ATAES132-SH-ER Atmel, ATAES132-SH-ER Datasheet - Page 48

• Manufacturer Part Number: ATAES132-SH-ER
• Description: EEPROM AES 32Kbit EE I2C
• Manufacturer: Atmel

Specifications of ATAES132-SH-ER

• Rohs: yes
• Maximum Clock Frequency: 1 MHz
• Operating Supply Voltage: 6 V
• Maximum Operating Temperature: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-8
• Interface Type: I2C
• Factory Pack Quantity: 2300

7.14.
KeyExport Command
The KeyExport command is used to encrypt a key for export to a second ATAES132 device. The source of the key can be the
internal random number generator, the VolatileKey register, or external data. The resulting encrypted key is used as the input
to the KeyImport command or KeyLoad command. This command does not modify the stored keys.
If mode bits 2 and 3 are 00b, then a new key is generated for export:
If Mode bit 1 is 0b, then the EEPROM seed register will be updated prior to key generation.
If Mode bits 2 and 3 are 01b, then the key in the input packet will be exported:
If Mode bits 2 and 3 are 10b or 11b, then the VolatileKey will be exported:
If KeyConfig[EKeyID].AuthKey bit is 1b or KeyConfig[EKeyID].ExportAuth bit is 1b, then prior authentication is required using
the KeyID stored in KeyConfig[EKeyID].LinkPointer.
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 encrypt KeyID on the origin
device to match the decrypt KeyID on the destination device. In this section, the device which encrypts the key is referred to as
the origin device – the device receiving the key is referred to as the destination device.
If mode bit 0 is 1b and 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 must be identical on both devices. If mode bit 0 is 0b and mode bit 5, 6, or 7 is 1b, then the
value of SecondBlock must match the associated values on the destination device – the value of mode bits 5, 6, and 7 of the
KeyExport command must also match the value in the FirstBlock field. 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 KeyExport command. If the KeyConfig[EKeyID].RandomNonce bit is 1b, then the nonce
must be random.
Warning:
•
•
•
•
The internal random number generator is used to generate the key
The KeyExport command InData field contains the key value
Mode bit 1 is ignored
Mode bit 1 is ignored
There is one random number generator (RNG) seed register in the EEPROM memory which is used by the
KeyCompute, KeyExport, nonce, and random commands. The RNG seed register is subject to the same
write endurance limitations as the other bytes in the EEPROM (see Section 9.2 for the EEPROM
specifications) – the application developer must not exceed the write endurance limit.
Atmel ATAES132 Preliminary Datasheet
8760A−CRYPTO−5/11
48