Embedded IoT devices – from smart sensors and wearables to industrial gateways – are increasingly critical to operations in energy, healthcare, manufacturing, and transportation. But this proliferation also opens new frontiers for attackers: firmware tampering, supply-chain breaches, and botnet hijacks remain top threats.
To address this challenge, companies are turning to trusted embedded development services that incorporate hardware-based protection from the ground up. A hardware-anchored root of trust (RoT) is essential to safeguard firmware integrity, ensure secure device identity, and prevent unauthorized access or code execution. Without this foundation, embedded systems remain exposed to escalating cyber risks.
What is a Hardware-backed Root of Trust?
A Root of Trust (RoT) is the foundation of a secure system: a collection of immutable, trustworthy functions only accessible through hardware. Key components include:
- Secure Boot: Ensures only authenticated firmware is executed.
- Trusted Execution Environments (TEE): Isolate critical code and operations.
- Secure Elements (SE) / TPM / HSM: Separate chips that protect keys and sensitive operations.
- PUFs (Physical Unclonable Functions): Hardware fingerprints to generate unique device secrets.
A hardware RoT differs fundamentally from software-only approaches by resisting offline key extraction, protecting secrets from vulnerabilities, and ensuring untampered boot sequences. It becomes the immutable anchor that higher-level security builds upon.
Why Embedded Devices Need Hardware RoT
Without hardware-backed RoT, embedded systems are at risk of:
- Firmware injection: Attackers replace legitimate code.
- Bootloader tampering: Unauthorized installations or rollback attacks.
- Key theft: Software keys are easily extracted if accessible.
In sectors like EV charging, medical equipment, and industrial control, the consequences are severe – ranging from safety failures to widespread outages. Hardware RoT ensures strong device identity, authenticated updates, and secure operational integrity.
Designing Embedded Systems with Secure Boot and RoT
A robust secure boot chain typically includes:
- Immutable Bootloader(in ROM): Initiates the chain.
- Firmware Verification: Checks signatures using asymmetric keys stored in hardware.
- Chaining Trust: Each stage verifies the next.
- Runtime Protections: Keys remain stored in SE/TPM; a TEE isolates sensitive processes.
Hardware elements used might include:
| Component | Role |
| Secure Element (e.g., ATECC608) | Stores keys, performs crypto offloading |
| TPM / HSM | Enables secure boot, logging, and attestation |
| TEE (e.g., ARM TrustZone) | Isolates crypto, credentials, and authentication |
These elements prevent offline attacks, support anti-rollback, and enable secure device identity and firmware provenance.
Case Study: ElectroCharge Connect
A real-world example of hardware-backed root of trust in action is ElectroCharge Connect, an EV charging platform developed by Embrox. The system includes embedded controllers at each station, cloud-based infrastructure, mobile apps for drivers, and partner dashboards for station owners. Due to its physical exposure, real-time control, and integration with financial transactions, the platform demanded strong, built-in security.
To address these needs, Embrox applied the following security architecture:
- Each charging station runs a secure boot sequence, starting from a ROM-based bootloader that verifies the firmware signature before allowing execution.
- Firmware is signed during release, and the public key used for verification is stored inside a hardware secure element to prevent tampering or extraction.
- An ATECC608A secure element chip is placed within the controller and is in charge of storing credentials and handling authentication and secure data transfer.
- All firmware updates are sent securely over the internet and only those with a digital signature are allowed to be installed by the devices.
- The system supports anti-rollback protection, ensuring attackers cannot downgrade firmware to exploit old vulnerabilities.
- Each device performs cryptographic authentication before connecting to backend services, ensuring mutual trust between device and cloud.
- The hardware-based root of trust enables strong protection against firmware injection, device spoofing, and supply-chain manipulation.
This implementation made it possible for Embrox to deliver a secure, scalable EV charging platform where every device in the field enforces a chain of trust rooted in hardware. As the system expands, each new station joins the network with an immutable identity and verified firmware, ensuring long-term integrity and operational resilience.
Challenges and Limitations
Implementing hardware RoT brings its own challenges:
- Cost & Complexity: Secure elements increase BOM and require secure provisioning environments.
- OTA Update Coordination: Infrastructure must ensure that only authenticated, rollback-protected updates deploy.
- Risk of Bricking: Malfunctions in key stages of the boot sequence demand robust recovery or fallback designs.
- Maintenance: Compromise of private keys, key rotation, and firmware update continuity must be operated securely throughout the product lifespan.
Despite these, the benefits in high-stakes environments often outweigh the complexity.
Hardware Trust + AI, Quantum Resistance
Several emerging trends will influence hardware RoT in embedded systems:
- On-device AI for anomaly detection: Deep learning models running inside the TEE can monitor firmware integrity and behavior at runtime.
- Post-quantum cryptography (PQC): FIPS-compliant PQC signatures and encryption will need hardware support for larger computational loads.
- Blockchain for provenance and audit: Firmware fingerprints could be recorded on a ledger to ensure traceable OTA and supply-chain transparency.
Embrox is already exploring these avenues, enhancing its embedded security offerings with AI-powered protection and blockchain-anchored audit trails.
Conclusion
In today’s threat landscape, trusting software alone leaves embedded IoT systems exposed. A Hardware-backed Root of Trust provides the necessary anchor – ensuring secure boot, firmware authenticity, device identity, and resilient updates.
Embrox’s implementation in the ElectroCharge Connect case demonstrates that robust hardware RoT is not only feasible but essential for secure, scalable IoT.
As AI and PQC become reality, it’s best practice to adopt hardware trust from day one: building devices that aren’t just connected – but truly secure.