From 66a519f55dc6b3a1c403b865f6675bef37a04d88 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Sat, 16 Jun 2018 23:06:15 +1200
Subject: [PATCH] Alter SaplingNote::nullifier() to take a
 SaplingFullViewingKey

This means the API will work if you only have a SaplingExtendedSpendingKey,
as will be the case with ZIP 32.
---
 src/gtest/test_sapling_note.cpp | 2 +-
 src/zcash/Note.cpp              | 3 +--
 src/zcash/Note.hpp              | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/gtest/test_sapling_note.cpp b/src/gtest/test_sapling_note.cpp
index 06f2d6188..3e336ec7e 100644
--- a/src/gtest/test_sapling_note.cpp
+++ b/src/gtest/test_sapling_note.cpp
@@ -49,7 +49,7 @@ TEST(SaplingNote, TestVectors)
 
     // Test nullifier
     SaplingSpendingKey spendingKey(sk);
-    ASSERT_EQ(note.nullifier(spendingKey, note_pos), nf);
+    ASSERT_EQ(note.nullifier(spendingKey.full_viewing_key(), note_pos), nf);
 }
 
 
diff --git a/src/zcash/Note.cpp b/src/zcash/Note.cpp
index 1108e1db5..c6c72e297 100644
--- a/src/zcash/Note.cpp
+++ b/src/zcash/Note.cpp
@@ -65,9 +65,8 @@ boost::optional<uint256> SaplingNote::cm() const {
 }
 
 // Call librustzcash to compute the nullifier
-boost::optional<uint256> SaplingNote::nullifier(const SaplingSpendingKey& sk, const uint64_t position) const
+boost::optional<uint256> SaplingNote::nullifier(const SaplingFullViewingKey& vk, const uint64_t position) const
 {
-    auto vk = sk.full_viewing_key();
     auto ak = vk.ak;
     auto nk = vk.nk;
 
diff --git a/src/zcash/Note.hpp b/src/zcash/Note.hpp
index 5a3e55dfe..f1b8e4323 100644
--- a/src/zcash/Note.hpp
+++ b/src/zcash/Note.hpp
@@ -57,7 +57,7 @@ public:
     virtual ~SaplingNote() {};
 
     boost::optional<uint256> cm() const;
-    boost::optional<uint256> nullifier(const SaplingSpendingKey &sk, const uint64_t position) const;
+    boost::optional<uint256> nullifier(const SaplingFullViewingKey &vk, const uint64_t position) const;
 };
 
 class BaseNotePlaintext {