I have below questions regarding SHA-1/HMAC authentication
a) The default plain text authentication key is 0x0123456789ABCDEFFEDCBA987654321 which is actually 15bytes and 4 bits, can you tell me should we use 0x00123456789ABCDEFFEDCBA987654321 or 0x0123456789ABCDEFFEDCBA9876543210
b) When I am authenticating the battery I need to send AuthenticateChecksum() after AuthenticateData(), can you please tell what method is used to generate the checksum.
c) Can you recommend any tool to generate 20 byte authentication challenge and as well as checksum? it will be a great help.
d) And finally in the data sheet it says “The resulting digest is written to AuthenticateData(), overwriting the pre-existing challenge”. What is this digest same as the challenge message sent by host?
I am referring to the sections 8.3.15.1, 8.3.15.2, 8.3.15.3 in bq34z100-g1 datasheet.