STMicroelectronics Secure Element Library (STSELib)

STSELib is a modular, portable middleware providing a high-level C API for embedded developers. It abstracts command/response frame serialization, cryptographic token management, secure transaction sequencing, and physical bus operations required for authentication, brand protection, and secure data storage using STMicroelectronics secure elements (STSAFE-A and STSAFE-L series).

The library enables turnkey integration of one or multiple secure elements across diverse host MCU and MPU ecosystems.

Architecture Overview

STSELib is designed around three decoupled software layers, offering varying levels of abstraction depending on system requirements:

• Application Programming Interface (API) Layer
  The primary entry point for embedded applications. It provides ready-to-use, high-level functions covering standard secure element operations (e.g., asymmetric authentication, key establishment, secure counter management).

• Service Layer
  Formats product-specific command frames, manages payload serialization and deserialization, and decodes response frames returned by the target device. Advanced applications can interface directly with this layer for specialized workflows.

• Core Layer
  Provides hardware-agnostic communication primitives, device handler abstractions, and the Platform Abstraction Layer (PAL) interface required to bind physical transport buses (I²C, 1-Wire) to the host hardware.

Documentation

Comprehensive HTML documentation generated via Doxygen is available through two channels:

• Precompiled packages: Download the standalone documentation archive from the STSELib Releases page.
• Local build: Generate it directly from the library repository:

cd Middleware/STSELib/doc/resources/
doxygen STSELib.doxyfile

Note

Building documentation locally requires Doxygen 1.14.0 or higher.

STSELib Integration

1. Add STSELib as a Git Submodule

Add the library to your host project tree:

git submodule add https://github.com/STMicroelectronics/STSELib.git lib/stselib
git submodule update --init --recursive

Tip

Ensure lib/stselib (along with its public header subdirectories) is added to your build system's include directories (e.g., target_include_directories in CMakeLists.txt).

2. Mandatory Configuration Files

To port STSELib, two configuration files must be available in your application include path:

• stse_conf.h: Defines device family targets, enabled features, cryptographic algorithms, and buffer allocations.
• stse_platform_generic.h: Maps the low-level Platform Abstraction Layer (PAL) hooks (bus read/write, GPIO toggle, millisecond delay, mutex primitives) to your target MCU/MPU hardware drivers.

3. Optional Configuration & Platform Bindings

Depending on your security architecture and target use case, additional headers can be implemented to plug in hardware-accelerated cryptographic primitives or RTOS synchronization wrappers. Detailed specifications and template implementations are provided in the Porting Guide.

Integration examples and reference platform bindings can be found across the repositories listed in Related Packages & Ecosystem Integrations below.

Related Packages & Ecosystem Integrations

Package / Repository	Target Secure Element	Compatible Framework / OS	Target Host MCU / MPU	Maintainer / Provider
X-CUBE-STSE01	STSAFE-A & STSAFE-L series	STM32Cube (HAL / LL)	STM32 MCUs	STMicroelectronics
stsafe-a-sdk	STSAFE-A series	Bare-metal, Portable ANSI C	Generic MCUs / STM32	STMicroelectronics
stsafe-l-sdk	STSAFE-L series	Bare-metal, Portable ANSI C	Generic MCUs / STM32	STMicroelectronics
stse-linux	STSAFE-A series	Linux (User-space / PKCS#11)	Linux MPUs (STM32MP1, etc.)	STMicroelectronics
wolfssl-examples	STSAFE-A series	wolfSSL / wolfCrypt	Embedded MCUs	wolfSSL
Zephyr_st-stsafe-a1xx	STSAFE-A series	Zephyr RTOS	Zephyr-supported MCUs	CATIE

License

This software package is licensed by STMicroelectronics under standard evaluation and BSD-3-Clause terms. Refer to the LICENSE file in the root directory for full licensing details.