Attack

The attack phase is the only mandatory step that should be implemented in a submission. It takes as input a set of traces and computes a subkey scores. It can also use Profiling data.

To this end, the method attack must be implemented in attack.py:

def attack(self, attack_dataset: DatasetReader) -> KeyGuess

where DatasetReader is defined in dataset.py and KeyGuess is defined in key_guess.py). When a profiling phase is used (as done in the demo submission), the computed/loaded profile is stored in the variable self.profiled_model (the assignement of this variable is handled by quick_eval.py).

The dataset reader points to a fixed key dataset that contains only the power traces and the unmasked plaintext (see Datasets).

The KeyGuess consists in a split of the 128-bit key in subkeys (of at most 16 bits, which can be non-contiguous), and, for each subkey, a list that gives a score for each of its possible values. The score of a key value is the sum of the scores of its subkeys, and it determines the rank. See also the documentation of KeyGuess.

In the demo submission, we use the SASCA implementation from SCALib to recover information about the 16 bytes of the key. While it works (as shown in Getting Started), the attack is not optimised and does not achieve good performance, but it is a starting point for the development of better attacks within our evaluation framework (see attack.py).