JP2006352499A - Data transmission method and system, transmitter, and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain secure data transmission by simple structure. <P>SOLUTION: A destination discrimination device 24 discriminates the destination of an input data frame. A matching confirmation pattern adding device 32 adds a matching confirmation pattern to a data frame to be transmitted. A divider 34 divides the output frame of the device 32 into two divided frames 78, 80 according to a predetermined division rule. One divided frame is input to an optical fiber transmission path 12 via an error correction coder 36a, a variable delay unit 38a and electric/optic converter 40a, and the other divided frame is input to an optical fiber transmission path 14 via an error correction coder 36b, a variable delay unit 38b and an electric/optic converter 40b. A delay controller 26 controls delay time of the variable delay units 38a, 38b so that both of the divided frames substantially simultaneously reach a receiver 50. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data transmission method and system, a transmission device, and a reception device.

  Conventionally, communication methods with improved security have been proposed for electronic commerce and exchange of secret information. In general, a method is adopted in which data is encrypted with an encryption key on the transmission side and data encrypted on the reception side is decrypted with a decryption key to obtain the original plaintext. However, in this method, if the decryption key is stolen, the data is decrypted.

In view of this, a system has been proposed in which encrypted information is divided into a plurality of pieces of data that are irrelevant alone, and these data are separately transmitted through a plurality of communication paths to enhance the confidentiality of communication (Patent Document 1). reference).
JP 2000-115162 A

  In the ring communication system, encryption has been used in the past. However, as described above, there is a risk that data may be decrypted when the decryption key is stolen.

  When the method described in Patent Document 1 is applied to a ring communication system, a method of dividing by wavelength and a method of dividing by a transmission direction can be considered as a communication path. In the former method, when the number of slave units (receivers) connected to the same ring increases, the master unit (transmitter) needs to prepare a large number of wavelengths. In the latter method, when a plurality of slave units are connected, specific data must be transmitted to the specific slave unit. However, such a method has not been known.

  An object of the present invention is to provide a data transmission method and system, a transmission device, and a reception device that can realize high security with a simple configuration.

  The data transmission method according to the present invention includes an alignment confirmation pattern adding step for adding an alignment confirmation pattern for confirming validity to a data frame, and dividing the data frame to which the alignment confirmation pattern is added into a plurality of divided frames. A dividing step, a delay step for providing each of the plurality of divided frames with a delay for compensating a propagation time difference between the plurality of transmission paths, and each of the delayed divided frames are different from each other in the plurality of transmission paths. An output step for outputting to the transmission line, a combining step for combining each divided frame from each transmission line, a matching check pattern determining step for determining whether or not a correct matching check pattern exists in the combined frame by the combining step, A step of discarding the composite frame when the matching confirmation pattern is not confirmed. Characterized by including the.

  A data transmission system according to the present invention is a data transmission system that transmits data from a transmission device to a reception device using a plurality of transmission paths. Characteristically, the transmission device determines a destination of an input data frame, a destination database that stores information on propagation times in a plurality of transmission paths for each destination, and a front of the input data frame. A preprocessing device for processing, a preprocessing device comprising a matching check pattern adding device for adding a matching check pattern for checking validity to the input data frame, and a frame output from the preprocessing device. A plurality of variable delay units each configured to delay each of the plurality of divided frames are set with a delay time that substantially compensates for a propagation time difference between a frame dividing apparatus that divides the frame into a plurality of divided frames and a transmission path used for transmission of each divided frame. Transmission of signals that carry the divided frames delayed by the delay device and the plurality of variable delay devices different from each other in the plurality of transmission paths Comprising a plurality of output devices for outputting the. The receiving device inputs a plurality of input devices that input signals carrying the divided frames from each of the plurality of transmission paths, and a combining device that combines the plurality of divided frames from the plurality of input devices into one frame. And a matching confirmation pattern discriminating device for discriminating whether or not the correct matching confirmation pattern is present in the synthesized frame output from the synthesizing device, and a device for discarding the synthesized frame when the correct matching confirmation pattern is not confirmed. To do.

  A transmission apparatus according to the present invention pre-processes an input data frame, a destination determination apparatus that determines a destination of the input data frame, a destination database that stores information on transmission times on a plurality of transmission paths for each destination, and the input data frame A preprocessing device comprising a matching check pattern adding device for adding a matching check pattern for checking validity to the input data frame, and a plurality of frames output from the preprocessing device. A frame dividing device that divides the frame into divided frames and a plurality of variable delay devices that are set with a delay time that substantially compensates for a propagation time difference between transmission lines used for transmission of the divided frames and delays each of the divided frames. And signals carrying each divided frame delayed by the plurality of variable delay devices to different transmission paths among the plurality of transmission paths. Characterized by comprising a plurality of output devices that force.

  A receiving apparatus according to the present invention is a receiving apparatus that receives a plurality of divided frames divided from one data frame through substantially different transmission paths, thereby receiving the data frames. A plurality of input devices that input signals carrying the divided frames from each of the transmission paths, a combining device that combines the plurality of divided frames from the plurality of input devices into one frame, and an output from the combining device A matching confirmation pattern discriminating device for discriminating whether or not the synthesized frame has a predetermined matching confirmation pattern, and a device for discarding the synthesized frame when the predetermined matching confirmation pattern is not confirmed. And

  In the present invention, one data frame is divided into a plurality of divided frames, and each divided frame is transmitted through a different transmission path after giving a delay time according to the propagation time difference of the transmission path to be used. Can be intercepted by the receiving device. By adding a matching confirmation pattern before transmission and confirming on the receiving side, it is possible to confirm whether or not the composite frame is correct. Thus, highly secure data transmission that is difficult to intercept can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 shows a transition of a frame configuration in the embodiment.

  The ring transmission line 10 includes an optical fiber transmission line 12 that transmits signal light in a clockwise direction and an optical fiber transmission line 14 that transmits signal light in a counterclockwise direction. An optical transmitter 20 and an optical receiver 50 are connected to the optical fiber transmission lines 12 and 14, and the optical transmitter 20 transmits data to the optical receiver 50 via the optical fiber transmission lines 12 and 14. Further, one or more other optical transmission devices or one or more optical reception devices can be connected to the optical fiber transmission lines 12 and 14. As a representative of these, an optical transceiver 70 connected to the optical fiber transmission lines 12 and 14 is shown.

  The optical transmitter 20 measures in advance the signal transmission time when passing through the optical fiber transmission line 12 and the signal propagation time when passing through the optical fiber transmission line 14 with respect to the optical receiver 50. The signal propagation time of the optical fiber transmission lines 12 and 14 from the optical transmitter 20 to the optical receiver 50 can be measured by, for example, the method described in Japanese Patent Application Laid-Open No. 2004-054494. The destination information database 22 stores, for each destination, information on the propagation time difference of the optical fiber transmission lines 12 and 14 (or time information itself), and information on the encryption method and its encryption key.

  A data frame to be transmitted to the optical receiving device 50, that is, a transmission frame 72 is input to the destination discriminating device 24 of the optical transmitting device 20. In this embodiment, the transmission frame 72 has an Ethernet (registered trademark) frame structure as shown in FIG. The Ethernet (registered trademark) frame structure has a 7-byte preamble, a 1-byte SFD (Start Frame Delimiter), a 6-byte destination address, a 6-byte transmission source address, a 46 to 1500-byte data part, and a 4-byte error. It consists of CRC (Cyclic Redundancy Check) for detection and correction. Data to be transmitted is stored in the data portion. The preamble consists of alternating repetitions of 1 and 0. The SFD is “10101011”.

  The destination discriminating device 24 discriminates the destination (here, the optical receiving device 50) from the destination address of the frame 72 shown in FIG. 2, refers to the destination information database 22, and optical fiber related to the destination (optical receiving device 50). Reads the propagation time difference information of the transmission lines 12 and 14 and the encryption method and its encryption key information, and controls the propagation time difference information to the delay control device 26 and the encryption method and encryption key information to the encryption control. Supply to device 28. The destination determination device 24 also outputs the input data frame 72 to the encryption device 30 as it is.

  The encryption control device 28 sets the encryption method and the encryption key from the destination determination device 24 in the encryption device 30. The encryption device 22 is an encryption method designated by the encryption control device 28 and uses the encryption key instructed by the encryption control device 28, and the data frame shown in FIG. The entire 72 is encrypted. That is, the encryption device 30 collectively encrypts the preamble, SFD, destination address, transmission source address, data, and CRC from the destination determination device 24, and outputs the encrypted frame 74 shown in FIG. To do.

  The matching confirmation pattern adding apparatus 32 adds a matching confirmation pattern having a predetermined number of bits immediately before the encrypted frame 74 from the encryption apparatus 30 and, as shown in FIG. A frame 76 composed of the matching confirmation pattern is output. In the present embodiment, one frame is divided into two, each transmitted through a different transmission path, and combined at the receiving side. The matching confirmation pattern is added for the purpose of easily confirming that two correct divided frames are combined when combining on the receiving side.

  Although the matching confirmation pattern adding device 32 is arranged at the subsequent stage of the encryption device 30, the reverse may be possible.

  The dividing device 34 converts the frame 76 shown in FIG. 2C output from the matching confirmation pattern adding device 32 into two divided frames 78, as shown in FIGS. 2D and 2E, according to a predetermined dividing rule. Divide into 80. At this time, as a predetermined division rule, the frame 76 shown in FIG. 2C output from the matching confirmation pattern adding device 32 is simply divided into the first half and the second half, or divided into even bits and odd bits. Possible methods. In terms of security, it is preferable to divide the frame 76 shown in FIG. 2 (c) into two according to more complicated rules, preferably according to rules that may differ for each destination. The split ratio is preferably 1: 1, but is not necessarily limited to 1: 1.

  The dividing device 34 supplies one divided frame 78 to the error correction coding device 36a, and supplies the other divided frame 80 to the error correction coding device 36b. The error correction encoding device 36a adds a parity or error correction code (ECC) for error correction to the frame 78, and outputs a frame 82 shown in FIG. 2 (f) to the variable delay device 38a. Similarly, the error correction coding device 36b adds a parity for error correction to the frame 80, and outputs the frame 84 shown in FIG. 2 (g) to the variable delay device 38b.

  The delay control device 26 sets a delay time for canceling the propagation time difference between the optical fiber transmission lines 12 and 14 in the variable delay devices 38a and 38b in accordance with the information on the propagation time difference from the destination discriminating device 24. For example, the propagation time of the optical fiber transmission line 12 is T1, and the propagation time of the optical fiber transmission line 14 is T2. When T1> T2, the delay control device 26 sets a delay time longer than the delay time of the variable delay device 38a by (T1-T2) in the variable delay device 38b. Conversely, when T1 <T2, the delay control device 26 sets a delay time longer than the delay time of the variable delay device 38b by (T2−T1) in the variable delay device 38a. Thus, by adjusting the delay times of the divided frames 82 and 84 with ECC, the transmission time difference in the case of transmitting different optical fiber transmission lines 12 and 14 can be compensated in advance. At the same time, it reaches the optical receiver 50.

  In the embodiment shown in FIG. 1, the error correction encoding devices 36a and 36b are arranged in front of the variable delay devices 38a and 38b. However, in the arrangement shown in FIG. 1, the delay time control by the variable delay devices 38a and 38b is more accurate than the reverse arrangement.

  The electrical / optical (E / O) conversion device 40 a converts the electrical signal output from the variable delay device 38 a into an optical signal and outputs the optical signal to the optical fiber transmission line 12. The electrical / optical (E / O) conversion device 40b converts the electrical signal output from the variable delay device 38b into an optical signal and outputs the optical signal to the optical fiber transmission line 14. As a result, the divided frame 82 with ECC reaches the optical receiver 50 via the optical fiber transmission path 12, and the divided frame 84 with ECC reaches the optical receiver 50 via the optical fiber transmission path 14. .

  In the optical receiver 50, an optical / electrical (O / E) converter 52a converts an optical signal from the optical fiber transmission line 12 into an electric signal, and an optical / electrical (O / E) converter 52b converts the optical signal to the optical fiber transmission line. The optical signal from 14 is converted into an electric signal. O / E converters 52a and 52b receive optical signals carrying frames 82 and 84, respectively, substantially simultaneously by delay adjustment by variable delay units 38a and 38b of optical transmitter 20. The binary discriminating device 54a performs binary discrimination on the output electrical signal of the O / E converter 52a, and the binary discrimination device 54b performs binary discrimination on the output electrical signal of the O / E converter 52b. The output of the binary discriminating device 54a corresponds to the frame 82 shown in FIG. 2 (f), and the output of the binary discriminating device 54b corresponds to the frame 84 shown in FIG. 2 (g).

  The error correction device 56a corrects the transmission error using the error correction code attached to the frame output from the binary discrimination device 54a, here, the error correction code added by the error correction coding device 36a. Similarly, the error correction device 56b corrects a transmission error using the error correction code attached to the frame output from the binary discriminating device 54b, here, the error correction code added by the error correction coding device 36b. To do. The output of the error correction device 56a corresponds to the divided frame 78 shown in FIG. 2D, and the output of the error correction device 56b corresponds to the divided frame 80 shown in FIG.

  The O / E conversion device 52a, the binary discrimination device 54a, and the error correction device 56a correspond to the input device referred to in the claims.

  The synthesizer 58 synthesizes the divided frames 78 and 80 in which the errors from the error correction devices 56 a and 56 b have been corrected into the original one frame 76 and writes the synthesized result in the buffer memory 60. When the rule for dividing the frame 76 into two divided frames 78 and 80 depends on the optical transmission device 20, the division rule (from the optical reception device 50 is considered) from the optical transmission device 20 to the optical reception device 50 prior to data transmission. , Composition rule). For data that does not require a high level of security, the optical transmission device 20 and the optical reception device 50 transmit data using only one of the optical fiber transmission lines 12 and 14, for example, only one predetermined. . In this case, the synthesizing device 58 passes through the output of the error correction devices 56a and 56b that is involved in reception.

  The buffer memory 60 temporarily stores the synthesized frame synthesized by the synthesis device 58. The matching pattern discriminating device 62 discriminates whether or not the same matching check pattern as that added by the matching check pattern adding device 32 of the optical transmission device 20 exists at the head of the combined frame stored in the memory 60.

  When there is a correct matching confirmation pattern, the combined frame stored in the memory 60 includes correct data transmitted from the optical transmission device 20, so the matching confirmation pattern determination device 62 discards the matching confirmation pattern from the buffer memory 60. Then, the part following the matching confirmation pattern, that is, the part corresponding to the encrypted frame 74 in FIG. The buffer memory 60 functions as a device that removes the matching confirmation pattern.

  The decryption device 64 decrypts the encrypted frame from the memory 60 using the decryption key corresponding to the encryption of the encryption device 30. The output of the decryption device 64 corresponds to the frame 72 shown in FIG. The output frame of the decryption device 64 is output to the outside as a reception frame.

  When the correct matching confirmation pattern does not exist in the buffer memory 60, the frame stored in the memory 60 does not include the correct data transmitted from the optical transmission device 20. In this case, the matching confirmation pattern determination device 62 deletes the frame stored in the buffer memory 60. As a result, data that is not addressed to the optical receiver 50 is discarded.

  In the reception system of the optical transceiver 70, there is a time difference between the frame received via the optical fiber transmission path 12 and the frame received via the optical fiber transmission path 14. Due to this time difference, the synthesis result by the synthesizing device 58 has a data content different from that of the frame 76 shown in FIG. 2C, more specifically, a content having a different alignment confirmation pattern portion at the head. Therefore, the correct matching confirmation pattern does not exist in the buffer memory corresponding to the buffer memory 60, and the optical transmission / reception device 70 discards the data from the optical transmission device 20. Even if the matching check pattern is skipped, the optical transmission / reception device 70 cannot correctly decrypt the encrypted frame 74 because the optical reception device 50 and the optical transmission / reception device 70 have different decryption keys.

  In this way, in this embodiment, (1) one data frame is divided into two divided frames, each divided frame is transmitted through a different transmission path, and (2) whether or not the divided frames are combined is determined. By providing a matching check pattern, that is, a matching confirmation pattern, it is possible to prevent another receiving apparatus from taking in data that is not addressed to it with a simple configuration. Further, (3) by performing encryption depending on the transmission device and the reception device, the possibility of interception by other reception devices can be reduced. Since the encryption is performed at the stage before the division, even if the decryption key is acquired, if both of the two divided frames are acquired and the correct delay time difference between the two divided frames cannot be acquired, the contents are changed. I can't decipher it. By having such three features, it is possible to eliminate interception by other receiving apparatuses and to realize highly confidential communication. In order to intercept, the optical signals of the corresponding divided frames must be received from both of the two optical fiber transmission lines 12 and 14, the received frames should be combined with the correct delay time difference, and the combined frame must be decoded. It is extremely difficult.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

It is a schematic block diagram of one Example of this invention. It is a schematic diagram explaining the procedure of the frame process in a present Example.

Explanation of symbols

10: Ring transmission line 12, 14: Optical fiber transmission line 20: Optical transmission device 22: Destination information database 24: Destination discrimination device 26: Delay control device 28: Encryption control device 30: Encryption device 32: Matching confirmation pattern addition Device 34: Splitting devices 36a, 36b: Error correction coding devices 38a, 38b: Variable delay devices 40a, 40b: Electric / optical conversion device 50: Optical receiving devices 52a, 52b: Optical / electrical (O / E) converter 54a 54b: Binary discriminating devices 56a, 56b: Error correcting device 58: Combining device 60: Buffer memory 62: Matching confirmation pattern discriminating device 64: Decoding device 70: Optical transceiver

Claims (21)

A matching check pattern adding step for adding a matching check pattern to the data frame for checking the correctness;
A dividing step of dividing the data frame to which the matching confirmation pattern is added into a plurality of divided frames;
A delay step for giving a delay for compensating a difference in propagation time between a plurality of transmission paths to each of the plurality of divided frames;
An output step of outputting each delayed divided frame to a different transmission path among the plurality of transmission paths;
A synthesis step of synthesizing each divided frame from each transmission path;
A matching confirmation pattern determination step for determining whether or not there is a correct matching confirmation pattern in the combined frame by the combining step;
And a step of discarding the composite frame when a correct matching confirmation pattern is not confirmed. Furthermore,
An encryption step for encrypting the data frame with a predetermined encryption key before division by the division step;
The data transmission method according to claim 1, further comprising: a decoding step of decoding a portion corresponding to the data frame of the composite frame in which a correct matching confirmation pattern is confirmed.   3. The data transmission method according to claim 2, wherein the predetermined encryption key is determined according to a transmission device and a reception device. Furthermore,
An error correction encoding step for error correcting encoding each divided frame;
The data transmission method according to any one of claims 1 to 3, further comprising: an error correction step of correcting each divided frame from each transmission.   The data transmission method according to any one of claims 1 to 4, wherein the plurality of transmission lines include two ring transmission lines having different transmission directions. A data transmission system for transmitting data from a transmission device to a reception device using a plurality of transmission paths,
The transmitting device (20)
A destination discriminating device (24) for discriminating the destination of the input data frame;
A destination database (22) for storing information on propagation times in a plurality of transmission paths (12, 14) for each destination;
Pre-processing device (30, pre-processing device for pre-processing the input data frame, comprising a matching check pattern adding device (32) for adding a matching check pattern for checking validity to the input data frame 32)
A frame dividing device (34) for dividing a frame output from the preprocessing device into a plurality of divided frames;
A plurality of variable delay devices (38a, 38b) configured to delay each of the plurality of divided frames, with a delay time that substantially compensates for a propagation time difference in a transmission path used for transmission of each divided frame;
A plurality of output devices (40a, 40b) for outputting signals carrying the divided frames delayed by the plurality of variable delay devices to different transmission paths among the plurality of transmission paths.
And
The receiving device (50)
A plurality of input devices (52a, 54a, 56a; 52b, 54b, 56b) for inputting signals carrying the divided frames from each of the plurality of transmission paths;
A combining device (58) for combining a plurality of divided frames from the plurality of input devices into one frame;
A matching confirmation pattern discriminating device (62) for discriminating whether or not there is a correct matching confirmation pattern in the synthesized frame output from the synthesizing device (58);
An apparatus (60) for discarding the composite frame when a correct alignment confirmation pattern is not confirmed
A data transmission system comprising: The preprocessing device comprises an encryption device (30) for encrypting the input data frame;
The receiving device further includes
A decrypting device (64) for decrypting the data portion encrypted by the encrypting device of the composite frame in which the correct matching confirmation pattern is confirmed
The data transmission system according to claim 6, further comprising:   8. The data transmission system according to claim 7, wherein the encryption device encrypts the input data frame with an encryption key corresponding to the destination determined by the destination determination device.   9. The data transmission system according to claim 8, wherein the destination information database stores information on an encryption key corresponding to the destination. The transmission device further includes an error correction coding device (36a, 36b) for performing error correction coding on each divided frame,
Each of the plurality of input devices of the receiving device includes an error correction device (56a, 56b) for correcting an error of a signal carrying the divided frame from the corresponding transmission path. 6. The data transmission system according to 6.   The data transmission system according to any one of claims 6 to 10, wherein the plurality of transmission lines include two ring transmission lines having different transmission directions. A destination discriminating device (24) for discriminating the destination of the input data frame;
A destination database (22) for storing information on propagation times in a plurality of transmission paths (12, 14) for each destination;
Pre-processing device (30, pre-processing device for pre-processing the input data frame, comprising a matching check pattern adding device (32) for adding a matching check pattern for checking validity to the input data frame 32)
A frame dividing device (34) for dividing a frame output from the preprocessing device into a plurality of divided frames;
A plurality of variable delay devices (38a, 38b) configured to delay each of the plurality of divided frames, with a delay time that substantially compensates for a propagation time difference in a transmission path used for transmission of each divided frame;
A plurality of output devices (40a, 40b) for outputting signals carrying the divided frames delayed by the plurality of variable delay devices to different transmission paths among the plurality of transmission paths.
A transmission apparatus comprising:   The transmission device according to claim 12, wherein the preprocessing device comprises an encryption device (30) for encrypting the input data frame.   14. The transmission apparatus according to claim 13, wherein the encryption apparatus encrypts the input data frame with an encryption key corresponding to the destination determined by the destination determination apparatus.   The transmission apparatus according to claim 14, wherein the destination information database holds information on an encryption key corresponding to the destination.   The transmission device according to claim 12, further comprising an error correction coding device (36a, 36b) for performing error correction coding on each divided frame.   The transmission device according to any one of claims 12 to 16, wherein the plurality of transmission lines are composed of two ring transmission lines having different transmission directions. A receiving device that receives a plurality of divided frames divided from one data frame substantially simultaneously via different transmission paths to receive the data frame,
A plurality of input devices (52a, 54a, 56a; 52b, 54b, 56b) for inputting signals carrying the divided frames from each of the plurality of transmission paths;
A combining device (58) for combining a plurality of divided frames from the plurality of input devices into one frame;
A matching confirmation pattern discriminating device (62) for discriminating whether or not there is a predetermined matching confirmation pattern in the synthesized frame output from the synthesizing device (58);
A device (60) for discarding the composite frame when the predetermined matching confirmation pattern is not confirmed
A receiving apparatus. The data frame is encrypted,
19. The receiving device according to claim 18, further comprising a decrypting device (64) for decrypting an encrypted data portion of the composite frame in which a correct matching confirmation pattern is confirmed.   20. Each of the plurality of input devices includes an error correction device (56a, 56b) that corrects an error of a signal carrying the divided frame from the corresponding transmission path. The receiving device described.   The receiving apparatus according to any one of claims 18 to 20, wherein the plurality of transmission lines include two ring transmission lines having different transmission directions.

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