Advantages of using wolfTPM with ST33 TPM 2.0

wolfTPM is the only TPM 2.0 library designed for baremetal and embedded systems. It also has native Windows and Linux support, alongside a TPM simulator for rapid development and testing.

When it comes to choosing a TPM 2.0 dedicated chip for your project, there are multiple options: Nuvoton NPCT75x, STMicroelectronics ST33, Infineon SLB9670, Microchip ATTPM20P, etc.

Here are our highlights when using ST33 chip with wolfTPM:

  • Only wolfTPM supports GPIO control for ST33
    • Depending on the chip variant, a ST33 could offer up to four(4) extra GPIO 
    • The access to these GPIO is protected by the TPM 2.0 authorization
    • Making the GPIO control offered by wolfTPM a great tool for signaling across subsystems for critical, important or security events
    • wolfTPM also provides an open-source example code ready for use

  • ST33 has the most Non-volatile memory storage on the market, right now
    • Typically, TPM 2.0 NVRAM storage is limited, this makes ST33  stand out. Multiple certificates and keys can be stored in the ST33 non-volatile memory
    • wolfTPM offers open-source examples on how to securely store secrets and keys in the TPM’s NVRAM
  • Using ST33 for Automotive, Industrial, Medical and Aerospace devices with wolfTPM is easy
    • Critical-safety systems often use state machines and RTOS
    • Baremetal and RTOS do not provide driver for TPM 2.0
    • Thanks to wolfTPM’s design, using ST33 without a driver is possible
    • wolfTPM has its own internal TIS layer and direct support for I2C and SPI
  • Using ST33 for IoT devices with wolfTPM is highly recommended, because our TPM 2.0 stack is lightweight. In comparison with other libraries, wolfTPM produces 20 times less code and 100 times less memory.
  • Only ST33 supports AES symmetric operations for encryption and decryption by default, using TPM2_EncryptDecrypt2. Other TPM 2.0 modules support by default only AES CFB for parameter encryption.


Contact us at if you want more information about wolfTPM or if you have any questions about using ST33 TPM 2.0 in embedded systems.