From 5451a3201660109d57a116578f7b4642e4432e20 Mon Sep 17 00:00:00 2001
From: Timofey Luin <timofey.luin@gmail.com>
Date: Wed, 3 Apr 2024 18:56:40 +0200
Subject: [PATCH] Revert "Avoid unexpected infinity when aggregating pub keys 
 (#65)"

This reverts commit 98a9362f961802cfb20b52e166880094da29815f.
---
 lightclient-circuits/src/sync_step_circuit.rs | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/lightclient-circuits/src/sync_step_circuit.rs b/lightclient-circuits/src/sync_step_circuit.rs
index f85d4ecd..b3f0eeb0 100644
--- a/lightclient-circuits/src/sync_step_circuit.rs
+++ b/lightclient-circuits/src/sync_step_circuit.rs
@@ -294,7 +294,7 @@ impl<S: Spec, F: Field> StepCircuit<S, F> {
         fp_chip: &FpChip<'_, F>,
         pubkey_affines: &[G1Affine],
         pariticipation_bits: &[bool],
-        assigned_affines: &mut Vec<G1Point<F>>,
+        assigned_pubkeys: &mut Vec<G1Point<F>>,
         y_signs_packed: &mut Vec<AssignedValue<F>>,
     ) -> (G1Point<F>, AssignedValue<F>) {
         let gate = fp_chip.gate();
@@ -330,22 +330,17 @@ impl<S: Spec, F: Field> StepCircuit<S, F> {
                 fp_chip.limb_bases[1],
             );
 
-            assigned_affines.push(assigned_affine);
+            assigned_pubkeys.push(assigned_affine);
             participation_bits.push(participation_bit);
             y_signs.push(y_sign);
         }
 
-        let mut acc = {
-            let x = fp_chip.load_constant(ctx, G1Affine::identity().x);
-            let y = fp_chip.load_constant(ctx, G1Affine::identity().y);
-            G1Point::new(x, y) // identity
-        };
-        acc = g1_chip.select(ctx, assigned_affines[0].clone(), acc, participation_bits[0]);
+        let rand_point = g1_chip.load_random_point::<G1Affine>(ctx);
+        let mut acc = rand_point.clone();
         for (bit, point) in participation_bits
             .iter()
             .copied()
-            .zip(assigned_affines.iter_mut())
-            .skip(1)
+            .zip(assigned_pubkeys.iter_mut())
         {
             let is_equal = g1_chip.is_equal(ctx, acc.clone(), point.clone());
             let add = g1_chip.add_unequal(ctx, acc.clone(), point.clone(), true);
@@ -353,6 +348,7 @@ impl<S: Spec, F: Field> StepCircuit<S, F> {
             let sum = g1_chip.select(ctx, doub, add, is_equal);
             acc = g1_chip.select(ctx, sum, acc, bit);
         }
+        let agg_pubkey = g1_chip.sub_unequal(ctx, acc, rand_point, false);
         let participation_sum = gate.sum(ctx, participation_bits);
 
         *y_signs_packed = y_signs
@@ -360,7 +356,7 @@ impl<S: Spec, F: Field> StepCircuit<S, F> {
             .map(|chunk| gate.bits_to_num(ctx, chunk))
             .collect_vec();
 
-        (acc, participation_sum)
+        (agg_pubkey, participation_sum)
     }
 }