Merge pull request #419 from nuttycom/nullifier_ct_eq

Additions needed for Orchard batch scanning

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to Rust's notion of
 
 ## [Unreleased]
 
+### Added
+- `impl subtle::ConstantTimeEq for note::Nullifier`
+- `impl Clone for note_encryption::CompactAction`
+- `note_encryption::CompactAction::cmx`
+
 ## [0.7.0] - 2024-01-26
 ### Licensing
 - The license for this crate is now "MIT OR Apache-2.0". The license

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::{ConstantTimeEq, CtOption};
 
 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")))]

src/note_encryption.rs

@@ -269,6 +269,7 @@ impl<T> ShieldedOutput<OrchardDomain, ENC_CIPHERTEXT_SIZE> for Action<T> {
 }
 
 /// A compact Action for light clients.
+#[derive(Clone)]
 pub struct CompactAction {
     nullifier: Nullifier,
     cmx: ExtractedNoteCommitment,
@@ -325,10 +326,15 @@ impl CompactAction {
         }
     }
 
-    ///Returns the nullifier of the note being spent.
+    /// Returns the nullifier of the note being spent.
     pub fn nullifier(&self) -> Nullifier {
         self.nullifier
     }
+
+    /// Returns the commitment to the new note being created.
+    pub fn cmx(&self) -> ExtractedNoteCommitment {
+        self.cmx
+    }
 }
 
 #[cfg(test)]