Chip maker STMicroelectronics is working with Microsoft to strengthen security in IoT applications. ST is integrating its ultra-low-power STM32U5 microcontrollers (MCUs) with Microsoft Azure RTOS & IoT Middleware and a certified secure implementation of Arm Trusted Firmware -M (TF-M) secure services for embedded systems.

The project has produced a TF-M based, Azure IoT cloud reference implementation that builds on the hardened security features of the STM32U5 complemented with the hardened key store of an STSAFE-A110 secure element.

Microsoft Azure RTOS provides middleware optimised for resource-constrained, connected applications such as IoT edge devices and endpoints. It combines the ThreadX real-time operating system with services for memory management and connectivity including NetX Duo IPv4/IPv6 and TLS secure socket support.

The Arm TF-M suite provides trusted services including secure boot, secure storage, cryptography, and attestation. Architected for Arm Cortex-M processors, TF-M suite integrates with ST’s STM32U5 MCUs, which are based on the Cortex-M33 embedded core.

Additional security features of the STM32U5 include physical-attack resistance, Arm’s proven TrustZone architecture that provides extra isolation for security-critical resources. STM32U5 MCUs achieved PSA Certified Level-3 and SESIP 3 certifications in 2021 and achieved an EEMBC SecureMark-TLS score of 133,000 for cryptographic processing efficiency.

ST will release an STM32Cube-based integration of the reference implementation in Q3 2022 that will further simplify IoT-device design leveraging tight integration with the wider STM32 ecosystem.

“Developers of IoT devices face intense pressure to meet time-to-market constraints at the same time as satisfying the highest-level security-industry standards,” said Daniel Colonna, Marketing Director, Microcontroller Division, STMicroelectronics. “Our solution accelerates embedded development by increasing security as well as power efficiency and performance.”

“Our collaboration with ST is effective and timely, enabling developer communities to meet widespread market demands for smart, connected solutions that are trusted, robust, and efficient,” said Moe Tanabian, Vice President and General Manager, Azure Edge Devices, Platform and Services.