Meeting Automotive Security Demands with TrustME^® W77T Secure Flash

With vehicles becoming more software-defined, new security and regulatory requirements are shaping how automotive systems are designed. The recent introduction of the EU Radio Equipment Directive (RED) and EN 18031 means that manufacturers must embed robust security features into their platforms. Secure Flash memory is key in protecting critical data, maintaining firmware integrity, and ensuring regional compliance. Winbond’s TrustME® W77T Secure Flash Memory has been developed to address these requirements with compliance, data protection, and efficient in-vehicle integration features.

Security and Compliance Built into the Design

The W77T Secure Flash Memory incorporates a range of embedded security mechanisms designed to help automotive engineers meet stringent regulatory requirements and protect against both current and emerging threats:

• Secure Boot Mechanisms: Using cryptographic signature verification at power-on, the W77T ensures that only authenticated firmware is executed. The device stores trusted root keys in a secure, non-modifiable region and supports one-time programmable (OTP) key storage and hardware-based boot code validation, blocking unauthorised or modified code from running.
• Post-Quantum Cryptography (PQC): The W77T integrates hardware-accelerated Leighton-Micali Signature (LMS) algorithms aligned with NIST’s draft standard for post-quantum digital signatures. LMS supports forward security and hash-based cryptographic techniques, which are resistant to attacks by quantum computers and suitable for constrained environments such as ECUs.
• NIST 800-193 Firmware Resilience: The device supports rollback prevention, secure recovery procedures, and protected firmware update paths. These safeguards prevent code corruption and unauthorised modifications, allowing systems to detect and respond to abnormal firmware states.
• LMS-OTS Remote Attestation (NIST 800-208): By leveraging LMS in combination with One-Time Signature (OTS) schemes, the W77T enables remote attestation of firmware throughout manufacturing and deployment. This cryptographically verifies that firmware installed on the device matches a trusted image—ensuring end-to-end firmware integrity across the supply chain.

Together, these features form a comprehensive security framework that supports secure boot, trusted updates, and firmware validation across the vehicle’s lifecycle, even as cybersecurity regulations become more demanding.

Technical Overview of the W77T Secure Flash Memory

The W77T is built to deliver high reliability, security, and performance for automotive-grade applications, combining advanced memory architecture with functional safety and cybersecurity compliance.

 Fig1. Automotive Certifications make Winbond’s secure memory ideal for automotive cybersecurity applications.

• High-Speed Interface: The device supports the Octal/xSPI interface operating at 200MHz in Double Transfer Rate (DTR) mode, achieving up to 400MB/s read bandwidth. This makes it well-suited for time-critical applications such as ADAS, infotainment systems, and fast OTA updates. It also supports backward compatibility with Quad SPI mode, ensuring integration flexibility across different system architectures.
• Scalable Density Options: With capacities ranging from 64Mb to 1Gb, the W77T supports use cases from code storage in basic ECUs to data logging and runtime memory for more complex automotive domains. The wide density range allows design engineers to right-size memory for cost, performance, and power requirements.
• Versatile Packaging: The W77T is offered in TFBGA (Octal SPI), SOIC (Quad SPI), and WSON (Quad SPI) packages, optimized for automotive-grade soldering, board space constraints, and thermal performance. These package types are qualified to AEC-Q100 standards and support high thermal cycling endurance.
• Reliability and Data Integrity: Built-in Error Correction Code (ECC) ensures correction of single-bit errors and detection of double-bit errors during read and write operations. The device also includes Replay-Protected Monotonic Counters (RPMC) to provide tamper-resistant time-stamping and anti-rollback protection for secure boot and firmware update processes.
• Functional Safety and Cybersecurity Compliance: The W77T is developed following ISO26262 to ASIL-D requirements, supporting safety mechanisms like diagnostic coverage and systematic fault avoidance. It also complies with ISO/SAE 21434, ensuring a secure development lifecycle and built-in countermeasures for common automotive cybersecurity threats, including firmware manipulation, key extraction, and fault injection.

Designed for Critical Automotive Use Cases

The W77T is engineered to support high-speed, secure data storage in various critical automotive subsystems. Advanced Driver-Assistance Systems (ADAS) enable rapid, low-latency access to sensor fusion data and AI inference results, supporting real-time decision-making under stringent timing constraints. Thanks to its high read bandwidth, the device provides fast boot capability and OTA update support for infotainment and connectivity modules. In Electric Vehicle (EV) and Battery Management Systems (BMS), the W77T safeguards calibration data, firmware configurations, and operational logs against tampering, supported by RPMC and ECC. For Software-Defined Vehicles (SDVs), the device enables secure and flexible software deployment across multiple domains, leveraging its integrated post-quantum cryptographic algorithms and remote attestation to maintain firmware authenticity.

Protecting the Supply Chain and Firmware Integrity

Winbond has included remote attestation capabilities in the W77T as concerns grow around supply chain vulnerabilities. This feature ensures that only verified firmware is installed, preventing tampering during production and distribution. It also helps block counterfeit components and unauthorised data changes—supporting end-to-end security.

Compliance with Global Automotive Security Standards

In addition to meeting EU regulations such as the Radio Equipment Directive (RED) and EN 18031, the W77T Secure Flash Memory is engineered to comply with a broad range of international security and functional safety standards—ensuring its suitability for global automotive platforms.

The device supports Common Criteria (CC) EAL-level assurance, validating its resistance to software and physical attacks in secure embedded environments. It complies with FIPS 140-3, the U.S. government standard for cryptographic module security, confirming its robust handling of encryption key storage, secure key generation, and tamper detection. The W77T is also SESIP-certified (Security Evaluation Standard for IoT Platforms), which verifies the integrity of its secure hardware implementation and lifecycle management features.

This combination of certifications allows automotive manufacturers to integrate the W77T into platforms targeting multiple regional markets—ensuring consistent security posture, regulatory alignment, and faster time-to-compliance across jurisdictions.

Balancing Security with Market Scalability

High-assurance security features—such as PQC, remote attestation, and secure boot—are often linked to higher system complexity, increased silicon area, and added design overhead. However, the W77T has been architected to deliver strong, standards-aligned security within a compact and cost-efficient footprint, making it suitable for high-end and volume-driven automotive platforms.

The device integrates lightweight yet robust PQC algorithms, including LMS, which are NIST-approved and designed for constrained environments. These are implemented in hardware to minimise processing overhead and reduce latency during cryptographic operations. The W77T also supports hardware-accelerated SHA, and TRNG functions, allowing secure operations to run independently of the host processor—freeing up system resources and simplifying integration.

Combined with flexible density options (ranging from 64Mb to 1Gb) and multiple package types optimised for automotive use cases, the W77T enables OEMs and Tier 1 suppliers to deploy a single secure flash platform across a wide range of ECUs—without compromising performance, compliance, or cost targets.

Scalable Architecture for Tomorrow’s Vehicles

As the industry moves from Level 2 to Level 5 autonomy, the need for secure, high-density memory will only increase. Winbond is continuing to develop technologies to stay ahead of these requirements, including:

• Higher-Density Secure Flash: Designed to handle larger volumes of critical data in autonomous platforms.
• Expanded Safety Features: Building on ISO26262 ASIL-D to support increasingly complex automotive systems.
• Quantum-Resistant Security: Future-ready cryptographic protections designed to withstand long-term cyber threats.

Conclusion

Winbond’s W77T Secure Flash Memory provides design engineers with a secure, high-speed solution built for the next generation of connected vehicles. Combining firmware protection, post-quantum cryptography, and remote attestation features, the W77T supports system security and global compliance.

With its scalability, industry certifications, and cost-effective design, the W77T offers more than just memory—it helps manufacturers build safer, more reliable automotive systems ready for the future.