How do you add security to microcontrollers?

1 Secure Boot

One of the first steps to secure your microcontroller is to implement a secure boot process. This means that the microcontroller will only execute firmware that is authenticated and verified by a trusted source. To do this, you need to use cryptographic methods, such as digital signatures, encryption, and hashing, to ensure the integrity and authenticity of the firmware. You also need to store the cryptographic keys and certificates in a secure memory, such as a read-only memory (ROM) or a secure element (SE), that is resistant to physical and logical attacks.

2 Secure Communication

Another important aspect of microcontroller security is to ensure that the communication between the microcontroller and other devices or networks is secure. This means that the data that is transmitted or received by the microcontroller is encrypted, authenticated, and protected from eavesdropping, tampering, or replay attacks. To do this, you need to use secure protocols, such as Transport Layer Security (TLS), Secure Shell (SSH), or MQTT with TLS, that provide end-to-end encryption and authentication. You also need to use secure key exchange and management mechanisms, such as Diffie-Hellman, RSA, or Elliptic Curve Cryptography (ECC), to generate and store the encryption keys and certificates.

3 Secure Firmware Update

A third aspect of microcontroller security is to ensure that the firmware update process is secure. This means that the microcontroller can receive and install new firmware versions that are authorized and verified by a trusted source. To do this, you need to use the same cryptographic methods and secure memory that you used for the secure boot process. You also need to use a secure channel, such as TLS or SSH, to download and transfer the firmware update. Additionally, you need to use a secure bootloader, such as MCUboot or Trusted Firmware-M, that can perform the firmware update safely and reliably.

4 Secure Debugging

A fourth aspect of microcontroller security is to ensure that the debugging process is secure. This means that the microcontroller can only be accessed and debugged by authorized and authenticated users or devices. To do this, you need to use secure debugging features, such as lock bits, password protection, or debug authentication, that can prevent unauthorized access or modification of the microcontroller memory or registers. You also need to use secure debugging tools, such as JTAG or SWD, that can provide encryption and authentication of the debugging commands and data.

5 Secure Coding

A fifth aspect of microcontroller security is to ensure that the coding process is secure. This means that the code that you write for your microcontroller is free of errors, vulnerabilities, or backdoors that can compromise the security of your microcontroller. To do this, you need to use secure coding practices, such as following coding standards, performing code reviews, testing and debugging your code, and using static and dynamic analysis tools, that can help you detect and fix any security issues in your code. You also need to use secure coding tools, such as compilers, libraries, or frameworks, that can provide security features, such as memory protection, stack protection, or randomization, that can prevent common attacks, such as buffer overflow, stack overflow, or code injection.

6 Secure Hardware

A sixth aspect of microcontroller security is to ensure that the hardware that you use for your microcontroller is secure. This means that the microcontroller chip and the board that you use are designed and manufactured with security in mind. To do this, you need to use secure hardware features, such as tamper detection, anti-fuse, or physical unclonable function (PUF), that can prevent physical attacks, such as probing, cloning, or extraction, of the microcontroller chip or the board. You also need to use secure hardware components, such as sensors, actuators, or connectors, that can prevent external attacks, such as power analysis, electromagnetic interference, or fault injection, of the microcontroller circuit or the board.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?