JP2009029298A - Communication system for train control - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure security higher than a conventional one, and to suppress the construction cost of a system, in a communication system for train control which encodes between a ground device and an on-vehicle device and transmits data by radio. <P>SOLUTION: The communication system for train control is composed of: a plurality of ground devices 10A, 10B provided in each predetermined zone on a railroad and managing trains existing in a zone about each zone; an on-vehicle device 20 mounted on each train; a transponder on-vehicle element 27 connected to the on-vehicle device; and transponder ground elements 17A1, 17A2, 17B1, 17B2, 17C1, 17C2 installed near borders of each section and connected to the ground device. A cryptogram is transmitted by radio transmission passage communications 2A, 2B, and a key is transmitted through a transponder transmission passage including the transponder on-vehicle element and the transponder ground elements simultaneously with authentication information. The key can be set and changed when the combination of a train and a base (the ground device) to be communicated is switched. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a train control system using radio, and more particularly to a train control communication system that transmits encrypted data using radio between a ground device and an on-board device mounted on a train.

  The train control system that has been widely used in the past sets sections that do not overlap with the train tracks, and detects the train in each section by the train axle short-circuiting the left and right rails. This is a system that provides a track circuit, detects the train position using the track circuit, and manages so that only one train can operate in each section. One of the train control communication systems employed in this conventional train control system is described in Japanese Patent Application Laid-Open No. 2000-233750 (Patent Document 1). This conventional train control communication system is a train control communication system that transmits encrypted data between a ground device and an on-board device using radio, and the ciphertext is transmitted by radio communication, and The key is transmitted through a transmission line using a track circuit, thereby ensuring high security.

In recent years, a train control system using radio is being standardized. Among such systems, a so-called ATACS (Advanced Train Administration and Communication System) described in Japanese Patent Application Laid-Open No. 2007-015517 (Patent Document 2) is a transponder installed at predetermined intervals along a track. A ground unit, a ground device to which the transponder ground unit is connected, an on-board device mounted on a train, and a system including a transponder on-board unit connected to the on-board device, The detection is performed by the on-board device itself. That is, in this system, the transponder ground unit number and installation position data are stored in the storage device of the on-board device. When communication is established between the transponder ground element and the transponder ground element, the on-board apparatus searches the storage device and recognizes the installation position of the transponder ground element. Subsequently, the on-board device calculates the travel distance of the train from the recognized installation position by adding the train speed, and adds this to the recognized installation position to identify the current position of the train. In this way, the on-board device detects the current position of the train. The ground device may be displayed as a base device.

In such a train control system using radio, the on-board device transmits the position information of the train identified by itself to the ground device by radio communication. Based on the position information of each train and other track information sent from the on-board device, the ground device generates the position information of the preceding train of each train and the information indicating the stop limit related to the route. It transmits by radio to the on-board equipment of the train. Based on the received information, the on-board device of each train creates a brake pattern and performs brake control when the train approaches the stop limit, thereby avoiding a train collision. By using such a train control system, costs can be reduced and safety can be improved as compared with a train control system that detects a train position using a conventional track circuit.

In the above-described train control system using radio, important information related to train control or operation is transferred between the ground device and the on-board device through a single radio transmission path. However, since wireless communication uses radio waves, information can be eavesdropped secretly, and security vulnerabilities such as tampering and spoofing have been pointed out. For this reason, an encryption technique is used to ensure security in such a case. For example, as shown in FIG. 5, a train control communication system including the ground device 10, the on-board device 20, and the wireless transmission path 1 is used. The ground device 10 includes a ground control device 11, an encryption / decryption unit 12, and an input / output unit 14. The on-board device 20 includes an on-board control device 21, an encryption / decryption unit 22, and an input / output unit 24. Information transmission between the ground device 10 and the on-vehicle device 20 is performed wirelessly.

Of the existing encryption technologies that can be applied to such cases, public key cryptosystems are generally guaranteed to be highly secure, but the amount of processing computation becomes very large when trying to increase the level of security. Therefore, it is not suitable for communication such as train control information with restrictions on them. On the other hand, in the secret key cryptosystem, the arithmetic processing is relatively simple, but management of key distribution is required, and there is a risk of the key being stolen. Therefore, for key management, the key is managed by a highly secure communication channel. Security measures must be taken to ensure security.

In addition, there is no guarantee that the decryption of the code can be surely prevented in the future due to the increase in the speed of computers and the development of the decryption algorithm. Therefore, applying a different key for each information transmission target and frequently changing the key is extremely effective in preventing illegal decryption of the ciphertext. However, frequent distribution of keys causes factors such as an increase in the risk of leakage of cryptographic information associated with distribution, an increase in facility costs for distribution, and an increase in processing load associated with distribution work. Therefore, it is necessary to set up a mechanism to do this for an appropriate target at an appropriate time.

However, the key distribution in the train control communication system proposed so far is performed at an appropriate time by wireless communication to the entire system, and security measures related to key management are sufficiently implemented. It's hard to say. Therefore, the present inventor employs the technology of the encrypted data transmission method disclosed in Patent Document 1, and the ciphertext is transmitted by radio communication between the on-board device and the ground device, and the key is the on-board device We examined whether the train control communication system that transmits through the transponder transmission line including the transponder vehicle connected to the ground and the transponder connected to the ground device is suitable for the train control system using radio. . As a result, this communication system for train control aims to reduce costs and improve safety compared to a train control system that uses radio, that is, a train control system that detects a train position using a conventional track circuit. It was concluded that it was still insufficient to ensure security commensurate with the feature of being able to.
JP 2000-233750 A JP 2007-015517 A

The problem to be solved by the present invention is to secure higher security than before and to construct a system in a train control communication system that encrypts data between a ground device and an on-board device and transmits data wirelessly. It is to control costs.

A first train control communication system that solves the above problems is connected to a ground device installed on the ground, an on-board device mounted on a train, a transponder ground element connected to the ground device, and the on-vehicle device. A train control communication system that is applied to a train control system in which the on-board device itself detects the train position, wherein the ciphertext is transmitted by wireless communication, and the key is The at least one authentication information of the on-board device and at least one of the authentication information of the transponder ground device and the ground device is transmitted simultaneously via a transponder transmission path including the transponder on-board device and the transponder ground device. It is characterized by.

A second train control communication system that solves the above-mentioned problems is a plurality of ground devices that are provided for each predetermined track and manages a train existing in a section for each section, an on-board device mounted on each train, A train composed of a transponder vehicle core connected to an on-vehicle device and a transponder ground device installed near the boundary of each section and connected to the ground device, and the on-vehicle device detects the train position by itself. A communication system for train control applied to a control system, wherein a ciphertext is transmitted by wireless communication, and a key is a transponder transmission path including a transponder vehicle core connected to the onboard device and the transponder ground unit. And at least one of the authentication information of the on-vehicle device and the authentication information of the transponder ground unit and the ground device is transmitted simultaneously. It is.

The train control communication system according to the present invention uses a transponder transmission line that is dedicated to railways and difficult to access from others for the transmission of keys with a relatively small amount of information. Sex was secured. In addition, the key can be set and changed for each combination of train / ground equipment to be communicated, so the effectiveness of security measures using the key is further improved and the risk of unauthorized decryption of the ciphertext is reduced. It could be greatly reduced. Moreover, since the key is transmitted simultaneously with the transmission of the authentication information of the on-board device, the authentication information of the transponder ground unit, and the authentication information of the ground device, the security of the key distribution is further increased.

In addition, the train control information is encrypted between the on-board device and the ground device, and the data is transmitted wirelessly. The key information stored in the memory is received by the transponder transmission path and checked for validity. Security is guaranteed. And in the train control system using radio, when the system for detecting the train on the ground device side is already installed in case the radio system becomes unusable, the transponder transmission line is in the existing one. Because it can be partially shared with other transmission lines, it is possible to realize a train control communication system that secures high security with a small capital investment.

A train control communication system suitable for a train control system using radio, a plurality of ground devices that manage a train that is provided in each section of a track and that is in the section for each section, and an on-board device that is mounted on each train A transponder vehicle connected to the on-board device, and a transponder ground installed near the boundary of each section and connected to the ground device, and the ciphertext is transmitted by wireless communication, and the key Is transmitted simultaneously with at least one of the authentication information of the on-board device and the authentication information of the transponder ground device and the ground device via a transponder transmission path including the transponder on-board device and the transponder ground device. .

FIG. 1 shows an embodiment of the present invention, that is, a ground device 10 installed on the ground, also called a base device, an onboard device 20 mounted on a train T traveling on a rail R, a wireless transmission path 2 and a transponder transmission path 3. It is a block diagram of the communication system for train control which consists of these. The ground device 10 includes a ground control device 11, an encryption / decryption unit 12, a ciphertext input / output unit 14, a key input unit 15, and an antenna 16. The onboard device 20 includes an onboard control device 21, an encryption / decryption unit 22, a key generation unit 23, a ciphertext input / output unit 24, a key output unit 25, and an antenna 26. The transponder transmission path 3 includes a transponder ground element 17 connected to the key input unit 15 of the ground apparatus 10 by the wired cable 4 and a transponder vehicle upper element 27 connected to the key output unit 25 of the onboard apparatus 20. .

In the on-board device 20, the key from the key generation unit 23 is sent from the key output unit 25 to the transponder transmission path 3 through the on-board transponder 27 together with the authentication information of the on-board device 20. In the ground device 10, the key and the authentication information are received by the transponder ground element 17 via the transponder transmission path 3 and input to the ground control device 11 from the key input unit 15. The ground control device 11 determines whether or not the on-board device can be authenticated from the authentication information of the on-board device stored in the memory and the received authentication information. When the on-board device can be authenticated, the received key is stored in the memory. To remember.

As information transmission from the on-board device 20 to the ground device 10, various information such as position information, speed information, and train identification number of each train is transmitted. Position information can be obtained by a method of calculating the distance traveled by combining absolute position detection using a ground element installed at a predetermined position in the orbit and wheel rotation speed detection, but this is also used in combination with an accelerometer or Doppler velocimeter It can also be obtained by a method using a GPS system. The on-board control device 21 generates position information, speed information, and the like obtained in this way. This information is converted into ciphertext in the encryption / decryption unit 22 using the key information stored in the memory of the on-board control device 21, sent from the ciphertext input / output unit 24 to the antenna 26, and It is transmitted toward the ground device 10 via the wireless transmission path 2.

In the ground device 10, the ciphertext input / output unit 14 receives the position information of the ciphertext transmitted through the wireless transmission path 2 via the antenna 16. Then, the encryption / decryption unit 12 converts the received ciphertext into plaintext position information using the key information stored in the memory of the ground control device 11, and stores this in the memory.

As information transmission from the ground device 10 to the on-board device 20, train control information is transmitted. The ground control device 11 generates train control information, and the encryption / decryption unit 12 encrypts the train control information using the key information received from the key input unit 23 and stored in the memory of the ground control device 11. Convert to The ciphertext train control information is transmitted from the ciphertext input / output unit 14 to the antenna 16 and transmitted to the on-board device 20 via the wireless transmission path 2.

In the onboard apparatus 20, the ciphertext train control information transmitted through the wireless transmission path 2 is received by the ciphertext input / output unit 24 via the antenna 26. Then, the encryption / decryption unit 22 converts the received ciphertext into plaintext train control information using the key information stored in the memory of the on-board controller 21, and stores this in the memory. A predetermined control operation is performed on the basis of the plaintext train control information. As described above, the ciphertext is wireless and the key is transmitted / received via the transponder device.

In the ground device 10 according to the embodiment of the present invention, the encryption / decryption unit 12 and the key input unit 14 are illustrated as devices different from the ground control device 11, but a part of the ground control device 11. May be configured respectively. Similarly, in the on-board device 20, the encryption / decryption unit 22, the key generation unit 23, and the key output unit 25 are illustrated as devices different from the on-board control device 21. Each may be configured as a part. The key generation unit and the key output unit are in the on-board device 20 and the key input unit is in the ground device 10, but the key generation unit and the key output unit are in the ground device 10 and the key input unit is in the vehicle. The upper device 20 may be provided. Further, the key generation unit and the key output unit may be configured to be in both the ground device and the on-board device. Also, the ground device is supposed to authenticate the on-board device based on the on-board device authentication information, but the transponder ground element authentication information and the ground device authentication information are simultaneously transmitted to the on-board device. The transponder ground unit and the ground device may be authenticated at the same time.

Embodiment 2 of the present invention is a system that enables setting / changing of a key for each combination of train / ground equipment to be communicated, and for each section, a train that is provided for each predetermined section of a track and that is present in the section. A plurality of ground devices managed on the train, a vehicle-mounted device mounted on each train, a transponder vehicle connected to the vehicle-mounted device, and a transponder installed near the boundary of each section and connected to the ground device A communication system for train control that is configured by a ground unit and is applied to a train control system in which the on-board device performs detection of a train position by itself, wherein a ciphertext is transmitted by wireless communication, and a key is on the transponder vehicle It transmits simultaneously with the authentication information of the onboard apparatus via a transponder transmission path including a child and the transponder ground element, and the key is changed for each section.

That is, FIG. 2 shows an embodiment of the present invention in which a key is set / changed for each combination of train / ground equipment to be communicated, and the existing line is within a predetermined section of the track. It is a block diagram at the time of applying to the train control system of the system which the ground apparatus in charge of each section manages each train to perform. In FIG. 2, bases A and B as control areas are set for each predetermined section on the track, ground equipment 10A as a base equipment is installed at base A, and ground equipment as a base equipment is installed at base B. A device 10B is installed. A train T2 traveling on the rail R2 is present at the base B. The train T1 traveling on the rail R1 is about to enter the base A from outside the system. Arrows attached to each train indicate the direction of travel.

A transponder ground element 17A1 is installed near the rail R1 and a transponder ground element 17A2 is installed near the rail R2 on the ground near the boundary between the base A and the outside of the non-displayed system. On the ground near the boundary between the base A and the base B, a transponder ground element 17B1 is installed near the rail R1, and a transponder ground element 17B2 is installed near the rail R2. Further, a transponder ground element 17C1 is installed in the vicinity of the rail R1 and a transponder ground element 17C2 is installed in the vicinity of the rail R2 on the ground near the boundary between the bases adjacent to the base B and not displayed. These transponder ground elements can also be used as those installed for train recognition in the JRTCS train control system.

The transponder ground element 17A1 and the transponder ground element 17A2 are connected to the ground device 10A at the base A via the ground cable 4A. Transponder ground element 17B1 and transponder ground element 17B2 are connected to ground apparatus 10B at base B and ground apparatus 10A at base A via ground cable 4B, respectively. Further, the transponder ground element 17C1 and the transponder ground element 17C2 are connected to the ground apparatus without display adjacent to the base B, the ground apparatus 10B, and the ground apparatus 10B at the base B via the ground cable 4C.

Hereinafter, the processing flow of the on-board device 20 and the ground device 10 at the time of key distribution will be described with reference to the flowcharts of FIGS. 3 and 4. The on-board control device 21 generates a new key by the key generation unit 23 (101), the train T1 reaches the boundary point of the base A from outside the system, and the on-board control device 21 of the on-board device 20 moves the transponder ground unit. When it is detected that a communication path with 17A1 has been formed (102), a new key is sent from the key output unit 25 to the transponder vehicle upper element 27 together with the authentication information of the on-board device 20, and the transponder vehicle upper element 27 is Transmission is performed toward the transponder ground unit 17A1 via the transponder transmission path (103). The on-board control device 21 searches the data stored in the memory to determine whether the detected transponder ground element is a transponder ground element installed at the boundary (104). If the determination result in step 104 is yes, the on-board controller 21 stores the changed new key in the memory (105), and returns the process flow to the first step. Even if the determination result in step 104 is no, the flow of processing returns to the first step.

In the ground device 20A, processing is performed according to the flow of FIG. That is, when the ground control device 11 of the ground device 20A receives the key and the authentication information via the transponder ground element 17A1 (201), it determines whether or not the on-board device can be authenticated by the received authentication information (202). ). If the determination result in step 202 is yes, the ground control apparatus 11 stores the received new key in the memory (203), and returns the processing flow to the first step. Even if the determination result in step 202 is no, the flow of processing returns to the first step.

Next, the flow of processing when distributing the key between the on-board device 20 of the train T2 and the ground device 10A is the key flow between the on-board device 20 of the train T1 and the ground device 10A. This is performed in the same manner as the processing flow of FIG. 3 at the time of distribution. That is, the on-board control device 21 generates a new key by the key generation unit 23 (101), the train T2 reaches the boundary point of the base A, and the on-board control device 21 of the on-board device 20 moves the transponder ground element 17B2. Is detected (102), a new key is sent together with the authentication information of the on-board device 20 from the key output unit 25 to the transponder vehicle upper 27, and the transponder vehicle upper 27 is transferred to the transponder. It transmits toward the transponder ground unit 17B2 via the transmission line (103). The on-board control device 21 searches the data stored in the memory to determine whether the detected transponder ground element is a transponder ground element installed at the boundary (104). If the determination result in step 104 is yes, the on-board controller 21 stores the changed new key in the memory (105), and returns the process flow to the first step. Even if the determination result in step 104 is no, the flow of processing returns to the first step.

In the ground apparatus 10A, processing is performed according to the flow of FIG. That is, when the ground control device 11 of the ground device 10A receives the key and the authentication information via the transponder ground element 17B2 (201), it determines whether or not the on-board device can be authenticated by the received authentication information (202). ). If the determination result in step 202 is yes, the ground control apparatus 11 stores the received new key in the memory (203), and returns the processing flow to the first step. Even if the determination result in step 202 is no, the flow of processing returns to the first step.

In the second embodiment, the on-board device converts position information and the like into ciphertext using a key stored in the memory, and transmits the converted ciphertext from the on-board device to the ground device via a wireless transmission path. The process of converting the ciphertext received by the ground device into the plaintext position information using the stored key is the same as in the first embodiment. In the second embodiment, the train apparatus converts the train control information into ciphertext using a key stored in the memory, transmits the converted ciphertext via a wireless transmission path, and Processing such as converting the received ciphertext into plain text train control information using the stored key is the same as in the first embodiment. In addition to the authentication of the on-board device, the authentication of the transponder ground unit and the ground device may be performed at the same time as in the first embodiment.

By the way, in general, rails are provided in bases to evacuate trains from the main line and anchor them. Security is also required for communication with trains that are anchored in such anchorage sections. Therefore, if a transponder ground element similar to the transponder ground elements 17A1, 17A2, 17B1, 17B2, 17C1, and 17C2 is provided at the entrance and exit of this anchorage section, the key can be changed. Further, the key may be changed by changing only the initial value of the key. This is advantageous when using a long key. Also, depending on the train operation, there may be a case where the key is not changed at an appropriate time. In that case, the key is changed by providing a transponder ground element similar to the transponder ground element at an appropriate point. be able to.

It is a block diagram of the communication system for train control of Example 1 of this invention. It is a block diagram of the communication system for train control of Example 2 of this invention. It is an example of the flowchart which shows the flow of a process of a vehicle-mounted apparatus. It is an example of the flowchart which shows the flow of a process of a ground apparatus. It is a block diagram of the conventional communication system for train control.

Explanation of symbols

1, 2 Radio transmission path 3 Transponder transmission paths 4, 4A, 4B, 4C Ground cable 10 Ground device 11 Ground control device 12 Encryption / decryption unit 14 Ciphertext input / output unit 15 Key input unit 16 Antennas 17, 17A1, 17A2 , 17B1, 17B2, 17C1, 17C2 On-board unit 20, 20A, 20B On-board device 21 On-board control unit 22 Encryption / decryption unit 23 Key generation unit 24 Ciphertext input / output unit 25 Key output unit 26 Antenna 27 On-board unit T, T1, T2 train R, R1, R2 tracks

Claims (3)

It consists of a ground device installed on the ground, an on-vehicle device mounted on a train, a transponder ground element connected to the ground device, and a transponder vehicle upper element connected to the on-vehicle device, and detects the train position. A communication system for train control applied to a train control system performed by the on-board device, wherein a ciphertext is transmitted by wireless communication, and a key is a transponder transmission path including the transponder vehicle upper element and the transponder ground element A train control communication system, wherein at least one of the authentication information of the on-board device and the authentication information of the transponder ground unit and the ground device is transmitted simultaneously via the vehicle. A plurality of ground devices that are provided for each predetermined track and manage the trains existing in the section for each section, an on-board device mounted on each train, a transponder onboard connected to the on-board device, and each of the above A train control communication system that is installed in a transponder ground unit installed near a boundary of a section and connected to the ground device, and that is applied to a train control system in which the on-board device performs detection of the train position itself, The ciphertext is transmitted by wireless communication, and the key is at least the authentication information of the on-board device, the authentication information of the transponder ground device and the ground device via a transponder transmission path including the transponder vehicle core and the transponder ground device. A train control communication system that transmits simultaneously with one piece of authentication information. The train control communication system according to claim 2, wherein the key is changed for each section.

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