Auto merge of #3272 - bitcartel:3061_sapling_add_notes, r=bitcartel

Add SaplingNote class

Part of #3061, adding SaplingNote class.

src/zcash/Note.cpp

@@ -2,12 +2,14 @@
 #include "prf.h"
 #include "crypto/sha256.h"
 
+#include "random.h"
 #include "version.h"
 #include "streams.h"
 
 #include "zcash/util.h"
+#include "librustzcash.h"
 
-namespace libzcash {
+using namespace libzcash;
 
 SproutNote::SproutNote() {
     a_pk = random_uint256();
@@ -38,6 +40,55 @@ uint256 SproutNote::nullifier(const SproutSpendingKey& a_sk) const {
     return PRF_nf(a_sk, rho);
 }
 
+// Construct and populate Sapling note for a given payment address and value.
+SaplingNote::SaplingNote(const SaplingPaymentAddress& address, const uint64_t value) : BaseNote(value) {
+    d = address.d;
+    pk_d = address.pk_d;
+    librustzcash_sapling_generate_r(r.begin());
+}
+
+// Call librustzcash to compute the commitment
+boost::optional<uint256> SaplingNote::cm() const {
+    uint256 result;
+    if (!librustzcash_sapling_compute_cm(
+            d.data(),
+            pk_d.begin(),
+            value(),
+            r.begin(),
+            result.begin()
+        ))
+    {
+        return boost::none;
+    }
+
+    return result;
+}
+
+// Call librustzcash to compute the nullifier
+boost::optional<uint256> SaplingNote::nullifier(const SaplingSpendingKey& sk, const uint64_t position) const
+{
+    auto vk = sk.full_viewing_key();
+    auto ak = vk.ak;
+    auto nk = vk.nk;
+
+    uint256 result;
+    if (!librustzcash_sapling_compute_nf(
+            d.data(),
+            pk_d.begin(),
+            value(),
+            r.begin(),
+            ak.begin(),
+            nk.begin(),
+            position,
+            result.begin()
+    ))
+    {
+        return boost::none;
+    }
+
+    return result;
+}
+
 SproutNotePlaintext::SproutNotePlaintext(
     const SproutNote& note,
     std::array<unsigned char, ZC_MEMO_SIZE> memo) : BaseNotePlaintext(note, memo)
@@ -86,5 +137,3 @@ ZCNoteEncryption::Ciphertext SproutNotePlaintext::encrypt(ZCNoteEncryption& encr
 
     return encryptor.encrypt(pk_enc, pt);
 }
-
-}

src/zcash/Note.hpp

@@ -7,6 +7,7 @@
 #include "NoteEncryption.hpp"
 
 #include <array>
+#include <boost/optional.hpp>
 
 namespace libzcash {
 
@@ -18,7 +19,6 @@ public:
     BaseNote(uint64_t value) : value_(value) {};
     virtual ~BaseNote() {};
 
-    virtual uint256 cm() const = 0;
     inline uint64_t value() const { return value_; };
 };
 
@@ -35,11 +35,31 @@ public:
 
     virtual ~SproutNote() {};
 
-    virtual uint256 cm() const override;
+    uint256 cm() const;
 
     uint256 nullifier(const SproutSpendingKey& a_sk) const;
 };
 
+
+class SaplingNote : public BaseNote {
+public:
+    diversifier_t d;
+    uint256 pk_d;
+    uint256 r;
+
+    SaplingNote(diversifier_t d, uint256 pk_d, uint64_t value, uint256 r)
+            : BaseNote(value), d(d), pk_d(pk_d), r(r) {}
+
+    SaplingNote() {};
+
+    SaplingNote(const SaplingPaymentAddress &address, uint64_t value);
+
+    virtual ~SaplingNote() {};
+
+    boost::optional<uint256> cm() const;
+    boost::optional<uint256> nullifier(const SaplingSpendingKey &sk, const uint64_t position) const;
+};
+
 class BaseNotePlaintext {
 protected:
     uint64_t value_ = 0;