Hi, I’ve computed the signal to noise ration (SNR) for the hardware AES-128 (1 round per cycle implementation) both for the leakage model `sbox_out`

and `last_round_state_diff`

.

The result is the one shown in figure below and it left me perplexed.

I expected a better SNR of the `last_round_state_diff`

than that of the `sbox_out`

, in particular with a high spike on the last round.

Indeed, I’m able to recover easily the key with the `last_round_state_diff`

but not with the `sbox_out`

leakage model.

What am i missing ? Thanks in advance

For completeness the code i used to compute the snr is :

```
leak_model = cwa.leakage_models.sbox_output
snr_so = cwa.calculate_snr(project.traces, leak_model=leak_model, db=False)
```