From 34bf166e5fd50fdd87135095d14c7ef19c1252c7 Mon Sep 17 00:00:00 2001
From: Simon <simon@bitcartel.com>
Date: Wed, 11 Jul 2018 22:03:04 -0700
Subject: [PATCH] Add encryption of SaplingNotePlaintext and
 SaplingOutgoingPlaintext classes.

This is part of #3061 to add Sapling note functionality.
---
 src/zcash/Note.cpp | 65 ++++++++++++++++++++++++++++++++++++++++++++++
 src/zcash/Note.hpp | 62 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+)

diff --git a/src/zcash/Note.cpp b/src/zcash/Note.cpp
index d84a98067..7e776c756 100644
--- a/src/zcash/Note.cpp
+++ b/src/zcash/Note.cpp
@@ -137,3 +137,68 @@ ZCNoteEncryption::Ciphertext SproutNotePlaintext::encrypt(ZCNoteEncryption& encr
 
     return encryptor.encrypt(pk_enc, pt);
 }
+
+
+
+// Construct and populate SaplingNotePlaintext for a given note and memo.
+SaplingNotePlaintext::SaplingNotePlaintext(
+    const SaplingNote& note,
+    std::array<unsigned char, ZC_MEMO_SIZE> memo) : BaseNotePlaintext(note, memo)
+{
+    d = note.d;
+    rcm = note.r;
+}
+
+
+boost::optional<SaplingNote> SaplingNotePlaintext::note(const SaplingIncomingViewingKey& ivk) const
+{
+    auto addr = ivk.address( d );
+    if (addr) {
+        return SaplingNote(addr.get(), value_);
+    } else {
+        return boost::none;
+    }
+}
+
+
+boost::optional<SaplingNotePlaintextEncryptionResult> SaplingNotePlaintext::encrypt(const uint256& pk_d) const
+{
+    // Get the encryptor
+    auto sne = SaplingNoteEncryption::FromDiversifier(d);
+    if (!sne) {
+        return boost::none;
+    }
+    auto enc = sne.get();
+
+    // Create the plaintext
+    CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
+    ss << (*this);
+    SaplingEncPlaintext pt;
+    assert(pt.size() == ss.size());
+    memcpy(&pt[0], &ss[0], pt.size());
+
+    // Encrypt the plaintext
+    auto encciphertext = enc.encrypt_to_recipient(pk_d, pt);
+    if (!encciphertext) {
+        return boost::none;
+    }
+    return SaplingNotePlaintextEncryptionResult(encciphertext.get(), enc);
+}
+
+
+SaplingOutCiphertext SaplingOutgoingPlaintext::encrypt(
+        const uint256& ovk,
+        const uint256& cv,
+        const uint256& cm,
+        SaplingNoteEncryption& enc
+    ) const
+{
+    // Create the plaintext
+    CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
+    ss << (*this);
+    SaplingOutPlaintext pt;
+    assert(pt.size() == ss.size());
+    memcpy(&pt[0], &ss[0], pt.size());
+
+    return enc.encrypt_to_ourselves(ovk, cv, cm, pt);
+}
diff --git a/src/zcash/Note.hpp b/src/zcash/Note.hpp
index 39610fce0..8bdc2de3b 100644
--- a/src/zcash/Note.hpp
+++ b/src/zcash/Note.hpp
@@ -116,6 +116,68 @@ public:
                                         ) const;
 };
 
+typedef std::pair<std::reference_wrapper<const SaplingEncCiphertext>, std::reference_wrapper<const SaplingNoteEncryption>> SaplingNotePlaintextEncryptionResult;
+
+class SaplingNotePlaintext : public BaseNotePlaintext {
+public:
+    diversifier_t d;
+    uint256 rcm;
+
+    SaplingNotePlaintext() {}
+
+    SaplingNotePlaintext(const SaplingNote& note, std::array<unsigned char, ZC_MEMO_SIZE> memo);
+
+    boost::optional<SaplingNote> note(const SaplingIncomingViewingKey& ivk) const;
+
+    virtual ~SaplingNotePlaintext() {}
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action) {
+        unsigned char leadingByte = 0x01;
+        READWRITE(leadingByte);
+
+        if (leadingByte != 0x01) {
+            throw std::ios_base::failure("lead byte of SaplingNotePlaintext is not recognized");
+        }
+
+        READWRITE(d);           // 11 bytes
+        READWRITE(value_);      // 8 bytes
+        READWRITE(rcm);         // 32 bytes
+        READWRITE(memo_);       // 512 bytes
+    }
+
+    boost::optional<SaplingNotePlaintextEncryptionResult> encrypt(const uint256& pk_d) const;
+};
+
+class SaplingOutgoingPlaintext
+{
+public:
+    uint256 pk_d;
+    uint256 esk;
+
+    SaplingOutgoingPlaintext() {};
+
+    SaplingOutgoingPlaintext(uint256 pk_d, uint256 esk) : pk_d(pk_d), esk(esk) {}
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action) {
+        READWRITE(pk_d);        // 8 bytes
+        READWRITE(esk);         // 8 bytes
+    }
+
+    SaplingOutCiphertext encrypt(
+        const uint256& ovk,
+        const uint256& cv,
+        const uint256& cm,
+        SaplingNoteEncryption& enc
+    ) const;
+};
+
+
 }
 
 #endif // ZC_NOTE_H_