Method open_subset_unchecked

delegatable_credentials/src/set_commitment.rs:321–355

Returns witness for the given subset of a set which is committed in this commitment

(
        &self,
        opening: &SetCommitmentOpening<E>,
        subset: BTreeSet<E::ScalarField>,
        set: BTreeSet<E::ScalarField>,
        srs: &SetCommitmentSRS<E>,
    )

    /// Returns witness for the given subset of a set which is committed in this commitment
    pub fn open_subset_unchecked(
        &self,
        opening: &SetCommitmentOpening<E>,
        subset: BTreeSet<E::ScalarField>,
        set: BTreeSet<E::ScalarField>,
        srs: &SetCommitmentSRS<E>,
    ) -> Result<SubsetWitness<E>, DelegationError> {
        let subset_size = subset.len();
        if subset_size == 0 {
            return Ok(SubsetWitness(self.0));
        }
        match opening {
            SetCommitmentOpening::SetWithTrapdoor(_, s) => {
                if subset.contains(s) {
                    Err(DelegationError::ShouldNotContainTrapdoor)
                } else {
                    let poly = poly_from_roots(&subset.into_iter().collect::<Vec<_>>());
                    let mut e = poly.evaluate(s);
                    e.inverse_in_place().unwrap();
                    Ok(SubsetWitness(self.0.mul(e).into()))
                }
            }
            SetCommitmentOpening::SetWithoutTrapdoor(r) => {
                let diff = set.difference(&subset).cloned().collect::<BTreeSet<_>>();
                let witness = if diff.is_empty() {
                    // Subset is same as the set
                    srs.get_P1().mul_bigint(r.into_bigint()).into_affine()
                } else {
                    // Commit to remaining elements
                    Self::commit_in_P1(r.into_bigint(), diff, srs)
                };
                Ok(SubsetWitness(witness))
            }
        }
    }

    /// Randomize the set commitment and the corresponding opening
    pub fn randomize(