SLUUCW8 October 2023 BQ27Z746
The BQ27Z746-R1 uses SHA-256 for authentication.
Detailed information about the SHA-256 algorithm can be found here:
The random number should be a 32-byte random number generated from the host processor system. Once this number is generated, it is used to generate the HMAC value using the random number as the message and the secure key as the secret key for SHA-256.