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Original question:

BQ27Z746: BQ27Z746: The HMAC SHA256 Keys

BQ27Z746: Device Security - Authentication keys (how to specify)

Maksim Dzerkach
Prodigy 10 points
Part Number: BQ27Z746

Tool/software:

According to documentation there are 3 keys, which can be used for HMAC. It's clear how to retrieve MAC by i2c, but i cannot understand how to choose which key will be used in HMAC generation (during i2c communication).

And also can you provide information what keys are stored on GG by default before rewriting them using tool.

  • 0
    TI__Mastermind 24931 points

    Hello, 

    You can choose which of the three keys you wish to use by changing bits 0 and 1 in the Auth Config register (see image below). 

    Additionally, we are unable to provide you with the default keys in the gauge as this is proprietary information. 

    Regards, 

    Jonny.