at88sa100s ATMEL Corporation, at88sa100s Datasheet - Page 13

• Manufacturer Part Number: at88sa100s
• Description: Battery Authentication Chip
• Manufacturer: ATMEL Corporation

4.1.
8558B–SMEM–09/09
MAC
Computes a SHA-256 digest of the key, challenge and other fixed information on the chip to generate an output
response. If MemValid is not set, indicating that no valid key is stored in the SRAM, then this command will return an
error. The hashed message includes the following bytes, concatenated in this order:
Table 7.
Table 8.
Table 9.
Opcode
Param1
Param2
Data
Response
6
0-5, 7
256 bits
256 bits
8 bits
8 bits
16 bits
88 bits
8 bits
32 bits
16 bits
16 bits
1 bit
255 bits
64 bits
Bit
Name
Input Parameters
Output Parameters
Mode Encoding
MAC
Mode
Zero
Challenge
If set, then the 4 bytes of Fuse SN and the two bytes of ROM SN will be included in the message,
otherwise these bits will be set to 0 in the message.
Ignored, must be all 0.
Key (Stored in Sram)
Challenge
Opcode (always 0x01)
Mode input
Param2 input
All 0’s
Fuse MfrID (Fuse[88-95])
Fuse SN (Fuse[96-127]), or 0’s
ROM MfrID
ROM SN, or 0’s
1’s – SHA-256 padding
0’s – SHA-256 padding
Length (704) per SHA-256
Name
Size
32
SHA-256 digest
Size
32
1
1
2
0x08
Refer to Table 9.
Must be 0x00 00
Input portion of message to be digested
Notes
AT88SA100S [ Preliminary]
Notes
Notes
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