You are finalizing the bill of materials for your next IoT device. The sensor choice is set. The MCU is locked in. Then you hit the secure element column. This one little chip can make or break your product’s trustworthiness. And most options on the market feel like a black box. You pay for a binary blob, sign an NDA, and hope the vendor’s claims hold up. But there is a better path. An open source secure element lets you see exactly what runs on the hardware, verify the cryptographic implementations, and customize the firmware to your use case. For IoT developers, hardware engineers, and product managers who care about long term security, transparency is no longer a nice to have. It is a requirement.
An open source secure element gives you full visibility into hardware security code, community vetted cryptography, and the freedom to tailor firmware to your IoT product. It eliminates vendor lock in, simplifies audits, and allows independent researchers to verify the chip’s security posture. For production IoT projects, this transparency directly reduces risk.
What Is an Open Source Secure Element?
A secure element is a dedicated tamper resistant microcontroller that stores cryptographic keys, performs encryption, and authenticates devices. Traditionally, these chips come with closed source firmware and proprietary APIs. An open source secure element follows the same hardware principles but publishes its firmware source code under a permissive license. Anyone can review the code, compile it, and flash it onto the silicon.
This approach flips the old security model on its head. Instead of trusting a vendor’s unverifiable claims, you rely on peer review and reproducible builds. The hardware still provides physical protections like side channel resistance and glitch detection. The difference is that the logic layer is open for inspection.
Why Open Source Matters for IoT Security
Connected devices are notoriously hard to patch. Once a sensor node or smart lock ships, updating the secure element firmware often requires a physical visit or an intricate key update protocol. If the proprietary firmware has a hidden vulnerability, you may never know until a breach happens.
Open source secure elements solve this by turning your security stack into a community asset. Bugs are found faster because researchers can run static analysis tools on the source. Patches are shared openly. You are also not dependent on a single vendor’s release schedule.
“The security community has proven time and again that openness wins. Proprietary crypto is not more secure, it is just harder to audit. With an open source secure element, you get the same hardware guarantees plus the ability to verify every line of code.” — Senior embedded security engineer, open source hardware project
The Transparency Advantage
When you evaluate a proprietary secure element, you typically receive a datasheet with claims like “AES 256 hardware accelerator” and “secure key storage.” But you cannot confirm how the key generation algorithm seeds its randomness. You cannot check whether the firmware has any backdoors. In contrast, an open source secure element publishes its entire firmware repository, including the random number generator implementation and the key derivation functions.
This transparency extends to the supply chain. Because the firmware is public, you can verify that the chip you receive matches the expected code. You can even build your own firmware image and lock the device to only accept authenticated updates.
Flexibility and Customization
Not every IoT project needs the same security profile. A smart thermostat may require only basic TLS authentication. A medical device may need FIPS compliant key storage and secure boot with rollback protection. Proprietary secure elements often force you into a one size fits all configuration. Open source alternatives let you strip out unnecessary features to reduce attack surface, or add custom cryptographic protocols.
You can also integrate the secure element more tightly with your main application processor. Since the firmware is open, you can modify the communication protocol to use a shared memory region instead of I2C, saving power and latency. This kind of enhancement of IoT security with open source embedded frameworks becomes possible when you control the full stack.
Community Audits and Faster Bug Fixes
The strength of an open source secure element grows over time. Every time a researcher in the community finds a subtle timing leak or a weak PRNG, a patch is contributed. Compare that to proprietary chips where you might wait months for a vendor to acknowledge a flaw and release a firmware update. For production IoT devices that remain in the field for years, this rapid response cycle is critical.
Consider the recent Ripple20 and Amnesia:33 vulnerabilities. They affected closed source TCP/IP stacks embedded in millions of devices. An open source secure element would have allowed security teams to audit the code before integration and push fixes without waiting for a vendor.
Open Source vs Proprietary Secure Elements: A Comparison
| Aspect | Proprietary Secure Element | Open Source Secure Element |
|---|---|---|
| Firmware visibility | Binary blob, no source access | Full source code published |
| Auditability | Vendor only; NDA required | Independent researchers, community, you |
| Customization | Fixed feature set; limited API | Modify firmware to match your use case |
| Supply chain trust | Rely on vendor assurances | Reproducible builds; verify your chip |
| Vulnerability disclosure | Vendor controlled timeline | Open bug tracker; patches from community |
| Long term support | Depends on vendor lifecycle | Community maintained; you can fork |
| Cost per chip | Often premium licensing | Hardware cost only; firmware is free |
How to Get Started with an Open Source Secure Element
Making the switch is simpler than you might think. Here are the steps:
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Select a compatible hardware platform. Start with a development board that includes an open source secure element. Many are based on RISC V or ARM Cortex M cores with open firmware. Check that the board has a debug interface for flashing custom images.
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Set up the build environment. Clone the firmware repository and install the required toolchain. Most projects provide a Docker image to avoid dependency issues. Verify you can compile the default firmware and flash it successfully.
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Review the cryptographic primitives. Examine the random number generator, the key derivation function, and the TLS library. Look for attestations from independent audits. Some projects publish a formal security assessment report.
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Customize the firmware. Remove features you do not need to reduce the attack surface. For example, if your device never uses ECDSA, disable that code path. Then implement your custom protocol between the host MCU and the secure element.
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Implement a secure update mechanism. Design a two stage bootloader that validates signed firmware images. The open source firmware will include sample code for this. Adapt it to your PKI infrastructure.
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Integrate with your main application. Write a HAL (hardware abstraction layer) that communicates with the secure element over SPI or I2C. The open source project should provide reference drivers. Test the full authentication flow end to end.
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Perform a security review. Use the same static analysis tools that the community uses. Run dynamic tests with fault injection if you have the equipment. Document any findings and contribute fixes upstream.
Common Mistakes to Avoid
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Ignoring the hardware attack surface. An open source secure element does not protect against probing if you leave debug pins enabled. Always disable JTAG and test interfaces in production.
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Assuming the default firmware is perfect. Even open source code can have bugs. Always run your own threat model and penetration tests.
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Not version locking the firmware. When you fork the repository, pin the commit SHA. Uncontrolled updates can introduce regressions.
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Using the secure element as a general purpose micro. These chips are designed for cryptographic operations. Offload non security tasks to your main processor.
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Skipping the reproducible build check. If two engineers compile separately, they should get identical binaries. If not, investigate your toolchain.
Making the Business Case for the Open Source Secure Element
Product managers often worry about support. Who will answer questions when a bug appears? The answer is the community. Active projects have mailing lists, Discord servers, and issue trackers where maintainers respond. You can also hire consulting engineers who specialize in the platform.
The cost difference is negligible. The hardware BOM may be similar to a proprietary chip. The real savings come from reduced licensing fees and from avoiding emergency firmware updates due to undisclosed vulnerabilities. For a production run of 50,000 devices, the open source approach can save tens of thousands of dollars over the product’s lifetime.
To understand how this fits into the larger ecosystem, see our discussion on how open source protocols enhance security and interoperability in IoT devices. The same principles of transparency and community validation apply across the stack.
A Practical Example: Deploying an Open Source Secure Element in a Smart Lock
Imagine building a smart lock. It needs to store a private key for TLS mutual authentication with the cloud, generate one time codes for local Bluetooth unlock, and verify firmware updates. A proprietary secure element would give you a fixed API. With an open source alternative, you can:
- Use the secure element as a true root of trust for attestation.
- Implement a custom protocol where the lock only responds to signed commands.
- Update the key derivation scheme when a new vulnerability is found without changing hardware.
One team we worked with cut their security certification time by 30 percent because they could point auditors to the open source code and the community’s audit reports. This type of future proofing of your IoT ecosystem with open source embedded security solutions is becoming a competitive advantage.
Building a Secure and Trustworthy IoT Ecosystem
The decision to use an open source secure element is not just about code. It is about taking ownership of your device’s security posture. You stop being a passive consumer of a black box and start being an active participant in a community that values verifiability. For hardware engineers, this means fewer surprises during certification. For developers, it means flexible APIs that you can tune. For product managers, it means lower risk of costly recalls.
Start small. Pick a development board from a well known open source secure element project. Compile the firmware. Flash it. Make it talk to your host MCU. Once you see the source code running on real silicon, you will understand why the industry is shifting. The old model of trust through obscurity is fading. The new model is trust through transparency. Your next IoT project deserves nothing less.
For more guidance on implementation, read our developer’s guide to open source embedded security for smart devices.
