From 8c018eff7e795b16fc68aed22d0fd4eebe2710ec Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@electriccoin.co>
Date: Wed, 17 Nov 2021 12:12:48 +0000
Subject: [PATCH] Migrate to `zcash_note_encryption::BatchDomain`

---
 Cargo.toml             |  2 +-
 src/note_encryption.rs | 30 ++++++++++++++++--------------
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index f6601004..fd3d9d72 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -84,5 +84,5 @@ debug = true
 debug = true
 
 [patch.crates-io]
-zcash_note_encryption = { git = "https://github.com/zcash/librustzcash.git", rev = "13b023387bafdc7b5712c933dc0e16ee94b96a6a" }
+zcash_note_encryption = { git = "https://github.com/zcash/librustzcash.git", rev = "35e75420657599fdc701cb45704878eb3fa2e59a" }
 incrementalmerkletree = { git = "https://github.com/zcash/incrementalmerkletree.git", rev = "b7bd6246122a6e9ace8edb51553fbf5228906cbb" }
diff --git a/src/note_encryption.rs b/src/note_encryption.rs
index 8053b8bb..d6d51063 100644
--- a/src/note_encryption.rs
+++ b/src/note_encryption.rs
@@ -5,7 +5,7 @@ use std::{convert::TryInto, fmt};
 use blake2b_simd::{Hash, Params};
 use halo2::arithmetic::FieldExt;
 use zcash_note_encryption::{
-    Domain, EphemeralKeyBytes, NotePlaintextBytes, NoteValidity, OutPlaintextBytes,
+    BatchDomain, Domain, EphemeralKeyBytes, NotePlaintextBytes, NoteValidity, OutPlaintextBytes,
     OutgoingCipherKey, ShieldedOutput, COMPACT_NOTE_SIZE, NOTE_PLAINTEXT_SIZE, OUT_PLAINTEXT_SIZE,
 };
 
@@ -141,19 +141,6 @@ impl Domain for OrchardDomain {
         secret.kdf_orchard(ephemeral_key)
     }
 
-    fn batch_kdf<'a>(
-        items: impl Iterator<Item = (Option<Self::SharedSecret>, &'a EphemeralKeyBytes)>,
-    ) -> Vec<Option<Self::SymmetricKey>> {
-        let (shared_secrets, ephemeral_keys): (Vec<_>, Vec<_>) = items.unzip();
-
-        SharedSecret::batch_to_affine(shared_secrets)
-            .zip(ephemeral_keys.into_iter())
-            .map(|(secret, ephemeral_key)| {
-                secret.map(|dhsecret| SharedSecret::kdf_orchard_inner(dhsecret, ephemeral_key))
-            })
-            .collect()
-    }
-
     fn note_plaintext_bytes(
         note: &Self::Note,
         _: &Self::Recipient,
@@ -255,6 +242,21 @@ impl Domain for OrchardDomain {
     }
 }
 
+impl BatchDomain for OrchardDomain {
+    fn batch_kdf<'a>(
+        items: impl Iterator<Item = (Option<Self::SharedSecret>, &'a EphemeralKeyBytes)>,
+    ) -> Vec<Option<Self::SymmetricKey>> {
+        let (shared_secrets, ephemeral_keys): (Vec<_>, Vec<_>) = items.unzip();
+
+        SharedSecret::batch_to_affine(shared_secrets)
+            .zip(ephemeral_keys.into_iter())
+            .map(|(secret, ephemeral_key)| {
+                secret.map(|dhsecret| SharedSecret::kdf_orchard_inner(dhsecret, ephemeral_key))
+            })
+            .collect()
+    }
+}
+
 /// Implementation of in-band secret distribution for Orchard bundles.
 pub type OrchardNoteEncryption = zcash_note_encryption::NoteEncryption<OrchardDomain>;