Public Key Digest Generation

A digest of a public key may be generated from a stored ECC public key and stored in TempKey. The Slot# must point to a stored public key, therefore this command is limited to Slots 8 and higher. Prior to running this command, the TempKey must be a valid value. The public key will not be output on the bus. The public key could however be read out using the Read command. Note that in this mode the 3 bytes in OtherData will be used to generate the digest and the mode and KeyID bytes will be ignored.

For the ATECC608A-TNGTLS, a digest can be created from Slot 11.

Table 1. Input Parameters - Public Key Digest Generation
Opcode (1 Byte)	Mode (1 Byte)	KeyID (2 Bytes)	OtherData (3 Bytes)	Comment
0x40	0x10	0x00 0[Slot]	0x[any value]	Public key digest is created and stored in TempKey

Table 2. Output Response - Public Key Digest Generation
Name	Size	Response
Response	1 byte	0x00 if command completes successfully ECC Fault code if command fails

Public Key Digest Creation

A SHA256 Hash is performed over 128 bytes to generate a digest from the public key.

32 bytes
1 byte
1 byte
2 bytes
1 byte
2 bytes
25 bytes
64 bytes

TempKey
OpCode
OtherData[0]
OtherData[1:2]
SN[8]
SN[0:1]
Zeros
X and Y coordinates of the public key