46.5.3.1.5 Generating The Tag

Follow these steps to generate the tag:

  1. Configure CTRLA:
    1. Set CTRLA.ENABLE to 0.
    2. Set CTRLA.AESMODE as CTR.
    3. Set CTRLA.ENABLE to ‘1’.
  2. Load J0 value to the INITVECTV register.
  3. Load GHASH value to the INDATA register.
  4. Set CTRLB.NEWMSG and CTRLB.START to start the counter mode operation.
  5. Wait for INTFLAG.ENCCMP to be set.
  6. AES Hardware generates the GCM tag output in the INDATA register.