make tx keys available to the user

They are also stored in the cache file, to be retrieved using
a new get_tx_key command.

src/cryptonote_core/cryptonote_format_utils.cpp

@@ -408,7 +408,7 @@ namespace cryptonote
     return encrypt_payment_id(payment_id, public_key, secret_key);
   }
   //---------------------------------------------------------------
-  bool construct_tx(const account_keys& sender_account_keys, const std::vector<tx_source_entry>& sources, const std::vector<tx_destination_entry>& destinations, std::vector<uint8_t> extra, transaction& tx, uint64_t unlock_time)
+  bool construct_tx(const account_keys& sender_account_keys, const std::vector<tx_source_entry>& sources, const std::vector<tx_destination_entry>& destinations, std::vector<uint8_t> extra, transaction& tx, uint64_t unlock_time, crypto::secret_key &tx_key)
   {
     tx.vin.clear();
     tx.vout.clear();
@@ -420,6 +420,7 @@ namespace cryptonote
     tx.extra = extra;
     keypair txkey = keypair::generate();
     add_tx_pub_key_to_extra(tx, txkey.pub);
+    tx_key = txkey.sec;
 
     // if we have a stealth payment id, find it and encrypt it with the tx key now
     std::vector<tx_extra_field> tx_extra_fields;

src/cryptonote_core/cryptonote_format_utils.h

@@ -69,7 +69,7 @@ namespace cryptonote
   };
 
   //---------------------------------------------------------------
-  bool construct_tx(const account_keys& sender_account_keys, const std::vector<tx_source_entry>& sources, const std::vector<tx_destination_entry>& destinations, std::vector<uint8_t> extra, transaction& tx, uint64_t unlock_time);
+  bool construct_tx(const account_keys& sender_account_keys, const std::vector<tx_source_entry>& sources, const std::vector<tx_destination_entry>& destinations, std::vector<uint8_t> extra, transaction& tx, uint64_t unlock_time, crypto::secret_key &txkey);
 
   template<typename T>
   bool find_tx_extra_field_by_type(const std::vector<tx_extra_field>& tx_extra_fields, T& field)

src/simplewallet/simplewallet.cpp

@@ -365,6 +365,7 @@ simple_wallet::simple_wallet()
   m_cmd_binder.set_handler("seed", boost::bind(&simple_wallet::seed, this, _1), tr("Get deterministic seed"));
   m_cmd_binder.set_handler("set", boost::bind(&simple_wallet::set_variable, this, _1), tr("available options: seed language - Set wallet seed langage; always-confirm-transfers <1|0> - whether to confirm unsplit txes"));
   m_cmd_binder.set_handler("rescan_spent", boost::bind(&simple_wallet::rescan_spent, this, _1), tr("Rescan blockchain for spent outputs"));
+  m_cmd_binder.set_handler("get_tx_key", boost::bind(&simple_wallet::get_tx_key, this, _1), tr("Get transaction key (r) for a given tx"));
   m_cmd_binder.set_handler("help", boost::bind(&simple_wallet::help, this, _1), tr("Show this help"));
 }
 //----------------------------------------------------------------------------------------------------
@@ -1724,6 +1725,37 @@ bool simple_wallet::sweep_dust(const std::vector<std::string> &args_)
   return true;
 }
 //----------------------------------------------------------------------------------------------------
+bool simple_wallet::get_tx_key(const std::vector<std::string> &args_)
+{
+  std::vector<std::string> local_args = args_;
+
+  if(local_args.size() != 1) {
+    fail_msg_writer() << tr("Usage: get_tx_key <txid>");
+    return true;
+  }
+
+  cryptonote::blobdata txid_data;
+  if(!epee::string_tools::parse_hexstr_to_binbuff(local_args.front(), txid_data))
+  {
+    fail_msg_writer() << tr("Failed to parse txid");
+    return false;
+  }
+  crypto::hash txid = *reinterpret_cast<const crypto::hash*>(txid_data.data());
+
+  crypto::secret_key tx_key;
+  bool r = m_wallet->get_tx_key(txid, tx_key);
+  if (r)
+  {
+    success_msg_writer() << tr("tx key: ") << tx_key;
+    return true;
+  }
+  else
+  {
+    fail_msg_writer() << tr("No tx key found for this txid");
+    return true;
+  }
+}
+//----------------------------------------------------------------------------------------------------
 bool simple_wallet::run()
 {
   std::string addr_start = m_wallet->get_account().get_public_address_str(m_wallet->testnet()).substr(0, 6);

src/simplewallet/simplewallet.h

@@ -122,6 +122,7 @@ namespace cryptonote
     bool set_variable(const std::vector<std::string> &args);
     bool rescan_spent(const std::vector<std::string> &args);
     bool set_log(const std::vector<std::string> &args);
+    bool get_tx_key(const std::vector<std::string> &args);
 
     uint64_t get_daemon_blockchain_height(std::string& err);
     bool try_connect_to_daemon();

src/wallet/wallet2.cpp

@@ -1251,6 +1251,8 @@ std::string wallet2::address_from_txt_record(const std::string& s)
 void wallet2::commit_tx(pending_tx& ptx)
 {
   using namespace cryptonote;
+  crypto::hash txid;
+
   COMMAND_RPC_SEND_RAW_TX::request req;
   req.tx_as_hex = epee::string_tools::buff_to_hex_nodelimer(tx_to_blob(ptx.tx));
   COMMAND_RPC_SEND_RAW_TX::response daemon_send_resp;
@@ -1259,14 +1261,16 @@ void wallet2::commit_tx(pending_tx& ptx)
   THROW_WALLET_EXCEPTION_IF(daemon_send_resp.status == CORE_RPC_STATUS_BUSY, error::daemon_busy, "sendrawtransaction");
   THROW_WALLET_EXCEPTION_IF(daemon_send_resp.status != CORE_RPC_STATUS_OK, error::tx_rejected, ptx.tx, daemon_send_resp.status);
 
+  txid = get_transaction_hash(ptx.tx);
   add_unconfirmed_tx(ptx.tx, ptx.change_dts.amount);
+  m_tx_keys.insert(std::make_pair(txid, ptx.tx_key));
 
-  LOG_PRINT_L2("transaction " << get_transaction_hash(ptx.tx) << " generated ok and sent to daemon, key_images: [" << ptx.key_images << "]");
+  LOG_PRINT_L2("transaction " << txid << " generated ok and sent to daemon, key_images: [" << ptx.key_images << "]");
 
   BOOST_FOREACH(transfer_container::iterator it, ptx.selected_transfers)
     it->m_spent = true;
 
-  LOG_PRINT_L0("Transaction successfully sent. <" << get_transaction_hash(ptx.tx) << ">" << ENDL
+  LOG_PRINT_L0("Transaction successfully sent. <" << txid << ">" << ENDL
             << "Commission: " << print_money(ptx.fee+ptx.dust) << " (dust: " << print_money(ptx.dust) << ")" << ENDL
             << "Balance: " << print_money(balance()) << ENDL
             << "Unlocked: " << print_money(unlocked_balance()) << ENDL
@@ -1511,7 +1515,8 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
     splitted_dsts.push_back(cryptonote::tx_destination_entry(dust, dust_policy.addr_for_dust));
   }
 
-  bool r = cryptonote::construct_tx(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time);
+  crypto::secret_key tx_key;
+  bool r = cryptonote::construct_tx(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(m_upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, m_upper_transaction_size_limit);
 
@@ -1530,7 +1535,7 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
   ptx.tx = tx;
   ptx.change_dts = change_dts;
   ptx.selected_transfers = selected_transfers;
-
+  ptx.tx_key = tx_key;
 }
 
 // Another implementation of transaction creation that is hopefully better
@@ -1857,7 +1862,8 @@ void wallet2::transfer_dust(size_t num_outputs, uint64_t unlock_time, uint64_t n
   THROW_WALLET_EXCEPTION_IF(dust_policy.dust_threshold < dust, error::wallet_internal_error, "invalid dust value: dust = " +
     std::to_string(dust) + ", dust_threshold = " + std::to_string(dust_policy.dust_threshold));
 
-  bool r = cryptonote::construct_tx(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time);
+  crypto::secret_key tx_key;
+  bool r = cryptonote::construct_tx(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(m_upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, m_upper_transaction_size_limit);
 
@@ -1876,6 +1882,7 @@ void wallet2::transfer_dust(size_t num_outputs, uint64_t unlock_time, uint64_t n
   ptx.tx = tx;
   ptx.change_dts = change_dts;
   ptx.selected_transfers = selected_transfers;
+  ptx.tx_key = tx_key;
 }
 
 //----------------------------------------------------------------------------------------------------
@@ -1989,6 +1996,15 @@ std::vector<wallet2::pending_tx> wallet2::create_dust_sweep_transactions()
   }
 }
 
+bool wallet2::get_tx_key(const crypto::hash &txid, crypto::secret_key &tx_key) const
+{
+  const std::unordered_map<crypto::hash, crypto::secret_key>::const_iterator i = m_tx_keys.find(txid);
+  if (i == m_tx_keys.end())
+    return false;
+  tx_key = i->second;
+  return true;
+}
+
 //----------------------------------------------------------------------------------------------------
 void wallet2::generate_genesis(cryptonote::block& b) {
   if (m_testnet)

src/wallet/wallet2.h

@@ -120,6 +120,7 @@ namespace tools
       cryptonote::tx_destination_entry change_dts;
       std::list<transfer_container::iterator> selected_transfers;
       std::string key_images;
+      crypto::secret_key tx_key;
     };
 
     struct keys_file_data
@@ -251,6 +252,9 @@ namespace tools
       if(ver < 7)
         return;
       a & m_payments;
+      if(ver < 8)
+        return;
+      a & m_tx_keys;
     }
 
     /*!
@@ -278,6 +282,8 @@ namespace tools
     bool always_confirm_transfers() const { return m_always_confirm_transfers; }
     void always_confirm_transfers(bool always) { m_always_confirm_transfers = always; }
 
+    bool get_tx_key(const crypto::hash &txid, crypto::secret_key &tx_key) const;
+
   private:
     /*!
      * \brief  Stores wallet information to wallet file.
@@ -316,6 +322,7 @@ namespace tools
     std::vector<crypto::hash> m_blockchain;
     std::atomic<uint64_t> m_local_bc_height; //temporary workaround
     std::unordered_map<crypto::hash, unconfirmed_transfer_details> m_unconfirmed_txs;
+    std::unordered_map<crypto::hash, crypto::secret_key> m_tx_keys;
 
     transfer_container m_transfers;
     payment_container m_payments;
@@ -334,7 +341,7 @@ namespace tools
     bool m_always_confirm_transfers;
   };
 }
-BOOST_CLASS_VERSION(tools::wallet2, 7)
+BOOST_CLASS_VERSION(tools::wallet2, 8)
 
 namespace boost
 {
@@ -565,7 +572,8 @@ namespace tools
       splitted_dsts.push_back(cryptonote::tx_destination_entry(dust, dust_policy.addr_for_dust));
     }
 
-    bool r = cryptonote::construct_tx(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time);
+    crypto::secret_key tx_key;
+    bool r = cryptonote::construct_tx(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(m_upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, m_upper_transaction_size_limit);
 
@@ -584,7 +592,7 @@ namespace tools
     ptx.tx = tx;
     ptx.change_dts = change_dts;
     ptx.selected_transfers = selected_transfers;
-
+    ptx.tx_key = tx_key;
   }
 
 

src/wallet/wallet_rpc_server.cpp

@@ -218,6 +218,7 @@ namespace tools
 
       // populate response with tx hash
       res.tx_hash = boost::lexical_cast<std::string>(cryptonote::get_transaction_hash(ptx_vector.back().tx));
+      res.tx_key = boost::lexical_cast<std::string>(ptx_vector.back().tx_key);
       return true;
     }
     catch (const tools::error::daemon_busy& e)
@@ -274,6 +275,7 @@ namespace tools
       for (auto & ptx : ptx_vector)
       {
         res.tx_hash_list.push_back(boost::lexical_cast<std::string>(cryptonote::get_transaction_hash(ptx.tx)));
+        res.tx_key_list.push_back(boost::lexical_cast<std::string>(ptx.tx_key));
       }
 
       return true;
@@ -318,6 +320,7 @@ namespace tools
       for (auto & ptx : ptx_vector)
       {
         res.tx_hash_list.push_back(boost::lexical_cast<std::string>(cryptonote::get_transaction_hash(ptx.tx)));
+        res.tx_key_list.push_back(boost::lexical_cast<std::string>(ptx.tx_key));
       }
 
       return true;

src/wallet/wallet_rpc_server_commands_defs.h

@@ -110,9 +110,11 @@ namespace wallet_rpc
     struct response
     {
       std::string tx_hash;
+      std::string tx_key;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_hash)
+        KV_SERIALIZE(tx_key)
       END_KV_SERIALIZE_MAP()
     };
   };
@@ -141,9 +143,11 @@ namespace wallet_rpc
     struct response
     {
       std::list<std::string> tx_hash_list;
+      std::list<std::string> tx_key_list;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_hash_list)
+        KV_SERIALIZE(tx_key_list)
       END_KV_SERIALIZE_MAP()
     };
   };
@@ -159,9 +163,11 @@ namespace wallet_rpc
     struct response
     {
       std::list<std::string> tx_hash_list;
+      std::list<std::string> tx_key_list;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_hash_list)
+        KV_SERIALIZE(tx_key_list)
       END_KV_SERIALIZE_MAP()
     };
   };