JP2012080227A - Communication system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a communication system which applies optical communication quantum cipher communication to a passive optical network (PON) system including one transmitter and multiple receivers.SOLUTION: A PON system includes one transmitter and multiple receivers. The transmitter includes management means for performing management by the association of common cipher keys for each of the multiple receivers with Y-00 quantum ciphers applied thereto. When data is transmitted to one receiver, the cipher key associated with the receiver by using the management means is selected, a Running key is generated through the use of the selected cipher key, and then, multiple value level signal of transmission data is generated in accordance with a value of the Running key. The receivers with the Y-00 quantum ciphers applied thereto generate Running keys in reception pseudo random number generation parts through the use of the common cipher keys managed by the transmitter, and then, generate multiple value level signals of reception data converted by a photoelectric converter, in accordance with the values of the Running keys.

Description

  The present invention relates to a communication system and method, and more particularly, to a PON (Passive Optical Network) system and communication method using optical communication quantum cryptography (Y-00).

  2. Description of the Related Art An Ethernet PON system that efficiently implements broadband IP (Internet Protocol) communication using a PON (Passive Optical Network) system type FTTH (Fiber to the Home) network has been put into practical use. An EPON (Ethernet (registered trademark) Passive Optical Network) system generally distributes a TDM optical signal output from one OLT (Optical Line Terminal) by an optical distributor to a plurality of ONUs (Optical Network Units). This is a configuration to be provided.

  Since the EPON system has a broadcast characteristic in the downstream direction, the downstream frame transmitted from the OLT is transmitted to all ONUs. Therefore, each ONU is filtered so as to receive only frames transmitted to itself. However, an eavesdropper (unauthorized subscriber) can alter the frame filtering function or forge and impersonate other ONUs, and easily view important information transmitted to other ONUs. In order to ensure the safety of communication on such an EPON, for example, Patent Document 1 discloses a step of encrypting a first type packet with a first short MACsec header and a first predetermined SAK; One type of packet is transmitted from the OLT to one ONU of the plurality of ONUs via the EPON, and a second type packet having a second short MACsec header is transmitted from the OLT to the ONU; A method is disclosed in which the type of packet is encrypted with a second predetermined SAK.

  By the way, the present applicant has proposed optical communication quantum cryptography (Y-00) communication based on Yuen-2000 quantum cryptography. This communication system is a communication technique that spreads light quantum fluctuations (quantum shot noise) by modulation and makes it impossible to receive an optical signal accurately by an eavesdropper, as disclosed in Patent Document 2, for example. Application to key quantum cryptography is proposed. In this common key quantum cryptography, a binary optical signal is set as one set (referred to as a base), a plurality of M bases are prepared, and which base is used to send data is determined by a pseudo-random number according to the encryption key. Decide on. Actually, the optical M-value signal is designed so that the distance between the signals is so small that it cannot be identified due to quantum fluctuations. Therefore, the eavesdropper cannot read the data information from the received signal and can prevent eavesdropping.

JP 2010-158028 A JP 2010-111462 A

  As described above, the EPON system is required to conceal information with higher safety. In addition, although optical communication quantum cryptography communication is attracting attention as one means for preventing eavesdropping, both Patent Documents 1 and 2 describe optical communication quantum cryptography for an EPON system having one transmission device and a plurality of reception devices. There is no suggestion about the application of communication.

An object of the present invention is to realize a communication system in which optical communication quantum cryptography communication is applied to a system having one transmission device and a plurality of reception devices.
More specifically, the present invention is to realize a PON system and a transmission method that can improve the concealment of information by applying optical communication quantum cryptography.

The communication system according to the present invention is preferably a communication system including a transmission device and a plurality of m reception devices connected to the transmission device via an optical transmission line.
The transmitting device;
Management means for managing a plurality of n (where n ≦ m) receivers to which optical communication quantum cryptography is applied in association with a common encryption key and managing data when transmitting data to a receiver Then, a selection means for selecting the encryption key associated with the receiving apparatus, and a multilevel optical signal for data to be transmitted to the receiving apparatus are controlled using the encryption key selected by the selection means. A multi-value encryption processing unit
Each of the plurality of n receiving apparatuses is an apparatus to which optical communication quantum cryptography is applied, and a photoelectric converter that receives and photoelectrically converts an optical signal transmitted from the transmitting apparatus, and a common managed by the transmitting apparatus And a multi-level decryption processing unit that decrypts the received data converted by the photoelectric converter into a binary signal using the encryption key.

In a preferred example, the multi-value encryption processing unit of the transmitting device is
A transmission pseudo-random number generation unit that generates a Running key using the encryption key selected by the selection unit, and a value of the Running key generated by the transmission pseudo-random number generation unit for data to be transmitted A multi-value light generation unit that generates a multi-value optical signal in response,
The multi-level decryption processing unit of the receiving device is generated by a receiving pseudo-random number generating unit that generates a Running key using a common encryption key managed by the transmitting device, and the receiving pseudo-random number generating unit. A threshold generation unit that generates a multi-value threshold signal for identification of received data converted by the photoelectric converter according to the value of the running key, and a multi-value threshold according to the multi-value threshold for identification generated by the threshold generation unit. A decoding processing unit for decoding the value signal.

  Preferably, in the communication system, the management unit determines a type of a receiving apparatus to which optical communication quantum cryptography is applied (first type) and a type of receiving apparatus to which optical communication quantum cryptography is not applied (second type). It has a management table for registering and registering information specifying the common encryption key used by each receiving apparatus for the first type receiving apparatus.

  Preferably, in the communication system, according to the type of the receiving device registered in the management table, a transmission line through which a multilevel optical signal that is an output from the multilevel encryption processor is passed, Alternatively, a selector that selects a transmission line that does not pass through the multi-value encryption processing unit is provided.

Preferably, in the communication system, the communication system is a PON system,
The transmitting device is an OLT, and the plurality of receiving devices are ONUs connected to the optical transmission line via an optical distributor.

The communication method according to the present invention is preferably a communication method for transmitting data from the transmitting device to the plurality of m receiving devices via an optical transmission line,
In the transmitting device;
Associating and managing a plurality of n (where n ≦ m) receiving devices to which optical communication quantum cryptography is applied are associated with each other, and
When transmitting data to a receiving device, selecting the encryption key associated with the receiving device;
Generating a Running key using the selected encryption key;
Generating a multi-level signal for the data to be transmitted in accordance with the value of the Running key;
In the plurality of n receiving apparatuses to which optical communication quantum cryptography is applied;
Receiving and photoelectrically converting optical signal transmission data transmitted from the transmitter; and
Generating a Running key using a common encryption key managed by the transmitting device;
Generating a multi-value threshold signal for identification of the received data subjected to photoelectric conversion according to the generated value of the Running key, and decoding the multi-value signal according to the multi-value threshold for identification. It is comprised as a communication method characterized by this.

  According to the present invention, a communication system such as a PON system having one transmission device and a plurality of reception devices, which further improves the concealment of information by applying the optical communication quantum cryptography (Y-00), is realized. Is possible.

The figure which shows the outline of the PON system by one Example. The figure which shows the structure of the PON system using the Y-00 quantum cryptography by one Example. The block diagram which shows the structure of the multilevel encryption process in OLT11 of one Example. The figure which shows the structural example of the management table of ONU in OLT of one Example.

An embodiment of the present invention will be described below with reference to the drawings.
First, the principle of the present invention will be described with reference to the PON system shown in FIG.
This PON system includes an OLT (Optical Line Terminal) 11 and a plurality of ONUs (Optical Network Units) 131 to 13m (generally indicated as 13), an optical transmission line and an optical distributor (optical splitter or star coupler). (Also referred to as 12).
The plurality of ONUs 13 include those to which Y-00 quantum cryptography is applied (herein referred to as Y-00 ONU) and those to which this is not applied (referred to as conventional ONU). For example, ONUs 131, 133, and 13m are Y-00 ONUs, but the ONU 132 is a conventional OUN. These are managed by a management table (see FIG. 4) that the OLT 11 has.
Incidentally, since the conventional ONU is not applied with the Y-00 quantum cryptography, high-level information concealment cannot be ensured. The conventional ONU is, for example, information processing using a special algorithm at a logic level, or security ensuring described in Patent Document 1.

  When sending a packet (downstream packet) P in the OLT 11, the packet P is encrypted using any one of the n encryption keys K (K 1 to Kn) shared with the corresponding ONU 13. And sent to the optical transmission line. For example, the packets P1 and P2 are encrypted with the encryption keys K1 and K2. Note that a packet that is not addressed to any Y-00ONU is not encrypted with these encryption keys.

  The ONU 13 decrypts the received packet using its own common encryption key Ki. At this time, since the common encryption key Ki does not match for a packet not addressed to its own ONU, the transmission data cannot be correctly decrypted. Similarly, the upstream packet can be encrypted using a common encryption key shared between each ONU and the OLT 11 and transmitted to the OLT 1 to improve the confidentiality of the information.

  FIG. 2 shows a configuration of a multi-value encryption processing unit mainly of OLT and ONU in a PON system using Y-00 quantum cryptography. Since the ONU 132 shown in FIG. 1 is a conventional ONU, it is not shown in FIG. 2, the left side is the OLT 11 of the transmitting device and the right side is a plurality of Y-00ONUs 13 of the receiving device.

  The OLT 11 manages the encryption keys K corresponding to the number n of Y-00ONUs, generates a pseudorandom number by inputting the encryption key K, and generates a running key. A transmission data generation unit 114 that generates transmission data and a multilevel light generation unit 113 that generates a multilevel analog signal (multilevel signal) according to the value of the Running key for the transmission data. Is done.

  Y-00ONUs 131 and 133 on the receiving side are multi-level decoding processing units, which are shared with the OLT 11 and the photoelectric converters 1313 and 1333 that receive and photoelectrically convert the optical signals that have passed through the optical transmission path 19 and the optical distributor 12. The transmission side pseudo random number generation unit 102, the reception side pseudo random number generation units 1312 and 1332 and the threshold value generation units 1314 and 1334, which generate the same synchronized running key by inputting the encrypted encryption key K, Configured. (Y-00ONUs 131 and 133 have the same configuration, so only the Y-00ONU131 side code will be quoted below). The threshold generation unit 1314 generates a reception threshold for multi-level signal determination using the Running key generated from the pseudo random number generation unit 1312 for the optical signal received by the photoelectric converter 1313. The decoding processing unit 1315 determines (discriminates) 1 and 0 according to the reception threshold value and outputs reception data.

In the PON system configured as described above, transmission data generated by the transmission data generation unit 114 of the OLT 11 is generated as a multi-level optical signal by the multi-level optical generation unit 113 according to the value of the running key, and the optical transmission line 19 and the optical distribution It is transmitted to all ONUs 13 through the device 12.
In the ONU 123, the received optical multilevel signal is photoelectrically converted by the photoelectric converter 1313. Further, in the Y-00ONU 131 having the common encryption key K1 among the Y-00ONUs, the pseudo random number generation unit 1312 generates a Running key using the same encryption key K1 used for encryption in the OLT 11. Using the Running key, the threshold generation unit 1314 generates a reception threshold, and the decryption processing unit 1315 determines the received data and outputs the received data. In this case, since the ONU that does not have the designated encryption key K, that is, other Y-00 ONUs or conventional NOUs does not match the encryption key K used on the OLT 11 side, the photoelectrically converted data is not decrypted. The confidentiality of transmission data can be improved.

FIG. 3 shows a block diagram of multi-value encryption processing in the OLT.
The OLT 11 includes an upper layer 101 that performs logical encryption processing on transmission data, a MAC (Media Access Control) 102 that performs processing such as designation of a transmission destination address and transmission source address of transmission data, framing processing, and access management. , Y-00 is composed of a physical layer 103 that performs multi-level encryption processing. Although logical encryption processing in the upper layer 101 is not directly related to the present invention, processing using a conventional encryption algorithm is performed.

  One feature of the present invention is the management of the encryption key of each ONU 13. For this purpose, the MAC 102 has an ONU management table 40 as shown in FIG. The ONU management table 40 registers numbers for designating the ONU type and Y-00 encryption key for all m ONUs 13. The ONU type indicates whether the ONU 13 is an ONU corresponding to Y-00 quantum cryptography (Y-00 ONU) or other ONUs (former ONUs). In Y-00ONU, a number for specifying an encryption key is registered. Here, the ONU numbers # 1 to #m are associated with the unique MAC address of each ONU 13, but the MAC address of each ONU may be directly registered.

On the other hand, each Y-00 ONU has an encryption key registered in the ONU management table 40, and decrypts received data using a Running key generated with the encryption key.
The physical layer 103 mainly includes a multi-value encryption processing unit 104 and a selector 105. The multi-value encryption processing unit 104 corresponds to the portion 11 in FIG. The selector 105 selects either the transmission line 108 or 109 for transmission data from the MAC 102 based on the ONU type selection signal 107 in the ONU management table 40.

Now, the transmission data created in the upper layer 101 is sent to the MAC 102 where it is framed. Further, the MAC 102 refers to the ONU management table 40 based on the transmission destination address, and determines the type of ONU of the transmission destination. As a result, if the transmission destination is the conventional ONU (that is, Other), the selector 105 selects the transmission line 109 by the ONU type selection signal 107 and transmits the transmission data as it is.
On the other hand, when the transmission destination is Y-00 ONU, the encryption key Ki corresponding to the ONU of the transmission destination is selected by the ONU management table 40, and the multi-value encryption processing unit 104 performs multi-value encryption as shown in FIG. A value level signal is generated. Further, the selector 105 selects the transmission line 108 by the ONU type selection signal 107 and transmits the transmission data of the multilevel signal output from the multilevel encryption processing unit 104.

  According to the present embodiment, in a PON system in which a plurality of ONUs, in particular Y-00 ONUs to which Y-00 quantum cryptography is applied, and conventional ONUs to which this is not applied are mixed in one OLT, Concealment can be ensured. That is, even if there is a problem in the logical processing of transmission data in the OLT 11 and the management of MAC addresses of a plurality of ONUs as transmission destinations, which have been conventionally proposed for ensuring information security, Y- With Y-00ONU to which 00 quantum cryptography is applied, it is possible to keep the concealment of received data.

  The example of the PON system to which the optical communication quantum cryptography is applied has been described above, but the present invention is not limited to the PON system, and an optical communication quantum cryptography communication system in which one transmission device and a plurality of reception devices are connected through an optical communication path. It is applicable to. Further, not only time division multiplexing but also wavelength multiplexing methods can be applied by using different keys for each wavelength.

11: OLT 12: Optical distributor 13, 131, 132, 133-13n: ONU
19: Optical transmission path K1, K6,..., K19: Encryption key P1 to Pi: Packet 112: Pseudorandom number generator 113: Multilevel light generator 114: Transmission data generator
1312, 1332: Pseudorandom number generator 1313, 1333: Photoelectric converter 1314, 1334: Threshold generator 1315, 1335: Decryption processor 101: Upper layer 102: MAC 103: Physical layer 104: Multi-level encryption processor 105: Selector .

Claims (6)

In a communication system including a transmission device and a plurality of m reception devices connected to the transmission device via an optical transmission path,
The transmitting device;
Management means for managing a plurality of n (where n ≦ m) receivers to which optical communication quantum cryptography is applied in association with a common encryption key and managing data when transmitting data to a receiver Then, a selection means for selecting the encryption key associated with the receiving apparatus, and a multilevel optical signal for data to be transmitted to the receiving apparatus are controlled using the encryption key selected by the selection means. A multi-value encryption processing unit
Each of the plurality of n receiving devices;
A device to which optical communication quantum cryptography is applied, using a photoelectric converter that receives and photoelectrically converts an optical signal transmitted from the transmission device, and a common encryption key managed by the transmission device, A multi-level decoding processing unit that generates a multi-level signal of received data converted by the photoelectric converter;
A communication system characterized by the above. The multi-value encryption processing unit of the transmitting device is
A transmission pseudo-random number generation unit that generates a Running key using the encryption key selected by the selection unit, and a value of the Running key generated by the transmission pseudo-random number generation unit for data to be transmitted A multi-level light generation unit that generates a multi-level signal in response,
The multi-level decryption processing unit of the receiving device is generated by a receiving pseudo-random number generating unit that generates a Running key using a common encryption key managed by the transmitting device, and the receiving pseudo-random number generating unit. A threshold generation unit that generates a multi-value threshold signal for identification of received data converted by the photoelectric converter according to the value of the running key, and a multi-value threshold according to the multi-value threshold for identification generated by the threshold generation unit. The communication system according to claim 1, further comprising: a decoding processing unit that decodes the value signal. The management means registers a type (first type) of a receiving device to which optical communication quantum cryptography is applied and a type (second type) of a receiving device to which optical communication quantum cryptography is not applied, and For the receiving device, it has a management table that registers and registers information specifying a common encryption key used by each receiving device.
The communication system according to claim 1 or 2. According to the type of the receiving device registered in the management table, a transmission line through which a multilevel optical signal that is an output from the multilevel encryption processing unit is passed is selected, or the multilevel encryption processing unit is not passed Having a selector for selecting a transmission line;
The communication system according to any one of claims 1 to 3, wherein The communication system is a PON system;
The transmitting device is an OLT;
The plurality of receiving devices are ONUs connected to the optical transmission line via an optical distributor.
The communication system according to any one of claims 1 to 4, characterized in that: A communication method for transmitting data from a transmission device to the plurality of m reception devices via an optical transmission line, wherein the transmission device includes:
Associating and managing a plurality of n (where n ≦ m) receiving devices to which optical communication quantum cryptography is applied are associated with each other, and
When transmitting data to a receiving device, selecting the encryption key associated with the receiving device;
Generating a Running key using the selected encryption key;
Generating a multi-level signal for the data to be transmitted in accordance with the value of the Running key;
In the plurality of n receiving apparatuses to which optical communication quantum cryptography is applied;
Receiving and photoelectrically converting optical signal transmission data transmitted from the transmitter; and
Generating a Running key using a common encryption key managed by the transmitting device;
Generating a multi-value threshold signal for identification of the received data subjected to photoelectric conversion according to the generated value of the Running key, and decoding the multi-value signal according to the multi-value threshold for identification. A communication method characterized by the above.

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