Method gen_partial_proof

bbs_plus/src/proof.rs:295–324

Generate a partial proof, i.e. don't generate responses for message indices in `skip_responses_for` as these will be generated by some other protocol.

(
        mut self,
        challenge: &E::ScalarField,
        revealed_msg_ids: &BTreeSet<usize>,
        skip_responses_for: &BTreeSet<usize>,
    )

    /// Generate a partial proof, i.e. don't generate responses for message indices in `skip_responses_for` as these will be
    /// generated by some other protocol.
    pub fn gen_partial_proof(
        mut self,
        challenge: &E::ScalarField,
        revealed_msg_ids: &BTreeSet<usize>,
        skip_responses_for: &BTreeSet<usize>,
    ) -> Result<PoKOfSignatureG1Proof<E>, BBSPlusError> {
        if !skip_responses_for.is_disjoint(revealed_msg_ids) {
            return Err(BBSPlusError::CommonIndicesFoundInRevealedAndSkip);
        }
        // Schnorr response for relation `A_bar - d == A'*{-e} + h_0*r2`
        let sc_resp_1 = mem::take(&mut self.sc_comm_1).gen_proof(challenge);

        let wits = schnorr_responses_to_msg_index_map(
            mem::take(&mut self.sc_wits_2),
            revealed_msg_ids,
            skip_responses_for,
        );
        // Schnorr response for relation `g1 + \sum_{i in D}(h_i*m_i)` = `d*r3 + {h_0}*{-s'} + \sum_{j not in D}(h_j*{-m_j})`
        let sc_resp_2 = self.sc_comm_2.partial_response(wits, challenge)?;

        Ok(PoKOfSignatureG1Proof {
            A_prime: self.A_prime,
            A_bar: self.A_bar,
            d: self.d,
            sc_resp_1,
            T2: self.sc_comm_2.t,
            sc_resp_2: None,
            sc_partial_resp_2: Some(sc_resp_2),
        })
    }

    /// Helper that serializes state to get challenge contribution. Serialized the randomized signature,
    /// and commitments and instances for both Schnorr protocols