Function pseud_factor_for_hub 

pub fn pseud_factor_for_hub(
    pseud_factor_secret: impl DigestibleSecret,
    hub_id: Id,
) -> Scalar

Computes the pseudonymisation factor $g_H$ for the hub identified by hub_id, from the transcryptor’s pseud_factor_secret. See crate::api::sso for the exact formula.