From 296447724ac9ee13a1c558a54a18244203f2177a Mon Sep 17 00:00:00 2001
From: Mark Spanbroek <mark@spanbroek.net>
Date: Tue, 23 Jan 2024 10:48:24 +0100
Subject: [PATCH] Refactor verifier contract: extract constants

---
 contracts/verifiers/local/verifier_groth.sol | 6 +++---
 verifier/template/verifier_groth.sol         | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/contracts/verifiers/local/verifier_groth.sol b/contracts/verifiers/local/verifier_groth.sol
index 9931b54..2e5e9e5 100644
--- a/contracts/verifiers/local/verifier_groth.sol
+++ b/contracts/verifiers/local/verifier_groth.sol
@@ -19,6 +19,8 @@
 // SPDX-License-Identifier: MIT
 pragma solidity 0.8.23;
 library Pairing {
+  // The prime q in the base field F_q for G1
+  uint constant private q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;
   struct G1Point {
     uint X;
     uint Y;
@@ -30,8 +32,6 @@ library Pairing {
   }
   /// The negation of p, i.e. p.addition(p.negate()) should be zero.
   function negate(G1Point memory p) internal pure returns (G1Point memory) {
-    // The prime q in the base field F_q for G1
-    uint q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;
     if (p.X == 0 && p.Y == 0)
       return G1Point(0, 0);
     return G1Point(p.X, q - (p.Y % q));
@@ -145,6 +145,7 @@ library Pairing {
 }
 contract Verifier {
   using Pairing for *;
+  uint256 constant private snark_scalar_field = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
   struct VerifyingKey {
     Pairing.G1Point alfa1;
     Pairing.G2Point beta2;
@@ -169,7 +170,6 @@ contract Verifier {
         vk.IC[3] = Pairing.G1Point(18155166643053044822201627105588517913195535693446564472247126736722594445000, 13816319482622393060406816684195314200198627617641073470088058848129378231754);
   }
   function verify(uint[] memory input, Proof memory proof) internal view returns (uint) {
-    uint256 snark_scalar_field = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
     VerifyingKey memory vk = verifyingKey();
     require(input.length + 1 == vk.IC.length,"verifier-bad-input");
     // Compute the linear combination vk_x
diff --git a/verifier/template/verifier_groth.sol b/verifier/template/verifier_groth.sol
index 6db6ab9..f2c2a53 100644
--- a/verifier/template/verifier_groth.sol
+++ b/verifier/template/verifier_groth.sol
@@ -19,6 +19,8 @@
 // SPDX-License-Identifier: MIT
 pragma solidity 0.8.23;
 library Pairing {
+  // The prime q in the base field F_q for G1
+  uint constant private q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;
   struct G1Point {
     uint X;
     uint Y;
@@ -30,8 +32,6 @@ library Pairing {
   }
   /// The negation of p, i.e. p.addition(p.negate()) should be zero.
   function negate(G1Point memory p) internal pure returns (G1Point memory) {
-    // The prime q in the base field F_q for G1
-    uint q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;
     if (p.X == 0 && p.Y == 0)
       return G1Point(0, 0);
     return G1Point(p.X, q - (p.Y % q));
@@ -145,6 +145,7 @@ library Pairing {
 }
 contract Verifier {
   using Pairing for *;
+  uint256 constant private snark_scalar_field = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
   struct VerifyingKey {
     Pairing.G1Point alfa1;
     Pairing.G2Point beta2;
@@ -166,7 +167,6 @@ contract Verifier {
     <%vk_ic_pts%>
   }
   function verify(uint[] memory input, Proof memory proof) internal view returns (uint) {
-    uint256 snark_scalar_field = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
     VerifyingKey memory vk = verifyingKey();
     require(input.length + 1 == vk.IC.length,"verifier-bad-input");
     // Compute the linear combination vk_x