Method and system for rail transit mobile terminal to access AFC based on bluetooth bridge

Abstract

The application discloses a kind of based on Bluetooth bridge's rail transit mobile terminal security access AFC method and system;Belong to urban rail transit automatic fare collection system technical field, including the following steps: device discovery and pairing authorization, two-way identity authentication, secure data transmission, data verification and forwarding, response reception and return, connection maintenance and monitoring;The system for realizing this method includes mobile terminal module, Bluetooth bridge relay module and AFC background system module.The application has the characteristics of application scene essential difference, security level qualitative leap, unique architecture and excellent cost, significant improvement in function depth and breadth;The application finds a perfect balance point of low cost, high security, easy deployment and platform expansion capability between the AFC system of high emphasis on security isolation and the flexible and convenient mobile application demand through innovative Bluetooth bridge architecture and multiple security mechanisms, provides a new idea and direction for the future development of this technical field.

Description

Technical Field

[0001] This invention belongs to the technical field of automatic fare collection (AFC) systems for urban rail transit, and relates to a method and system for enabling mobile terminals to securely and reliably access the AFC dedicated network through Bluetooth bridge technology; specifically, it relates to a method and system for securely accessing the AFC system for rail transit mobile terminals based on Bluetooth bridge. Background Technology

[0002] With the widespread adoption of QR code tickets, passenger demand for faster ticket checking is increasing. Rail transit mobile terminals (PCAs), due to their portability, should ideally be the tool for processing QR code tickets and improving service. However, because the AFC network carries sensitive ticketing and transaction data, its security management requirements are extremely high, and it is typically a dedicated network isolated from the outside world. Traditional PCAs cannot directly access this network, preventing them from synchronizing parameters in real time, uploading transaction data, or interacting with backend systems (such as station computers (SC) and line control centers (LC). This significantly limits the role of PCAs in modern ticketing services (e.g., real-time inquiry, mobile ticket purchase, anomaly handling), resulting in low operational efficiency and a poor passenger experience.

[0003] Currently, some solutions attempt to connect via wired connections or Wi-Fi networks, but these suffer from inflexible deployment, high modification costs, and security vulnerabilities. Therefore, there is an urgent need for a network access solution that can meet the high security requirements of AFC systems while also enabling convenient, flexible, and real-time PCA access. Summary of the Invention

[0004] Purpose of the Invention: The purpose of this invention is to provide a method for securely accessing the AFC network for rail transit mobile terminals based on Bluetooth bridges, which aims to construct a secure, reliable, and low-power data channel through Bluetooth technology without compromising the physical isolation of the AFC network. This enables PCA to indirectly interact with the AFC network, thereby achieving mobile office, real-time data synchronization, and passenger services, while ensuring the security, integrity, and non-repudiation of data transmission.

[0005] Another object of the present invention is to provide a system that can implement the above-described method.

[0006] The technical solution of the present invention is: the method for secure access to AFC by a rail transit mobile terminal based on a Bluetooth bridge, as described in the present invention, includes the following steps: Step (1) Device discovery and pairing authorization: The mobile terminal PCA enables Bluetooth and scans to discover smart customer service terminals or turnstiles that are connected to the AFC network and act as relay devices. The repeater device has a pre-generated device whitelist built in, and only responds to pairing requests issued by PCAs authorized within the whitelist to complete Bluetooth pairing and establish a physical layer connection; Step (2) Two-way authentication: In the early stage of establishing the communication link, the PCA and the relay device conduct two-way authentication based on an asymmetric key system; The relay equipment further acts as an intermediary between the PCA and the Certificate Authority (CA) in the AFC system to complete device access authentication based on digital certificates, ensuring the legitimacy of the access devices; Step (3) Secure Data Transmission: After authentication, PCA packages the data (such as transaction records and query requests) that needs to be sent to backend systems like SC, and generates a digital signature using its private key. The data packet and signature are transmitted to the relay device via Bluetooth link; Step (4) Data verification and forwarding: After receiving the data, the relay device uses the PCA public key to verify the validity of the digital signature and confirm that the data has not been tampered with during transmission. Once the verification is successful, the relay device forwards the data to the target server (such as SC) within the AFC network through its inherent secure network interface (such as Ethernet). Step (5) Response reception and return: The response data generated by the target server after processing the request is returned to the relay device along the original path, and the relay device then sends it back to the PCA via the Bluetooth link; Similarly, downlink data also needs to undergo security processes such as signature verification; Step (6) Connection maintenance and monitoring: The system continuously monitors the Bluetooth link status and quality, supports multi-channel parallel processing to improve throughput, and has a fault warning mechanism. When the link is interrupted or the signal quality is poor, an alarm can be triggered and a reconnection attempt can be made.

[0007] Furthermore, a system for implementing the above method includes: (1) Mobile terminal module: integrated into PCA, including: Bluetooth communication unit, used to discover relay devices and establish connections; The business processing unit is used to generate business data (transactions, queries, etc.). The secure unit is used to store private keys, generate digital signatures, and verify server signatures. (2) Bluetooth bridge relay module: integrated into the AFC terminal (such as smart customer service, turnstile) as a relay device, including: Bluetooth communication unit, used for Bluetooth communication with PCA; The whitelist management unit is used to store and manage a list of authorized PCA device identifiers and control access permissions. The security authentication agent unit is used to act as an agent for PCA to authenticate with the CA center and to verify the digital signature of PCA data; A data routing unit is used to securely forward data between the Bluetooth interface and the AFC network interface; (3) AFC back-end system module: including SC, LC, ACC (clearing center) and CA authentication center, used to process business requests, issue parameters, and indirectly realize secure communication with PCA through interaction with relay module.

[0008] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: 1. High Security: Through triple security protection of "whitelist mechanism," "CA center two-way authentication," and "asymmetric key digital signature," it ensures the security of the entire process from device access to data transmission, effectively preventing unauthorized access and data tampering, and fully complies with AFC network security specifications; 2. Low Cost and Easy Deployment: It fully utilizes existing AFC terminal equipment (gates, ticket vending machines, etc.) as relays, requiring only the addition of Bluetooth modules and software upgrades, without the need to build a large amount of dedicated network infrastructure, greatly reducing the transformation cost and engineering complexity; 3. Real-time Performance and Efficiency: It achieves P... The near real-time data interaction between the CA and AFC networks eliminates the need for manual periodic synchronization of parameters, transaction uploads, and alarm reception, significantly improving operational efficiency and emergency response capabilities. 4. Flexibility and scalability: Bluetooth connectivity frees the PCA from physical location limitations, allowing staff to move flexibly within the station hall to serve passengers. This architecture is easily expandable and can smoothly integrate with various service platforms such as mobile payment and voice knowledge bases in the future. 5. Low power consumption and high reliability: The use of low-power Bluetooth technology ensures the PCA's long battery life. The relay equipment supports multi-channel and link monitoring, guaranteeing the stability and reliability of the system connection. Attached Figure Description

[0009] Figure 1 This is a block diagram of the overall architecture of the system of the present invention; Figure 2 This is a flowchart illustrating the operation of the method of the present invention; Figure 3 This is a timing diagram of data packet signing, transmission, and verification in this invention; Figure 4 This is a schematic diagram of the data transmission protocol in this invention. Detailed Implementation

[0010] The specific technical solution of the present invention will be further described in detail below with reference to specific examples.

[0011] As shown in the figure, the method for secure access to AFC by a rail transit mobile terminal based on a Bluetooth bridge according to the present invention includes the following steps: Step (1) Device discovery and pairing authorization: The mobile terminal PCA enables Bluetooth and scans to discover smart customer service terminals or turnstiles that are connected to the AFC network and act as relay devices. The repeater device has a pre-generated device whitelist built in, and only responds to pairing requests issued by PCAs authorized within the whitelist to complete Bluetooth pairing and establish a physical layer connection; Step (2) Two-way authentication: In the early stage of establishing the communication link, the PCA and the relay device conduct two-way authentication based on an asymmetric key system; The relay equipment further acts as an intermediary between the PCA and the Certificate Authority (CA) in the AFC system to complete device access authentication based on digital certificates, ensuring the legitimacy of the access devices; Step (3) Secure Data Transmission: After authentication, PCA packages the data (such as transaction records and query requests) that needs to be sent to backend systems like SC, and generates a digital signature using its private key. The data packet and signature are transmitted to the relay device via Bluetooth link; Step (4) Data verification and forwarding: After receiving the data, the relay device uses the PCA public key to verify the validity of the digital signature and confirm that the data has not been tampered with during transmission. Once the verification is successful, the relay device forwards the data to the target server (such as SC) within the AFC network through its inherent secure network interface (such as Ethernet). Step (5) Response reception and return: The response data generated by the target server after processing the request is returned to the relay device along the original path, and the relay device then sends it back to the PCA via the Bluetooth link; Similarly, downlink data also needs to undergo security processes such as signature verification; Step (6) Connection maintenance and monitoring: The system continuously monitors the Bluetooth link status and quality, supports multi-channel parallel processing to improve throughput, and has a fault warning mechanism. When the link is interrupted or the signal quality is poor, an alarm can be triggered and a reconnection attempt can be made.

[0012] A system for implementing the above method includes a mobile terminal module integrated in a PCA, a Bluetooth bridge relay module integrated in an AFC terminal (such as a smart customer service center or a turnstile) that serves as a relay device, and an AFC backend system module for processing business requests, issuing parameters, and indirectly achieving secure communication with the PCA through interaction with the relay module.

[0013] The example uses a pilot project on Nanjing Metro Line 5. A smart customer service terminal is selected as a relay device and modified as follows: an industrial-grade Bluetooth module (e.g., supporting BLE 5.0) is added, its system software is upgraded, and the "Bluetooth bridge relay module" of this invention is implanted; simultaneously, the software of a designated PCA is upgraded, the "mobile terminal module" software is implanted, and its MAC address is registered in the whitelist of the smart customer service terminal.

[0014] During operation, staff hold a PCA (Personalized Travel Assistance Provider) close to the smart customer service terminal. The PCA automatically initiates a connection, establishes a secure link after whitelist verification and CA authentication, and the staff performs the "mobile phone number query for travel records" operation on the PCA. The query request is sent to the smart customer service terminal after being signed, and forwarded to the SC (Smart Service Center) after verification. The SC processes the request and returns the result, which is finally displayed on the PCA screen. The entire process requires no manual intervention and the data is secure and reliable.

[0015] The specific differences between this invention and the prior art are shown in Table 1: .

[0016] In summary, the features of this invention are: 1. Fundamentally different application scenarios: This invention focuses on secure, real-time, and mobile interconnection between mobile terminals on the operation side and closed backend systems; 2. A qualitative leap in security level: This invention combines enterprise-level security authentication (CA) with Bluetooth links, deeply meeting the high security requirements of AFC networks and solving the key security problem of achieving "logical isolation" in a wireless environment; 3. Original architecture and excellent cost: This invention proposes and implements an architecture using "existing AFC terminals as Bluetooth relays," eliminating the need to deploy dedicated relay hardware, greatly reducing modification costs and engineering complexity, and improving deployment flexibility; 4. Significantly enhanced functional depth and breadth: This invention transforms PCA from an offline tool into an online intelligent node, greatly expanding the mobile application ecosystem and real-time response capabilities of rail transit operations.

[0017] This invention is mainly characterized by: 1. Innovatively solving core operational pain points: For the first time, it systematically provides a complete solution for PCA to achieve secure, real-time, and mobile access while meeting AFC network security protocols, filling a technological gap in this field; 2. Achieving a balance between security and convenience: Through a multi-layered security system of "whitelist + CA authentication + digital signature," it constructs a secure channel comparable to wired networks in an open wireless environment, completely eliminating the concerns of operations departments regarding wireless access security risks; 3. Providing significant economic and practical advantages: Utilizing existing AFC equipment (gates, TVMs, etc.) as the core design for relays avoids large-scale new installations. The reduced investment and line upgrades saved significant costs and construction time, making the large-scale promotion of this technology extremely feasible; 4. Improved operational efficiency and passenger experience: Real-time data synchronization and mobile processing were achieved, freeing staff from fixed workstations, significantly shortening transaction processing time, and providing technical possibilities for more efficient on-site services and emergency response, ultimately improving passenger satisfaction; 5. Provided powerful platform-based expansion capabilities: This architecture provides a unified communication platform for PCA to access more services in the future (such as mobile payment, voice assistant, indoor positioning), laying a solid foundation for building "smart stations" and "mobile integrated operation terminals," and has a long technology lifecycle.

[0018] The core of this invention is to find a perfect balance between the high emphasis on safety isolation in rail transit AFC and the need for flexible and convenient mobile applications. Through an innovative Bluetooth bridge architecture and multiple security mechanisms, it achieves a low cost, high security, easy deployment, and platform-based scalability, providing a brand-new idea and direction for the future development of this technology.

Claims

1. A method for secure access to AFC by a rail transit mobile terminal based on a Bluetooth bridge, characterized in that, Includes the following steps: Step (1) Device discovery and pairing authorization; Step (2) Two-way authentication; Step (3) Secure data transmission; Step (4) Data verification and forwarding; Step (5) Response reception and return; Step (6) Connect for maintenance and monitoring.

2. The method for secure access to AFC for rail transit mobile terminals based on Bluetooth bridges according to claim 1, characterized in that, The device discovery and pairing authorization described in step (1) are as follows: the mobile terminal PCA enables Bluetooth, scans and discovers smart customer service terminals or turnstiles that are connected to the AFC network and act as relay devices; the relay device has a pre-generated device whitelist built in it, and only responds to pairing requests issued by authorized PCAs within the whitelist, completes Bluetooth pairing, and establishes a physical layer connection.

3. The method for secure access to AFC for rail transit mobile terminals based on Bluetooth bridges according to claim 1, characterized in that, The two-way authentication described in step (2) is as follows: In the early stage of establishing the communication link, the PCA and the relay device conduct two-way authentication based on the asymmetric key system; the relay device further acts as an agent for the PCA to communicate with the certificate authentication center in the AFC system to complete the device access authentication based on the digital certificate and ensure the legitimacy of the access device.

4. The method for secure access to AFC for rail transit mobile terminals based on Bluetooth bridges according to claim 1, characterized in that, The secure data transmission in step (3) specifically involves the following steps: After authentication, the PCA packages the data to be sent to the SC backend system and generates a digital signature using the private key; the data packet and the signature are transmitted to the relay device via a Bluetooth link.

5. The method for secure access to AFC for rail transit mobile terminals based on Bluetooth bridges according to claim 1, characterized in that, The data verification and forwarding described in step (4) are as follows: After receiving the data, the relay device uses the PCA public key to verify the validity of the digital signature and confirm that the data has not been tampered with during transmission. After the verification is successful, the relay device forwards the data to the target server in the AFC network through its inherent secure network interface.

6. The method for secure access to AFC for rail transit mobile terminals based on Bluetooth bridges according to claim 1, characterized in that, The response reception and return mentioned in step (5) are as follows: the response data generated by the target server after processing the request is returned to the relay device along the original path, and the relay device then sends it back to the PCA via the Bluetooth link; Similarly, downlink data also needs to go through a secure signature verification process.

7. The method for secure access to AFC by a rail transit mobile terminal based on a Bluetooth bridge according to claim 1, characterized in that, The connection maintenance and monitoring described in step (6) specifically involves the system continuously monitoring the Bluetooth link status and quality, supporting multi-channel parallel processing to improve throughput, and having a fault warning mechanism. When the link is interrupted or the signal quality is poor, an alarm is triggered and an attempt is made to reconnect.

8. A system for implementing a secure access method (AFC) for rail transit mobile terminals based on a Bluetooth bridge; characterized in that, include: The mobile terminal module integrated in the PCA; the Bluetooth bridge relay module integrated in the AFC terminal as a relay device, and the AFC backend system module including SC, LC, ACC and CA authentication center, used to process service requests, issue parameters, and indirectly realize secure communication with the PCA through interaction with the relay module.

9. The system according to claim 8, characterized in that, The mobile terminal module includes a Bluetooth communication unit for discovering relay devices and establishing connections; a business processing unit for generating business data; and a security unit for storing private keys, generating digital signatures, and verifying server signatures.

10. The system according to claim 8, characterized in that, The Bluetooth bridge relay module includes a Bluetooth communication unit for Bluetooth communication with the PCA; a security authentication proxy unit for storing and managing a list of authorized PCA device identifiers and controlling access permissions; and a data routing unit for securely forwarding data between the Bluetooth interface and the AFC network interface.

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