieces of SPD information, that is, SPD1 that specifies SA1 and SPD2 that specifies SA2. In the SPD database 162, for each SPD, flags such as encryption algorithm to be used, selector information such as IP, protocol, and port, information such as the IP header parameter of the designated SA, and a data type to which the SA is applied And information such as an SPD identifier is stored. The selector searches the SPD database for appropriate SPD information and attaches it to each fragment.

  The selector searches the SA database 163 for SA information corresponding to the SPD information attached to each fragment. In the SA database 163 shown in FIG. 10C, for each SA, an SA identifier called SPI (Security Policy Index), an encryption algorithm used by the SA, an encryption type, a corresponding SPD identifier, and Information such as position information specifying data or fragments in a packet to which encryption by the SA is applied is stored. When SA1 and SA2 are established, the SA search processing unit 156 sets data position information or fragment information in a packet to which encryption by the SA is applied, in the configuration contents of the SA database 163.

  Returning to FIG. 9, the description will be continued. The fragment is input to the normal encryption processing unit 158 and the NULL encryption processing unit 159 according to the SA assigned by the operations of the SPD search processing unit 155 and the SA search processing unit 156. The normal encryption processing unit 158 and the NULL encryption processing unit 159 encrypt each input fragment using a specified encryption algorithm.

  The key exchange processing unit 157 exchanges an encryption key using the IKE protocol with the security GW 250 based on the SPD information and the corresponding SA information, and establishes the SA. The key exchange processing unit 157 establishes two SAs SA1 and SA2 by exchanging keys with the security GW 250 for encryption keys having different encryption algorithms for a plurality of SAs according to the SPD identifier.

  The normal cryptographic processing unit 158 is one of a plurality of cryptographic processing units provided in the network processor 105 of the eNB 150, and establishes SA using the cryptographic algorithm such as AES or KASUMI having relatively high cryptographic strength with the security GW 250. And perform encrypted communication of data. The NULL encryption processing unit 159 establishes an SA using the NULL encryption algorithm having a relatively low encryption strength with the security GW 250, and performs encrypted communication of data. In the example of FIG. 9, two cipher processing units, a normal cipher processing unit 158 corresponding to SA1 and a NULL cipher processing unit 159 corresponding to SA2, are provided, but more ciphers are used depending on the SA used. A processing unit may be provided.

  The security GW 250 is configured to include each functional unit described below in order to perform encrypted communication of data. Note that each functional unit described below is shown separately for the convenience of the functions of the security GW 250, and is not limited to a mode in which each functional unit actually exists as an independent entity. Alternatively, it may be a function in software.

  The key exchange processing unit 251 exchanges encryption keys with the key exchange processing unit 157 of the eNB 150 using the IKE protocol. The SA search processing unit 252 establishes an SA with an encryption processing unit such as the normal encryption processing unit 158 or the NULL encryption processing unit 159 of the eNB 150 and transmits / receives data by encrypted communication. Among the received data, the SA search processing unit 252 inputs the control data fragment encrypted by the normal encryption processing unit 158 of the eNB 150 to the normal decryption processing unit 253 and encrypts it in the NULL encryption processing unit 159 of the eNB 150. The obtained user data fragment is input to the NULL decoding processing unit 254.

  The normal decryption processing unit 253 receives the input of the encrypted control data fragment, decrypts the fragment, and inputs the decrypted fragment to the SPD search processing unit 255. The NULL decryption processing unit 254 receives an input of the encrypted user data fragment, decrypts the fragment, and inputs the decrypted fragment to the SPD search processing unit 255.

  The SPD search processing unit 255 refers to the header attached to the fragment of the input data, and determines whether each fragment satisfies the rules described in the SPD. After the determination, the SPD search processing unit 255 transmits to the transmission processing unit 256 an appropriate fragment that satisfies the rules described in the SPD.

  The transmission processing unit 256 is an interface for transmitting and receiving data to and from the serving GW 350 or MME, which is an upper node on the core network of the security GW 250. The transmission processing unit 256 transmits a fragment of data that has been transmitted after being transmitted from the eNB 150 to the serving GW 350 or the MME. 9 illustrates an example of a core network having the serving GW 350 as an upper node, and the transmission control unit of the security GW 250 transmits data fragments to the serving GW 350.

  FIG. 9 shows functional units that receive and reassemble data transmitted from the security GW 250 in the serving GW 350.

  The reception processing unit 351 is an interface for transmitting / receiving data to / from the security GW 250, receives a data fragment transmitted from the security GW 250, and inputs the data fragment to the reassembly processing unit 352. The reassembling processing unit 352 restores original data by combining fragments of input data.

  In addition, the serving GW 350 has an interface (not shown) that transmits / receives data to / from an upper protocol on the core network, and transmits the reassembled data to the upper protocol.

(4-2) Operation Example A basic operation example of encrypted communication processing in IPsec communication performed in the communication system 1 will be described with reference to FIGS. FIG. 11 is a diagram showing a sequence in each device in the encrypted communication process, FIG. 12 is a flowchart showing a basic operation flow of the encrypted communication process, and FIG. It is a figure which shows the image of the data transmitted.

  As shown in the sequence diagram of FIG. 11, in the communication system 1, data from the user's mobile terminal is transmitted from the end of the GTPU via the SA formed between the eNB 150 that performs encrypted communication and the security GW 250. transmitted to the eNB 150. Data from the mobile terminal is encrypted by the eNB 150 and transmitted to the security GW 250. The security GW 250 decrypts the received encrypted data and transmits it to the serving GW 350, which is an upper node on the core network. The serving GW 350 reassembles the received data and transmits it to the GTPU end. Hereinafter, a specific processing flow will be described.

  At the start of the encrypted communication process, the eNB 150 and the security GW 250 negotiate the exchange of the SA encryption key, and set the SA based on the encryption key. As a specific example, the eNB 150 transmits to the security GW 250 an encryption key exchange request for setting SA1 using an AES encryption algorithm or the like. In response to the exchange request, if the security GW 250 authenticates after the authentication, the security GW 250 transmits a response to the SA1 encryption key exchange request to the eNB 150 (FIG. 12: Step S101). ). With the above operation, SA1 having relatively high encryption strength is established (FIG. 12: Step S102).

  At the same time as or after the setting of SA1, the eNB 150 transmits, to the security GW 250, an encryption key exchange request for setting the SA2 using the NULL encryption algorithm. If the security GW 250 authenticates the exchange request after the authentication, the security GW 250 transmits a response to the SA2 encryption key exchange request to the eNB 150 (FIG. 12: Step S103). ). With the above operation, SA2 having relatively low encryption strength is established (FIG. 12: Step S104).

  Subsequently, the eNB 150 receives data transmitted from the user's mobile terminal or the like via the GTPU termination, and determines the protocol of the packet of the received data (FIG. 12: step S105). As illustrated in FIG. 13, the IP packet received by the eNB 150 from the GTPU end is configured to include data fields of an IP header, a UDP header, a GTPU header, and GTPU data 1 to 6. The eNB 150 analyzes the data field based on the GTPU protocol format for the GTPU packet in the received data, and identifies the data type such as control data and user data for each data field (FIG. 12: step S106). Through the analysis, the eNB 150 acquires the data type, the offset indicating the start position, and the data size of each data field. On the other hand, the eNB 150 obtains an offset of each data field and an array of data sizes based on an MTU (Maximum Transmission Unit) for a received packet of a protocol other than GTPU (FIG. 12: step S107).

  Specifically, as a result of analyzing each data field of the received IP packet, the eNB 150 determines that the control data is relatively highly important control data, a GTPU header, and GTPU data. A flag indicating control data is added to 1 and 6. On the other hand, a flag indicating user data is added to GTPU data 2 to 5 that are determined to be user data with relatively low importance.

  After analyzing the packet, the eNB 150 performs fragment processing for fragmenting the packet for each data field based on the analysis result (FIG. 12: step S108). For each data field fragmented by fragment processing, as shown in FIG. 13, the eNB 150 adds an IP header with the UDP header, GTPU header, and GTPU data 1 as one fragment and also sets GTPU data 6 as one fragment. An IP header is added as a fragment. Further, an IP header is added with GTPU data 2 to 5 as one fragment.

  Subsequently, the eNB 150 searches the SPD for each fragment using a flag indicating the data type as a key, and assigns an SPD corresponding to the condition (FIG. 12: step S109). The eNB 150 first confirms a flag indicating the data type for one fragment, and if the flag indicates identification data, assigns SPD 1 to the fragment (FIG. 12: step S110). On the other hand, when the flag of the fragment indicates user data, SPD2 is assigned (FIG. 12: step S111).

  Subsequently, the eNB 150 searches the SA corresponding to the assigned SPD for each fragment (FIG. 12: step S112). The eNB 150 first confirms the assigned SPD identifier for one fragment (FIG. 12: step S113), and if the SPD identifier is SPD1, assigns SA1 (FIG. 12: step S114). Since SA1 is an SA that uses the AES encryption algorithm, the eNB 150 performs AES encryption processing on the fragment.

  On the other hand, when the SPD identifier of the fragment is SPD2, SA2 is assigned (FIG. 12: step S115). Since SA2 is an SA that uses a NULL encryption algorithm, the eNB 150 performs a NULL encryption process that substantially does not encrypt the fragment.

  After the encryption process, the eNB 150 transmits the encrypted fragment to the security GW 250 (FIG. 12: step S116). Specifically, the ASE encryption process is performed on the fragment composed of the UDP header, the GTPU header, and the GTPU data 1 and the fragment composed of the GTPU data 6, and is transmitted to the security GW 250 via SA1. Also, a NULL encryption process is performed on the fragment consisting of GTPU data 2 to 5, and the fragment is transmitted to the security GW 250 via SA2.

  The eNB 150 repeatedly performs a series of processes of encryption transmission by SPD search and SA search (FIG. 12: step S109 to step S116) for all fragments generated from the received packet, and for all fragments in the packet After the transmission is completed, data analysis and a series of encryption transmission processes (FIG. 12: Steps S105 to S116) are repeatedly performed on the next packet.

  As shown in FIG. 11, the security GW 250 that has received the data decrypts the encrypted fragment and transmits it to the serving GW 350. The serving GW 350 reassembles the received fragment and restores the original data. The restored data is transmitted by the serving GW 350 to the GTPU end in the upper protocol in the core network, and data communication is performed.

  As described above, according to the configuration and operation of the modified example described above, control data and user data are cut out into separate fragments from packets transmitted from the eNB 150 to the security GW 250, and encrypted communication using different SAs is applied. I can do it. For example, by applying a cryptographic algorithm having a relatively high cryptographic strength to the SA for communicating control data, it is possible to ensure high security for important control data. On the other hand, with respect to SA for user data communication, the processing amount for encryption can be reduced by applying an encryption algorithm having a relatively low encryption strength and a small processing amount for encryption processing. In addition, when applying a NULL encryption algorithm that does not perform substantial encryption in user data encryption, the amount of processing for encryption processing can be greatly reduced. Even in this case, since the user data is protected by the authentication algorithm by the SA, even if the user data is illegally acquired, the data is used without being decrypted or falsified. Can protect your data.

  Further, in order to encrypt the user data portion, the processing load is relatively smaller than that used for encryption of the control data portion, such as DES (Data Encryption Standard) encryption algorithm, instead of the NULL encryption algorithm. Low cryptographic algorithms may be applied. With this configuration, it is possible to improve both the security of the user data portion and reduce the overall encryption processing amount.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. A method, a communication system, and the like are also included in the technical scope of the present invention.

The embodiments described in this specification are summarized in the following supplementary notes.
(Appendix 1)
A communication device that communicates with an opposite device via a network,
Encryption means for encrypting a predetermined area determined according to the type of data in the packet;
Transmitting means for transmitting the packet to the opposite device;
A communication device comprising: notification means for notifying the opposite device of position information of the predetermined area in the packet.
(Appendix 2)
Further comprising construction means for exchanging encryption keys with the opposing device to construct an encrypted tunnel;
2. The communication apparatus according to appendix 1, wherein the notifying unit notifies the opposite apparatus of the position information during the encryption key exchange negotiation process.
(Appendix 3)
The communication apparatus according to appendix 1, wherein the notifying unit includes the position information in the packet and notifies the opposite apparatus.
(Appendix 4)
A communication device that communicates with an opposite device via a network,
Construction means for constructing a first encrypted tunnel and a second encrypted tunnel using different encryption algorithms with the opposite device;
A dividing means for dividing the packet into a plurality of fragments;
First encryption means for encrypting a part of the plurality of fragments using an encryption algorithm corresponding to the first encryption tunnel;
Second encryption means for encrypting fragments other than the partial fragment using an encryption algorithm corresponding to the second encrypted tunnel;
Transmission means for transmitting the partial fragment to the opposing device via the first encrypted tunnel and transmitting fragments other than the partial fragment to the opposing device via the second encrypted tunnel A communication apparatus comprising:
(Appendix 5)
The communication apparatus according to appendix 6, wherein the encryption algorithm corresponding to the second encryption tunnel has lower encryption strength than the encryption algorithm corresponding to the first encryption tunnel.
(Appendix 6)
A communication system comprising a communication device that transmits and receives packets via a network and an opposite device,
The communication device
Encryption means for encrypting a predetermined area determined according to the type of data in the packet;
Transmitting means for transmitting the packet to the opposite device;
Notification means for notifying the opposing device of the position information of the predetermined area in the packet,
The opposing device is
A communication system, comprising: restoration means for decoding the received packet and restoring data based on the position information.
(Appendix 7)
A communication method for communicating with an opposite device via a network,
An encryption step for encrypting a predetermined area determined according to the type of data in the packet;
A transmission step of transmitting the packet to the opposite device;
A notification step of notifying the opposing device of positional information of the predetermined area in the packet.
(Appendix 8)
The encryption means determines the predetermined area to be encrypted before the packet is encrypted,
2. The communication apparatus according to appendix 1, wherein the notifying unit notifies the opposite apparatus by including position information of the predetermined area in the packet.
(Appendix 9)
The communication apparatus according to any one of appendices 1 to 4, wherein the encryption unit encrypts an area including data for managing or controlling data in another area in the packet. .
(Appendix 10)
The communication apparatus according to appendix 4 or 5, wherein an encryption algorithm corresponding to the second encryption tunnel is a NULL encryption algorithm.
(Appendix 11)
The communication apparatus according to any one of appendices 1 to 5, further comprising an authentication unit that adds authentication data for performing communication between the opposite apparatuses to the packet.
(Appendix 12)
A communication system comprising a communication device that transmits and receives packets via a network and an opposite device,
The communication device
Construction means for constructing a plurality of the encrypted tunnels including a first encrypted tunnel and a second encrypted tunnel using different encryption algorithms with the opposite device;
First encryption means for encrypting a part of the plurality of fragments using an encryption algorithm corresponding to the first encrypted tunnel;
Second encryption means for encrypting fragments other than the partial fragment using an encryption algorithm corresponding to the second encrypted tunnel;
The partial fragment is transmitted to the opposite device via the first encrypted tunnel, and the fragment other than the partial fragment is transmitted to the opposite device via the second encrypted tunnel. A transmission means for transmitting, and
The opposing device is
First decryption means for decrypting the received partial fragment using a cryptographic algorithm corresponding to the first encrypted tunnel;
And a second decryption means for decrypting a fragment other than the partial fragment using an encryption algorithm corresponding to the second encrypted tunnel.
(Appendix 13)
A communication method for communicating with an opposite device via a network,
Constructing a plurality of the encrypted tunnels including a first encrypted tunnel and a second encrypted tunnel using different encryption algorithms with the opposite device; and
A first encryption step of encrypting some of the plurality of fragments using an encryption algorithm corresponding to the first encrypted tunnel;
A second encryption step of encrypting fragments other than the partial fragment using an encryption algorithm corresponding to the second encrypted tunnel;
The partial fragment is transmitted to the opposite device via the first encrypted tunnel, and the fragment other than the partial fragment is transmitted to the opposite device via the second encrypted tunnel. A communication method comprising: a transmission step of transmitting.

100, 150 radio base station (eNB),
101 L2 switch,
102 PHY,
103 receiver,
104 translator,
105 network processor,
106 network processor memory,
107 memory,
108 memory controller,
109 CPU,
110 PCI interface,
111 reception processing unit,
112 Key exchange processing unit,
113 SPD search processing unit,
114 SA search processing unit,
115 encrypted position extraction unit,
116 cryptographic processing unit,
117 decryption processing unit,
118 transmission processing unit,
200, 250 Security GW,
300, 350 Serving GW.

Claims (7)

A communication device that communicates with an opposite device via a network,
Encryption means for encrypting a predetermined area determined according to the type of data in the packet;
Transmitting means for transmitting the packet to the opposite device;
A communication device comprising: notification means for notifying the opposite device of position information of the predetermined area in the packet. Further comprising construction means for exchanging encryption keys with the opposing device to construct an encrypted tunnel;
The communication device according to claim 1, wherein the notification unit notifies the opposite device of the position information during negotiation processing for exchanging the encryption key.   The communication device according to claim 1, wherein the notification unit notifies the opposite device of the packet including the position information. A communication device that communicates with an opposite device via a network,
Construction means for constructing a first encrypted tunnel and a second encrypted tunnel using different encryption algorithms with the opposite device;
A dividing means for dividing the packet into a plurality of fragments;
First encryption means for encrypting a part of the plurality of fragments using an encryption algorithm corresponding to the first encryption tunnel;
Second encryption means for encrypting fragments other than the partial fragment using an encryption algorithm corresponding to the second encrypted tunnel;
Transmission means for transmitting the partial fragment to the opposing device via the first encrypted tunnel and transmitting fragments other than the partial fragment to the opposing device via the second encrypted tunnel A communication apparatus comprising:   The communication apparatus according to claim 6, wherein an encryption algorithm corresponding to the second encryption tunnel has lower encryption strength than an encryption algorithm corresponding to the first encryption tunnel. A communication system comprising a communication device that transmits and receives packets via a network and an opposite device,
The communication device
Encryption means for encrypting a predetermined area determined according to the type of data in the packet;
Transmitting means for transmitting the packet to the opposite device;
Notification means for notifying the opposing device of the position information of the predetermined area in the packet,
The opposing device is
A communication system, comprising: restoration means for decoding the received packet and restoring data based on the position information. A communication method for communicating with an opposite device via a network,
An encryption step for encrypting a predetermined area determined according to the type of data in the packet;
A transmission step of transmitting the packet to the opposite device;
A notification step of notifying the opposing device of positional information of the predetermined area in the packet.

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