@e-sushi Nice one: "seven of the ten most common vulnerabilities seen across federal agency networks at the issuance of this directive would be addressed through complying with the required actions in this directive related to web security" xD
Unbalanced Feistel networks can be homogenous (F-function identical in each round), or they can be heterogeneous (F-function not always identical in each round).
The advantage of heterogeneous UFNs is, that its internal properties change each round, making it more difficult to find specific char...
First of all do we know that when we have $g^{2i}$ that this will be a quadratic residue modulo p, and if we consider $g^{2i+1}$ that it will be not? @SEJPM
I see... And we see that for $i \in [\frac{1}{2}(p-1),p)$ and for $j=i-\frac{p-1}{2} \in [1, \frac{p-1}{2})$, it holds that $g^{2i}=g^{2j}$, so there are in total $\frac{p-1}{2}$ quadratic residues, right? @SEJPM