From 514221ebb052f6757c49c0c7ed2ff097fb878b34 Mon Sep 17 00:00:00 2001
From: Piotr Roslaniec <p.roslaniec@gmail.com>
Date: Wed, 31 Jan 2024 12:18:45 +0100
Subject: [PATCH] refactor(dkg): hide dkg fields in the internal api

---
 ferveo/src/dkg.rs  | 11 ++---------
 ferveo/src/lib.rs  |  4 ++--
 ferveo/src/pvss.rs | 12 +++++++++---
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/ferveo/src/dkg.rs b/ferveo/src/dkg.rs
index b6560691..e8afbe30 100644
--- a/ferveo/src/dkg.rs
+++ b/ferveo/src/dkg.rs
@@ -94,12 +94,9 @@ pub struct PubliclyVerifiableDkg<E: Pairing> {
     pub pvss_params: PubliclyVerifiableParams<E>,
     pub validators: ValidatorsMap<E>,
     pub vss: PVSSMap<E>,
-    // TODO: Remove pub?
-    // TODO: Consider replacing with domain_points entirely
     pub domain: ark_poly::GeneralEvaluationDomain<E::ScalarField>,
     pub me: Validator<E>,
-    // TODO: Remove pub?
-    pub state: DkgState<E>,
+    state: DkgState<E>,
 }
 
 impl<E: Pairing> PubliclyVerifiableDkg<E> {
@@ -123,10 +120,7 @@ impl<E: Pairing> PubliclyVerifiableDkg<E> {
 
         let validators: ValidatorsMap<E> = validators
             .iter()
-            .enumerate()
-            .map(|(_validator_index, validator)| {
-                (validator.address.clone(), validator.clone())
-            })
+            .map(|validator| (validator.address.clone(), validator.clone()))
             .collect();
 
         // Make sure that `me` is a known validator
@@ -200,7 +194,6 @@ impl<E: Pairing> PubliclyVerifiableDkg<E> {
             .into_affine()
     }
 
-    // TODO: Use instead of domain.element
     /// Return a domain point for the share_index
     pub fn get_domain_point(&self, share_index: u32) -> Result<E::ScalarField> {
         let domain_points = self.domain_points();
diff --git a/ferveo/src/lib.rs b/ferveo/src/lib.rs
index bba06458..d5f1fb11 100644
--- a/ferveo/src/lib.rs
+++ b/ferveo/src/lib.rs
@@ -405,7 +405,7 @@ mod test_dkg_full {
         // dkg.vss.remove(&removed_validator_addr); // TODO: Test whether it makes any difference
 
         // Remember to remove one domain point too
-        let mut domain_points = dkg.domain.elements().collect::<Vec<_>>();
+        let mut domain_points = dkg.domain_points();
         domain_points.pop().unwrap();
 
         // Now, we're going to recover a new share at a random point,
@@ -557,7 +557,7 @@ mod test_dkg_full {
             validator_keypairs.as_slice(),
         );
 
-        let domain_points = dkg.domain.elements().collect::<Vec<_>>();
+        let domain_points = dkg.domain_points();
 
         // Each participant prepares an update for each other participant
         let share_updates = dkg
diff --git a/ferveo/src/pvss.rs b/ferveo/src/pvss.rs
index 7be4fac2..34695bd3 100644
--- a/ferveo/src/pvss.rs
+++ b/ferveo/src/pvss.rs
@@ -4,7 +4,7 @@ use ark_ec::{pairing::Pairing, AffineRepr, CurveGroup, Group};
 use ark_ff::{Field, Zero};
 use ark_poly::{
     polynomial::univariate::DensePolynomial, DenseUVPolynomial,
-    EvaluationDomain,
+    EvaluationDomain, Polynomial,
 };
 use ferveo_tdec::{
     prepare_combine_simple, CiphertextHeader, DecryptionSharePrecomputed,
@@ -140,7 +140,13 @@ impl<E: Pairing, T> PubliclyVerifiableSS<E, T> {
         );
 
         // Evaluations of the polynomial over the domain
-        let evals = phi.0.evaluate_over_domain_by_ref(dkg.domain);
+        let evals = dkg
+            .domain_points()
+            .iter()
+            .map(|x| phi.0.evaluate(x))
+            .collect::<Vec<_>>();
+        debug_assert_eq!(evals.len(), dkg.validators.len());
+
         // commitment to coeffs, F_i
         let coeffs = fast_multiexp(&phi.0.coeffs, dkg.pvss_params.g);
         let shares = dkg
@@ -150,7 +156,7 @@ impl<E: Pairing, T> PubliclyVerifiableSS<E, T> {
                 // ek_{i}^{eval_i}, i = validator index
                 fast_multiexp(
                     // &evals.evals[i..i] = &evals.evals[i]
-                    &[evals.evals[validator.share_index as usize]], // one share per validator
+                    &[evals[validator.share_index as usize]], // one share per validator
                     validator.public_key.encryption_key.into_group(),
                 )[0]
             })