ATECC608A datasheet(32/81 Pages) MICROCHIP

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Input Data Param2 = 0x00 00

Input Data Param2 = 0x80 00

LSB of Param2 (always 0x00)

5.1.4.2

Nonce - Fixed

A fixed nonce is passed to the device and stored in one of the internal buffers. The size of the nonce may be either

32 or 64 bytes. The TempKey.SourceFlag is always set to input after this command is run. This mode of the Nonce

command does not run a SHA256 calculation or generate a random number.

Table 5-15. Fixed Nonce Input Parameters

Opcode

Mode

Param2

Data

Description

0x16

0x03

0x43

0x83

0x00

32 bytes

• 32 bytes written to TempKey

• 32 bytes written to Message Digest Buffer

• 32 bytes written to Alternate Key Buffer

0x23

0x63

0x00

64 bytes

• 64 bytes written to TempKey

• 64 bytes written to Message Digest Buffer

Table 5-16. Fixed Nonce Output Response

Name

Size

Description

Response

1 byte 0x00 if the command is completed successfully. Otherwise an error code is received.

Notes:

TempKey.SourceFlag is set to ‘1’ upon successful command completion, indicating nonce value was fixed

input value.

TempKey.Valid is set to ‘1’, indicating the value is valid for other use.

5.1.5

Random Command

The Random command generates a random number to be used by the system. Random numbers are generated via

the internal NIST 800-90 A/B/C random number generator. The output of the command is always a 32-byte number

placed on the bus. The number cannot be stored in any data slot or SRAM location.

Table 5-17. Input Parameters - Random

OpCode

(1 Byte)

Mode

(1 Byte)

Param2

(2 Bytes)

Data

(0 Bytes)

Description

0x1B

0x00

0x00 00

—

Random command

Table 5-18. Output Response - Random

Name

Size

Description

RandOut

32 bytes

The output of the RNG

5.1.6

Read Command

The Read command can be used to access any of the EEPROM zones of the ATECC608A-TNGLoRaWAN device.

Data zone access is limited based on the access policies set for each of the slots. Encrypted reads are possible only

on the Data zone slots if specific access policies are set.

ATECC608A-TNGLoRaWAN

Device Commands

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