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CCS/BQ27Z561: SHA-256 Key and challenge <==> message?

WU xlxl
Prodigy 20 points
Part Number: BQ27Z561
Other Parts Discussed in Thread: BQSTUDIO, SHA-256

Tool/software: Code Composer Studio

SHA-256 Key and challenge on the bqstudio Authentication View are both 256bits, but I have no idea about what is  the message input for SHA-256?

I want to make a  Authentication test.

  • 0
    TI__Mastermind 24870 points
    Please refer to SHA-256 documentation.
  • 0 in reply to Kang Kang
    Prodigy 20 points

    Glad to receive your reply.

    But what is the SHA-256 message  is still a puzzle for me.

    I  combined challenge and key in the following ways to find the expected output digest. However they both do not work.

    1) SHA-256 Message =  key append challenge append 0x80, 0x00,...0x00, 0x0200(256bits key+256bits challenge= 0x200 bytes),  total 2*512 bits.

    2) SHA-256 Message =  challenge append  key append 0x80, 0x00,...0x00, 0x0200(256bits key+256bits challenge= 0x200 bytes),  total 2*512 bits.

    Note: The key and challenge are the input bytes on bqStudio Authentication View.

    Do something else? Substitute the 20 bytes calculate output for the challenge and calculate it again?

    So, beg for some hint devoutly.

  • 0 in reply to WU xlxl
    TI__Guru* 76230 points
    Hi

    Have you reviewed section 8.2 of the TRM?

    www.ti.com/.../sluubo7.pdf

    thanks
    Onyx