Safe communication validity period calculation method and system suitable for all-electronic

Abstract

The invention provides a safe communication validity period calculation method and system suitable for full electronic. The method comprises the step of adding a validity period information packet in a data format transmitted between a first signal system and a second signal system. The first signal system sends a first message to the second signal system, the second signal system processes the first message to generate a second message, and the second signal system sends the second message to the first signal system. And the first signal system calculates the remaining validity period of the second message according to the validity period information packet in the second message. According to the method, calculation of the validity period of the safety communication message among the signal subsystems with different architecture designs can be realized, and the calculation method is simple and easy to implement, has good universality and has great benefits for promoting interconnection and intercommunication of a rail transit system.

Description

Technical Field

[0001] The present invention relates to the field of rail transit communication signal technology, and in particular to a method and system for calculating the validity period of fully electronic safety communications. Background Art

[0002] In the context of interconnection of rail transit systems, the signal subsystems can use agreed secure communication transmission protocols to exchange secure data, thereby protecting the timeliness of data frames at the communication level.

[0003] However, due to differences in the architectural design and implementation methods of equipment from different manufacturers, the secure communication transmission protocol and secure logic operations may be implemented by the same board, or may be implemented separately by a communication board and a logic operation board, with data transmission between the communication board and the logic operation board achieved through internal communication.

[0004] The message receiver cannot know the implementation method of the message sender, nor the communication transmission delay between the other party's communication board and the logic operation board, so it is impossible to accurately calculate the remaining validity period of the received message. From a security perspective, this is unacceptable.

[0005] On the other hand, with the promotion and application of all-electronic target controllers in rail transit systems, the types of signal systems with safety communication interfaces are increasing, and the above problems are becoming increasingly prominent in applications. Summary of the invention

[0006] The purpose of the present invention is to provide a method and system for calculating the validity period of fully electronic safety communications, so as to realize the calculation of the validity period of safety communication messages between signal subsystems with different architectural designs. The calculation method is simple and easy to implement, has good versatility, and is of great benefit to promoting the interconnection and interoperability of rail transit systems.

[0007] In order to achieve the above object, the present invention provides a method for calculating the validity period of secure communication applicable to all-electronic communication, comprising:

[0008] Adding a validity period information package in the data format transmitted between the first signal system and the second signal system;

[0009] When the first signal system sends a message to the second signal system, the first signal system is the sender and the second signal system is the receiver; when the second signal system sends a message to the first signal system, the second signal system is the sender and the first signal system is the receiver;

[0010] The first signal system sends a first message to the second signal system, the second signal system processes the first message to generate a second message, the second signal system sends the second message to the first signal system, and the first signal system calculates the remaining validity period of the second message based on the validity period information package in the second message.

[0011] Optionally, the validity period information package in the second message includes:

[0012] A first field, in which a communication cycle count of the second signal system when sending the second message is entered;

[0013] A second field, in which the communication cycle time of the second signal system is entered;

[0014] A third field, in which the communication cycle count of the first signal system when sending the first message filled in the first field of the validity period information packet of the first message when the first message sent by the first signal system is received is entered;

[0015] A fourth field, in which the communication cycle count of the second signal system when the first message sent by the first signal system is received is entered.

[0016] Optionally, the method for the first signal system to calculate the remaining validity period of the second message comprises: calculating the safety reaction time T of transmitting the second message between the first signal system and the second signal system 反应 , and the processing time T of the first message in the second signal system 消耗 , and then obtain the remaining validity period of the second message transmitted between the first signal system and the second signal system, the remaining validity period is expressed as:

[0017] MessageRemainingValidity=MSG_VALIDITY_TIME-(T 反应 -T 消耗 )

[0018] In the formula, MessageRemainingValidity is the remaining validity period of the second message after being transmitted by the first signal system and the second signal system, and MSG_VALIDITY_TIME is the validity period of the predefined message during the transmission process between the first signal system and the second signal system.

[0019] Optionally, the safety validity period T 反应 The calculation methods include:

[0020] T 反应 =(R_Local_Msg_SeqNum-NewRcvMg Remote_Msg_SeqNum )×Com_period

[0021] Where, R_Local_Msg_SeqNum is the cycle count of the first signal system when receiving the second message, NewRcvMg Remote_Msg_SeqNum It is the third field in the validity period information packet of the second message, and Com_period is the communication cycle time of the first signal system.

[0022] Optionally, the processing time T of the second message in the second signal system 消耗 The calculation methods include:

[0023] T 消耗 =(NewRcvMsg Local_Msg_SeqNum -NewRcvMsg Local_Msg_SeqNum_Pre )×NewRcvMsg Com_period

[0024] In the formula, NewRcvMsg Local_Msg_SeqNum The first field in the validity period information packet of the second message, NewRcvMsg Local_Msg_SeqNum_Pre The fourth field in the validity period information packet of the second message, NewRcvMsg Com_period It is the second field in the validity period information packet of the second message.

[0025] Optionally, before sending the validity period information packet, each field in the validity period information packet is entered. During the entry process, when the second signal system does not receive the first message sent by the first signal system within the grace period or the communication is interrupted, the entry values ​​of the third field and the fourth field in the validity period information packet of the second message sent by the second signal system are both default values.

[0026] Optionally, during the entry of the validity period information package, when the entry values ​​of the third field and the fourth field in the validity period information package of the second message are both default values, the validity period information package is in an unavailable state;

[0027] The first field in the validity period information packet of the second message serves as the third field in the validity period information packet when the first signal system sends the next message; and the current cycle count of the first signal system serves as the fourth field in the validity period information packet when the first signal system sends the next message.

[0028] In addition, the present invention also provides a communication system, including: a first signal system and a second signal system, wherein the first signal system and the second signal system are respectively provided with a message board card; the first signal system sends a first message through the message board card, and the second signal system processes the first message through the message board card to generate and send a second message.

[0029] Optionally, the message board includes: a communication board and a logic operation board; the communication board can implement a secure communication transmission protocol and complete message transmission between the first signal system and the second signal system; the logic operation board is connected to the communication board signal, can perform logic operations on the received messages, and complete the entry of validity period information packages.

[0030] Optionally, the communication board and the logic operation board are integrated on the same board.

[0031] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0032] The validity period calculation method of the present invention makes a small change in the data format of the existing architecture design. By adding necessary message sequence number and period information to the application layer data format of the existing secure communication transmission protocol, a message validity period information packet is formed, and the validity period information packet is expressed in the form of a communication period, so that the meanings of the message sequence number and the period information are unified, and the calculation of the validity period of secure communication messages between signal subsystems with different architecture designs is realized.

[0033] The present invention calculates the remaining validity period of the message by calculating the security reaction time of the message during the transmission process between the two parties and the time consumed by the message processing. The calculation method is simple and easy to implement, which makes the present invention have good versatility and is of great benefit to promoting the interconnection and interoperability of rail transit systems. At the same time, the method described in the present invention also simplifies the calculation method of the security reaction time of the message during the transmission process between the two parties, which is conducive to security application analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of the method for calculating the validity period of fully electronic secure communications.

[0035] Figure 2 The figure is a schematic diagram of calculating the validity period of a message in one embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] like Figure 1 As shown, the present invention provides a method for calculating the validity period of fully electronic secure communications. By adding validity period-related fields to the application layer data, the receiver can fully determine the transmission delay of the message in the network, and then calculate the remaining validity period of the message. The specific steps are as follows:

[0040] Step 1: Create a new validity period information package.

[0041] The validity period fields containing the message transmission logic between the receiver and the sender are concentrated into a validity period information package, and the validity period information package is added to the application layer data format of the existing secure communication transmission protocol, so that the entry of the validity period field in the validity period information package can be completed during the communication transmission process.

[0042] When the validity period field of the message is entered into the validity period information package, it is entered in the form of a communication sequence or a communication cycle (including: cycle count, cycle time), ensuring the unity of the meaning of the entry value of the validity period field in the validity information package generated by the sender. In a preferred embodiment, the entry value in the validity period information package is entered in the form of a communication cycle.

[0043] Among them, the validity period information package is shown in Table 1, including: a first field, a second field, a third field and a fourth field. The first field is the "Own message sequence number", which indicates the communication cycle count when the sender sends this message. The second field is the "communication cycle time", which indicates the communication cycle of the sender's software or device. The third field is the "Other party message sequence number", which indicates the cycle count when the sender of the previous message sent the previous message (that is, the "Own message sequence number" in the validity period information package when the sender of the previous message sent the previous message). The fourth field is the "Own sequence number when receiving the previous message", which indicates the cycle count of the sender of this message when receiving the previous message. Among them, the cycle count increases with the increase of the message transmission time, and the cycle count will increase by 1 for each device / application software communication cycle time.

[0044] Table 1 Validity period related fields

[0045]

[0046]

[0047] Step 2: The message sender enters the validity period field in the validity period information package.

[0048] The process in which the sender sends a message and the receiver replies to the message after receiving the message is regarded as the process of message transmission between the first signal system and the second signal system. In the message transmission logic between the first signal system and the second signal system (i.e., the message transmission process between the two communicating parties), the first signal system sends a first message to the second signal system, the second signal system processes the first message to generate a second message, and the second signal system sends the second message to the first signal system; wherein, when the first signal system sends a message to the second signal system, the first signal system is the sender and the second signal system is the receiver; when the second signal system sends a message to the first signal system, the second signal system is the sender and the first signal system is the receiver.

[0049] At this time, the "own message sequence number" in the validity period field is the communication cycle count of the second signal system when sending the second message entered in the first field; the "communication cycle time" is the communication cycle time of the second signal system entered in the second field; the "other party message sequence number" is the communication cycle count of the first signal system when sending the first message filled in the first field in the validity period information package of the first message when receiving the first message sent by the first signal system, which is entered in the third field; and the "own sequence number when receiving the previous message" is the communication cycle count of the second signal system when receiving the first message sent by the first signal system, which is entered in the fourth field.

[0050] Furthermore, when the second signal system (i.e., the recipient of the first message) does not receive the first message sent by the first signal system (i.e., the sender of the first message) within the tolerance period or the communication is interrupted, the entry values ​​of "the other party's message sequence number" and "our own sequence number when receiving the last message" in the validity information package of the second message sent by the second signal system are both the default values ​​(0xFFFFFFFF).

[0051] When the first signal system (i.e., the receiver of the second message) receives the second message with the "Other party message sequence number" and "Own party sequence number when receiving the last message" in the validity period information packet of the second message as the default value, the validity period information packet of the second message is unavailable and cannot be used to calculate the remaining validity period of the message. However, at this time, the first signal system (i.e., the receiver of the second message) should record the "Own party message sequence number" in the validity period information packet (i.e., the cycle count when the second signal system sends the second message) and the current cycle count of the first signal system (i.e., the receiver of the second message), so that the "Own party message sequence number" in the validity period information packet of the second message is used as the "Other party message sequence number" in the validity period information packet when the first signal system (i.e., the receiver of the second message) sends the third message (at this time, the first signal system replies to the second message sent by the second signal system, making the first signal system the sender of the next message); and the first signal system (i.e., the receiver of the second message) uses the current cycle count as the "Own party sequence number when receiving the last message" in the validity period information packet when the first signal system (i.e., the receiver of the second message) sends the third message.

[0052] Step 3: Calculate the remaining validity period of the message.

[0053] During the process of message transmission between the two communicating parties (i.e., the first signal system and the second signal system), when the second signal system (i.e., the sender of the new message) replies to the first message sent by the first signal system (i.e., the receiver of the new message), the second signal system will send a second message. If the cycle count of the second signal system when receiving the first message sent by the first signal system is A, then the cycle count of the second signal system when replying to the first message (i.e., the second signal system sends the second message) is A+m (m≥1); where m is the number of cycle times of the second signal system that the second signal system needs to process the first message and generate the second message, reflecting the processing time consumed by the first message in the equipment or software of the second signal system.

[0054] In the process of sending the second message, the total time consumed by the message in the two-way transmission process (i.e., the process from the first signal system sending the first message to receiving the second message) (i.e., the safety response time) is calculated based on the current cycle count of the first signal system and the cycle count of the second signal system when the second signal system replies to the first message sent by the first signal system, and then the processing time consumed by the first message in the equipment or software of the second signal system is subtracted to obtain the delay time in the transmission process of the second message. And according to the message transmission validity period agreed in the project, the remaining validity period of the message in the transmission process of both parties is obtained.

[0055] Among them, the safety reaction time T 反应 It is the time required for the first signal system to send the first message and receive the second message. The specific calculation method is as follows:

[0056] T 反应 =(R_Local_Msg_SeqNum-NewRcvMg Remote_Msg_SeqNum ) ×Com_period (Formula 1)

[0057] The processing time T consumed by the first message in the device or software of the second signal system 消耗 It can be expressed as:

[0058] T 消耗 =(NewRcvMsg Local_Msg_SeqNum -NewRcvMsg Local_Msg_SeqNum_Pre )×NewRcvMsg Com_period (Formula 2)

[0059] Then, the remaining validity period of the message during the transmission between the two parties is obtained, which can be expressed as:

[0060] MessageRemainingValidity=MSG_VALIDITY_TIME-(T 反应 -T消耗 ) (Formula 3)

[0061] Where, MessageRemainingValidity is the remaining validity period of the message after transmission between the two parties, MSG_VALIDITY_TIME is the validity period of the message specified in the project during the transmission between the two parties, R_Local_Msg_SeqNum is the cycle count of the first signal system when receiving a new message, NewRcvMg Remote_Msg_SeqNum The period count of the second signal system when the second signal system replies to the first message sent by the first signal system (i.e., the "other message sequence number" in the validity period information packet of the second message), Com_period is the period time of the device or software of the first signal system, NewRcvMsg Local_Msg_SeqNum is the cycle count of the second signal system when sending the second message (i.e., the "local message sequence number" in the validity period information packet of the second message), NewRcvMsg Local_Msg_SeqNum_Pre is the cycle count of the second signal system when receiving the first message (i.e., the "sequence number of the party when receiving the last message" in the validity period information packet of the second message), NewRcvMsg Com_period The cycle time of the device or software for the second signal system.

[0062] The present invention also provides a communication system, including: a first signal system and a second signal system, wherein the first signal system and the second signal system are respectively provided with a message board card; the first signal system sends a first message through the message board card, and the second signal system processes the first message through the message board card to generate and send a second message.

[0063] The message board includes: a communication board and a logic operation board. The communication board can implement a secure communication transmission protocol and complete message transmission between the first signal system and the second signal system. The logic operation board is connected to the communication board signal, can perform logic operations on the received message, and complete the entry of the validity period field in the validity period information packet. In a preferred embodiment, the communication board and the logic operation board are integrated on the same board.

[0064] Embodiment 1

[0065] In this embodiment, bidirectional message transmission is performed between system 1 (sys-1) and system 2 (sys-2). System 1 sends a message to system 2, and system 2 processes the message, and then system 2 sends a new message to reply to the message. The software cycle time of system 1 is 250ms, the software cycle time of system 2 is 500ms, and the validity period of the message transmission is agreed to be 5000ms.

[0066] like Figure 2 As shown, when system 1 receives a new message sent by system 2 when the cycle count is 201, the sender of the new message is system 2. When sending the new message, the cycle count of system 2 is 2002. At this time, the entry value of "our message sequence number" in the validity period information package of the new message is 2002; when the previous message was sent to system 2, the cycle count of system 2 was 2001. At this time, the entry value of "our sequence number when receiving the previous message" in the validity period information package is 2001; system 1, as the sender of the previous message, has a cycle count of 190 when sending the previous message, that is, the entry value of "the other party's message sequence number" in the validity period information package is 190; therefore, the validity period information package of the new message is (2002, 500, 190, 2001).

[0067] At this time, the remaining validity period of the message after transmission between system 1 and system 2 is calculated according to Formula 3, and the remaining validity period is obtained as MessageRemainingValidity=5000-[(201-190)×250-(2002-2001)×500]=2750ms.

[0068] In summary, the present invention realizes the calculation of the validity period of security communication messages between signal subsystems of different architecture designs by adding necessary message sequence numbers and periodic information to the application layer data format of the existing security communication transmission protocol; by calculating the security response time of the message during the transmission process between the two parties and the time consumed by the message processing, the remaining validity period of the message is calculated. The method is simple and easy to implement, and has good versatility, which is of great benefit to promoting the interconnection and interoperability of rail transit systems.

[0069] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for calculating the validity period of fully electronic secure communications, characterized in that: Include: Adding a validity period information package in the data format transmitted between the first signal system and the second signal system; When the first signal system sends a message to the second signal system, the first signal system is the sender and the second signal system is the receiver; when the second signal system sends a message to the first signal system, the second signal system is the sender and the first signal system is the receiver; The first signal system sends a first message to the second signal system, the second signal system processes the first message to generate a second message, the second signal system sends the second message to the first signal system, and the first signal system calculates the remaining validity period of the second message based on the validity period information package in the second message.

2. The method for calculating the validity period of fully electronic secure communication according to claim 1, characterized in that: The validity period information package in the second message includes: A first field, in which a communication cycle count of the second signal system when sending the second message is entered; A second field, in which the communication cycle time of the second signal system is entered; A third field, in which the communication cycle count of the first signal system when sending the first message filled in the first field of the validity period information packet of the first message when the first message sent by the first signal system is received is entered; A fourth field, in which the communication cycle count of the second signal system when the first message sent by the first signal system is received is entered.

3. The method for calculating the validity period of fully electronic secure communication according to claim 2, characterized in that: The method for calculating the remaining validity period of the second message by the first signal system comprises: calculating the safety reaction time T of transmitting the second message between the first signal system and the second signal system 反应 , and the processing time T of the first message in the second signal system 消耗 , and then obtain the remaining validity period of the second message transmitted between the first signal system and the second signal system, the remaining validity period is expressed as: MessageRemainingValidity=MSG_VALIDITY_TIME-(T 反应 -T 消耗 ) In the formula, MessageRemainingValidity is the remaining validity period of the second message after being transmitted by the first signal system and the second signal system, and MSG_VALIDITY_TIME is the validity period of the predefined message during the transmission process between the first signal system and the second signal system.

4. The method for calculating the validity period of fully electronic secure communication according to claim 3, characterized in that: The safe validity period T 反应 The calculation methods include: T 反应 =(R_Local_Msg_SeqNum-NewRcvMg Remote_Msg_SeqNum )×Com_period Where R_Local_Msg_SeqNum is the cycle count of the first signal system when receiving the second message, NewRcvMg Remote_Msg_SeqNum It is the third field in the validity period information packet of the second message, and Com_period is the communication cycle time of the first signal system.

5. The method for calculating the validity period of fully electronic secure communication according to claim 3, characterized in that: The processing time T of the second message in the second signaling system 消耗 The calculation methods include: T 消耗 =(NewRcvMsg Local_Msg_SeqNum -NewRcvMsg Local_Msg_SeqNum_Pre )×NewRcvMsg Com_period In the formula, NewRcvMsg Local_Msg_SeqNum is the first field in the validity period information packet of the second message, NewRcvMsg Local_Msg_SeqNum_Pre The fourth field in the validity period information packet of the second message, NewRcvMsg Com_period It is the second field in the validity period information packet of the second message.

6. The method for calculating the validity period of fully electronic secure communication according to claim 2, characterized in that: Before sending the validity period information packet, each field in the validity period information packet is entered. During the entry process, when the second signal system does not receive the first message sent by the first signal system within the grace period or the communication is interrupted, the entry values ​​of the third field and the fourth field in the validity period information packet of the second message sent by the second signal system are both default values.

7. The method for calculating the validity period of fully electronic secure communication according to claim 6, characterized in that: During the entry of the validity period information package, when the entry values ​​of the third field and the fourth field in the validity period information package of the second message are both default values, the validity period information package is in an unavailable state; The first field in the validity period information packet of the second message serves as the third field in the validity period information packet when the first signal system sends the next message; and the current cycle count of the first signal system serves as the fourth field in the validity period information packet when the first signal system sends the next message.

8. A communication system, used to implement the method for calculating the validity period of fully electronic secure communication as claimed in any one of claims 1 to 7, characterized in that: include: A first signal system and a second signal system, wherein the first signal system and the second signal system are respectively provided with a message board; The first signal system sends a first message through the message board, and the second signal system processes the first message through the message board to generate and send a second message.

9. The communication system according to claim 8, characterized in that: The message board includes: a communication board and a logic operation board; the communication board can implement a secure communication transmission protocol and complete message transmission between the first signal system and the second signal system; the logic operation board is connected to the communication board signal, can perform logic operations on the received messages, and complete the entry of validity period information packages.

10. The communication system according to claim 9, characterized in that: The communication board and the logic operation board are integrated on the same board.

Images