Dear sir:
The DAC private key is generated using P256, and the key length is 256 bits, which is 32 bytes.
As below link, why is 68 bytes planned in the factory data?
developer.nordicsemi.com/.../nrfconnect_factory_data_configuration.html
dac_key |
DAC private key | 68 B | byte string | mandatory | The private key associated with the Device Attestation Certificate (DAC). This key should be encrypted and maximum security should be guaranteed while generating and providing it to factory data. |