From ff7287e3929fde7da517a49273e7e97e3dcf8b90 Mon Sep 17 00:00:00 2001
From: Kris Nuttycombe <kris@nutty.land>
Date: Fri, 23 Feb 2024 22:06:10 -0700
Subject: [PATCH] Add `impl subtle::ConstantTimeEq for note::Nullifier`

---
 CHANGELOG.md          | 3 +++
 src/note/nullifier.rs | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 445a7a3e..07637e07 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to Rust's notion of
 
 ## [Unreleased]
 
+### Added
+- `impl subtle::ConstantTimeEq for note::Nullifier`
+
 ## [0.7.0] - 2024-01-26
 ### Licensing
 - The license for this crate is now "MIT OR Apache-2.0". The license
diff --git a/src/note/nullifier.rs b/src/note/nullifier.rs
index a18e77fe..7fa97230 100644
--- a/src/note/nullifier.rs
+++ b/src/note/nullifier.rs
@@ -3,7 +3,7 @@ use halo2_proofs::arithmetic::CurveExt;
 use memuse::DynamicUsage;
 use pasta_curves::pallas;
 use rand::RngCore;
-use subtle::CtOption;
+use subtle::{CtOption, ConstantTimeEq};
 
 use super::NoteCommitment;
 use crate::{
@@ -62,6 +62,12 @@ impl Nullifier {
     }
 }
 
+impl ConstantTimeEq for Nullifier {
+    fn ct_eq(&self, other: &Self) -> subtle::Choice {
+        self.0.ct_eq(&other.0)
+    }
+}
+
 /// Generators for property testing.
 #[cfg(any(test, feature = "test-dependencies"))]
 #[cfg_attr(docsrs, doc(cfg(feature = "test-dependencies")))]