rct amount key modified as per luigi1111's recommendations

This allows the key to be not the same for two outputs sent to
the same address (eg, if you pay yourself, and also get change
back). Also remove the key amounts lists and return parameters
since we don't actually generate random ones, so we don't need
to save them as we can recalculate them when needed if we have
the correct keys.

4 files changed, 20 insertions, 61 deletions

diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index c3fb160a0..b3b8e6561 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -207,16 +207,25 @@ void wallet2::check_acc_out(const account_keys &acc, const tx_out &o, const cryp
   error = false;
 }
 //----------------------------------------------------------------------------------------------------
-static uint64_t decodeRct(const rct::rctSig & rv, const rct::key & sk, unsigned int i, rct::key & mask)
+static uint64_t decodeRct(const rct::rctSig & rv, const crypto::public_key pub, const crypto::secret_key &sec, unsigned int i, rct::key & mask)
 {
+  crypto::key_derivation derivation;
+  bool r = crypto::generate_key_derivation(pub, sec, derivation);
+  if (!r)
+  {
+    LOG_ERROR("Failed to generate key derivation to decode rct output " << i);
+    return 0;
+  }
+  crypto::secret_key scalar1;
+  crypto::derivation_to_scalar(derivation, i, scalar1);
   try
   {
     switch (rv.type)
     {
     case rct::RCTTypeSimple:
-      return rct::decodeRctSimpleFromSharedSecret(rv, sk, i, mask);
+      return rct::decodeRctSimple(rv, rct::sk2rct(scalar1), i, mask);
     case rct::RCTTypeFull:
-      return rct::decodeRctFromSharedSecret(rv, sk, i, mask);
+      return rct::decodeRct(rv, rct::sk2rct(scalar1), i, mask);
     default:
       LOG_ERROR("Unsupported rct type: " << rv.type);
       return 0;
@@ -308,8 +317,7 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, const s
           if (money_transfered == 0)
           {
             const cryptonote::account_keys& keys = m_account.get_keys();
-            rct::key amount_key = rct::hash_to_scalar(rct::scalarmultKey(rct::pk2rct(pub_key_field.pub_key), rct::sk2rct(keys.m_view_secret_key)));
-            money_transfered = tools::decodeRct(tx.rct_signatures, amount_key, 0, mask[0]);
+            money_transfered = tools::decodeRct(tx.rct_signatures, pub_key_field.pub_key, keys.m_view_secret_key, 0, mask[0]);
           }
           amount[0] = money_transfered;
           tx_money_got_in_outs = money_transfered;
@@ -352,8 +360,7 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, const s
               if (money_transfered[i] == 0)
               {
                 const cryptonote::account_keys& keys = m_account.get_keys();
-                rct::key amount_key = rct::hash_to_scalar(rct::scalarmultKey(rct::pk2rct(pub_key_field.pub_key), rct::sk2rct(keys.m_view_secret_key)));
-                money_transfered[i] = tools::decodeRct(tx.rct_signatures, amount_key, i, mask[i]);
+                money_transfered[i] = tools::decodeRct(tx.rct_signatures, pub_key_field.pub_key, keys.m_view_secret_key, i, mask[i]);
               }
               tx_money_got_in_outs += money_transfered[i];
               amount[i] = money_transfered[i];
@@ -401,8 +408,7 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, const s
           if (money_transfered[i] == 0)
           {
             const cryptonote::account_keys& keys = m_account.get_keys();
-            rct::key amount_key = rct::hash_to_scalar(rct::scalarmultKey(rct::pk2rct(pub_key_field.pub_key), rct::sk2rct(keys.m_view_secret_key)));
-            money_transfered[i] = tools::decodeRct(tx.rct_signatures, amount_key, i, mask[i]);
+            money_transfered[i] = tools::decodeRct(tx.rct_signatures, pub_key_field.pub_key, keys.m_view_secret_key, i, mask[i]);
           }
           tx_money_got_in_outs += money_transfered[i];
           amount[i] = money_transfered[i];
@@ -434,8 +440,7 @@ void wallet2::process_new_transaction(const cryptonote::transaction& tx, const s
             if (money_transfered == 0)
             {
               const cryptonote::account_keys& keys = m_account.get_keys();
-              rct::key amount_key = rct::hash_to_scalar(rct::scalarmultKey(rct::pk2rct(pub_key_field.pub_key), rct::sk2rct(keys.m_view_secret_key)));
-              money_transfered = tools::decodeRct(tx.rct_signatures, amount_key, i, mask[i]);
+              money_transfered = tools::decodeRct(tx.rct_signatures, pub_key_field.pub_key, keys.m_view_secret_key, i, mask[i]);
             }
             amount[i] = money_transfered;
             tx_money_got_in_outs += money_transfered;
@@ -2896,8 +2901,7 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
   }
 
   crypto::secret_key tx_key;
-  std::vector<crypto::secret_key> amount_keys;
-  bool r = cryptonote::construct_tx_and_get_tx_keys(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key, amount_keys);
+  bool r = cryptonote::construct_tx_and_get_tx_key(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key);
   THROW_WALLET_EXCEPTION_IF(!r, error::tx_not_constructed, sources, splitted_dsts, unlock_time, m_testnet);
   THROW_WALLET_EXCEPTION_IF(upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, upper_transaction_size_limit);
 
@@ -2924,7 +2928,6 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
   ptx.change_dts = change_dts;
   ptx.selected_transfers = selected_transfers;
   ptx.tx_key = tx_key;
-  ptx.amount_keys = amount_keys;
   ptx.dests = dsts;
 }
 
@@ -3113,8 +3116,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
   dsts.push_back(change_dts);
 
   crypto::secret_key tx_key;
-  std::vector<crypto::secret_key> amount_keys;
-  bool r = cryptonote::construct_tx_and_get_tx_keys(m_account.get_keys(), sources, dsts, extra, tx, unlock_time, tx_key, amount_keys, true);
+  bool r = cryptonote::construct_tx_and_get_tx_key(m_account.get_keys(), sources, dsts, extra, tx, unlock_time, tx_key, true);
   THROW_WALLET_EXCEPTION_IF(!r, error::tx_not_constructed, sources, dsts, unlock_time, m_testnet);
   THROW_WALLET_EXCEPTION_IF(upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, upper_transaction_size_limit);
 
@@ -3135,7 +3137,6 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
   ptx.change_dts = change_dts;
   ptx.selected_transfers = selected_transfers;
   ptx.tx_key = tx_key;
-  ptx.amount_keys = amount_keys;
   ptx.dests = dsts;
 }
 
@@ -3764,8 +3765,7 @@ void wallet2::transfer_from(const std::vector<size_t> &outs, size_t num_outputs,
   }
 
   crypto::secret_key tx_key;
-  std::vector<crypto::secret_key> amount_keys;
-  bool r = cryptonote::construct_tx_and_get_tx_keys(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key, amount_keys);
+  bool r = cryptonote::construct_tx_and_get_tx_key(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key);
   THROW_WALLET_EXCEPTION_IF(!r, error::tx_not_constructed, sources, splitted_dsts, unlock_time, m_testnet);
   THROW_WALLET_EXCEPTION_IF(upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, upper_transaction_size_limit);
 
@@ -3785,7 +3785,6 @@ void wallet2::transfer_from(const std::vector<size_t> &outs, size_t num_outputs,
   ptx.change_dts = change_dts;
   ptx.selected_transfers = selected_transfers;
   ptx.tx_key = tx_key;
-  ptx.amount_keys = amount_keys;
   ptx.dests = dsts;
 }
 
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index 488902d5d..0d61f90e2 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -162,7 +162,6 @@ namespace tools
       std::list<transfer_container::iterator> selected_transfers;
       std::string key_images;
       crypto::secret_key tx_key;
-      std::vector<crypto::secret_key> amount_keys;
       std::vector<cryptonote::tx_destination_entry> dests;
     };
 
@@ -828,8 +827,7 @@ namespace tools
     }
 
     crypto::secret_key tx_key;
-    std::vector<crypto::secret_key> amount_keys;
-    bool r = cryptonote::construct_tx_and_get_tx_keys(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key, amount_keys);
+    bool r = cryptonote::construct_tx_and_get_tx_key(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key);
     THROW_WALLET_EXCEPTION_IF(!r, error::tx_not_constructed, sources, splitted_dsts, unlock_time, m_testnet);
     THROW_WALLET_EXCEPTION_IF(upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, upper_transaction_size_limit);
 
@@ -855,7 +853,6 @@ namespace tools
     ptx.change_dts = change_dts;
     ptx.selected_transfers = selected_transfers;
     ptx.tx_key = tx_key;
-    ptx.amount_keys = amount_keys;
     ptx.dests = dsts;
   }
 
diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index 1786b776f..4c190b005 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -256,13 +256,6 @@ namespace tools
       if (req.get_tx_key)
       {
         res.tx_key = epee::string_tools::pod_to_hex(ptx_vector.back().tx_key);
-        if (ptx_vector.back().tx.version > 1)
-        {
-          for (const auto &i: ptx_vector.back().amount_keys)
-          {
-            res.amount_keys.push_back(epee::string_tools::pod_to_hex(i));
-          }
-        }
       }
       return true;
     }
@@ -325,14 +318,6 @@ namespace tools
         if (req.get_tx_keys)
         {
           res.tx_key_list.push_back(epee::string_tools::pod_to_hex(ptx.tx_key));
-          res.amount_key_list.push_back(wallet_rpc::COMMAND_RPC_TRANSFER_SPLIT::key_list());
-          if (ptx.tx.version > 1)
-          {
-            for (const auto &i: ptx.amount_keys)
-            {
-              res.amount_key_list.back().keys.push_back(epee::string_tools::pod_to_hex(i));
-            }
-          }
         }
       }
 
@@ -381,14 +366,6 @@ namespace tools
         if (req.get_tx_keys)
         {
           res.tx_key_list.push_back(epee::string_tools::pod_to_hex(ptx.tx_key));
-          res.amount_key_list.push_back(wallet_rpc::COMMAND_RPC_SWEEP_DUST::key_list());
-          if (ptx.tx.version > 1)
-          {
-            for (const auto &i: ptx.amount_keys)
-            {
-              res.amount_key_list.back().keys.push_back(epee::string_tools::pod_to_hex(i));
-            }
-          }
         }
       }
 
@@ -450,14 +427,6 @@ namespace tools
         if (req.get_tx_keys)
         {
           res.tx_key_list.push_back(epee::string_tools::pod_to_hex(ptx.tx_key));
-          res.amount_key_list.push_back(wallet_rpc::COMMAND_RPC_SWEEP_ALL::key_list());
-          if (ptx.tx.version > 1)
-          {
-            for (const auto &i: ptx.amount_keys)
-            {
-              res.amount_key_list.back().keys.push_back(epee::string_tools::pod_to_hex(i));
-            }
-          }
         }
       }
 
diff --git a/src/wallet/wallet_rpc_server_commands_defs.h b/src/wallet/wallet_rpc_server_commands_defs.h
index 4df259242..27b897dab 100644
--- a/src/wallet/wallet_rpc_server_commands_defs.h
+++ b/src/wallet/wallet_rpc_server_commands_defs.h
@@ -178,12 +178,10 @@ namespace wallet_rpc
     {
       std::list<std::string> tx_hash_list;
       std::list<std::string> tx_key_list;
-      std::list<key_list> amount_key_list;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_hash_list)
         KV_SERIALIZE(tx_key_list)
-        KV_SERIALIZE(amount_key_list)
       END_KV_SERIALIZE_MAP()
     };
   };
@@ -214,12 +212,10 @@ namespace wallet_rpc
     {
       std::list<std::string> tx_hash_list;
       std::list<std::string> tx_key_list;
-      std::list<key_list> amount_key_list;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_hash_list)
         KV_SERIALIZE(tx_key_list)
-        KV_SERIALIZE(amount_key_list)
       END_KV_SERIALIZE_MAP()
     };
   };
@@ -260,12 +256,10 @@ namespace wallet_rpc
     {
       std::list<std::string> tx_hash_list;
       std::list<std::string> tx_key_list;
-      std::list<key_list> amount_key_list;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_hash_list)
         KV_SERIALIZE(tx_key_list)
-        KV_SERIALIZE(amount_key_list)
       END_KV_SERIALIZE_MAP()
     };
   };