ATAES132-TH-EQ Atmel, ATAES132-TH-EQ Datasheet - Page 31

• Manufacturer Part Number: ATAES132-TH-EQ
• Description: EEPROM AES 32Kbit EE SPI
• Manufacturer: Atmel

Specifications of ATAES132-TH-EQ

• Rohs: yes
• Maximum Clock Frequency: 10 MHz
• Operating Supply Voltage: 6 V
• Maximum Operating Temperature: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-8
• Interface Type: SPI
• Factory Pack Quantity: 2300

7.3.
AuthCompute Command
The AuthCompute command is used to compute a MAC which will be used to execute the Auth command or the counter
command on a second ATAES132 device.
To use this command, the nonce must be identical on both devices (see Section 7.21.1) and the MacCount must have the
same value. Both devices must also contain identical key values, but it is not necessary for the KeyID on the origin device to
match the KeyID on the destination device. In this section, the device which generates the MAC is referred to as the origin
device, and the device checking the MAC is referred to as the destination device.
If mode bit 5, 6, or 7 is 1b, then the associated usage counter, SerialNum register value, or the first four bytes of the
SmallZone register in the SecondBlock field must match the values on the destination device. The ManufacturingID register
must be identical on both devices, since it is always included in the MAC calculation.
A valid nonce is required to run the AuthCompute command. If the KeyConfig[MacKeyID].RandomNonce bit is 1b, then the
nonce must be random.
The AuthCompute command always sets the AuthComplete status flag to NoAuth.
Table 7-23. Input parameters
Table 7-24. Output parameters
The command and response packet is transmitted as a block beginning with the count and ending with a packet checksum.
This block format is described in Section 6.1.
Opcode
Mode
Param1
Param2
Data1
Data2
Name
ReturnCode
OutMac
Name
AuthCompute
Mode
MacKeyID
Zero
FirstBlock
SecondBlock
(Bytes)
Size
16
1
Notes
Upon success, 0x00 will be returned. Any command execution or validation failure generates a
non-zero error code, per Section 6.3.
The 16 byte MAC
(Bytes)
Size
11
16
1
1
2
2
Notes
0x14
The value of this field must match the mode field value to be used when
executing the Auth command or the counter command on the destination device
Upper byte is always 0x00. Lower byte is the pointer to the key.
Legal values: 0x00 to 0x0F, 0xFF
Always 0x0000
The value of this field must match the first authenticate-only block to be used
when executing the Auth command or the counter command on the destination
device
The value of this field must match the second authenticate-only block to be used
when executing the Auth command or the counter command on the destination
device. If mode bits 5, 6, and 7 are 0b, then this field must be present, but is
ignored.
Atmel ATAES132 Preliminary Datasheet
8760A−CRYPTO−5/11
31