ATSHA204A_14 Datasheet, PDF (48/82 Pages) ATMEL Corporation – Atmel CryptoAuthentication

The key written to the target slot is the result of a SHA-256 of the following message:
32 bytes
1 byte
1 byte
2 bytes
1 byte
2 bytes
25 bytes
32 bytes
Target or parent key (depending on SlotConfig Bit12)
Opcode
Param1
Param2
SN[8]
SN[0:1]
Zeros
TempKey.value
The data flow for this command is shown graphically in the figure below:
Figure 8-2. Data Flow for DeriveKey Command
Input MAC
Parent
Key
Target
Key
SHA
(AUTH)
Mode
Source
Key
Nonce
SHA
(Dervice)
Match
48 ATSHA204A [DATASHEET]
Atmel-8885D-CryptoAuth-ATSHA204A-Datasheet_072014