SLUUBT5C November 2018 – June 2021 BQ40Z80
The hardware supports 163-bit EC-KCDSK Elliptic Curve Cryptography (ECC) authentication, using the hardware authentication engine.
ECC authentication assumes the ECC key pair (private and public keys) is stored in secure memory. If the ECC key is not programmed in secure memory, the authentication response always returns 0.
The challenge length can vary from 1 byte to 20 bytes. TI recommends sending at least a 10-byte challenge to provide a certain level of randomness. The response is always 42 bytes in length.
The challenge should be sent via Authenticate() (0x2F). The response is returned via Authenticate() (0x2F). The device can return all 42 bytes in a single block read if Auth Config[SPLIT_RESPONSE] = 0. If [SPLIT_RESPONSE] = 1, the response is split into two blocks: The first block of the response is 31 bytes and the second block of the response is 11 bytes. Both blocks are returned via Authenticate(). The response data is available until the next authentication challenge is sent.
Additionally, an ECC test option is available: