Function kernel_generator 

pub fn kernel_generator(
    curve: &Curve,
    p_pt: &Point,
    q_pt: &Point,
    s: &BigInt,
) -> Point

The SIDH kernel generator P + [s]·Q from a torsion basis (P, Q) and the secret scalar s. The secret isogeny is the quotient by ⟨P + [s]Q⟩; Kani’s gluing is what lets an attacker recover s from the published torsion images, after which derive_isogeny_path unfolds the whole chain.