Why anti-tamper sensors matter

In this guest blog post, Raj Uppala, Senior Director Silicon IP at Rambus, outlines why anti-tamper sensors are so crucial and explains how Rambus and Agile Analog are collaborating to deliver complementary security solutions that offer comprehensive protection against security attacks.

Evolving security attacks

If your device processes valuable data, controls a critical function, or connects to a wider network, it’s a target. Attackers don’t just try to break software; they increasingly physically tamper with hardware: probing, fault injecting, or opening enclosures to bypass protections and extract secrets. The consequences range from IP theft and fraud to orchestrated downtime across fleets of connected devices.

Anti-tamper sensors are an essential tool among several defenses used to protect against these security threats. By continuously monitoring for abnormal environmental or electrical conditions, anti-tamper sensors help ensure that when a device is touched, opened, glitched, or zapped, your security stack knows and reacts to protect your system.

Today’s adversaries use voltage glitching to skip instructions, clock manipulation to desynchronize logic, and electromagnetic fault injection (EMFI) to flip bits at precise moments. They may also use strong magnets or environmental shifts to blind sensors or disrupt measurements, especially in metering and industrial systems.

Why does this matter? Because hardware secrets (keys, certificates) underpin secure boot, encrypted communications, and software trust. Physical compromise of just one device can open a backdoor to a much larger network if unique per-device protections and real-time anti-tamper responses aren’t in place.‍

Recurring challenges

From conversations with SoC teams and device makers, several recurring challenges emerge:

Evolving attack techniques: Digital-only countermeasures often miss analog domain faults like voltage, clock, and EMFI attacks. Systems need diverse, low-latency sensors that can spot subtle, nanosecond-scale anomalies before damage is done.

Integration across process nodes and foundries: Analog IP is traditionally process specific, making portability painful when supply constraints or costs push a design to another process node or foundry. Re-engineering slows releases and consumes scarce analog engineering talent.

Tuning and false positives and negatives: Anti-tamper sensors must be sensitive without being noisy. Poor thresholding or inadequate environmental compensation can trigger needless shutdowns or, worse, miss an actual attack. Getting that balance right demands robust IP and good system architecture.

Compliance pressure: Regulations and certifications (e.g., FIPS 1403 Level 3 and 4, Common Criteria High Assurance Levels, SESIP L3, ISO 21434) add requirements for key protection, anti-tamper responses, and secure boot. Meeting them while hitting power, area, and schedule targets is hard.

Anti-tamper strategy

A resilient anti-tamper strategy embraces sensor diversity, secure event handling, and automated responses:

• Multi‑modal sensing (voltage, clock, temperature, magnetic/EMFI) to detect a broad spectrum of physical attacks.
• Secure response paths anchored in a hardware Root of Trust (RoT) so detected events can trigger policy-driven actions like key zeroization, boot lockdown, or secure telemetry, even if an application code is compromised.
• Per-device uniqueness (unique keys, secure provisioning) to contain the blast radius if one unit falls into the wrong hands.

Here’s a checklist that system designers and security architects can employ:

Threat model by device class: Map likely physical attacks (serviceable vs. sealed units, field vs. factory) and decide which sensors you need (voltage, clock, temperature, EMFI) for layered coverage.

Place sensors near assets: Position voltage and clock monitors on relevant domains and route signals securely to the RoT—short paths, shielded where practical.

Calibrate and test: Use built-in programmability to tune thresholds across PVT corners. Run fault injection tests (voltage glitches, clock glitches, EMFI) pre- and post-silicon to validate coverage and false positive rates.

Provision uniquely, attest continuously: Unique keys and attestation to prevent a single device compromise from scaling to a fleet.

Plan for updates: As attacks evolve, update RoT policies and, where applicable, firmware to refine responses without re-spinning silicon.

Anti-tamper sensors are non-negotiable in a world where physical attacks are mainstream. But sensors alone aren’t enough. You need a secure control plane that can decide and act, anchored in hardware, with the independent analysis that certifications bring and countermeasures to withstand threats both today and tomorrow.

Comprehensive complementary security solutions

Agile Analog and Rambus offer comprehensive, complementary security solutions that provide best-in-class anti-tamper protection:

• Agile Analog delivers highly configurable analog tamper detection and tamper prevention IP through its agileSecure portfolio—portable across processes, tuned for advanced nodes, and designed to spot the faults attackers rely on.
• Rambus provides CryptoManager Root of Trust and cryptographic backbone IP products with state-of-the-art anti-tamper hardening, QuantumSafe readiness, and a proven path to compliance.
  

Together, Agile Analog and Rambus offer a defense-in-depth blueprint that addresses customer pain points: better detection, simpler integration, fewer false positives, and smoother certification. If your roadmap includes secure SoCs for AI, automotive, industrial, or payments, pairing Agile Analog’s agileSecure with Rambus CryptoManager is a pragmatic way to raise the bar.

To find out more about Agile Analog’s anti-tamper solutions, please go to Agile Analog's Security IP web page.