From 3b3ff487555958255cdd078cd553f534f074b108 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20N=C3=BA=C3=B1ez?= <david@nucypher.com>
Date: Wed, 13 Sep 2023 11:39:08 +0200
Subject: [PATCH] TODOs and comments

---
 ferveo/src/lib.rs      | 8 +++-----
 ferveo/src/pvss.rs     | 1 +
 ferveo/src/refresh.rs  | 2 ++
 tpke/src/combine.rs    | 2 ++
 tpke/src/decryption.rs | 2 ++
 5 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/ferveo/src/lib.rs b/ferveo/src/lib.rs
index 5107a261..fa5340f1 100644
--- a/ferveo/src/lib.rs
+++ b/ferveo/src/lib.rs
@@ -413,7 +413,7 @@ mod test_dkg_full {
         // Participants share updates and update their shares
 
         // Now, every participant separately:
-        // TODO: Move this logic outside tests
+        // TODO: Move this logic outside tests (see #162, #163)
         let updated_shares: Vec<_> = remaining_validators
             .iter()
             .map(|(_validator_address, validator)| {
@@ -440,7 +440,7 @@ mod test_dkg_full {
             })
             .collect();
 
-        // TODO: Rename updated_private_shares to something that doesn't imply mutation
+        // TODO: Rename updated_private_shares to something that doesn't imply mutation (see #162, #163)
 
         // Now, we have to combine new share fragments into a new share
         let new_private_key_share = recover_share_from_updated_private_shares(
@@ -549,7 +549,7 @@ mod test_dkg_full {
         // Participants share updates and update their shares
 
         // Now, every participant separately:
-        // TODO: Move this logic outside tests
+        // TODO: Move this logic outside tests (see #162, #163)
         let updated_shares: Vec<_> = dkg
             .validators
             .iter()
@@ -577,8 +577,6 @@ mod test_dkg_full {
             })
             .collect();
 
-        // TODO: Rename updated_private_shares to something that doesn't imply mutation
-
         // Get decryption shares, now with refreshed private shares:
         let decryption_shares: Vec<DecryptionShareSimple<E>> =
             validator_keypairs
diff --git a/ferveo/src/pvss.rs b/ferveo/src/pvss.rs
index 050e3dfd..91976ee9 100644
--- a/ferveo/src/pvss.rs
+++ b/ferveo/src/pvss.rs
@@ -374,6 +374,7 @@ impl<E: Pairing, T: Aggregate> PubliclyVerifiableSS<E, T> {
         .map_err(|e| e.into())
     }
 
+    // TODO: Consider relocate to different place, maybe PrivateKeyShare? (see #162, #163)
     pub fn update_private_key_share_for_recovery(
         &self,
         validator_decryption_key: &E::ScalarField,
diff --git a/ferveo/src/refresh.rs b/ferveo/src/refresh.rs
index da6bd8e7..bb11bb48 100644
--- a/ferveo/src/refresh.rs
+++ b/ferveo/src/refresh.rs
@@ -22,6 +22,7 @@ pub fn prepare_share_updates_for_recovery<E: Pairing>(
     prepare_share_updates_with_root::<E>(domain_points, h, x_r, threshold, rng)
 }
 
+// TODO: Consider relocating to PrivateKeyShare (see #162, #163)
 /// From PSS paper, section 4.2.3, (https://link.springer.com/content/pdf/10.1007/3-540-44750-4_27.pdf)
 pub fn apply_updates_to_private_share<E: Pairing>(
     private_key_share: &PrivateKeyShare<E>,
@@ -147,6 +148,7 @@ mod tests_refresh {
         remaining_participants: &[PrivateDecryptionContextSimple<E>],
     ) -> Vec<PrivateKeyShare<E>> {
         // Each participant prepares an update for each other participant
+        // TODO: Extract as parameter
         let domain_points = remaining_participants[0]
             .public_decryption_contexts
             .iter()
diff --git a/tpke/src/combine.rs b/tpke/src/combine.rs
index a46477fb..f9d8ddbb 100644
--- a/tpke/src/combine.rs
+++ b/tpke/src/combine.rs
@@ -56,6 +56,8 @@ pub fn prepare_combine_fast<E: Pairing>(
         .collect::<Vec<_>>()
 }
 
+// TODO: Combine `tpke::prepare_combine_simple` and `tpke::share_combine_simple` into
+//  one function and expose it in the tpke::api?
 pub fn prepare_combine_simple<E: Pairing>(
     domain: &[E::ScalarField],
 ) -> Vec<E::ScalarField> {
diff --git a/tpke/src/decryption.rs b/tpke/src/decryption.rs
index 01ae5df7..0622e6a8 100644
--- a/tpke/src/decryption.rs
+++ b/tpke/src/decryption.rs
@@ -56,11 +56,13 @@ impl<E: Pairing> ValidatorShareChecksum<E> {
         h: &E::G2,
         ciphertext: &Ciphertext<E>,
     ) -> bool {
+        // See https://github.com/nucypher/ferveo/issues/42#issuecomment-1398953777
         // D_i == e(C_i, Y_i)
         if *decryption_share != E::pairing(self.checksum, *share_aggregate).0 {
             return false;
         }
 
+        // TODO: use multipairing here (h_inv)
         // e(C_i, ek_i) == e(U, H)
         if E::pairing(self.checksum, *validator_public_key)
             != E::pairing(ciphertext.commitment, *h)