Verification Process
The process for firmware verification is shown in the figure below.
To verify the signature:
- Public key verification: Users pass the RSA_Public_Key to Application Image through GProgrammer. After the Application Image is downloaded to Flash, verify RSA_Public_Key with RSA_PUBLIC_KEY_HASH in eFuse. eFuse is OTP. Therefore, in update or upgrade, the hash value generated by RSA_Public_Key in Application Image shall be consistent with RSA_PUBLIC_KEY_HASH stored in eFuse, or the verification fails.
- Signature verification: GR5xx decrypts a firmware signature with RSA_Public_Key to obtain the decrypted hash value, and calculates the Application Image with a one-way hash function to obtain the hash value. Compare the hash value obtained from decryption and the value obtained from calculation by calling the one-way hash function. If the hash values are consistent, the signature passes verification.
