STM32U5
Root Security Services-
Secure Firmware Install
Rev 1.0
Hello, and welcome to this presentation describing the
secure firmware install (SFI) feature offered by the Root
Security Services.
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Overview
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• RSS is the secure part of the STM32 immutable
bootloader (BL), Available when TrustZone is activated
• RSS provides services for (SFI) secure firmware install
solutions
• Immutable root security services
• Enables Secure Firmware Install (SFI)
Application benefits
STM32 Cube
Programmer
RSS/BL
Contract Manufacturer
STM32U5
Flash
SFI
HSM
HSM
OEM
STM32 Trusted
Package Creator
The Root Security Services (RSS) are the secure part of
the STM32U5 immutable bootloader. They are available
only when TrustZone is activated on the device.
RSS provides immutable root security services, used for
example to run the STM32 secure firmware install (SFI)
solution in an untrusted environment.
For more information on TrustZone and protected
memories please refer to the on-line training module
“STM32U5 Security Overview”.
A hardware security module (HSM) is in charge of:
- Securely storing OEM AES secret key
- Checking the STM32 device certificate that is used to
authenticate STM32 device
- Generating and providing the license to the secure
bootloader to securely install the encrypted firmware
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