ATAES132-SH-ER Atmel, ATAES132-SH-ER Datasheet - Page 42

• 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

7.11.
7.11.1. Encrypted Key Writes
EncWrite Command
The EncWrite command decrypts the ciphertext input data, verifies the input MAC, and then writes 1 to 32 bytes to a user
zone or 16 bytes to key memory.
The ZoneConfig[UZ].EncWrite bit determines if a user zone can be accessed with the EncWrite command. If the
ZoneConfig[UZ].EncWrite bit is 1b, then the EncWrite command can write the user zone if the access requirements have been
satisfied. A single EncWrite command writes data to a single user zone – the data can not span multiple user zones. A single
EncWrite command writes data to a single EEPROM page – the data can not cross page boundaries (see Section B.2).
If ZoneConfig[UZ].Auth is 1b, then prior authentication is required with the following restrictions:
When EncWrite is used to write the key memory prior to locking, then the key data must be encrypted using KeyID 00. The
input MAC is also calculated using KeyID 00. Writes to key memory must be 16 bytes in length, and begin at the starting
address of the key.
If LockKeys has a value of 0x55 and the EncWrite address points to key memory, then key personalization mode is selected.
In the key personalization mode, the following requirements are in effect:
If the key memory is locked, then the new key data is encrypted with the current value of the key being written. The key can
only be updated if all of the following requirements are satisfied:
See section 7.19 for the lock command.
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The Auth command Usage.WriteOK bit must be 1b
The authentication key AKeyID must match ZoneConfig[UZ].AuthID
The Auth command must be run in Inbound Only Authentication or Mutual Authentication mode
A valid Nonce is required to run the EncWrite command. If KeyConfig[KeyID].RandomNonce for the Write key is 1b,
The Count field value must be 16
The Address must match the starting address of the key register
The input data must be encrypted with the current value in KeyID 00. If KeyConfig[WriteID].RandomNonce is 1b
The input MAC must be generated with the current value in KeyID 00. The input MAC will be verified.
The corresponding KeyConfig[KeyID].ChangeKeys bit is set to 1b (see Section 4.2)
The count field value must be 16
The address must match the starting address of the key register.
The input data must be encrypted with the current value of the key. If KeyConfig[WriteID].RandomNonce is 1b then
The input MAC must be generated with the current value of the key. The input MAC will be verified.
then the Nonce must be random.
then the nonce must be random (See Section 7.20).
nonce be random (See Section 7.20).
Atmel ATAES132 Preliminary Datasheet
8760A−CRYPTO−5/11
42