JP6908914B2 - Data transmitters, data receivers, communication systems, and programs - Google Patents

Description

The present invention relates to a technique for realizing secure communication by distributing and transmitting data over a plurality of routes.

Various threats have been pointed out in communication on the Internet. One such threat is eavesdropping of transferred data. For example, in communication by public wireless LAN, in wireless communication between an access point and a terminal, communication is often executed without encryption. Therefore, there is a risk that important personal information such as a user identifier and a password may be stolen or the communication contents may be intercepted during communication.

In order to deal with such a situation, TLS (Transport Layer Security), which performs end-to-end encryption in communication between a server and a client, is widely used. In many cases, it does not apply to communications such as e-mail and VoIP.

On the other hand, in recent years, terminals equipped with a plurality of communication interfaces, such as smartphones and tablets, have become widespread. Then, in order to effectively use such a terminal, multipath TCP that realizes one TCP communication via a plurality of paths using different interfaces has been used.

In the communication realized through such a plurality of paths, it is not possible to grasp the entire communication only by eavesdropping the communication of one path by distributing the transfer data during communication to the plurality of paths. Research and development of technology to do so is being done. Such a technique aims to improve confidentiality by distributing the data in a plurality of paths instead of encrypting the data. Therefore, such a technique has an advantage that it is not necessary to register a pre-encryption key or prepare a certificate.

The development of such technology is considered to be even more important in the next-generation (5G) mobile communication network that actively uses a plurality of radio access networks.

Research and development of similar technology has been carried out in the past.

For example, Non-Patent Document 1 discloses a method in which one data transfer using TCP is distributed over communication of a plurality of routes so that the entire image of data cannot be grasped. Since the method disclosed in Non-Patent Document 1 does not guarantee the confidentiality of the data itself, if the communication via a certain route is eavesdropped, the data may be deciphered. If the eavesdropped data contains important personal information, etc., there is a risk that the important personal information, etc. will be leaked, and there is a risk of being attacked illegally based on the leaked information.

A technique called the secret sharing method is also being researched. In the secret sharing method, the process is executed as follows.
(1) A certain secret information is divided into n pieces (n is a natural number of 2 or more), and the divided secret information is distributed to n users.
(2) When k secret information is collected out of n divided secret information (when divided secret information is collected from k users out of n users), the original Confidential information is restored.

This secret sharing method is used when the encryption key is divided and held by a plurality of users.

However, the secret sharing method is inefficient because the amount of data to be transferred is n times larger.

M. Nacher, et al., “Evaluation of the Impact of Multipath Data Dispersion for Anonymous TCP Connections,” in Proc. International Conference on Emerging Security Information, Systems and Technologies, pp. 24-29, Oct. 2007.

As described above, in the prior art, it is difficult to ensure security without increasing the amount of data to be transferred in communication using a plurality of paths.

Therefore, in view of the above problems, the present invention has a data transmitting device, a data receiving device, and a communication system capable of ensuring security without increasing the amount of data to be transferred in communication using a plurality of paths. , And the purpose is to realize the program.

In order to solve the above problems, the first invention is a data transmission device having a function of transmitting data to a data reception device using a plurality of communication paths, and includes a scramble key data generation unit and a scramble key data generation unit. It includes a scramble data generation unit and a subflow data generation unit.

The scramble key data generation unit acquires scramble processing key data for scrambling the unit length transmission data, which is the first unit length data of the unit length data obtained by dividing the transmission data into data having a predetermined unit length. do. Then, the scramble key data generation unit (1) in the first process, divides the initial value data derived from the key data, which is the data for identifying the own device, into data having a predetermined unit length. Using the unit length initial value data, which is the data, the key data for scramble processing for scrambling processing is acquired by performing a predetermined logical operation. (2) In the second and subsequent processing, the unit length initial value data , And both the scrambled unit length transmission data, or only the scrambled unit length transmission data, and the scramble processing key data is acquired by performing a predetermined logical operation.

The scramble data generation unit is scrambled unit length data by performing a predetermined logical operation using the scramble processing key data acquired by the scramble key data generation unit and the unit length transmission data. A single scrambled transmission data is generated by acquiring the scrambled unit length transmission data and collecting a plurality of the acquired scrambled unit length transmission data.

The subflow data generation unit generates subflow data for transmission using a plurality of routes from the scrambled transmission data generated by the scramble data generation unit.

In this data transmission device, scrambled transmission data can be acquired by executing the above processing, and the acquired scrambled transmission data can be transmitted using a plurality of routes (for example, TCP subflow). ..

That is, the transmission data scrambled by this data transmission device is distributed by a plurality of routes (for example, TCP subflow) and transmitted from the transmission side to the reception side, so that a part of the transmission data is transmitted in the middle of the communication path. Even if the data is eavesdropped or intercepted, the original data cannot be restored.

Further, the transmission data scrambled by this data transmission device has the same length as the transmission data before scrambling, and does not increase the amount of data to be transferred.

In this way, by using this data transmission device, it is possible to ensure security without increasing the amount of data to be transferred in communication using a plurality of communication paths.

The data transmission device may have a reception function.

The second invention is the first invention, and the predetermined logical operation is an exclusive OR operation.

As a result, in this data transmission device, the scramble processing of the transmission data can be executed by the exclusive OR operation.

The third invention is the first or second invention, and the unit length data is 1 byte data.

Thereby, in this data transmission device, the scramble processing of the transmission data can be executed by the logical operation in 1-byte units (for example, the exclusive OR operation).

The fourth invention is any one of the first to third inventions, and the initial value data is when the key data which is the data for identifying the own device is the key data keyA.
MsgDig = SHA1 (keyA)
IDSN = Lower_8bytes (MsgDig)
SHA1 (x): A function that obtains a message digest by SHA-1 for x.
Lower_8bytes (x): A function to get the lower 8 bytes of x.
Is the IDSN value obtained by.

As a result, in this data transmission device, the IDSN value can be used as the initial value data. Then, since the IDSN value is derived from the key data of the own device, if the key data is transmitted between the transmitting side and the receiving side, for example, at the time of establishing a connection, for scrambling processing and descramble processing. It is not necessary to separately transmit the initial value from the transmitting side to the receiving side.

A fifth invention is any one of the first to fourth inventions, further including an MPTCP connection establishment processing unit that has a function of executing communication using MPTCP and executes an MPTCP connection establishment process.

The MPTCP connection establishment processing unit generates a SYN segment in which a predetermined flag of the MP_CAPABLE option is set to a predetermined value at the time of the MPTCP connection establishment process, and transmits the SYN segment to the data receiving device to provide a scramble function. Notify the data receiving device that the used data transfer will be performed.

As a result, the data transmitting device can notify the data receiving device that the data is transferred using the scramble function at the time of establishing the MPTCP connection. Therefore, it is not necessary to separately communicate from the transmitting side to the receiving side to notify the data transfer using the scramble function, and as a result, the amount of data communication is not increased.

A sixth invention is a data receiving device having a function of receiving data transmitted by a data transmitting device using a plurality of communication paths, and is an MPTCP data acquisition unit, a scramble key data generation unit, and reception data acquisition. It has a part and.

The MPTCP data acquisition unit executes a process of arranging a plurality of subflow data received from the data transmission device in the order of the data sequence number included in the subflow data by a plurality of communication paths, thereby arranging the plurality of subflow data as one. Acquire the received data collected together.

The scramble key data generation unit descrambles the unit length reception scramble data, which is the first unit length data of the unit length data obtained by dividing the reception data acquired by the MPTCP data acquisition unit into data having a predetermined unit length. Acquire key data for scramble processing to do so. Then, the scramble key data generation unit (1) in the first process, uses the initial value data derived from the key data, which is the data for identifying the data transmission device as the communication partner, as the data having a predetermined unit length. Using the unit length initial value data, which is the unit length data divided into, the key data for scrambling processing for descramble processing is acquired by performing a predetermined logical operation, and (2) in the second and subsequent processing. , Unit length initial value data and unit length received data that has been descrambled, or only unit length received data that has been descrambled is used for scramble processing by performing a predetermined logical operation. Get key data.

The reception data acquisition unit is a descrambled unit length data by performing a predetermined logical operation using the scramble processing key data acquired by the scramble key data generation unit and the unit length reception scramble data. By acquiring a certain unit length reception data and collecting a plurality of acquired unit length reception data, one descrambled reception data is acquired.

The data receiving device may have a data transmitting function.

In this data receiving device, by executing the above processing, the scrambled data transmitted from the data transmitting device using a plurality of routes (for example, TCP subflow) is descrambled and the received data is acquired. be able to.

That is, the data received by this data receiving device is the transmission data scrambled by the data transmitting device, and the transmitted data is distributed by a plurality of routes (for example, TCP subflow) from the transmitting side. It is sent to the receiving side. Therefore, the data transmitted from the data transmission device cannot be restored to the original data even if some data is eavesdropped or intercepted in the middle of the communication path.

Therefore, by using this data receiving device together with the data transmitting device, it is possible to ensure security without increasing the amount of data to be transferred in communication using a plurality of communication paths.

The data receiving device may have a transmission function.

The seventh invention is the sixth invention, and the predetermined logical operation is an exclusive OR operation.

As a result, in this data receiving device, the scrambled received data can be descrambled by a logical operation in 1-byte units (for example, an exclusive OR operation).

The eighth invention is the sixth or seventh invention, and the unit length data is 1 byte data.

As a result, in this data receiving device, the scrambled received data can be descrambled by a logical operation in 1-byte units (for example, an exclusive OR operation).

The ninth invention is any one of the sixth to eighth inventions, when the initial value data is the key data key data keyA, which is the data for identifying the data transmission device which is the communication partner.
MsgDig = SHA1 (keyA).
IDSN = Lower_8bytes (MsgDig).
SHA1 (x): A function that obtains a message digest by SHA-1 for x.
Lower_8bytes (x): A function to get the lower 8 bytes of x.
Is the IDSN value obtained by.

As a result, in this data receiving device, the IDSN value can be used as the initial value data. Then, since the IDSN value is derived from the key data of the data transmitting device which is the communication partner, if the key data is transmitted between the transmitting side and the receiving side, for example, when establishing a connection, scrambling processing and decoding are performed. It is not necessary to separately transmit the initial value for scrambling processing from the transmitting side to the receiving side.

The tenth invention is any one of the sixth to ninth inventions, further comprising an MPTCP connection establishment processing unit which has a function of executing communication using MPTCP and executes an MPTCP connection establishment process.

The MPTCP connection establishment processing unit receives the SYN segment in which the predetermined flag of the MP_CAPABLE option is set to a predetermined value by the data transmission device at the time of the MPTCP connection establishment process, so that the data transmission device uses the scramble function. It is determined that it has a function to perform transfer.

As a result, in this data receiving device, information indicating that data transfer using the scramble function is performed during the MPTCP connection establishment process can be obtained from the data transmitting device. Therefore, it is not necessary to separately communicate from the transmitting side to the receiving side to notify the data transfer using the scramble function, and as a result, the amount of data communication is not increased.

The eleventh invention is a communication system including a data transmitting device according to any one of the first to fifth inventions and a data receiving device according to any one of the sixth to tenth inventions.

Thereby, it is possible to realize a communication system including the data transmitting device according to any one of the first to fifth inventions and the data receiving device according to any one of the sixth to tenth inventions.

The twelfth invention is a program for causing a computer to execute a data transmission method used when transmitting data from a data transmission device to a data reception device using a plurality of communication paths.

The data transmission method includes a scramble key data generation step, a scramble data generation step, and a subflow data generation step.

The scramble key data generation step acquires scramble processing key data for scrambling the unit length transmission data, which is the first unit length data of the unit length data obtained by dividing the transmission data into data having a predetermined unit length. do. Then, in the scramble key data generation step, (1) in the first process, the initial value data derived from the key data, which is the data for identifying the data transmission device, is divided into data having a predetermined unit length. Using the unit length initial value data, which is long data, the key data for scramble processing for scrambling processing is acquired by performing a predetermined logical operation. (2) In the second and subsequent processing, the unit length initial value The scramble processing key data is acquired by performing a predetermined logical operation using both the data and the unit length transmission data for which scrambling has been completed, or only the unit length transmission data for which scramble has been completed.

The scramble data generation step is scrambled unit length data by performing a predetermined logical operation using the scramble processing key data acquired by the scramble key data generation step and the unit length transmission data. A single scrambled transmission data is generated by acquiring the scrambled unit length transmission data and collecting a plurality of the acquired scrambled unit length transmission data.

The subflow data generation step generates subflow data for transmission using a plurality of routes from the scrambled transmission data generated by the scrambled data generation step.

This makes it possible to realize a program for causing a computer to execute a data transmission method having the same effect as that of the first invention.

A thirteenth invention is a program for causing a computer to execute a data receiving method used when receiving data transmitted by a plurality of communication paths from a data transmitting device in a data receiving device.

The data receiving method includes an MPTCP data acquisition step, a scramble key data generation step, and a received data acquisition step.

The MPTCP data acquisition step executes a process of arranging a plurality of subflow data received from the data transmission device in the order of the data sequence number included in the subflow data by a plurality of communication paths, thereby arranging the plurality of subflow data as one. Acquire the received data collected together.

The scramble key data generation step descrambles the unit length reception scramble data, which is the first unit length data of the unit length data obtained by dividing the reception data acquired by the MPTCP data acquisition step into data of a predetermined unit length. Acquire key data for scramble processing to do so. Then, in the scramble key data generation step, (1) in the first process, the initial value data derived from the key data, which is the data for identifying the data transmission device, is divided into data having a predetermined unit length. Using the unit length initial value data, which is long data, the key data for scramble processing for descramble processing is acquired by performing a predetermined logical operation. (2) In the second and subsequent processing, the unit length initial value is obtained. Acquire key data for scramble processing by performing a predetermined logical operation using both the value data and the unit length received data for which descrambled completion, or only the unit length received data for which descrambled has been completed. do.

The received data acquisition step is a descrambled unit length data by performing a predetermined logical operation using the scramble processing key data acquired by the scramble key data generation step and the unit length reception scramble data. By acquiring a certain unit length reception data and collecting a plurality of acquired unit length reception data, one descrambled reception data is acquired.

This makes it possible to realize a program for causing a computer to execute a data receiving method having the same effect as that of the sixth invention.

According to the present invention, a data transmitting device, a data receiving device, a communication system, and a program capable of ensuring security without increasing the amount of data to be transferred are realized in communication using a plurality of paths. can do.

The schematic block diagram of the communication system 1000 which concerns on 1st Embodiment. The figure which schematically showed the outline about the processing and the data to be handled by the communication system 1000 which concerns on 1st Embodiment. The schematic block diagram of the 1st data communication module 1 of the communication system 1000 which concerns on 1st Embodiment. The schematic block diagram of the scramble key data generation part 12 and the scramble data generation part 13 of the communication system 1000 which concerns on 1st Embodiment. The schematic block diagram of the 2nd data communication module 2 of the communication system 1000 which concerns on 1st Embodiment. The schematic block diagram of the descramble data acquisition part 24 and the scramble key data generation part 25 of the communication system 1000 which concerns on 1st Embodiment. Sequence diagram of MPTCP connection establishment processing. Sequence diagram of data transfer processing by MPTCP connection. Sequence diagram of MPTCP connection release processing. The figure which shows the data format (data format which displayed the width in a horizontal direction as 32 bits) of the MP_CAPABLE option specified in RFC6824. The figure for demonstrating the scramble data generation process (the first process (sender side)). The figure for demonstrating the scramble data generation processing (second processing (sending side)). The figure for demonstrating the scramble data generation processing (third processing (sending side)). The figure for demonstrating the acquisition process of descramble data (the first process (reception side)). The figure for demonstrating the acquisition process of descramble data (second process (reception side)). The figure for demonstrating the acquisition process of descramble data (third process (reception side)). The figure which shows the CPU bus configuration.

[First Embodiment]
The first embodiment will be described below with reference to the drawings.

<1.1: Communication system configuration>
FIG. 1 is a schematic configuration diagram of the communication system 1000 according to the first embodiment.

FIG. 2 is a diagram schematically showing an outline of processing and data to be handled by the communication system 1000 according to the first embodiment.

FIG. 3 is a schematic configuration diagram of the first data communication module 1 of the communication system 1000 according to the first embodiment.

FIG. 4 is a schematic configuration diagram of a scramble key data generation unit 12 and a scramble data generation unit 13 of the communication system 1000 according to the first embodiment.

FIG. 5 is a schematic configuration diagram of a second data communication module 2 of the communication system 1000 according to the first embodiment.

FIG. 6 is a schematic configuration diagram of a descramble data acquisition unit 24 and a scramble key data generation unit 25 of the communication system 1000 according to the first embodiment.

As shown in FIG. 1, the communication system 1000 includes a first communication device H1 and a second communication device H2. The communication system 1000 may be provided with a plurality of communication devices. Hereinafter, for convenience of explanation, a case where the first communication device H1 has a function for transmitting data and the second communication device H2 has a function for receiving data will be described. However, the present invention is not limited to this, and the communication system 1000 includes a plurality of communication devices, and a part or all of each communication device has both a transmission function and a reception function. May be good. Further, the first communication device H1 may be provided with a data receiving function. Further, the second communication device H2 may have a data transmission function.

Further, the communication system 1000 has a function capable of executing communication by MPTCP (Multipath Transition Control Protocol), and data communication can be performed by a plurality of paths. In the following, for convenience of explanation, a case where communication by MPTCP is performed using two paths will be described.

As shown in FIG. 1, the first communication device H1 includes an application unit H1_ap and a first data communication module 1. As shown in FIG. 2, the first communication device H1 has a function capable of executing communication by MPTCP. The first communication device H1 has a function of scrambling transmission data to acquire scrambled data, and transmitting the acquired scrambled data by a TCP subflow.

The application unit H1_ap processes the application layer. The application unit H1_ap outputs the transmission data Data_tx to the first data communication module 1. The transmission data Data_tx may be stored inside the first communication device H1 (for example, a storage device (not shown)), or may be input from the outside of the first communication device H1. It may be.

As shown in FIG. 3, the first data communication module 1 includes an MPTCP connection establishment processing unit 10, a transmission data acquisition unit 11, a scramble key data generation unit 12, a scramble data generation unit 13, and a TCP subflow data generation. A unit 14, a first communication interface 15, and a second communication interface 16 are provided. In the present embodiment, since there are two communication paths by MPTCP (Multipath Transition Control Protocol), the first data communication module 1 has two communication units (first communication interface 15 and second communication interface 16). have. When the number of communication paths by MPTCP (Multipath Transmission Control Protocol) is N (N: natural number), the first data communication module 1 includes N communication units.

The MPTCP connection establishment processing unit 10 is a functional unit that executes processing for establishing an MPTCP connection with an external communication device (communication device as a communication partner). The MPTCP connection establishment processing unit 10 executes a process for establishing an MPTCP connection with an external communication device (communication device as a communication partner) via the first communication interface 15. The MPTCP connection establishment processing unit 10 also performs processing for releasing the MPTCP connection with an external communication device (communication device as a communication partner). The MPTCP connection establishment processing unit 10 executes a process for releasing the MPTCP connection via the first communication interface 15.

The transmission data acquisition unit 11 inputs the transmission data Data_tx output from the application unit H1_ap. The transmission data acquisition unit 11 acquires data of a predetermined length (for example, 1-byte data) from the transmission data Data_tx, and uses the acquired data as data D_tx [k] for scramble key data generation unit 12 and scramble data generation. Output to unit 13. Further, the transmission data acquisition unit 11 inputs the control signal Ctrl1 from the scramble data generation unit 13. In the following, for convenience of explanation, it is assumed that the above "predetermined length" is the data length corresponding to 1 byte. Then, the data D_tx [k] is byte data of the kth byte (k: integer, 0 ≦ k <N1) when the transmission data Data_tx consists of N1 bytes. In the following, the same notation (notation indicating that it is the k-th byte data) will be used for explanation.

As shown in FIG. 4, the scramble key data generation unit 12 includes a shift buffer control unit 121, a shift buffer 122, and a first XOR calculation unit 123.

The shift buffer control unit 121 inputs the data D_tx [k] output from the transmission data acquisition unit 11 and the control signal Ctrl1 output from the scramble data generation unit 13. Further, the shift buffer control unit 121 inputs an initial value. The shift buffer control unit 121 outputs the initial value or the data D_tx [k] to the shift buffer 122 as the data D_byte. Further, the shift buffer control unit 121 generates a control signal Ctl2 for controlling the shift buffer 122 based on the control signal Ctl1, and outputs the generated control signal Ctl2 to the shift buffer control unit 121.

The shift buffer 122 is a buffer (for example, a FIFO (First In First Out) memory) for shifting the data stored and held in a predetermined unit (for example, byte unit). The shift buffer 122 inputs the data D_byte output from the shift buffer control unit 121 and stores it in a predetermined area of the shift buffer 122. Further, the shift buffer 122 inputs the control signal Ctrl2 output from the shift buffer control unit 121, and shifts the stored data by a predetermined unit (for example, byte unit) based on the control signal Ctrl2. conduct.

The first XOR operation unit 123 reads the data stored in the shift buffer 122 in a predetermined unit (for example, byte unit), performs a logical operation process (for example, XOR operation) on the read data, and performs the logical operation. The processing result is output to the scramble data generation unit 13 as data Dky [k].

As shown in FIG. 4, the scramble data generation unit 13 includes a second XOR calculation unit 131 and a scramble data acquisition unit 132.

The second XOR calculation unit 131 inputs the data Dky [k] output from the scramble key data generation unit 12 and the data D_tx [k] output from the transmission data acquisition unit 11. The second XOR calculation unit 131 performs a logical operation process (for example, an XOR operation) using the data Dky [k] and the data D_tx [k], and scrambles the result of the logical operation process as the data D_txs [k]. Output to the acquisition unit 132.

The scramble data acquisition unit 132 inputs the data D_txs [k] output from the second XOR calculation unit 131. When the scramble data acquisition unit 132 inputs the data D_txs [k] from the second XOR calculation unit 131, the scramble data acquisition unit 132 generates a control signal Ctl1 for operating the shift buffer 122, and outputs the generated control signal Ctl1 to the shift buffer control unit 121. do. Further, the scramble data acquisition unit 132 collects a predetermined number of data D_txs [k] to generate transmission data D_txs having a predetermined data length. For example, when the transmission data D_txs is N1 bytes, after the N1 bytes of data D_txs [k] are prepared, the transmission data D_txs is acquired from the N1 bytes of data D_txs [k], and the acquired transmission data is acquired. Output D_txs to the TCP subflow data generation unit 14.

The TCP subflow data generation unit 14 inputs the transmission data D_txs output from the scramble data generation unit 13. The TCP subflow data generation unit 14 acquires data that can be transmitted by a plurality of TCP subflows from the transmission data D_txs. In the present embodiment, since the number of TCP subflows is "2", the TCP subflow data generation unit 14 acquires the data D_txs_sub1 and D_txs_sub2 that can be transmitted by the two TCP subflows from the transmission data D_txs. Then, the TCP subflow data generation unit 14 outputs the TCP subflow data D_txs_sub1 to the first communication interface 15, and outputs the TCP subflow data D_txs_sub2 to the second communication interface 16.

The first communication interface 15 generates communication data necessary for MPTCP connection establishment processing by a command from the MPTCP connection establishment processing unit 10, and uses the generated communication data as an external communication device (communication device to be a communication partner). Send to. Further, the first communication interface 15 outputs data received from an external communication device (communication device as a communication partner) to the MPTCP connection establishment processing unit 10.

Further, the first communication interface 15 inputs TCP subflow data D_txs_sub1 output from the TCP subflow data generation unit 14, generates transmission data D_sub1 based on TCP subflow data D_txs_sub1, and generates transmission data. D_sub1 is transmitted to the second communication device H2 which is the communication partner.

The second communication interface 16 inputs TCP subflow data D_txs_sub2 output from the TCP subflow data generation unit 14, generates transmission data D_sub2 based on TCP subflow data D_txs_sub2, and generates transmission data D_sub2. It transmits to the second communication device H2 which is the communication partner.

As shown in FIG. 1, the second communication device H2 includes an application unit H2_ap and a second data communication module 2. As shown in FIG. 2, the second communication device H2 has a function capable of executing communication by MPTCP.

The application unit H2_ap processes the application layer. The application unit H2_ap inputs the received data Data_rx output from the second data communication module 2.

As shown in FIG. 5, the second data communication module 2 includes an MPTCP connection establishment processing unit 20, a third communication interface 21, a fourth communication interface 22, an MPTCP data acquisition unit 23, and a descramble data acquisition unit 24. A scramble key data generation unit 25 and a reception data acquisition unit 26 are provided.

In the present embodiment, since there are two communication paths by MPTCP (Multipath Transmission Control Protocol), the second data communication module 2 has two communication units (third communication interface 21 and fourth communication interface 22). have. When the number of communication paths by MPTCP is N (N: natural number), the second data communication module 2 includes N communication units.

The MPTCP connection establishment processing unit 20 is a functional unit that executes processing for establishing an MPTCP connection with an external communication device (communication device as a communication partner). The MPTCP connection establishment processing unit 20 executes a process for establishing an MPTCP connection with an external communication device (communication device as a communication partner) via the third communication interface 21. The MPTCP connection establishment processing unit 20 also performs processing for releasing the MPTCP connection with an external communication device (communication device as a communication partner). The MPTCP connection establishment processing unit 20 executes a process for releasing the MPTCP connection via the third communication interface 21.

The third communication interface 21 generates communication data necessary for MPTCP connection establishment processing according to a command from the MPTCP connection establishment processing unit 20, and uses the generated communication data as an external communication device (communication device to be a communication partner). Send to. Further, the third communication interface 21 outputs the data received from the external communication device (communication device to be the communication partner) to the MPTCP connection establishment processing unit 20.

Further, the third communication interface 21 receives the data D_sub1 transmitted from the first communication device H1 and outputs the received data as the data D_rxs_sub1 to the MPTCP data acquisition unit 23.

The fourth communication interface 22 receives the data D_sub2 transmitted from the first communication device H1 and outputs the received data as the data D_rxs_sub2 to the MPTCP data acquisition unit 23.

The MPTCP data acquisition unit 23 inputs data D_rxs_sub1 output from the third communication interface 21 and data D_rxs_sub2 output from the fourth communication interface 22. The MPTCP data acquisition unit 23 acquires MPTCP data D_rxs from the data D_rxs_sub1 and the data D_rxs_sub2, which are TCP subflow data. Then, the MPTCP data acquisition unit 23 outputs the acquired MPTCP data D_rxs to the descramble data acquisition unit 24.

As shown in FIG. 6, the descramble data acquisition unit 24 includes a byte data extraction unit 241 and a third XOR calculation unit 242.

The byte data extraction unit 241 inputs the data D_rxs output from the MPTCP data acquisition unit 23. The byte data extraction unit 241 extracts data having a data length (for example, 1 byte) of a predetermined unit from the data D_rxs, and outputs the extracted data as data D_rxs [k] to the third XOR calculation unit 242.

The third XOR calculation unit 242 inputs the data D_rxs [k] output from the byte data extraction unit 241 and the data Dky [k] output from the scramble key data generation unit 25. The third XOR operation unit 242 performs a logical operation process (for example, an XOR operation) using the data D_rxs [k] and the data Dky [k], and receives the result of the logical operation process as the data D_rx [k]. Output to the acquisition unit 26.

The scramble key data generation unit 25 has the same configuration as the scramble key data generation unit 12 included in the first data communication module 1.

As shown in FIG. 6, the scramble key data generation unit 25 includes a shift buffer control unit 251, a shift buffer 252, and a first XOR calculation unit 253.

The shift buffer control unit 251 inputs the data D_tx [k] output from the descramble data acquisition unit 24 and the control signal Ctrl3 output from the reception data acquisition unit 26. Further, the shift buffer control unit 251 inputs an initial value. The shift buffer control unit 251 outputs the initial value or the data D_tx [k] to the shift buffer 252 as the data D_byte. Further, the shift buffer control unit 251 generates a control signal Ctrl4 for controlling the shift buffer 252 based on the control signal Ctrl3, and outputs the generated control signal Ctrl4 to the shift buffer control unit 121.

The shift buffer 252 is a buffer (for example, a FIFO memory) for shifting the data stored and held in a predetermined unit (for example, byte unit). The shift buffer 252 inputs the data D_byte output from the shift buffer control unit 251 and stores it in a predetermined area of the shift buffer 252. Further, the shift buffer 252 inputs a control signal Ctrl4 output from the shift buffer control unit 251 and shifts the stored data by a predetermined unit (for example, byte unit) based on the control signal Ctrl4. conduct.

The first XOR operation unit 253 reads the data stored in the shift buffer 252 in a predetermined unit (for example, byte unit), performs a logical operation process (for example, XOR operation) on the read data, and performs the logical operation. The processing result is output to the descramble data acquisition unit 24 as data Dky [k].

The reception data acquisition unit 26 inputs the data D_rx [k] output from the descramble data acquisition unit 24. The reception data acquisition unit 26 collects a predetermined number of data D_rx [k] and acquires data Data_rx having a predetermined data length. Then, the received data acquisition unit 26 outputs the acquired data Data_rx to the application unit H2_ap.

<1.2: Operation of communication system>
The operation of the communication system 1000 configured as described above will be described below.

Hereinafter, a case where MPTCP is used for communication between the first communication device H1 and the second communication device will be described. It is assumed that the first communication device H1 has two IP addresses (address A1 and address A2) and the second communication device has one IP address (address B), and the address A1 and the address. A case where communication is executed by two TCP subflows (two communication paths (communication paths)) between the address B and the address A2 and the address B will be described. Further, it is assumed that the first communication device H1 and the second communication device have a normal TCP / IP communication function and an MPTCP communication function.

FIG. 7 is a sequence diagram of MPTCP connection establishment processing.

FIG. 8 is a sequence diagram of data transfer processing by MPTCP connection.

FIG. 9 is a sequence diagram of MPTCP connection release processing.

(1.2.1: MPTCP connection establishment process)
First, the MPTCP connection establishment process will be described.

In the communication system 1000, a process for establishing an MPTCP connection between the first communication device H1 and the second communication device H2 is executed. The basic procedure of this MPTCP connection establishment process follows RFC6824 (Request for Comments: 6824, "TCP Extensions for Multipath Operation with Multiple Adlesses").

As shown in FIG. 7, the first communication device H1 uses the address A1 and is one of the TCP segments addressed to the address B of the second communication device H2. (TCP segment with (1 bit) set) is generated. Then, the MP_CAPABLE option is included in the TCP option of the SYN segment.

FIG. 10 is a data format of the MP_CAPABLE option defined by RFC 6824 (a data format in which the width in the horizontal direction is displayed as 32 bits).

As shown in FIG. 7, the first communication device H1 has a key of the first communication device H1 (this is referred to as a “host A key” or an “A key”) in the “Sender's Key” area of the MP_CAPABLE option. Is included, and a predetermined flag is set to generate the data of the MP_CAPABLE option, and the generated data of the MP_CAPABLE option is included in the SYN segment. Then, the first communication device H1 transmits the data including the SYN segment generated in this way from the address A1 to the address B of the second communication device H2.

The "key" is 64-bit (8-byte) information. The key is information for authenticating the TCP subflow established in the MPTCP connection, and is transferred only when the connection is established. The "flag" specifies whether to request a checksum, the type of encryption algorithm (currently only the SHA-1 based HMAC method is defined), and so on.

The first communication device H1 notifies the second communication device H2 of the key of the first communication device H1 (the key of the host A) by the SYN segment (step S101).

Then, the second communication device H2 is referred to as a key of the second communication device H2 (this is called a "host B key" or a "B key" by the SYN + ACK segment (TCP segment in which the SYN flag and the ACK flag are set). ) Is notified to the first communication device H1 (step S102).

Finally, due to the 3-way handshake ACK segment (TCP segment with the ACK flag set), the first communication device H1 presses both the host A key and the host B key to the second communication device H2. Notify (step S103).

As for the key, a different value is dynamically generated for each MPTCP connection.

If the second communication device H2 on the receiving side does not recognize the MP_CAPABLE option in step S102, the SYN + ACK segment does not include the corresponding option (information such as the key of the host B). In this case, it is determined that the second communication device H2 cannot communicate by MPTCP, and a normal TCP connection is established between the first communication device H1 and the second communication device H2 to start the communication.

The above-mentioned MPTCP connection establishment process is performed by the MPTCP connection establishment processing unit 10 of the first communication device H1, the first communication interface 15, the MPTCP connection establishment processing unit 20 of the second communication device H2, and the third communication. It is executed by the interface 21.

When an MPTCP connection, that is, a connection of the first TCP subflow is established between the first communication device H1 and the second communication device H2 by the above processing, in the communication system 1000, the first communication device H1 and the first communication device H1 and the first communication device H1 are established. A process for establishing a connection of a second TCP subflow (additional TCP subflow) is executed between the two communication devices H1.

As shown in FIG. 7, at the time of connection establishment processing of the second TCP subflow, the first communication device H1 sets the MP_JOIN option (MP_JOIN option defined by RFC 6824) in the SYN segment. Then, the token of host B, the nonce of host A, the address ID of host A, and the flag are included in the MP_JOIN option. In the following, the "first communication device H1" may be referred to as "host A", and the "second communication device H2" may be referred to as "host B".

The "token" is a value generated from the key exchanged between the transmitting side (first communication device H1) and the receiving side (second communication device H2) when the MPTCP connection is established, and the subflow is to which MPTCP connection. Indicates whether it belongs. The token is obtained by calculating a message digest (20 bytes) by SHA-1 with respect to the key value (8 bytes) of the MP_CAPABLE option and extracting the high-order 32 bits (4 bytes). The nonce is a 32-bit (4 bytes) random number.

The "nonce" is a 32-bit random number.

The "address ID" makes it possible to identify the transmission address even if a NAT exists in the middle and the address is changed.

The "token", "nonce", and "address ID" are defined by RFC 6824.

In step S104, the first communication device H1 transmits data including the SYN segment (SYN segment including the MP_JOIN option) generated as described above from the address A2 to the address B of the second communication device H2. ..

In step S105, the second communication device H2 acquires the token B of the host B (second communication device H2) from the data received from the first communication device H1 in step S104. The second communication device H2 checks whether or not any of the keys issued by itself in the past matches the received token B. Then, if there is a match, the second communication device H2 can select the MPTCP connection established in the past and obtain the key of the first communication device H1 (host A) corresponding to the MPTCP connection.

The second communication device H2 includes the HMAC of the host B, the nonce of the host B, the address ID of the host B, and the flag in the MP_JOIN option, and generates a SYN + ACK segment including the MP_JOIN option. Then, the second communication device H2 transmits the generated data including the SYN + ACK segment to the first communication device H1.

In the SYN + ACK segment, the HMAC sent from the second communication device H2 to the first communication device H1 is the upper of the 20 bytes obtained by obtaining the nonce of B + the nonce of A with the key of B + the key of A. It is 64 bits (8 bytes). This is used to authenticate each other between the first communication device H1 and the second communication device H2.

In step S106, the first communication device H1
The MP_JOIN option includes the HMAC of host A, and an ACK segment containing the MP_JOIN option is generated. Then, the first communication device H2 transmits the data including the generated ACK segment to the second communication device H2.

The HMAC sent from the first communication device H1 to the second communication device H2 in the ACK segment is a 20-byte value obtained by obtaining the nonce of A + the nonce of B with the key of A + the key of B.

By the above processing, two TCP subflow connections are established between the first communication device H1 and the second communication device H2, and communication by MPTCP is established between the first communication device H1 and the second communication device H2. Is possible.

(1.2.2: Data transfer processing by MPTCP connection)
Next, the data transfer process by the MPTCP connection will be described.

As shown in FIG. 9, the first communication device H1 communicates with the second communication device H2 by MPTCP by two TCP subflows.

In data transfer by MPTCP, a 64-bit data sequence number (DSN) is assigned to the data flowing through the MPTCP connection.

In addition, the DATA_SEQUCE_SIGNAL option (see RFC 6824) is used to map this DSN to the 32-bit sequence number of the TCP subflow, as shown in FIG.

The "data sequence mapping" is defined by RFC 6824, and the data sequence mapping includes information on the subflow sequence number corresponding to the DSN and the length in which the mapping of this data (transfer data) is valid. The data sequence mapping also includes data ACK for connection-level acknowledgments.

The lower 8 bytes of the result (20 bytes) of the SHA-1 message digest calculation for the key value of its own (own device) are used as the initial value (Initial Data Sequence Number: IDSN) of the data sequence number. do. This eliminates the need to explicitly exchange IDSN values between the transmitting side and the receiving side.

(12.3: MPTCP connection release process)
Next, the process of releasing the MPTCP connection will be described.

FIG. 9 shows a sequence of releasing MPTCP connections.

As shown in FIG. 9, the first communication device H1 transmits data to the second communication device H2, including the data FIN as a part of DATA_SEQUCE_SIGNAL. The second communication device H2 releases the connection of the corresponding TCP subflow by receiving the data FIN from the first communication device H1. In the present embodiment, as shown in FIG. 9, the connection between the two TCP subflows is released, so that the MPTCP connection between the first communication device H1 and the second communication device H2 is released.

The above-mentioned MPTCP connection release processing is performed by the MPTCP connection establishment processing unit 10 of the first communication device H1, the first communication interface 15, the MPTCP connection establishment processing unit 20 of the second communication device H2, and the third communication. It is executed by the interface 21.

(12.4: Scrambled data transfer processing by MPTCP connection)
Next, the scrambled data transfer process by the MPTCP connection will be described.

The first communication device H1 transmits a flag of the MP_CAPABLE option, for example, a SYN segment in which the flag G of FIG. 10 is set to “1”, to the second communication device H2 at the time of establishing the MPTCP connection. That is, by setting a predetermined flag (flag G in the above case) of the MP_CAPABLE option, it is determined in advance to notify the receiving side (second communication device H2) that data transfer using the scramble function will be performed. back.

The flag pattern for notifying that data transfer using the scramble function is performed is not limited to the above. For example, by setting the value of each flag to a bit pattern other than the bit pattern already used (or reserved) (bit pattern by flags A to H), a scramble function can be performed from the transmitting side to the receiving side. It may be notified that the data transfer is performed using.

The second communication device H2 confirms that a predetermined flag (flag G in the above) of the MP_CAPABLE option of the SYN segment generated as described above is set, and receives data using the scramble function. Be prepared.

≪Processing on the sending side≫
The transmission data acquisition unit 11 of the first communication device H1 inputs the transmission data Data_tx output from the application unit H1_ap, and acquires data of a predetermined length (1 byte) from the transmission data Data_tx. Then, the transmission data acquisition unit 11 outputs the acquired data as data D_tx [k] to the scramble key data generation unit 12 and the scramble data generation unit 13.

In the following, the transmission data Data_tx is N1 byte (N1: natural number) data, and the transmission data acquisition unit 11 is from the first byte (N1-1 byte data) to the 0th byte data of the transmission data Data_tx. Are sequentially acquired (extracted) in byte units.

Therefore, the transmission data acquisition unit 11 first acquires the data D_tx [N1-1] of the first byte (N-1th byte) of the transmission data Data_tx, and the scramble key data generation unit 12 and the scramble data generation unit 13 Output to.

In the following, for convenience of explanation, a case where N1 = 8, that is, the transmission data Data_tx is 8 bytes of data will be described as an example.

In the first data communication module 1, initial values for creating scrambled data are set. Specifically, the first data communication module 1 sets the IDSN, which is the initial value of the data sequence number, to the initial value. That is, the first data communication module 1 sets the lower 8 bytes of the result (20 bytes) of the SHA-1 message digest calculation for the key value keyA of the own device (first communication device H1) as a data sequence. Let it be IDSN, which is the initial value of the number. That is, the first data communication module 1
MsgDig = SHA1 (keyA)
IDSN = Lower_8bytes (MsgDig)
SHA1 (x): Function to acquire a message digest by SHA-1 for x Lower_8bytes (x): Acquire IDSN by a function to acquire the lower 8 bytes of x.

The shift buffer control unit 121 of the scramble key data generation unit 12 writes the above initial value, that is, IDSN, which is 8-byte data, to the shift buffer 122. It is assumed that the IDSN is composed of byte data of D7 to D0.

FIG. 11 is a diagram for explaining the scramble data generation process, and is a diagram for explaining the process of generating the scramble data from the first (first) byte data of the transmission data Data_tx (first process). ..

As shown in FIG. 11, from D7, which is the data of the 7th byte of the IDSN, to D0, which is the data of the 0th byte of the IDSN, are written to the shift buffer 122 in order.

The shift buffer 122 is a buffer for shifting the data held in byte units, and new byte data is written at the right end of FIG. 11, and the data held one byte at a time in the left direction of FIG. 11 ( It is a buffer that shifts byte data). Then, the oldest data (byte data at the left end in FIG. 11) held in the shift buffer 122 is discarded when the next shift operation is executed.

Further, for convenience of explanation, the shift buffer 122 is assumed to be a buffer that holds 64 bytes of data.

The scramble key data generation unit 12 writes the data for 8 bytes of the IDSN, which is the initial value, to the shift buffer 122 by the shift buffer control unit 121 from the state where all the byte data is 0x00. When this process is completed, the shift buffer 122 is in the state shown in FIG. The IDSN is composed of eight 1-byte data of D7 to D0. D7 is the 7th byte data, and D0 is the 0th byte data.

Then, in the first process (state shown in FIG. 11), the first XOR calculation unit 123 reads out all the byte data of the shift buffer 122, that is, 64 byte data, and reads out 64 byte data. Take an exclusive OR. That is, the first XOR calculation unit 123
Dky [N1-1] = Dbuf [63] ^ Dbuf [62] ^ ...
^ Dbuf [2] ^ Dbuf [1] ^ Dbuf [0]
Performs a logical operation corresponding to 1 to acquire 1-byte data Dky [N1-1] (= Dky [7]).

Note that "^" represents an operator that takes an exclusive OR.

Further, Dbuf [x] represents byte data (1 byte data) of the xth byte of the shift buffer 122.

In the first process (state shown in FIG. 11), Dbuf [63] to Dbuf [8] are all 0x00, so that
Dky [N1-1] = D7 ^ D6 ^ ... ^ D2 ^ D1 ^ D0
Will be. That is, in the first process (state shown in FIG. 11), the value obtained by taking the exclusive OR of each byte data of the IDSN becomes Dky [N1-1] (= Dky [7]).

Then, as shown in FIG. 11, the second XOR calculation unit 131
D_txs [N1-1] = Dky [N1-1] ^ D_tx [N1-1]
The process corresponding to (the process of exclusive-ORing) is executed, and D_txs [N1-1] (= D_txs [7]) is acquired. In FIG. 11, D_txs [N1-1] is displayed as Ds7.

When the above process (first process) is completed and D_txs [N1-1] (= D_txs [7]) is input to the scramble data acquisition unit 132, the scramble data acquisition unit 132 performs the next process (2). The control signal Ctrl1 is output to the transmission data acquisition unit 11 and the shift buffer control unit 121 so that the second process) is executed.

FIG. 12 is a diagram for explaining the scramble data generation process, and is a diagram for explaining the process of generating the scramble data from the second byte data from the beginning of the transmission data Data_tx (second time). process).

The transmission data acquisition unit 11 extracts the next byte data D_tx [N1-2] (= D_tx [6]) from the transmission data Data_tx and outputs it to the shift buffer control unit 121.

The shift buffer control unit 121 shifts the shift buffer 122 by 1 byte according to the control signal Ctrl1 and byte data D_tx [N1-1] (= D_tx [7]) of the transmission data used in the first processing (FIG. 12). Then, "Dx7" is displayed) is written in the shift buffer 122.

Then, in the second process (state shown in FIG. 12), the first XOR calculation unit 123 reads out all the byte data of the shift buffer 122, that is, 64 byte data, and reads out 64 byte data. Take an exclusive OR. That is, the first XOR calculation unit 123
Dky [N1-2] = Dbuf [63] ^ Dbuf [62] ^ ...
^ Dbuf [2] ^ Dbuf [1] ^ Dbuf [0]
Performs a logical operation corresponding to 1 to acquire 1-byte data Dky [N1-2] (= Dky [6]).

In the second process (state shown in FIG. 12), Dbuf [63] to Dbuf [9] are all 0x00, so that
Dky [N1-2] = D7 ^ D6 ^ ... ^ D2 ^ D1 ^ D0 ^ Dx7
Will be. That is, in the second process (state shown in FIG. 12), the exclusive OR of each byte data of the IDSN and the byte data D_tx [N1-2] (= D_tx [6] = Dx6) of the transmission data is taken. The value is Dky [N1-2] (= Dky [6]).

Then, as shown in FIG. 12, the second XOR calculation unit 131
D_txs [N1-2] = Dky [N1-2] ^ D_tx [N1-2]
The process corresponding to (the process of exclusive-ORing) is executed, and D_txs [N1-2] (= D_txs [6]) is acquired. In FIG. 12, D_txs [N1-2] is displayed as Ds6.

When the above process (second process) is completed and D_txs [N1-2] (= D_txs [6]) is input to the scramble data acquisition unit 132, the scramble data acquisition unit 132 performs the next process (3). The control signal Ctrl1 is output to the transmission data acquisition unit 11 and the shift buffer control unit 121 so that the second process) is executed.

FIG. 13 is a diagram for explaining the scramble data generation process, and is a diagram for explaining the process of generating the scramble data from the byte data of the third byte from the beginning of the transmission data Data_tx (third time). process).

The transmission data acquisition unit 11 extracts the next byte data D_tx [N1-3] (= D_tx [5]) from the transmission data Data_tx and outputs it to the shift buffer control unit 121.

The shift buffer control unit 121 shifts the shift buffer 122 by 1 byte according to the control signal Ctrl1 and byte data D_tx [N1-2] (= D_tx [6]) of the transmission data used in the second processing (FIG. 13). Then, "Dx6" is displayed) is written in the shift buffer 122.

Then, in the third process (state shown in FIG. 13), the first XOR calculation unit 123 reads out all the byte data of the shift buffer 122, that is, 64 byte data, and reads out 64 byte data. Take an exclusive OR. That is, the first XOR calculation unit 123
Dky [N1-3] = Dbuf [63] ^ Dbuf [62] ^ ...
^ Dbuf [2] ^ Dbuf [1] ^ Dbuf [0]
Performs a logical operation corresponding to 1 to acquire 1-byte data Dky [N1-3] (= Dky [5]).

In the third process (state shown in FIG. 13), Dbuf [63] to Dbuf [10] are all 0x00, so that
Dky [N1-3] = D7 ^ D6 ^ ... ^ D2 ^ D1 ^ D0 ^ Dx7 ^ Dx6
Will be. That is, in the third process (state shown in FIG. 13), the exclusive OR of each byte data of the IDSN and the byte data D_tx [N1-3] (= D_tx [5] = Dx5) of the transmission data is taken. The value is Dky [N1-3] (= Dky [5]).

Then, as shown in FIG. 13, the second XOR calculation unit 131
D_txs [N1-3] = Dky [N1-3] ^ D_tx [N1-3]
The process corresponding to (the process of exclusive-ORing) is executed, and D_txs [N1-3] (= D_txs [5]) is acquired. In FIG. 13, D_txs [N1-3] is displayed as Ds5.

When the above process (third process) is completed and D_txs [N1-3] (= D_txs [5]) is input to the scramble data acquisition unit 132, the scramble data acquisition unit 132 performs the next process (4). The control signal Ctrl1 is output to the transmission data acquisition unit 11 and the shift buffer control unit 121 so that the second process) is executed.

By repeating the same process as above, scramble data Data_txs is acquired.

Then, when the byte data for N1 bytes (= 8 bytes) is prepared, the scramble data acquisition unit 132 outputs the scramble data Data_txs to the TCP subflow data generation unit 14.

The TCP subflow data generation unit 14 acquires data that can be transmitted by a plurality of TCP subflows from the transmission data D_txs. In the present embodiment, since the number of TCP subflows is "2", the TCP subflow data generation unit 14 acquires the data D_txs_sub1 and D_txs_sub2 that can be transmitted by the two TCP subflows from the transmission data D_txs. Then, the TCP subflow data generation unit 14 outputs the TCP subflow data D_txs_sub1 to the first communication interface 15, and outputs the TCP subflow data D_txs_sub2 to the second communication interface 16.

The first communication interface 15 inputs the TCP subflow data D_txs_sub1 output from the TCP subflow data generation unit 14, and generates the transmission data D_sub1 based on the TCP subflow data D_txs_sub1. Then, the first communication interface 15 transmits the generated transmission data D_sub1 to the second communication device H2 which is a communication partner. At this time, the first communication interface 15 transmits data by using the connection of the TCP subflow connection established between the address A1 of the first communication device H1 and the address B of the second communication device H2.

The second communication interface 16 inputs TCP subflow data D_txs_sub2 output from the TCP subflow data generation unit 14, generates transmission data D_sub2 based on TCP subflow data D_txs_sub2, and generates transmission data D_sub2. It transmits to the second communication device H2 which is the communication partner. At this time, the second communication interface 16 transmits data using the TCP subflow connection established between the address A2 of the first communication device H1 and the address B of the second communication device H2.

When the application unit H1_ap requests the first data communication module to transmit the next transmission data Data_rx, the byte data stored in the shift buffer 122 (transmission scramble buffer) at that time is used. The same processing as above may be performed to acquire the byte data Dky [k] of the key data for scrambling, and the transmission data may be scrambled by the same processing as above using the byte data.

≪Processing on the receiving side≫
The third communication interface 21 of the second communication device H2 uses the TCP subflow connection established between the address A1 of the first communication device H1 and the address B of the second communication device H2 to use the first communication device. Receives the data D_sub1 transmitted from H1. Then, the third communication interface 21 outputs the received data as data D_rxs_sub1 to the MPTCP data acquisition unit 23.

The fourth communication interface 22 of the second communication device H2 uses the TCP subflow connection established between the address A2 of the first communication device H1 and the address B of the second communication device H2 to use the first communication device. Receives the data D_sub2 transmitted from H1. Then, the fourth communication interface 22 outputs the received data as data D_rxs_sub2 to the MPTCP data acquisition unit 23.

The MPTCP data acquisition unit 23 inputs data D_rxs_sub1 output from the third communication interface 21 and data D_rxs_sub2 output from the fourth communication interface 22. The MPTCP data acquisition unit 23 acquires MPTCP data D_rxs by executing a process of arranging the data D_rxs_sub1 and the data D_rxs_sub2, which are TCP subflow data, in the order of the data sequence numbers. Then, the MPTCP data acquisition unit 23 outputs the acquired MPTCP data D_rxs to the descramble data acquisition unit 24.

The byte data extraction unit 241 of the descramble data acquisition unit 24 extracts data having a data length (1 byte) of a predetermined unit from the data D_rxs output from the MPTCP data acquisition unit 23, and extracts the extracted data into data D_rxs [ As k], it is output to the third XOR calculation unit 242.

The third XOR operation unit 242 performs a logical operation process (for example, an XOR operation) using the data D_rxs [k] and the data Dky [k], and receives the result of the logical operation process as the data D_rx [k]. Output to the acquisition unit 26.

In the second data communication module 2, initial values for creating scrambled data are set. Specifically, the second data communication module 2 sets the IDSN, which is the initial value of the data sequence number, to the initial value. That is, the second data communication module 2 sets the lower 8 bytes of the result (20 bytes) of the result of calculating the message digest by SHA-1 with respect to the key value keyA of the second communication device H2, which is the communication partner, as a data sequence. Let it be IDSN, which is the initial value of the number. That is, the second data communication module 2
MsgDig = SHA1 (keyA)
IDSN = Lower_8bytes (MsgDig)
SHA1 (x): Function to acquire a message digest by SHA-1 for x Lower_8bytes (x): Acquire IDSN by a function to acquire the lower 8 bytes of x.

The shift buffer control unit 251 of the scramble key data generation unit 25 writes the above initial value, that is, IDSN, which is 8-byte data, to the shift buffer 122. It is assumed that the IDSN is composed of byte data of D7 to D0.

FIG. 14 is a diagram for explaining a process of acquiring descrambled data, and is a diagram for explaining a process of generating descrambled data from the first (first) byte data of the received scrambled data Data_rxs. (First process (reception side)).

As shown in FIG. 14, from D7, which is the data of the 7th byte of the IDSN, to D0, which is the data of the 0th byte of the IDSN, are written to the shift buffer 252 in order.

The shift buffer 252 is a buffer for shifting the data held in byte units, and new byte data is written at the right end of FIG. 14, and the data held one byte at a time in the left direction of FIG. 14 ( It is a buffer that shifts byte data). Then, the oldest data (byte data at the left end in FIG. 14) held in the shift buffer 122 is discarded when the next shift operation is executed.

Further, the shift buffer 252 is a buffer that holds 64 bytes of data like the shift buffer 122 on the transmitting side.

The scramble key data generation unit 25 writes the data for 8 bytes of the IDSN, which is the initial value, to the shift buffer 252 by the shift buffer control unit 251 from the state where all the byte data is 0x00. When this process is completed, the shift buffer 252 is in the state shown in FIG. The IDSN is composed of eight 1-byte data of D7 to D0. D7 is the 7th byte data, and D0 is the 0th byte data.

Then, in the first process (state shown in FIG. 14), the first XOR calculation unit 253 reads out all the byte data of the shift buffer 252, that is, 64 byte data, and reads out 64 byte data. Take an exclusive OR. That is, the first XOR calculation unit 253
Dky [N1-1] = Dbuf [63] ^ Dbuf [62] ^ ...
^ Dbuf [2] ^ Dbuf [1] ^ Dbuf [0]
Performs a logical operation corresponding to 1 to acquire 1-byte data Dky [N1-1] (= Dky [7]).

Note that "^" represents an operator that takes an exclusive OR.

Further, Dbuf [x] represents byte data (1 byte data) of the xth byte of the shift buffer 122.

In the first process (state shown in FIG. 14), Dbuf [63] to Dbuf [8] are all 0x00, so that
Dky [N1-1] = D7 ^ D6 ^ ... ^ D2 ^ D1 ^ D0
Will be. That is, in the first process (state shown in FIG. 14), the value obtained by taking the exclusive OR of each byte data of the IDSN becomes Dky [N1-1] (= Dky [7]).

Then, as shown in FIG. 14, the third XOR calculation unit 242
D_rx [N1-1] = Dky [N1-1] ^ D_rxs [N1-1]
The process corresponding to (the process of exclusive-ORing) is executed, and D_rx [N1-1] (= D_rx [7]) is acquired. In FIG. 14, D_rxs [N1-1] is displayed as Ds7, and D_rx [N1-1] is displayed as Dx7.

When the above process (first process) is completed and D_rx [N1-1] (= D_rx [7]) is input to the received data acquisition unit 26, the received data acquisition unit 26 performs the next process (2). The control signal Ctrl3 is output to the descramble data acquisition unit 24 and the shift buffer control unit 251 so that the second process) is executed.

FIG. 15 is a diagram for explaining the process of acquiring the descrambled data, and is a diagram for explaining the process of generating the descrambled data from the byte data of the second byte from the beginning of the received scrambled data Data_rxs. Yes (second processing (reception side)).

The byte data extraction unit 241 extracts the next byte data D_txs [N1-2] (= D_txs [6] = Ds6) from the received scrambled data Data_txs and outputs it to the third XOR calculation unit 242.

The shift buffer control unit 251 shifts the shift buffer 252 by 1 byte according to the control signal Ctrl3, and the byte data D_rx [N1-1] (= D_rx [7]) of the received data acquired in the first process (FIG. 15). Then, "Dx7" is displayed) is written in the shift buffer 252.

Then, in the second processing (state shown in FIG. 15), the first XOR calculation unit 253 reads out all the byte data of the shift buffer 252, that is, 64 byte data, and reads out 64 byte data. Take an exclusive OR. That is, the first XOR calculation unit 253
Dky [N1-2] = Dbuf [63] ^ Dbuf [62] ^ ...
^ Dbuf [2] ^ Dbuf [1] ^ Dbuf [0]
Performs a logical operation corresponding to 1 to acquire 1-byte data Dky [N1-2] (= Dky [6]).

In the second process (state shown in FIG. 15), Dbuf [63] to Dbuf [9] are all 0x00, so that
Dky [N1-2] = D7 ^ D6 ^ ... ^ D2 ^ D1 ^ D0 ^ Dx7
Will be. That is, in the second process (state shown in FIG. 15), the exclusive OR of each byte data of the IDSN and the byte data D_rxs [N1-2] (= D_rxs [6] = Ds6) of the received scrambled data. The value obtained by taking is Drx [N1-2] (= Dx [6] = Dx6).

Then, as shown in FIG. 15, the third XOR calculation unit 242
D_rx [N1-2] = Dky [N1-2] ^ D_rxs [N1-2]
The process corresponding to (the process of exclusive-ORing) is executed, and D_rx [N1-2] (= D_rx [6] = Dx6) is acquired.

When the above process (second process) is completed and D_rx [N1-2] (= D_rx [6]) is input to the received data acquisition unit 26, the received data acquisition unit 26 performs the next process (3). The control signal Ctrl3 is output to the descramble data acquisition unit 24 and the shift buffer control unit 251 so that the second process) is executed.

FIG. 16 is a diagram for explaining the process of acquiring the descrambled data, and is a diagram for explaining the process of generating the descrambled data from the byte data of the third byte from the beginning of the received scrambled data Data_rxs. Yes (third processing (reception side)).

The byte data extraction unit 241 extracts the next byte data D_txs [N1-3] (= D_txs [5] = Ds5) from the received scrambled data Data_txs and outputs it to the third XOR calculation unit 242.

The shift buffer control unit 251 shifts the shift buffer 252 by 1 byte according to the control signal Ctrl3, and shifts the byte data D_rx [N1-2] (= D_rx [6] = Dx7) of the received data acquired in the second process. Write to shift buffer 252.

Then, in the third process (state shown in FIG. 16), the first XOR calculation unit 253 reads out all the byte data of the shift buffer 252, that is, 64 byte data, and reads out 64 byte data. Take an exclusive OR. That is, the first XOR calculation unit 253
Dky [N1-3] = Dbuf [63] ^ Dbuf [62] ^ ...
^ Dbuf [2] ^ Dbuf [1] ^ Dbuf [0]
Performs a logical operation corresponding to 1 to acquire 1-byte data Dky [N1-3] (= Dky [5]).

In the third process (state shown in FIG. 16), Dbuf [63] to Dbuf [10] are all 0x00, so that
Dky [N1-3] = D7 ^ D6 ^ ... ^ D2 ^ D1 ^ D0 ^ Dx7 ^ Dx6
Will be. That is, in the third process (state shown in FIG. 16), the exclusive OR of each byte data of the IDSN and the byte data D_rxs [N1-3] (= D_rxs [5] = Ds5) of the received scrambled data. The value obtained by taking is Drx [N1-3] (= Dx [5] = Dx5).

Then, as shown in FIG. 16, the third XOR calculation unit 242
D_rx [N1-3] = Dky [N1-3] ^ D_rxs [N1-3]
The process corresponding to (the process of exclusive-ORing) is executed, and D_rx [N1-3] (= D_rx [5] = Dx5) is acquired.

When the above process (third process) is completed and D_rx [N1-3] (= D_rx [5]) is input to the received data acquisition unit 26, the received data acquisition unit 26 performs the next process (4). The control signal Ctrl3 is output to the descramble data acquisition unit 24 and the shift buffer control unit 251 so that the second process) is executed.

By repeating the same process as above, the descrambled received data Data_rx is acquired.

In this way, in the communication system 1000, the transmitting side and the receiving side perform a process of exclusive-oring using the data Dky [k], which is the same key data for scrambling, so that the transmitting side (first). The data scrambled by the communication device H1) can be descrambled on the receiving side (second communication device H2) and returned to the original data.

That is, in the communication system 1000, D_txs [k] = D_tx [k] ^ Dky [k] on the transmitting side (first communication device H1).
By performing the process corresponding to, the scrambled byte data D_txs [k] of the transmitted data is acquired from the byte data D_tx [k] of the transmission data.
D_rx [k] = D_txs [k] ^ Dky [k] on the receiving side (second communication device H2)
By performing the process corresponding to, the scrambled byte data D_txs [k] (= D_rxs [k]) of the transmitted data is descrambled, and the received data that matches the byte data D_tx [k] of the transmitted data Byte data D_rx [k] can be acquired.

Then, in the communication system 1000, the initial value of the data Dky [k], which is the key data for scrambling used for the scrambling process on the transmitting side, is set to the IDSN (8-byte data) of the transmitting side (first communication device H1). The 1-byte data Dky [k] obtained by performing the process of exclusive-oring each byte is used. Then, in the scrambling process of the next transmission data byte data D_tx [k + 1], the scrambled transmission data byte data D_tx [k] and the IDSN (8 bytes) of the transmitting side (first communication device H1) are used. The 1-byte data Dky [k + 1] acquired by performing the process of exclusive-oring each byte of the data) is used as the scramble key data.

In the communication system 1000, the scramble key data Dky used for the scramble processing on the receiving side is made the same as the key data Dky for scrambling used for the scrambling processing on the transmitting side. Therefore, in the communication system 1000, the data scrambled on the transmitting side can be descrambled on the receiving side and returned to the original data.

Further, in the communication system 1000, the byte data of the scrambled key data is constantly updated by using the byte data of the transmitted data that has already been scrambled (the byte data of the received data that has already been descrambled), so that the scramble key is used. The value of the data is constantly changing. Therefore, in the communication system 1000, scrambling processing with high security strength can be realized.

Further, in the communication system 1000, the transmission data scrambled as described above is distributed by MPTCP by a plurality of TCP subflows and transmitted from the transmission side to the reception side, so that the transmission data is transmitted in the middle of the communication path. , Even if some data is eavesdropped or intercepted, the original data cannot be restored.

Further, in the communication system 1000, at the time of establishing the MPTCP connection, a SYN segment in which a predetermined flag of the MP_CAPABLE option is set to a predetermined value (for example, a SYN segment including the MP_CAPABLE option in which the flag G is set to "1") is provided. It is generated and the SYN segment is transmitted from the transmitting side (first communication device H1) to the receiving side (second communication device H2). As a result, in the communication system 1000, the transmitting side (first communication device H1) notifies the receiving side (second communication device H2) that the data transfer using the scramble function is performed.

That is, in the communication system 1000, it is possible to notify the receiving side (second communication device H2) from the transmitting side (first communication device H1) that the data transfer using the scramble function is performed by the conventional MPTCP. Therefore, in the communication system 1000, the scramble function can be realized without increasing the amount of data to be transferred.

As described above, in the communication system 1000, in communication using a plurality of paths, security can be ensured without increasing the amount of data to be transferred.

[Other Embodiments]
In the above embodiment, the case where the process is executed in 1-byte units in the scramble process and the descramble process has been described, but the present invention is not limited to this. For example, the scramble processing and the descramble processing may be executed in units of 2 bytes, N bytes, or a predetermined number of bits.

Further, in the above embodiment, the case where communication using MPTCP is performed by two TCP subflows in the communication system 1000 has been described, but the present invention is not limited to this, and MPTCP is used by three or more TCP subflows. Communication may be performed.

Further, in the communication system 1000, a communication process (processing of steps S101 to S103 in FIG. 7) for exchanging a transmission side key and a reception side key is performed on a highly reliable (high security strength) communication network (for example, a mobile phone). It may be performed using a communication network (telephone communication network), and scrambled data may be transmitted / received using a communication network having low security strength (for example, a wireless LAN communication network).

That is, in the communication system 1000, a TCP subflow that performs communication processing for exchanging a transmission side key and a reception side key is performed by using a highly reliable (high security strength) communication network (for example, a mobile phone communication network). It may be realized and transmission / reception of scrambled data may be realized by using a communication network having low security strength (for example, a communication network of wireless LAN (WiFi)).

Further, in the above embodiment, the case where the exclusive OR (XOR) is used as the logical operation process in the scrambled process and the descrambled process has been described, but the present invention is not limited to this, and for example, scrambling is performed. In the processing and descramble processing, as the logical operation processing, instead of the exclusive OR, the logical operation processing by "exclusive OR" (XOR + NOT) or "NOT + exclusive OR" (NOT + XOR) is performed. You may.

Further, in the communication system 1000, the first communication device H1, and the second communication device H2 described in the above embodiment, each block may be individually integrated into one chip by a semiconductor device such as an LSI, or a part or all of the blocks. It may be made into one chip so as to include.

Although it is referred to as an LSI here, it may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration.

Further, the method of making an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and settings of the circuit cells inside the LSI may be used.

Further, a part or all of the processing of each functional block of each of the above embodiments may be realized by a program. Then, a part or all of the processing of each functional block of each of the above embodiments is performed by the central processing unit (CPU) in the computer. Further, the program for performing each process is stored in a storage device such as a hard disk or a ROM, and is read and executed in the ROM or the RAM.

Further, each process of the above embodiment may be realized by hardware, or may be realized by software (including a case where it is realized together with an OS (operating system), middleware, or a predetermined library). Further, it may be realized by mixed processing of software and hardware.

For example, when each functional unit of the above embodiment is realized by software, the hardware configuration shown in FIG. 17 (for example, a hardware configuration in which a CPU, ROM, RAM, input unit, output unit, etc. are connected by a bus Bus). May be used to realize each functional unit by software processing.

Further, the execution order of the processing methods in the above-described embodiment is not necessarily limited to the description of the above-described embodiment, and the execution order can be changed without departing from the gist of the invention.

A computer program that causes a computer to perform the above-mentioned method and a computer-readable recording medium on which the program is recorded are included in the scope of the present invention. Here, examples of computer-readable recording media include flexible disks, hard disks, CD-ROMs, MOs, DVDs, DVD-ROMs, DVD-RAMs, large-capacity DVDs, next-generation DVDs, and semiconductor memories. ..

The computer program is not limited to the one recorded on the recording medium, and may be transmitted via a telecommunication line, a wireless or wired communication line, a network represented by the Internet, or the like.

The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the gist of the invention.

1000 Communication system H1 1st communication device (data transmission device)
H2 2nd communication device (data receiving device)
1 1st data communication module 10 MPTCP connection establishment processing unit 11 Transmission data acquisition unit 12 Scramble key data generation unit 13 Scramble data generation unit 14 TCP subflow data generation unit (subflow data generation unit)
2 Second data communication module 20 MPTCP connection establishment processing unit 23 MPTCP data acquisition unit 24 Desk rumble data acquisition unit 25 Scramble key data generation unit 26 Received data acquisition unit

Claims (13)

A data transmitting device having a function of transmitting data to a data receiving device using a plurality of communication paths.
It is a scramble key data generation unit that acquires scramble processing key data for scrambling the unit length transmission data, which is unit length data obtained by dividing the transmission data into data having a predetermined unit length. In the process of, the initial value data derived from the key data, which is the data for identifying the own device, is divided into the data of the predetermined unit length, and the unit length initial value data, which is the unit length data, is used to perform a predetermined logic. By performing the calculation, the key data for the scramble processing for the scramble processing is acquired, and (2) in the second and subsequent processing, the unit length initial value data and the scramble processing at a time before the current time. Both the unit length transmission data that is the target of the unit length transmission data before being scrambled , or the unit length transmission data that is the target of scramble processing at a time before the current time. The scramble key data generation unit that acquires the scramble processing key data by performing a predetermined logical operation using only the unit length transmission data before being scrambled.
By performing a predetermined logical operation using the scramble processing key data acquired by the scramble key data generation unit and the unit length transmission data, scrambling processing is executed and scramble which is unit length data. A scrambled data generation unit that generates one scrambled transmission data by acquiring the scrambled unit length transmission data and collecting a plurality of the acquired scrambled unit length transmission data.
A subflow data generation unit that generates subflow data for transmission using a plurality of routes from the scrambled transmission data generated by the scrambled data generation unit.
A data transmitter equipped with. The predetermined logical operation is an exclusive OR operation.
The data transmission device according to claim 1. The unit length data is 1 byte data.
The data transmission device according to claim 1 or 2. The initial value data is
When the key data, which is the data for identifying the own device, is the key data keyA,
MsgDig = SHA1 (keyA)
IDSN = Lower_8bytes (MsgDig)
SHA1 (x): Function for acquiring a message digest by SHA-1 for x Lower_8bytes (x): IDSN value acquired by a function for acquiring the lower 8 bytes of x.
The data transmission device according to any one of claims 1 to 3. It has a function to execute communication using MPTCP, and has a function to execute communication.
It also has an MPTCP connection establishment processing unit that executes MPTCP connection establishment processing.
The MPTCP connection establishment processing unit is
At the time of establishing an MPTCP connection, a SYN segment in which a predetermined flag of the MP_CAPABLE option is set to a predetermined value is generated, and the SYN segment is transmitted to the data receiving device to perform data transfer using the scramble function. Notify the data receiving device of the fact.
The data transmission device according to any one of claims 1 to 4. A data receiving device having a function of receiving data transmitted by a data transmitting device using a plurality of communication paths.
By executing a process of arranging a plurality of subflow data received from the data transmission device in the order of the data sequence numbers included in the subflow data by a plurality of communication paths, the plurality of subflow data are collectively received. MPTCP data acquisition unit to acquire data and
Scramble key data for acquiring scramble processing key data for descrambled unit length reception scramble data, which is unit length data obtained by dividing the received data acquired by the MPTCP data acquisition unit into data having a predetermined unit length. In the generation unit, (1) in the first processing, the initial value data derived from the key data, which is the data for identifying the data transmission device as the communication partner, is divided into data having a predetermined unit length. Using the unit length initial value data, which is the unit length data, the key data for scramble processing for descramble processing is acquired by performing a predetermined logical operation, and (2) in the second and subsequent processing, the unit is described. Both the long initial value data and the unit length received data that was descrambled at a time earlier than the current time and the unit length transmitted data after being scrambled , or more than the current time. The scramble processing key data is obtained by performing a predetermined logical operation using only the unit length transmission data that was the target of the descramble processing at the previous time and the unit length reception data after being scrambled. The scramble key data generation unit to be acquired and
By performing a predetermined logical operation using the scramble processing key data acquired by the scramble key data generation unit and the unit length reception scramble data, the descramble processing is executed and the unit length data is used. A reception data acquisition unit that acquires one descrambled reception data by acquiring a certain unit length reception data and collecting a plurality of the acquired unit length reception data.
A data receiver comprising. The predetermined logical operation is an exclusive OR operation.
The data receiving device according to claim 6. The unit length data is 1 byte data.
The data receiving device according to claim 6 or 7. The initial value data is
When the key data, which is the data for identifying the data transmission device that is the communication partner, is the key data keyA,
MsgDig = SHA1 (keyA)
IDSN = Lower_8bytes (MsgDig)
SHA1 (x): Function for acquiring a message digest by SHA-1 for x Lower_8bytes (x): IDSN value acquired by a function for acquiring the lower 8 bytes of x.
The data receiving device according to any one of claims 6 to 8. It has a function to execute communication using MPTCP, and has a function to execute communication.
It also has an MPTCP connection establishment processing unit that executes MPTCP connection establishment processing.
The MPTCP connection establishment processing unit is
At the time of establishing an MPTCP connection, the data transmission device receives a SYN segment in which a predetermined flag of the MP_CAPABLE option is set to a predetermined value, so that the data transmission device performs a function of performing data transfer using the scramble function. Judge to have,
The data receiving device according to any one of claims 6 to 9. The data transmission device according to any one of claims 1 to 5.
The data receiving device according to any one of claims 6 to 10.
Communication system including. A data transmission method used when data is transmitted from a data transmission device to a data reception device using a plurality of communication paths.
This is a scramble key data generation step for acquiring scramble processing key data for scrambling the unit length transmission data, which is unit length data obtained by dividing the transmission data into data having a predetermined unit length. (1) The first time. In the process of, the initial value data derived from the key data, which is the data for identifying the data transmission device, is divided into the data of a predetermined unit length, and the unit length initial value data, which is the unit length data, is used. By performing the logical calculation of, the key data for scrambling processing for scrambling processing is acquired, and (2) in the second and subsequent processing, the unit length initial value data and scrambled at a time before the current time. both unit length transmission data subjected to the processing, or only the unit length transmission data before being scrambled by a unit length transmission data subjected to the scramble process at the time before the current time The scramble key data generation step of acquiring the scramble processing key data by performing a predetermined logical operation using
By performing a predetermined logical operation using the scramble processing key data acquired in the scramble key data generation step and the unit length transmission data, scrambling processing is executed and scramble which is unit length data. A scramble data generation step of acquiring one scrambled transmission data and aggregating a plurality of the acquired scrambled unit length transmission data to generate one scrambled transmission data.
A subflow data generation step for generating subflow data for transmission using a plurality of routes from the scrambled transmission data generated by the scrambled data generation step, and a subflow data generation step.
A program that causes a computer to execute a data transmission method. A data receiving method used when receiving data transmitted from a data transmitting device using a plurality of communication paths in a data receiving device.
By executing a process of arranging a plurality of subflow data received from the data transmission device in the order of the data sequence numbers included in the subflow data by a plurality of communication paths, the plurality of subflow data are collectively received. MPTCP data acquisition step to acquire data and
Scramble key data for acquiring scramble processing key data for descrambled unit length reception scramble data, which is unit length data obtained by dividing the received data acquired by the MPTCP data acquisition step into data having a predetermined unit length. In the generation step, (1) in the first process, the initial value data derived from the key data, which is the data for identifying the data transmission device, is divided into the unit length data having a predetermined unit length. Using a certain unit length initial value data, the key data for scramble processing for descramble processing is acquired by performing a predetermined logical operation, and (2) in the second and subsequent processing, the unit length initial value data is obtained. , and both unit length transmission data after being a unit length received data subjected to the descrambling process scrambled in time before the current time, or at time before the current time The scramble that acquires the scramble processing key data by performing a predetermined logical operation using only the unit length transmission data that is the target of the descramble processing and the unit length reception data that has been scrambled. Key data generation step and
By performing a predetermined logical operation using the scramble processing key data acquired in the scramble key data generation step and the unit length reception scramble data, the descramble processing is executed and the unit length data is used. A reception data acquisition step of acquiring a certain descrambled reception data by acquiring a certain unit length reception data and collecting a plurality of the acquired unit length reception data.
A program that causes a computer to execute a data receiving method.

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