User Manual

Apollo3 Blue Datasheet
DS-A3-0p9p1 Page 173 of 909 2019 Ambiq Micro, Inc.
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4. Security
4.1 Functional Overview
The Apollo3 Blue MCU includes the following security features:
▪ Secure Boot
▪ Secure OTA
▪ Secure Key Storage
▪ Key Revocation
▪ AES128, SHA256
▪ CRC32
▪ External Flash Inline Encryption/Decryption
More details on the Apollo3 Blue MCU security features are described in the Ambiq Apollo3 Blue MCU
Security Whitepaper.
4.2 Secure Boot
The Secure Boot feature on the Apollo3 Blue MCU provides a secure foundation for customer firmware.
The secure boot loader provides authentication, decryption and integrity validation for customer firmware
on installation and boot/reset. Secure boot loader provides firmware recovery and OTA update support.
Secure boot is configurable leveraging OTP to direct the secure boot loader based on the customer
security requirements.
The secure boot flow is illustrated in Figure 9.
Figure 9. Secure Boot Flow
Boot/Reset
Secure OTA Update?
no
yes
Perform OTA updates
Perform Dec/Auth
Validation
Ambiq Secure Boot
Loader Execution
Customer Secure
Firmware Execution
ERROR
Error
ERROR
Error