From 166b1dac44e7ea94e0e1fdbbc68d4acf3ba6d8a6 Mon Sep 17 00:00:00 2001
From: Luke Parker <lukeparker5132@gmail.com>
Date: Mon, 6 May 2024 10:58:15 -0400
Subject: [PATCH] Remove y from the in-circuit hash

---
 crypto/fcmps/src/circuit.rs | 2 +-
 crypto/fcmps/src/lib.rs     | 9 ++++-----
 crypto/fcmps/src/tests.rs   | 3 +--
 3 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/crypto/fcmps/src/circuit.rs b/crypto/fcmps/src/circuit.rs
index f7f1cb52..8edec616 100644
--- a/crypto/fcmps/src/circuit.rs
+++ b/crypto/fcmps/src/circuit.rs
@@ -167,7 +167,7 @@ impl<C: Ciphersuite> Circuit<C> {
     let c_blind = self.discrete_log(transcript, curve, c_blind);
     self.incomplete_add_pub(C_tilde, c_blind, C);
 
-    self.tuple_member_of_list(transcript, vec![O.x, I.x, I.y, C.x], branch);
+    self.tuple_member_of_list(transcript, vec![O.x, I.x, C.x], branch);
   }
 
   pub(crate) fn additional_layer<T: Transcript>(
diff --git a/crypto/fcmps/src/lib.rs b/crypto/fcmps/src/lib.rs
index ecc604e3..6f581560 100644
--- a/crypto/fcmps/src/lib.rs
+++ b/crypto/fcmps/src/lib.rs
@@ -467,7 +467,6 @@ where
       flattened_leaves.extend(&[
         OC::G::to_xy(leaf.O).0,
         OC::G::to_xy(leaf.I).0,
-        OC::G::to_xy(leaf.I).1,
         OC::G::to_xy(leaf.C).0,
       ]);
     }
@@ -668,9 +667,9 @@ where
       (C[0], C[1]),
       //
       c1_branches[0]
-        .chunks(4)
+        .chunks(3)
         .map(|chunk| {
-          assert_eq!(chunk.len(), 4);
+          assert_eq!(chunk.len(), 3);
           chunk.to_vec()
         })
         .collect(),
@@ -912,9 +911,9 @@ where
       (C[0], C[1]),
       //
       c1_branches[0]
-        .chunks(4)
+        .chunks(3)
         .map(|chunk| {
-          assert_eq!(chunk.len(), 4);
+          assert_eq!(chunk.len(), 3);
           chunk.to_vec()
         })
         .collect(),
diff --git a/crypto/fcmps/src/tests.rs b/crypto/fcmps/src/tests.rs
index f6ed5d9f..19b39e7f 100644
--- a/crypto/fcmps/src/tests.rs
+++ b/crypto/fcmps/src/tests.rs
@@ -86,7 +86,6 @@ fn test() {
         [
           <Ed25519 as Ciphersuite>::G::to_xy(output.O).0,
           <Ed25519 as Ciphersuite>::G::to_xy(output.I).0,
-          <Ed25519 as Ciphersuite>::G::to_xy(output.I).1,
           <Ed25519 as Ciphersuite>::G::to_xy(output.C).0,
         ]
       })
@@ -146,7 +145,7 @@ fn test() {
     curve_1_layers.push(curve_1_layer);
   }
 
-  let mut layer_lens = vec![4 * leaves.len()];
+  let mut layer_lens = vec![3 * leaves.len()];
   for (a, b) in curve_2_layers.iter().zip(&curve_1_layers) {
     layer_lens.push(a.len());
     layer_lens.push(b.len());