JP2004343731A - Encrypted packet processing device, method, program, and program recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the encrypted packet processing device which is capable of realizing a predetermined classification process according to a data type while reducing a burden on a processing device in a communication environment in which encrypted packets of different data type exist. <P>SOLUTION: For the encrypted packet, a block specifying part 13 specifies a location in the packet where information necessary for a priority level determination process in a priority level determination part 161 is stored. A specified block decryption part 14 decrypts only a block specified by the block specifying part 13 and extracts the information necessary for a priority level determination process. The priority level determination part 161 searches in a priority level information DB 162 by using information extracted by the specified block decryption part 14 as a key and determines a priority level of the packet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an encrypted packet processing device, a method, a program, and a program recording medium, and more particularly, to an encrypted packet processing device that determines a type of an encrypted packet and performs a predetermined classification process, and an encryption device. The present invention relates to an encrypted packet processing method, and a computer program and a program recording medium for executing the method.

  In recent years, with the spread of the Internet environment, various data has been easily communicated between a server device and a user terminal device via the Internet. This data is roughly divided into data that does not require real-time processing such as application programs and e-mails (hereinafter referred to as non-real-time data) and data that requires real-time processing such as video and audio (hereinafter referred to as real-time data). ) Exists. In the case where the two types of data are mixed and processed, if the processing of the real-time data is delayed, there is a possibility that video / audio may be stopped or missing. For this reason, it is preferable that the user terminal device and the like classify the input data into real-time data and non-real-time data, and process the real-time data in preference to the non-real-time data. This classification process is generally determined based on specific information indicating the type of data and the like.

  On the other hand, along with the fact that various data has been easily communicated between the server device and the user terminal device, communication including particularly important information and communication of information relating to personal privacy are required. Therefore, security as high as that of a dedicated line is required. For example, there are fields such as electronic commerce and electronic settlement. Various techniques have been proposed as a technique for securing the security (for example, see Patent Documents 1 and 2). One of the typical techniques for securing the security is an IPsec (Internet Protocol Security) technique. Can be

  IPsec is a security protocol that performs encryption and authentication at the network layer (third layer of the OSI reference model), and is standardized by the Internet Engineering Task Force (IETF). For details, refer to the standard specifications RFC2401 to 2412 and 2451. By connecting the user terminal device equipped with the IPsec function to the Internet, or connecting the user terminal device to the Internet via a network connection device (modem, router, etc.) equipped with the IPsec function, a wide area network such as the Internet can be obtained. A virtual private network (VPN) can be constructed on the virtual private network. That is, the user can safely use the Internet without performing special processing such as encryption.

  When performing communication using IPsec, information such as an encryption algorithm, an authentication algorithm, an encryption key, and an authentication key to be used for communication is previously matched between devices equipped with the IPsec function on the transmission side and the reception side. Need to be kept. This information is called a security parameter, and includes an encryption algorithm, an encryption key, an authentication algorithm, an authentication key, an SPI value (Security Parameter Index), a protocol (ESP for encryption and AH for authentication), a mode (transport or tunnel), and the like. Consists of Normally, in order to match the security parameters between the transmitting apparatus and the receiving apparatus, mutual communication between the apparatuses is performed by an application called IKE (Internet Key Exchange). As a result of the mutual communication, the security parameters matched between the transmission side and the reception side are held by a framework called SA (Security Association) and notified to the IPsec processing unit in each device. The IPsec processing unit converts an IP packet to be transmitted into an IPsec packet or restores a received IPsec packet into an IP packet based on an encryption algorithm, an authentication algorithm, an encryption key, an authentication key, and the like defined by SA. I do.

  In IPsec, two modes, a transport mode and a tunnel mode, are prepared. In the transport mode, as shown in FIG. 16, among the IP packets to be encrypted, a protocol header or data corresponding to a layer higher than the IP protocol, that is, a fourth or higher layer such as TCP or UDP is encrypted. In the tunnel mode, as shown in FIG. 17, all the IP packets to be encrypted are encrypted and encapsulated by a new IP packet. Therefore, in the tunnel mode, all original IP packets (including protocol headers and data of the fourth and higher layers) are all encrypted.

  Here, a case is considered in which the above-described classification processing is performed on an IP packet encrypted in one of the modes, that is, an IPsec packet. In this case, the specific information necessary to determine the type of data corresponds to an encrypted protocol header or data. Therefore, in order to determine the data type, a process of once decoding all the IPsec packets is essential. Hereinafter, a conventional apparatus that classifies IPsec packets based on a data type and performs priority processing according to the classification will be described. FIG. 18 is a block diagram showing a configuration example of the conventional processing apparatus 200.

  18, a conventional processing device 200 includes an input processing unit 201, an encryption determination unit 202, a decryption processing unit 203, a SAD 204, a priority determination unit 205, a priority information DB 206, and an output processing unit 207. And The SAD 204 is a database that stores information on security parameters of various SAs. The priority information DB 206 is a database in which a set of specific information and a predetermined priority is stored.

  The input processing unit 201 is, for example, a network interface, and inputs an IP packet from the outside. The encryption determining unit 202 refers to the header information of the IP packet input by the input processing unit 201 and determines whether the IP packet is encrypted, that is, whether the IP packet is an IPsec packet. The decryption processing unit 203 extracts, from the header information, information on the SA of the encryption applied to the packet from the IPsec packet determined by the encryption determination unit 202. Next, the decryption processing unit 203 searches the SAD 204 using the extracted information as a key, and acquires a security parameter corresponding to the extracted information. Then, the decryption processing unit 203 decrypts all ciphers applied to the IPsec packet based on the acquired security parameters. The priority determination unit 205 checks the type of the IPsec packet according to the specific information included in the IPsec packet decrypted by the decryption processing unit 203, searches the priority information DB 206 using the type as a key, and classifies the IPsec packet. That is, the priority is determined. The output processing unit 207 performs a predetermined output process according to the priority determined by the priority determining unit 205. For example, it is conceivable to configure the output processing unit 207 with a plurality of processing queues provided for each priority, and to change the processing queue to be queued according to the determined priority.

By the above processing, even in a communication environment in which a packet including real-time data and a packet including non-real-time data are encrypted and mixed, it is possible to realize priority processing according to the data type. it can.
JP 2002-182560 A JP 2001-344228 A

  Usually, a great deal of processing time is required for encrypting and decrypting a packet. For this reason, the method of decrypting all ciphers applied to a packet as in the above-described conventional apparatus imposes an enormous time burden on the processing apparatus, and when the encrypted packets are continuous. However, there is a problem that a delay in packet processing occurs. Such a processing delay makes the priority processing famous and innocent.

  Therefore, an object of the present invention is to realize a predetermined classification process according to the data type while reducing the load on the processing device in a communication environment in which encrypted packets having different data types are mixed. It is an object of the present invention to provide a packetized packet processing device, method, program and program recording medium.

  The present invention is directed to an encrypted packet processing device that performs a predetermined classification process on a packet in which at least a part of data is encrypted in block units. In order to achieve the above object, an encrypted packet processing device according to the present invention includes a block specifying unit, a specific block decrypting unit, and a classification processing unit.

  The block identifying unit identifies one or a plurality of encrypted blocks in the input packet that include identification information necessary for a predetermined classification process. The specific block decryption unit decrypts the encrypted block specified by the block specification unit. The classification processing unit classifies the input packet based on the specific information included in the block decoded by the specific block decoding unit.

  The block specifying unit may specify a part or all of the encrypted block including the specific information necessary for the predetermined classification process from the information included in the unencrypted block in the input packet. For example, when the input packet is a packet encrypted according to the IPsec protocol, a protocol number included in an IP header can be used as information included in an unencrypted block.

  Alternatively, the block specifying unit first specifies another encrypted block including information for specifying the encrypted block including the specific information necessary for the predetermined classification process, and the other block decrypted by the specific block decrypting unit. A part or all of the encrypted block including the specific information necessary for the predetermined classification processing may be specified from the information included in the block. For example, when the input packet is a packet encrypted according to the IPsec protocol, at least the IP header length, the service type, or the protocol number included in the IP header is used as information for specifying the encrypted block including the specific information. One can be used. If this packet is an ESP transport mode packet, the next header included in the ESP trailer, the source port number included in the fourth layer header, or the fourth At least one of the destination port numbers included in the layer header can be used. If the packet is an ESP tunnel mode packet, the source IP address, the destination IP address, or the service type and the protocol number included in the encapsulated IP header are specified information necessary for the predetermined classification process. , At least one of the source port number included in the fourth layer header or the destination port number included in the fourth layer header can be used.

  Alternatively, if a database that stores information relating to correspondence between encryption applicable to a packet and an encryption block including specific information necessary for a predetermined classification process is provided in advance, the block identification unit includes From the applied encryption and the information stored in the database, it is also possible to specify a part or all of the encrypted block including the specific information necessary for the predetermined classification processing. Here, when the input packet is a packet encrypted according to the IPsec protocol, the database can be a security association database (SAD) that stores security parameters including an encryption key.

As a typical classification processing unit, a priority information database that stores information in which specific information and priorities are associated with each other, and a specific information included in a decoded block and information stored in the priority information database. There is a configuration including a priority determining unit that determines the priority of the input packet based on the priority.
Alternatively, as another classification processing unit, a distribution destination information database storing information in which specific information is associated with a distribution destination, and specific information included in a decrypted block and information stored in the distribution destination information database And a distribution destination determining unit that determines the distribution destination of the input packet based on

  In these configurations, a plurality of queues uniquely corresponding to priorities or distribution destinations, and a distribution processing unit that sequentially extracts packets from the plurality of queues based on a predetermined rule and performs decoding processing, or a distribution unit that transmits packets to the distribution destinations If the processing unit is further provided, the priority determining unit or the distribution destination determining unit can cause the input packet to be queued in a queue corresponding to the determined priority or distribution destination.

  At this time, the priority determining unit or the distribution destination determining unit queues the input packet and the block decoded by the specific block decoding unit in the queue corresponding to the determined priority or the distribution destination, and executes the decoding processing unit or the distribution processing. Preferably, the unit performs a decoding process on a block other than the decoded block of the input packet, or sends the decoded block together with the input packet to the distribution destination.

  The present invention is also directed to an encrypted packet processing method for performing a predetermined classification process on a packet in which at least a part of data is encrypted in block units. In order to achieve the above object, an encrypted packet processing method according to the present invention includes a block specifying step of specifying one or a plurality of encrypted blocks including specific information necessary for a predetermined classification process in an input packet. A specific block decoding step of decoding the encrypted block specified in the block specifying step, and a classification processing step of classifying the input packet based on the specific information included in the block decoded in the specific block decoding step. Have.

  The functional blocks constituting the above-described encrypted packet processing device may be realized as an LSI which is an integrated circuit. The encrypted packet processing method is provided in the form of a program for causing a computer to execute a series of processing procedures. This program may be introduced into a computer in a form recorded on a computer-readable recording medium.

  As described above, according to the present invention, when performing the packet classification process, the position (block) where the specific information necessary for the determination of the classification process is stored is specified from among the encrypted packets. Decode only the position data (block). This makes it possible to minimize the load on the device required for the decoding process, and to increase the effectiveness of the priority process and distribution process performed in the subsequent stage. Further, even when the position of the block including the specific information changes, it can be dealt with by specifying and decrypting another encrypted block indicating the block.

  The encrypted packet processing apparatus and method of the present invention use a security protocol in which information necessary for a predetermined classification process (hereinafter, referred to as specific information) among information included in a packet is encrypted and packet-communicated. Applicable to various systems. In the following embodiments, an encrypted packet processing apparatus and method of the present invention will be described by taking, as an example, a system using a security protocol based on IPsec described in the above-described related art.

(1) Transport Mode of IPsec FIG. 1 is a diagram illustrating an example of a network configuration of an encryption communication system including an encryption packet processing device according to an embodiment of the present invention. In FIG. 1, the encryption communication system includes an encrypted packet processing device 10, a network connection device 20, and a server device 30. The encrypted packet processing device 10 is a characteristic functional part of the present invention. The encrypted packet processing device 10 may be incorporated in a user terminal device such as a personal computer, or may be configured separately from a user terminal device like a relay device. The network connection device 20 is a modem, a router, or the like, and may be configured as a single unit as shown in FIG. 1 or may be configured integrally with the encrypted packet processing device 10. The server device 30 encrypts and transmits a packet including real-time data such as video and audio and a packet including non-real-time data such as e-mail.

  An SA is set in advance between the encrypted packet processing device 10 and the server device 30, and communication is performed by IPsec. In the following description, it is assumed that the IP address of the encrypted packet processing device 10 is “132.182.2.2” and the IP address of the server device 30 is “132.182.1.2”. The SA set between the encrypted packet processing device 10 and the server device 30 is referred to as “SA1”, and the information of the SA1 includes the protocol “ESP”, the mode “transport”, and the encryption algorithm “DES- CBC "and an authentication algorithm" HMAC-MD5 ". Therefore, the packet transmitted from the server device 30 to the encrypted packet processing device 10 via the network connection device 20 is IPsec in which the IP packet is encrypted in the ESP transport mode.

First, before describing the encrypted packet processing device 10 of the present invention, various packet structures and protocol formats will be described.
The configuration of the IPsec packet in the ESP transport mode is as shown in FIG. This IPsec packet is composed of an IP header, an ESP (Encapsulated Security Payload) header, an IV (Initial Vector), a fourth layer header, data, an ESP trailer, and an ICV (authentication data).

  As the IP header, the IP header added to the IP packet before encryption is used as it is. FIG. 2 shows the configuration of the IP header. In this configuration, the fields used in the present invention are a protocol, a source IP address, and a destination IP address. The protocol field stores the number of the protocol located at the beginning of the packet data area following the IP header. In the IP packet before encryption, since a fourth layer header is added following the IP header (see the left diagram in FIG. 16), a number indicating the fourth layer protocol is stored in the protocol field. In an IPsec packet in the ESP transport mode, an ESP header is added after the IP header (see the right diagram in FIG. 16), and thus a number indicating the ESP protocol is stored in the protocol field. Therefore, by confirming the number of the protocol field, it is possible to immediately determine whether the packet is an encrypted IPsec packet or an unencrypted IP packet.

  FIG. 3 is a diagram showing the format of the ESP protocol after the IP header. In FIG. 3, the area of the SPI and the sequence number is the ESP header. IV is an initial vector for block-encrypting data. In the payload data, the fourth layer header and data of the IP packet before encryption are encrypted and stored. The area from padding for adjusting the length of the payload portion to the next header is the ESP trailer. The next header field stores the number of the protocol located at the beginning of the payload data. For example, when the fourth layer protocol before encryption is UDP, a number indicating UDP is stored, and when the fourth layer protocol is TCP, a number indicating TCP is stored. This ESP trailer is encrypted like the payload data. ICV is authentication data for an area from the ESP header to the ESP trailer. In this format, the SPI, IV, part of the payload data and the next header are used in the present invention, and the part of the payload data and the next header correspond to the specific information.

  The format of the packet stored in the payload data portion shown in FIG. 3 will be described. FIG. 4 is a diagram showing a format of a UDP packet. A UDP packet is composed of a UDP header and payload data. The UDP header has a fixed length of 8 bytes. The first 4 bytes store a source port number and a destination port number, and the next 4 bytes store a packet length and a checksum. FIG. 5 is a diagram showing a format of a TCP packet. A TCP packet is composed of a TCP header and payload data. The TCP header has a fixed length of 24 bytes. The first four bytes store the source port number and the destination port number, and the remaining 20 bytes store the data as shown. In this format, the source port number and the destination port number (part of the payload data described above) correspond to the specific information.

Next, the configuration of the encrypted packet processing device 10 of the present invention will be described.
FIG. 6 is a block diagram showing the configuration of the encrypted packet processing device 10 according to one embodiment of the present invention. 6, an encrypted packet processing device 10 includes an input processing unit 11, an encryption determination unit 12, a block identification unit 13, a specific block decryption unit 14, a SAD 15, a classification processing unit 16, an output processing unit 17 are provided. The classification processing unit 16 is a functional part that classifies an input packet according to its type, and this classification can be used for various purposes. In the following embodiment, a case will be described in which the classification processing unit 16 is configured by the priority determination unit 161 and the priority information DB 162, and the classification result is used for priority processing. 6, the input processing unit 11 and the output processing unit 17 are included in the configuration of the encrypted packet processing device 10, but these configurations are not essential. Alternatively, it may be configured in a device connected at a later stage.

The SAD 15 is a database that stores information on security parameters of various SAs. FIG. 7 is a diagram illustrating an example of the SAD 15.
In the SAD 15, security parameters such as an SPI value, a protocol, a mode, an encryption algorithm, an encryption key, an authentication algorithm, and an authentication key are registered for each SA set with the server device. SA1 set between the above-described encrypted packet processing device 10 and the server device 30 is registered in the first record in FIG. 7 with the SPI value being “5000”. The database stored in the SAD 15 can be searched using the SPI value as a key.

The priority information DB 162 is a database that stores a set of specific information and a predetermined priority. FIG. 8 is a diagram illustrating an example of the priority information DB 162.
In the priority information DB 162, a plurality of entries including information of an IP header, information of a fourth layer header, priority, and the like are registered. The information of the IP header includes a source IP address which is the IP address of the server device, and a destination IP address which is the IP address of the self (encrypted packet processing device). The information of the fourth layer header includes a protocol type, a source port number, and a destination port number. The portion indicated by “*” in FIG. 8 indicates that the information is arbitrary. The priority is information used in the order of processing executed by the output processing unit 17 and the like. This priority has the same meaning as the classification number, and the number can be set arbitrarily according to the processing purpose.

Next, the operation of the encrypted packet processing device 10 of the present invention will be described.
In the present embodiment, a case where the server device 30 transmits the following three types of packets A1 to A3 encrypted based on SA1 will be described as an example. The packet A1 is an IPsec packet that is set to the source port number “1000” and the destination port number “2000” and includes a UDP packet storing real-time data. The packet A2 is an IPsec packet that is set to the source port number “1001” and the destination port number “2000” and includes a UDP packet storing non-real-time data. The packet A3 is an IPsec packet that is set to the source port number “1000” and the destination port number “2000” and includes a TCP packet storing non-real-time data. In each of the packets A1 to A3, the SPI value of the ESP header is set to “5000”.

FIG. 9 is a flowchart illustrating a procedure of an encrypted packet processing method performed by the encrypted packet processing device 10 of the present invention.
The input processing unit 11 is, for example, a network interface, and inputs a packet from outside. The encryption determining unit 12 refers to the protocol field of the packet input by the input processing unit 11 (FIG. 2) and determines whether the packet has been encrypted (step S901). Specifically, the encryption determining unit 12 determines whether the ESP protocol number indicating that the packet is an IPsec packet encrypted by IPsec is stored in the protocol field, or the IP packet is an unencrypted IP packet. It is determined whether the number of the indicated fourth layer protocol is stored. If the ESP protocol number is stored, the encryption determining unit 12 sends the packet (IPsec packet) to the block identifying unit 13, otherwise, the packet (IP packet) to the priority determining unit 161. Output each.

  The block identifying unit 13 extracts the SPI value in the ESP header of the IPsec packet determined by the encryption determining unit 12 (FIG. 3), searches the SAD 15 (FIG. 7) using the SPI value as a key, and converts the SAD 15 (FIG. 7) into an IPsec packet. The security parameter of the used SA is acquired (step S902). For example, when the SPI value is “5000”, the block identifying unit 13 determines from the SAD 15 the security parameter whose SPI value is “5000”, that is, the security parameter of SA1 (the encryption algorithm “DES-CBC”, the encryption key “abcdefgh”). , An authentication algorithm “HMAC-MD5” and an authentication key “QRSTU”). Then, based on the acquired security parameters, the block specifying unit 13 specifies a position where information necessary for the priority determination process in the priority determination unit 161 is stored from the encrypted data (step S903). In this embodiment, the type of the fourth layer protocol, the source port number, and the destination port number are necessary information.

  Here, the encryption algorithm “DES-CBC” is a method of encrypting and decrypting data of 8-byte length as one block in block units (refer to the standard specification RFC2405). As shown in FIG. 10, in the encryption process, the result of the XOR operation between the first blocks P1 and IV of the plaintext is encrypted with the encryption key, thereby generating the encrypted first block b1. Thereafter, the encrypted n-th block bn (n = an integer equal to or greater than 2) is the result of XOR operation of the plaintext n-th block Pn and the encrypted (n-1) -th block b (n-1) Is generated by encrypting with an encryption key. Also, as shown in FIG. 11, in the decryption processing, the result of decrypting the encrypted first block b1 with the encryption key is XORed with IV to reproduce the plaintext first block P1. Thereafter, the n-th block Pn of the plain text is reproduced by performing XOR operation on the result of decrypting the encrypted n-th block bn with the encryption key using the encrypted (n-1) -th block b (n-1). Is done. As described above, the encryption algorithm “DES-CBC” can easily decrypt data in units of one block. In the case of the encryption algorithm “3DES-CBC”, the other units are the same except that one block unit is replaced with 16-byte data. Therefore, the position where the information necessary for the priority determination processing is stored may be specified in units of this block. The specification of this block will be described later.

  The specific block decoding unit 14 decodes the block specified by the block specifying unit 13 and extracts information necessary for the priority determining process in the priority determining unit 161 from the decoded data (Step S904). If necessary information is not extracted by one block specification and block decoding, for example, when the block to be decoded next is indicated by the decoding result of the specified block, steps S903 and S904 are performed as many times as necessary. This is repeatedly performed (step S905).

The block specification performed by the block specification unit 13 and the block decoding performed by the specific block decoding unit 14 in order to extract information necessary for the priority determination processing will be described in detail.
First, based on the block unit of the encryption algorithm, the encrypted data area is divided into a plurality of blocks b1, b2,. Note that the variable m varies depending on the size of the encrypted data area, and the block bm indicates the last block to be encrypted. As described with reference to FIG. 3, the type of the fourth layer protocol is stored in the next header field, which is the last byte of the ESP trailer, according to the IPsec specification (refer to the standard specification RFC2406). It can be seen that it is included in the block bm. Therefore, the block bm is specified and decoded, and first, the type of the fourth layer protocol is extracted.

  When the type of the extracted fourth-layer protocol is TCP or UDP, the source port number and the destination port number are set to the first header of each header according to the TCP and UDP specifications (standard specifications RFC793 and RFC768). It can be seen that it is stored in two bytes and the following two bytes (see FIGS. 4 and 5). Also, the fourth layer header is located immediately after the IV according to the IPsec specification (see FIG. 16). This indicates that the source port number and the destination port number are included in the first block b1. Therefore, the block b1 is specified and decoded, and the source port number and the destination port number are extracted from the first two bytes and the following two bytes.

  As described above, only the blocks b1 and bm are specified from many blocks by the block specifying unit 13, and only the specified blocks are decoded by the specific block decoding unit 14, thereby determining the priority. The type of the fourth layer protocol, the source port number, and the destination port number required for the process can be extracted. These pieces of information are output to the priority determining unit 161 together with the original IPsec packet that has not been decrypted.

  The priority determining unit 161 inputs the type of the fourth layer protocol, the source port number, the destination port number, and the IPsec packet from the specific block decoding unit 14, and reads the source IP address and the destination from the IP header portion of the IPsec packet. Extract the IP address. Then, the priority determination unit 161 searches the priority information DB 162 using the source IP address, the destination IP address, the type of the fourth layer protocol, the source port number and the destination port number as keys, and determines the priority of the packet. It is determined (step S906). When an unencrypted IP packet is input from the encryption determining unit 12, the priority determining unit 161 extracts all the above information from the IP header and the fourth layer header of the IP packet, and outputs the information as an extraction result. The priority of the packet is determined based on the priority. For example, the source IP address “132.182.1.2”, the destination IP address “132.182.2.2”, the protocol type “UDP”, the source port number “1000”, and the destination port number “2000” The priority of packet A1 is “1” according to FIG. The priority of the packets A2 and A3 is "2" according to FIG. Since the destination IP address is the IP address of the encrypted packet processing device 10 itself, it may be omitted from the priority information DB 162.

  The output processing unit 17 performs a predetermined output process according to the priority determined by the priority determining unit 161. For example, as shown in FIG. 12, the output processing unit 17 includes a queue processing unit 171 including a first queue corresponding to the priority “1” and a second queue corresponding to the priority “2”, and a decoding processing unit. 172. With this configuration, the queue processing unit 171 can queue the packet A1 in the first queue and the packets A2 and A3 in the second queue based on the priority. Then, the decoding processing unit 172 can execute the decoding processing of the packet stored in the first queue with higher priority than the packet stored in the second queue. It should be noted that the information on the security parameters necessary for the decryption of the packet by the decryption processing unit 172 may be obtained from the SAD 15 as shown in FIG. 12 or may be received from the priority determination unit 161 in association with the packet. . In the latter case, for example, it is conceivable that pointer information indicating the SA corresponding to the packet and information indicating the decoded specific block and its block identifier are added to the end of the packet in a predetermined format. Thus, in the decoding processing unit 172, it is possible to eliminate unnecessary decoding processing that is duplicated with the specific block decoding unit 14.

Further, for example, instead of the queue processing unit 171, a table capable of storing a set of priority and packet in order from the top of the area may be used. In this case, the decryption processing unit 172 extracts one of the packets with the highest priority and the highest priority registered in the table and performs the decryption process.
Further, for example, the output processing unit 17 may be configured by a distribution processing unit that distributes a packet to another user terminal device or the like. In this case, the configuration of the priority information DB 162 and the configuration of the priority determining unit 161 correspond to the distribution information DB storing the set of the specific information and the predetermined distribution destination, respectively, and the specific information and the distribution information DB. Instead of the distribution destination determining unit that determines the distribution destination based on the distribution destination.

(2) IPsec Tunnel Mode In the tunnel mode, the processing is basically the same as in the transport mode, but the configuration of the IPsec packet is slightly different. Hereinafter, the different parts will be mainly described.
FIG. 13 is a diagram illustrating a network configuration example of another cryptographic communication system including the encrypted packet processing device according to the embodiment of the present invention. In FIG. 13, the encryption communication system includes an encrypted packet processing device 10, a network connection device 20, an SGW 40, and terminals 50 and 60. The SGW 40 is a security gateway that encrypts and transmits a packet transmitted from the terminal 50 to the terminal 60.

  An SA is set in advance between the encrypted packet processing device 10 and the SGW 40, and communication is performed by IPsec. The information of the SA set between the encrypted packet processing device 10 and the SGW 40 includes the protocol “ESP”, the mode “tunnel”, the encryption algorithm “DES-CBC”, and the authentication algorithm “HMAC-MD5”. I do. The SGW 40 holds an IP address of “192.168.1.1” for the LAN (terminal 50) and an IP address of “132.182.1.2” for the WAN (network connection device 20). Further, the encrypted packet processing device 10 sets the IP address of “192.168.2.1” for the LAN (terminal 60) and the IP address of “132.182.2.2” for the WAN (network connection device 20). Have an IP address.

  The configuration of the IPsec packet in the ESP tunnel mode is as shown in FIG. This IPsec packet includes an IP header, an ESP header, an IV, an IP header, a fourth layer header, data, an ESP trailer, and an ICV. In the case of the tunnel mode, the entire original IP packet is encrypted. Therefore, the source IP address, destination IP address, and TOS stored in the IP header of the original IP packet, and the protocol headers of the fourth and higher layers included in the original IP packet are decoded in order to determine the priority. May be necessary specific information. TOS is information indicating a service type of an IP packet, and can be used as specific information. Therefore, in the tunnel mode in which the entire IP packet is encrypted, it is conceivable to identify and decrypt the block including the TOS.

Since the size of the IP header is variable, the start position of the upper layer protocol of the encapsulated IP packet in the tunnel mode is determined by the size of the IP header. Therefore, a block including the IHL (field indicating the IP header length) of the encapsulated IP header is identified and decoded, and the start position of the upper layer TCP protocol or UDP protocol is identified with reference to the IHL value. As a result, a block including the source port number and the destination port number included in the TCP protocol and the UDP protocol can be specified.
As described above, in order to specify the block position including the specific information, information on the header length and the packet length necessary for specifying the block position including the specific information may be used. Accordingly, it is possible to cope with a case where the position of the specific information changes for each packet.

  FIG. 14 shows an example of the priority information DB 162 for such a packet. As shown in FIG. 14, in the priority information DB 162, IP header information for the inside of the tunnel is added to the registration items shown in FIG. The IP header information for the inside of the tunnel is also composed of a source IP address and a destination IP address, like the IP header information. Note that items other than the above included in the IP header may be included in the IP header information for the inside of the tunnel. All the items shown in FIG. 14 are not essential. Therefore, items that are not required may be deleted from the table of FIG.

  In the case of the tunnel mode, the source IP address is stored in the 13th to 16th bytes and the destination IP address is stored in the 17th to 20th bytes according to the IP specification. Therefore, the block b2 and the block b3 are decoded, and the source IP address and the destination IP address can be obtained from the last four bytes of the block b2 and the first four bytes of the block b3. The type of the fourth layer protocol is stored in the tenth byte of the IP header. Therefore, by decoding the block b2 and referring to the second byte of the block b2, the type of the fourth layer protocol can be obtained. The source port number and the destination port number of the fourth layer are stored in the first eight bytes of the TCP header and the UDP header, as in the transport mode. However, since the IP header length is variable, it is necessary to first determine the IP header length and specify the position where the fourth layer header starts. The IP header length (IHL) is stored in the second byte of the IP header. Therefore, the IP header length can be obtained by decoding the block b1 and referring to the second byte of the block b1. In this example, IHL = 5 (a value indicating 20 bytes) can be obtained, and it can be seen that the source port number and the destination port number are stored in the 21st to 24th bytes from the head of the encrypted data area. . Therefore, the block b3 is decoded, and the source port number and the destination port number are obtained from the last four bytes of the block b3.

  The priority information DB 162 is searched using the IP header information, the IP header information for the inside of the tunnel, and the fourth layer header information obtained by the block specifying process and the block decoding process as keys. As a result, the priority “1” can be obtained for the IPsec packet.

  As described above, when performing the packet classification process, the encrypted packet processing device according to the embodiment of the present invention stores the specific information necessary to determine the classification process from among the encrypted packets. The position (block) is specified, and only the data (block) at that position is decoded. This makes it possible to minimize the load on the device required for the decoding process, and to increase the effectiveness of the priority process and distribution process performed in the subsequent stage.

In this embodiment, the case where header information of the fourth layer protocol is used as the specific information has been described. However, any information can be used as long as the position can be specified based on the protocol header of the fourth layer or higher, header information, or the like. Absent.
Further, the present embodiment has been described on the assumption that the IPsec packet encrypted by the ESP protocol and the non-encrypted IP packet are mixed and input. However, if only an IPsec packet is input, the configuration of the encryption determination unit 12 can be omitted.

  Further, in the present embodiment, when only one encryption algorithm and one encryption key are set in the SAD 15, the block identification unit 13 and the specific block decryption unit 14 do not search the SAD 15 but only hold the SAD 15 in advance. May be configured to perform decryption processing using the encryption algorithm and the encryption key. The encryption key may be a key manually registered by an administrator or the like, or may be a key acquired by a key exchange program such as IKE. In the present embodiment, the case where the encryption algorithm is “DES-CBC” has been described. However, if the encryption algorithm is a block cipher and does not require another decrypted block to decrypt a certain block, DES -An encryption algorithm other than CBC may be used.

  Further, in the present embodiment, the priority is determined based on the protocol type and the source port number, with the destination port number being an arbitrary value as in the priority information DB 162 shown in FIGS. 8 and 14. However, the determination method is not limited to this. With the source port number as an arbitrary value, the priority may be determined based on the protocol type and the destination port number, or the protocol type, the source port number, and the destination port number may be determined without using any values. The priority may be determined based on all of them.

(3) Security Protocols Other Than IPsec In the above embodiments, the case where the method of the present invention is applied to IPsec packets has been described. Next, TLS_ver. Stipulated in the standard specification RFC2246. A case where the method of the present invention is applied to a packet encrypted by No. 1 will be described. In the TLS encryption method, two types, a stream encryption and a block encryption, are defined. Here, the case of the block encryption will be described.

  FIG. 15 shows a packet format transmitted and received using the TLS encryption method. In FIG. 15, an IP header and a TCP header are as shown in FIGS. 2 and 5, respectively. The type is a protocol type in the TLS, and 0x17 (application_data) is set when data handled by the application is transmitted / received. The area below content is an encrypted area. “content” stores a header and data used by the application. MAC is a hash value obtained from content by an algorithm to be used. Padding is a field for adjusting an encrypted area to be an integral multiple of a predetermined block. Padding length indicates the length of padding.

  Therefore, when constructing the priority information DB corresponding to the TLS, the source IP address, the destination IP address, and the fourth layer header information as the IP header information (TLS is always limited to TCP because TLS always uses TCP). At least the source port number and destination port number, the field value of interest in the header used by the application, and the priority. The block including the field of interest is fixedly specified for each application as in the case of IPsec.

Note that the functional blocks such as the block specifying unit 13, the specific block decrypting unit 14, the SAD 15, and the classification processing unit 16 in the encrypted packet processing device of the present invention are typically LSIs (integrated circuits). Accordingly, the device is realized as an IC, a system LSI, a super LSI, an ultra LSI, or the like. These may be individually integrated into one chip, or may be integrated into one chip so as to include a part or all of them.
Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, an FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure connection and setting of circuit cells inside the LSI may be used.
Further, if a technology for forming an integrated circuit that replaces the LSI appears due to the progress of the semiconductor technology or another derived technology, the functional blocks may be naturally integrated using the technology. Adaptation of biotechnology is possible.

  Further, the encrypted packet processing method of the present invention is realized by the CPU interpreting and executing predetermined program data stored in a storage device (ROM, RAM, hard disk, etc.) capable of executing the above-described processing procedure. You may. In this case, the program data may be introduced into the storage device via a recording medium such as a CD-ROM or a flexible disk, or may be executed directly from the recording medium.

  INDUSTRIAL APPLICABILITY The encrypted packet processing device and method of the present invention can be used in a communication environment or the like in which encrypted packets having different data types coexist, and in particular, according to the data type while reducing the load on the processing device This is suitable for implementing a predetermined classification process.

FIG. 1 is a diagram illustrating a network configuration example of an encryption communication system (transport mode) including an encryption packet processing device according to an embodiment of the present invention. The figure which shows the structure of an IP header Diagram showing ESP protocol format Diagram showing the format of a UDP packet Diagram showing the format of a TCP packet FIG. 1 is a block diagram illustrating a configuration of an encrypted packet processing device according to an embodiment of the present invention. The figure which shows an example of SAD Diagram showing an example of a priority information DB (transport mode) 5 is a flowchart illustrating a procedure of an encrypted packet processing method performed by the encrypted packet processing device according to the embodiment of the present invention. Diagram for explaining packet encryption processing in DES-CBC The figure explaining packet decoding processing in DES-CBC FIG. 6 is a block diagram showing a specific configuration example of the output processing unit in FIG. FIG. 1 is a diagram illustrating a network configuration example of an encryption communication system (tunnel mode) including an encryption packet processing device according to an embodiment of the present invention. Diagram showing an example of a priority information DB (tunnel mode) The figure which shows the packet format transmitted / received using TLS encryption system The figure which shows the structure of the IPsec packet of a transport mode. Diagram showing the configuration of an IPsec packet in tunnel mode FIG. 2 is a block diagram illustrating a configuration example of a conventional processing device that performs priority processing of packets.

Explanation of reference numerals

Reference Signs List 10 encrypted packet processing device 11, 201 input processing unit 12, 202 encryption determination unit 13 block identification unit 14 specific block decryption unit 15, 204 SAD
16 Classification processing unit 17, 207 Output processing unit 20 Network connection device 30 Server device 40 Security gateway (SGW)
50, 60 Terminal 161, 205 Priority determination unit 162, 206 Priority information DB
171 queue processing unit 172, 203 decryption processing unit

Claims (20)

An encrypted packet processing device that performs a predetermined classification process on a packet in which at least a part of data is encrypted in block units,
A block identification unit that identifies one or a plurality of encrypted blocks including identification information necessary for the predetermined classification process in the input packet;
A specific block decryption unit that decrypts the encrypted block specified by the block specification unit,
A classification processing unit that classifies the input packet based on specific information included in the block decoded by the specific block decoding unit.   The block specifying unit specifies a part or all of an encrypted block including specific information necessary for the predetermined classification process from information included in an unencrypted block in the input packet. The encrypted packet processing device according to claim 1, wherein   The block specifying unit first specifies another encrypted block including information for specifying an encrypted block including the specific information necessary for the predetermined classification process, and the specific block decrypted by the specific block decrypting unit. 2. The encrypted packet processing device according to claim 1, wherein a part or all of an encrypted block including specific information necessary for the predetermined classification processing is specified from information included in another block. A database that stores information on correspondence between encryption applicable to the packet and an encryption block including specific information necessary for the predetermined classification processing,
The block specifying unit specifies, from the encryption applied to the input packet and information stored in the database, a part or all of an encrypted block including specific information necessary for the predetermined classification process. The encrypted packet processing device according to claim 1, wherein: The classification processing unit,
A priority information database that stores information in which the specific information and the priority are associated with each other;
The device according to claim 1, further comprising: a priority determination unit configured to determine a priority of the input packet based on specific information included in the decoded block and information stored in the priority information database. Encrypted packet processing device. The classification processing unit,
A distribution destination information database that stores information in which specific information and distribution destinations are associated with each other;
The distribution destination determining unit according to claim 1, further comprising: a distribution destination determination unit that determines a distribution destination of the input packet based on specific information included in the decoded block and information stored in the distribution destination information database. Encrypted packet processing device. Multiple queues that uniquely correspond to priorities,
A decoding processing unit that sequentially extracts packets from the plurality of queues and performs a decoding process based on a predetermined rule,
The encrypted packet processing device according to claim 5, wherein the priority determining unit queues the input packet in the queue corresponding to the determined priority. Multiple queues uniquely corresponding to distribution destinations,
A distribution processing unit that retrieves packets from the plurality of queues and sends the packets to distribution destinations,
The encrypted packet processing device according to claim 6, wherein the distribution destination determination unit queues the input packet in the queue corresponding to the determined distribution destination. The priority determination unit, in the queue corresponding to the determined priority, queue the input packet and the block decoded by the specific block decoding unit,
The encrypted packet processing device according to claim 7, wherein the decryption processing unit performs decryption processing on blocks other than the decrypted blocks of the input packet. The distribution destination determination unit queues the input packet and the block decoded by the specific block decoding unit in the queue corresponding to the determined distribution destination,
The encrypted packet processing device according to claim 8, wherein the distribution processing unit sends the decrypted block together with the input packet to a distribution destination. The input packet is a packet encrypted according to the IPsec protocol,
3. The encrypted packet processing device according to claim 2, wherein the information included in the unencrypted block is at least a protocol number included in an IP header. The input packet is a packet encrypted according to the IPsec protocol,
4. The encryption according to claim 3, wherein the information for specifying the encrypted block including the specific information is at least one of an IP header length, a service type, and a protocol number included in an IP header. Packet processing device. The input packet is an ESP transport mode packet encrypted according to the IPsec protocol,
The specific information required for the predetermined classification processing is at least one of a next header included in an ESP trailer, a source port number included in a fourth layer header, or a destination port number included in a fourth layer header. The encrypted packet processing device according to claim 3, wherein: The input packet is an ESP tunnel mode packet encrypted according to the IPsec protocol;
4. The method according to claim 3, wherein the specific information required for the predetermined classification processing is at least one of a source IP address, a destination IP address, and a service type included in the encapsulated IP header. Encrypted packet processing device. The input packet is an ESP tunnel mode packet encrypted according to the IPsec protocol;
The specific information required for the predetermined classification processing is at least one of a protocol number included in the encapsulated IP header, a source port number included in the fourth layer header, or a destination port number included in the fourth layer header. 4. The encrypted packet processing device according to claim 3, wherein: The input packet is a packet encrypted according to the IPsec protocol,
The encrypted packet processing device according to claim 4, wherein the database is a security association database (SAD) that stores security parameters including an encryption key. An encrypted packet processing method for performing a predetermined classification process on a packet in which at least a part of data is encrypted in block units,
A block specifying step of specifying one or a plurality of encrypted blocks including specific information necessary for the predetermined classification process in the input packet;
A specific block decryption step of decrypting the encrypted block identified in the block identification step,
A classification processing step of classifying the input packet based on the specific information included in the block decrypted in the specific block decrypting step. A computer-readable program for causing a computer to execute a method of performing a predetermined classification process on a packet in which at least a part of data is encrypted in block units,
A block specifying step of specifying one or a plurality of encrypted blocks including specific information necessary for the predetermined classification process in the input packet;
A specific block decryption step of decrypting the encrypted block identified in the block identification step,
A classification processing step of classifying the input packet based on the specific information included in the block decoded in the specific block decoding step. A method for performing a predetermined classification process on a packet in which at least a part of data is encrypted in block units, a recording medium recording a computer-readable program for causing a computer to execute,
A block specifying step of specifying one or a plurality of encrypted blocks including specific information necessary for the predetermined classification process in the input packet;
A specific block decryption step of decrypting the encrypted block identified in the block identification step,
And a classification processing step of classifying the input packet based on the specific information included in the block decoded in the specific block decoding step. An integrated circuit of an encrypted packet processing device that performs a predetermined classification process on a packet in which at least a part of data is encrypted in block units,
A block identification unit that identifies one or a plurality of encrypted blocks including identification information necessary for the predetermined classification process in the input packet;
A specific block decryption unit that decrypts the encrypted block specified by the block specification unit,
An integrated circuit, comprising: a classification processing unit configured to classify the input packet based on specific information included in a block decoded by the specific block decoding unit.

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