3.6.2 Key Code Format

The key code includes a 128-bit header carrying a unique value and the context provided during the Wrap or Wrap Generated Random operation, a payload, and a 32-bit checksum checked for transfer errors.

The length of the key code in bytes is calculated through the key length in bits using DRV_PUF_KEY_CODE_SIZE(keyLenBits) macro in the PUF driver. The size is computed as: 36 bytes (base) + (keyLenBits / 8) bytes (key length in bytes) + 16 bytes for each 384 bits in the key length (rounded up).

The length of the key code for the accepted key length is provided in the following table.