Im new to cryptoanalysis and started reading A Tutorial on
Linear and Differential Cryptanalysis. The author is trying to explain it as simple as he can. But I still got some questions, can anybody help me please? He uses this example of simple spn.
As far as I have understood if we dont use k1 we just skip all S1 sboxes and first permutation and start attack at second key mixing. There is still difference with some probability for if we use generated pairs of texts. How does removing k1 mixing or k5 mixing affect our attack? Do we generate pair at start of k2 key mixing?