New "Halfway RingCT" outputs for coinbase transactions

When RingCT is enabled, outputs from coinbase transactions
are created as a single output, and stored as RingCT output,
with a fake mask. Their amount is not hidden on the blockchain
itself, but they are then able to be used as fake inputs in
a RingCT ring. Since the output amounts are hidden, their
"dustiness" is not an obstacle anymore to mixing, and this
makes the coinbase transactions a lot smaller, as well as
helping the TXO set to grow more slowly.

Also add a new "Null" type of rct signature, which decreases
the size required when no signatures are to be stored, as
in a coinbase tx.

1 files changed, 17 insertions, 0 deletions

diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index b3b8e6561..985ebe778 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -489,10 +489,17 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, const s
             {
               td.m_mask = mask[o];
               td.m_amount = amount[o];
+              td.m_rct = true;
+            }
+            else if (miner_tx && tx.version == 2)
+            {
+              td.m_mask = rct::identity();
+              td.m_rct = true;
             }
             else
             {
               td.m_mask = rct::identity();
+              td.m_rct = false;
             }
 	    set_unspent(td);
 	    m_key_images[td.m_key_image] = m_transfers.size()-1;
@@ -529,10 +536,17 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, const s
             {
               td.m_mask = mask[o];
               td.m_amount = amount[o];
+              td.m_rct = true;
+            }
+            else if (miner_tx && tx.version == 2)
+            {
+              td.m_mask = rct::identity();
+              td.m_rct = true;
             }
             else
             {
               td.m_mask = rct::identity();
+              td.m_rct = false;
             }
             THROW_WALLET_EXCEPTION_IF(td.m_key_image != ki[o], error::wallet_internal_error, "Inconsistent key images");
 	    THROW_WALLET_EXCEPTION_IF(td.m_spent, error::wallet_internal_error, "Inconsistent spent status");
@@ -2847,6 +2861,7 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
     cryptonote::tx_source_entry& src = sources.back();
     transfer_details& td = *it;
     src.amount = td.amount();
+    src.rct = td.is_rct();
     //paste keys (fake and real)
 
     for (size_t n = 0; n < fake_outputs_count + 1; ++n)
@@ -3037,6 +3052,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
     cryptonote::tx_source_entry& src = sources.back();
     transfer_details& td = *it;
     src.amount = td.amount();
+    src.rct = td.is_rct();
     //paste mixin transaction
     if(it->is_rct())
     {
@@ -3732,6 +3748,7 @@ void wallet2::transfer_from(const std::vector<size_t> &outs, size_t num_outputs,
     cryptonote::tx_source_entry& src = sources.back();
     transfer_details& td = *it;
     src.amount = td.amount();
+    src.rct = td.is_rct();
 
     //paste real transaction to the random index
     auto it_to_insert = std::find_if(src.outputs.begin(), src.outputs.end(), [&](const tx_output_entry& a)