46.5.3.1.1 Generating Hashkey

Follow these steps to generate the Hashkey:

1. Configure the CTRLA register as follows:
   1. CTRLA.STARTMODE as manual (Auto for DMAC).
   2. CTRLA.CIPHER as encryption.
   3. CTRLA.KEYSIZE as per the key used.
   4. CTRLA.AESMODE as ECB.
   5. CTRLA.CTYPE as per the countermeasures required.
2. Set CTRLA.ENABLE.
3. Write zero to the CIPLEN register.
4. Write the key in the KEYWORD register.
5. Write the zeros to the INDATA register.
6. Set CTRLB.Start.
7. Wait for INTFLAG.ENCCMP to be set.
8. AES Hardware generates Hash Subkey in the HASHKEY register.