This website requires Javascript for some parts to function propertly. Your experience may vary.

MACsec and Layer 2 Security in Automotive Ethernet | STAR ELECTRONICS

MACsec and Layer 2 Security: What every Automotive Network needs to know

MACsec (Media Access Control Security, IEEE 802.1AE) is becoming a vital component of automotive Ethernet networks, ensuring that critical in-vehicle data remains confidential, authentic, and tamper-proof. As vehicles become increasingly connected - with ADAS, infotainment, and V2X communication - Layer 2 security is essential to protect sensitive data from unauthorized access and cyber threats.
What Is MACsec?

MACsec is a Layer 2 security protocol designed to encrypt and authenticate traffic directly at the Ethernet level. Unlike firewalls or higher-layer encryption methods, MACsec operates at the Data Link Layer (Layer 2), ensuring that data packets between ECUs (Electronic Control Units), sensors, or gateways remain secure - even within the vehicle’s internal network.

Key Benefits of MACsec:

  • Confidentiality: Data frames are encrypted to prevent eavesdropping

  • Integrity: Ensures that frames are not altered during transmission

  • Authentication: Validates devices to prevent unauthorized network access

MKA Protocol: The Backbone of MACsec

The MACsec Key Agreement (MKA) protocol manages encryption keys and ensures secure session establishment between devices. It:

  • Dynamically exchanges keys between authenticated devices

  • Supports automatic key refresh to maintain continuous security

  • Enables scalability for multi-device communication across complex automotive networks

128-bit vs. 256-bit Encryption

MACsec supports two encryption strengths:

  • 128-bit encryption: Offers strong security with lower processing overhead, ideal for real-time automotive systems

  • 256-bit encryption: Provides a higher security margin, suitable for critical ECUs such as gateways or autonomous driving modules, but requires more processing power

Why Layer 2 Security Matters in Automotive Environments

Automotive Ethernet connects multiple ECUs, sensors, and cameras that share high-bandwidth data. Without proper security:

  • Intrusions could lead to system manipulation (e.g., false ADAS signals)

  • Data tampering could compromise safety-critical features like braking or collision avoidance

  • Unauthorized diagnostics or updates could introduce vulnerabilities

MACsec mitigates these risks by securing communication directly over Ethernet links, without relying on application-level protocols.

Real-World Automotive Use Cases

  • ADAS and autonomous driving: Securing LiDAR and radar data transmissions against interference

  • Infotainment and connectivity: Protecting personal data, streaming content, and OTA updates

  • Vehicle gateways: Ensuring safe communication between zonal architectures and cloud-connected platforms

STAR ELECTRONICS’ Approach to MACsec

STAR ELECTRONICS offers Ethernet switches and TAPs and media converters with MACsec support, enabling automotive engineers to implement Layer 2 encryption with minimal configuration. These solutions are designed for plug-and-play security, reducing integration complexity and ensuring interoperability with leading vendors such as Cisco, Juniper, and Fortinet.

Explore STAR ELECTRONICS’ secure Ethernet solutions: STAR ELECTRONICS Products

Key Takeaway

MACsec is no longer optional for modern automotive Ethernet architectures - it is a must-have for building secure, future-proof vehicles. By combining encryption, authentication, and integrity checks at the Ethernet level, MACsec ensures that in-vehicle communications remain both reliable and protected.

Glossary

Term

Definition

MACsec (Media Access Control Security)

Layer 2 protocol for encrypting and authenticating Ethernet traffic

IEEE 802.1AE

Standard defining MACsec

Layer 2 (Data Link Layer)

OSI layer responsible for node-to-node data transfer

MKA (MACsec Key Agreement)

Protocol for managing encryption keys in MACsec

ECU (Electronic Control Unit)

Embedded system controlling vehicle functions

ADAS

Advanced Driver Assistance Systems

V2X (Vehicle-to-Everything)

Communication between a vehicle and its surroundings

128-bit / 256-bit encryption

Levels of cryptographic strength used in MACsec

OTA (Over-the-Air)

Wireless updates for vehicle software

Plug-and-play security

Security features that require minimal setup or configuration

Contact us

Back to top