Data Encryption Function of Serial Port to Ethernet Adapter: How to Ensure Communication Security in Industrial Sites?

1. The "Invisible Battlefield" of Industrial Site Communication Security: The Cost of Data Leakage and the Urgency of Protection
A DCS control system in a chemical enterprise was once hacked due to unencrypted serial port communication. The attacker intercepted Modbus RTU protocol frames and tampered with the temperature parameters of the reaction kettle, causing the equipment to shut down for 12 hours and direct economic losses exceeding 2 million yuan. This case reveals the core pain point of industrial site communication: in the wave of digital transformation, unencrypted serial port communication has become a "backdoor" for attackers to infiltrate industrial networks. According to IDC statistics, in 2024, attacks triggered by serial port communication vulnerabilities accounted for 37% of global industrial cybersecurity incidents, with an increasing trend year by year.

The communication security requirements in industrial sites are unique:

• Device Heterogeneity: Devices such as PLCs, sensors, and instruments mostly use serial port communication with various protocol types (e.g., Modbus RTU, DNP3, IEC 60870-5-104).
• Environmental Complexity: Harsh working conditions such as high temperature, strong electromagnetic interference, and vibration pose stringent requirements on device stability.
• Real-time Requirements: Production control instructions need to be transmitted within millisecond-level delays, and encryption algorithms must balance security and efficiency.
  How to build a "secure-stable-efficient" industrial communication network through the data encryption function of serial port to ethernet adapters has become a key proposition for enterprises' digital transformation.

2. The "Five Technical Defenses" of Serial Port to Ethernet Adapter Data Encryption: Full-link Protection from the Protocol Layer to the Physical Layer
2.1 Protocol Layer Encryption: The "Double Insurance" of SSL/TLS and MQTT over TLS
In industrial scenarios, data transmission needs to cross public or private networks, and the SSL/TLS protocol has become a core technology for ensuring communication security:

• SSL/TLS Handshake Protocol: It exchanges session keys through asymmetric encryption (e.g., RSA, ECC), and subsequent communication uses symmetric encryption (e.g., AES-256), balancing security and efficiency.
• MQTT over TLS: It overlays TLS encryption on the lightweight IoT protocol MQTT, suitable for resource-constrained industrial devices, ensuring the confidentiality of data transmission in the cloud.
  Case: The USR-N520 serial port to ethernet adapter supports SSL/TLS 1.2/1.3 protocols and can establish encrypted channels with platforms such as Alibaba Cloud and AWS. A smart water project achieved secure collection of water meter data through this function, with no data leakage incidents occurring.

2.2 Data Integrity Verification: The "Double Verification" of CRC and HMAC
Encrypted data still needs to guard against tampering risks. Data integrity verification technology ensures that data has not been modified by adding verification codes:

• CRC Verification: It appends a cyclic redundancy check code at the end of data packets to detect bit errors during transmission.
• HMAC (Hash-based Message Authentication Code): It combines a cryptographic hash function (e.g., SHA-256) and a key to generate a fixed-length authentication code, verifying the source and integrity of data.
  Technical Implementation: During the conversion of Modbus RTU to TCP, the USR-N520 automatically adds a CRC verification code to each frame of data and enables HMAC-SHA256 at the SSL/TLS layer, building a double defense of "transport layer + application layer".

2.3 Identity Authentication and Access Control: From "Open Access" to "Whitelist Management"
Industrial networks need to strictly restrict device access permissions to prevent attacks from illegal terminals:

• IP/MAC-based Whitelist: Only devices with preset IP or MAC addresses are allowed to access the serial port to ethernet adapter.
• Digital Certificate Authentication: It verifies device identities through X.509 certificates, suitable for scenarios with high security requirements.
• Multi-factor Authentication: It combines usernames, passwords, and dynamic tokens to enhance the security of management interface access.
  Configuration Example: The USR-N520 supports the IP whitelist function. Users can set allowed IP segments in the management interface, and unauthorized devices attempting to connect will trigger log alarms.

2.4 Hardware-level Encryption: Achieving "Both Performance and Security" with Dedicated Chips
Software encryption may affect device performance due to resource consumption. Hardware encryption chips achieve efficient encryption through independent computing units:

• AES Hardware Acceleration: It integrates an AES coprocessor, improving encryption speed by more than 10 times compared to software implementation.
• True Random Number Generator (TRNG): It provides a physical entropy source for key generation, avoiding the prediction risks of pseudo-random algorithms.
• Secure Boot: It prevents firmware tampering, ensuring the security of the device startup process.
  Product Highlights: The USR-N520 adopts an ST Cortex-M7 core and is equipped with a built-in hardware encryption module, supporting the AES-256 encryption algorithm. The encryption delay is less than 2ms under a 100Mbps bandwidth.

2.5 Physical Layer Protection: The "Last Line of Defense" of Electromagnetic Shielding and Anti-interference Design
Strong electromagnetic interference in industrial sites may cause data errors or device failures. Physical layer protection technologies include:

• Electromagnetic Shielding Enclosure: It uses a sheet metal enclosure to shield external electromagnetic interference.
• Isolation Transformer: It adds an isolation transformer at the power input end to block common-mode interference.
• Watchdog Circuit: It has a built-in hardware watchdog to monitor the program running status and automatically restart abnormal devices.
  Environmental Adaptability: The USR-N520 has an operating temperature range of -40°C to 85°C and has passed the IEC 61000-4-5 surge immunity test, suitable for harsh scenarios such as power and transportation.

3. USR-N520 Serial Port to Ethernet Adapter: An "All-round Player" in Industrial-grade Encrypted Communication
In the field of serial port to ethernet adapters, the USR-N520 has become a benchmark product for industrial site communication security with its characteristics of "high performance, high security, and high compatibility":

• Dual Serial Port Independent Encryption: It supports 2 RS-232/485/422 interfaces, and each port can be independently configured with SSL/TLS encryption parameters.
• Protocol Conversion Engine: It has a built-in Modbus RTU/TCP bidirectional conversion function and supports custom protocol development.
• Edge Computing Capability: It can complete data preprocessing at the device end, reducing the amount of sensitive data transmitted over the network.
• Industrial-grade Design: It has a sheet metal enclosure and ear-mounted installation and has passed the IEC 61000-6-2 industrial environment certification.
  Typical Application Scenarios:
• Power Monitoring: It connects devices such as electricity meters and circuit breakers and uploads data to the dispatching system through SSL encryption.
• Smart Manufacturing: It achieves a secure connection between PLCs and MES systems, preventing production parameters from being tampered with.
• Smart Transportation: It encrypts and transmits data from traffic lights and cameras, ensuring the security of urban traffic command.

4. From "Passive Defense" to "Active Security": Building an "Immune System" for Industrial Communication
Ensuring communication security in industrial sites requires establishing a three-dimensional protection system of "technology-management-operation and maintenance":

• Technical Level: Deploy serial port to ethernet adapters (such as the USR-N520) that support SSL/TLS and hardware encryption to build encrypted communication links.
• Management Level: Formulate the "Industrial Cybersecurity Management System" to clarify processes such as device access, key management, and log auditing.
• Operation and Maintenance Level: Regularly conduct vulnerability scans and security assessments and update device firmware and encryption algorithms.
  Practice of an Energy Enterprise: By deploying USR-N520 serial port to ethernet adapters and implementing the above protection system, the frequency of security incidents in its industrial network has decreased from 3 times per month to 1 time per year, and operation and maintenance costs have been reduced by 40%.

5. Contact Us: Get Your Exclusive Encrypted Communication Solution
The communication security requirements in industrial sites vary greatly. For example:

• Device Quantity: If more than 50 devices need to be connected, a solution supporting multi-serial port expansion (such as the USR-N580 eight-serial port to ethernet adapter) should be selected.
• Protocol Complexity: If device protocols are diverse, devices that support automatic protocol recognition should be given priority.
• Compliance Requirements: If compliance with the Classified Protection 2.0 or IEC 62443 standard is required, products that have passed relevant certifications should be selected.
  Submit an inquiry immediately, and we will provide you with:
• Requirement Assessment: Customize an encrypted communication solution based on your device types, protocols, and security requirements.
• Product Selection Recommendations: Recommend suitable serial port to ethernet adapter models (such as the USR-N520) and configuration parameters.
• Deployment Guidance: Provide detailed tutorials on device installation, protocol configuration, and encryption parameter settings.
• Operation and Maintenance Support: Provide remote assistance for vulnerability repair, firmware upgrades, and security audits.
  From an enterprise achieving a security upgrade of its power monitoring system through the USR-N520 serial port to ethernet adapter to a transportation project ensuring the stable operation of traffic lights through encrypted communication, numerous cases have proved that a scientific encrypted communication solution is the "cornerstone" of industrial cybersecurity.