diff --git a/libraries/chain/bitcoin_transaction_evaluator.cpp b/libraries/chain/bitcoin_transaction_evaluator.cpp
index 4c0d54f2..0b2d8ec6 100644
--- a/libraries/chain/bitcoin_transaction_evaluator.cpp
+++ b/libraries/chain/bitcoin_transaction_evaluator.cpp
@@ -25,21 +25,11 @@ object_id_type bitcoin_transaction_send_evaluator::do_apply( const bitcoin_trans
 {
    bitcoin_transaction_send_operation& mutable_op = const_cast<bitcoin_transaction_send_operation&>( op );
    database& d = db();
-   std::vector< info_for_used_vin_id_type > new_vins;
    sidechain::bytes wit_script;
 
    finalize_bitcoin_transaction( mutable_op );
 
-   for( auto itr : op.vins ){
-      auto itr_id = d.create< info_for_used_vin_object >( [&]( info_for_used_vin_object& obj )
-      {
-         obj.identifier = itr.identifier;
-         obj.out = itr.out;
-         obj.address = itr.address;
-         obj.script = itr.script;
-      }).get_id();
-      new_vins.push_back( itr_id );
-   }
+   auto new_vins = create_transaction_vins( mutable_op );
 
    const bitcoin_transaction_object& btc_tx = d.create< bitcoin_transaction_object >( [&]( bitcoin_transaction_object& obj )
    {
@@ -62,6 +52,27 @@ object_id_type bitcoin_transaction_send_evaluator::do_apply( const bitcoin_trans
    return btc_tx.id;
 }
 
+std::vector< info_for_used_vin_id_type > bitcoin_transaction_send_evaluator::create_transaction_vins( bitcoin_transaction_send_operation& op )
+{
+   database& d = db();
+   std::vector< info_for_used_vin_id_type > new_vins;
+
+   for( auto itr : op.vins ){
+      auto itr_id = d.create< info_for_used_vin_object >( [&]( info_for_used_vin_object& obj )
+      {
+         obj.identifier = itr.identifier;
+         obj.out = itr.out;
+         obj.address = itr.address;
+         obj.script = itr.script;
+      }).get_id();
+      new_vins.push_back( itr_id );
+
+      auto obj_itr = d.i_w_info.find_info_for_vin( itr.identifier );
+      if( obj_itr.valid() )
+         d.i_w_info.remove_info_for_vin( *obj_itr );
+   }
+}
+
 void bitcoin_transaction_send_evaluator::finalize_bitcoin_transaction( bitcoin_transaction_send_operation& op )
 {
    database& d = db();
diff --git a/libraries/chain/include/graphene/chain/bitcoin_transaction_evaluator.hpp b/libraries/chain/include/graphene/chain/bitcoin_transaction_evaluator.hpp
index 9a9364d4..3d456477 100644
--- a/libraries/chain/include/graphene/chain/bitcoin_transaction_evaluator.hpp
+++ b/libraries/chain/include/graphene/chain/bitcoin_transaction_evaluator.hpp
@@ -15,6 +15,8 @@ public:
 
    object_id_type do_apply( const bitcoin_transaction_send_operation& op );
 
+   std::vector< info_for_used_vin_id_type > create_transaction_vins( bitcoin_transaction_send_operation& op );
+
    void finalize_bitcoin_transaction( bitcoin_transaction_send_operation& op );
 
    void send_bitcoin_transaction( const bitcoin_transaction_object& btc_tx );
diff --git a/libraries/chain/include/graphene/chain/bitcoin_transaction_object.hpp b/libraries/chain/include/graphene/chain/bitcoin_transaction_object.hpp
index b2adc786..eb4beea7 100644
--- a/libraries/chain/include/graphene/chain/bitcoin_transaction_object.hpp
+++ b/libraries/chain/include/graphene/chain/bitcoin_transaction_object.hpp
@@ -20,7 +20,7 @@ class bitcoin_transaction_object : public abstract_object<bitcoin_transaction_ob
       std::vector< info_for_vout_id_type >   vouts;
 
       sidechain::bitcoin_transaction         transaction;
-      std::string                            transaction_id;
+      fc::sha256                             transaction_id;
 
       uint64_t                               fee_for_size;
 
@@ -33,7 +33,7 @@ typedef boost::multi_index_container<
    bitcoin_transaction_object,
    indexed_by<
       ordered_unique< tag< by_id >, member< object, object_id_type, &object::id > >,
-      ordered_unique< tag< by_transaction_id >, member< bitcoin_transaction_object, string, &bitcoin_transaction_object::transaction_id > >
+      ordered_unique< tag< by_transaction_id >, member< bitcoin_transaction_object, fc::sha256, &bitcoin_transaction_object::transaction_id > >
    >
 > bitcoin_transaction_multi_index_container;
 typedef generic_index<bitcoin_transaction_object, bitcoin_transaction_multi_index_container> bitcoin_transaction_index;
diff --git a/libraries/chain/include/graphene/chain/database.hpp b/libraries/chain/include/graphene/chain/database.hpp
index fbcb8c5c..6b6d42de 100644
--- a/libraries/chain/include/graphene/chain/database.hpp
+++ b/libraries/chain/include/graphene/chain/database.hpp
@@ -41,6 +41,7 @@
 #include <graphene/chain/protocol/protocol.hpp>
 
 #include <sidechain/input_withdrawal_info.hpp>
+#include <sidechain/bitcoin_transaction_confirmations.hpp>
 #include <sidechain/primary_wallet_vout_manager.hpp>
 #include <atomic>
 
@@ -538,6 +539,8 @@ namespace graphene { namespace chain {
 
          sidechain::input_withdrawal_info i_w_info;
 
+         sidechain::thread_safe_index<sidechain::btc_tx_confirmations_index> bitcoin_confirmations;
+
          sidechain::primary_wallet_vout_manager pw_vout_manager;
 
          std::atomic<uint64_t> estimated_feerate;
diff --git a/libraries/chain/proposal_evaluator.cpp b/libraries/chain/proposal_evaluator.cpp
index 2e592f42..6314f6ae 100644
--- a/libraries/chain/proposal_evaluator.cpp
+++ b/libraries/chain/proposal_evaluator.cpp
@@ -151,16 +151,15 @@ void sidechain_hardfork_visitor::operator()( const bitcoin_transaction_send_oper
    });
 
    for( auto& vin : v.vins ) {
-      auto itr = db.i_w_info.find_info_for_vin( vin.identifier );
-      if( !itr.first )
-         continue;
-      db.i_w_info.mark_as_used_vin( *itr.second );
+      auto obj = db.i_w_info.find_info_for_vin( vin.identifier );
+      if( obj.valid() )
+         db.i_w_info.mark_as_used_vin( *obj );
    }
 
    for( auto& vout : v.vouts ) {
-      auto itr = db.i_w_info.find_info_for_vout( vout );
-      FC_ASSERT( itr.first, "info_for_vout_object don't exist." );
-      db.i_w_info.mark_as_used_vout( *itr.second );
+      auto obj = db.i_w_info.find_info_for_vout( vout );
+      FC_ASSERT( obj.valid(), "info_for_vout_object don't exist." );
+      db.i_w_info.mark_as_used_vout( *obj );
    }
 
    fc::sha256 hashid = v.pw_vin.valid() ? *v.pw_vin : SIDECHAIN_NULL_HASH;
diff --git a/libraries/sidechain/include/sidechain/bitcoin_transaction_confirmations.hpp b/libraries/sidechain/include/sidechain/bitcoin_transaction_confirmations.hpp
new file mode 100644
index 00000000..95e32c45
--- /dev/null
+++ b/libraries/sidechain/include/sidechain/bitcoin_transaction_confirmations.hpp
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <boost/multi_index_container.hpp>
+#include <boost/multi_index/member.hpp>
+#include <boost/multi_index/ordered_index.hpp>
+
+#include <sidechain/thread_safe_index.hpp>
+#include <fc/crypto/sha256.hpp>
+
+#include <graphene/chain/protocol/types.hpp>
+
+using boost::multi_index_container;
+using namespace boost::multi_index;
+
+namespace graphene { namespace chain { class database; } }
+
+namespace sidechain {
+
+struct btc_tx_confirmations
+{
+   btc_tx_confirmations() = default;
+
+   btc_tx_confirmations( fc::sha256 trx_id ) : transaction_id( trx_id ) {}
+
+   fc::sha256 transaction_id;
+
+   uint64_t count_blocks = 0;
+   bool confirmed = false;
+};
+
+struct by_hash;
+
+using btc_tx_confirmations_index = boost::multi_index_container<btc_tx_confirmations,
+   indexed_by<
+      ordered_unique<tag<by_hash>, member<btc_tx_confirmations, fc::sha256, &btc_tx_confirmations::transaction_id>>
+   >
+>;
+
+}
\ No newline at end of file
diff --git a/libraries/sidechain/include/sidechain/input_withdrawal_info.hpp b/libraries/sidechain/include/sidechain/input_withdrawal_info.hpp
index b1534e92..461122b0 100644
--- a/libraries/sidechain/include/sidechain/input_withdrawal_info.hpp
+++ b/libraries/sidechain/include/sidechain/input_withdrawal_info.hpp
@@ -59,17 +59,10 @@ class input_withdrawal_info
 {
 
 public:
-
-   using iterator_identifier_vin = typename info_for_vin_index::template index<by_identifier>::type::iterator;
-   using iterator_id_vout = typename graphene::chain::info_for_vout_index::index_type::template index<graphene::chain::by_id>::type::iterator;
-
-
    input_withdrawal_info( graphene::chain::database& _db ) : db( _db ) {}
 
-
    fc::optional<info_for_vin> get_info_for_pw_vin();
 
-
    void insert_info_for_vin( const prev_out& out, const std::string& address, bytes script = bytes() );
 
    void modify_info_for_vin( const info_for_vin& obj, const std::function<void( info_for_vin& e )>& func );
@@ -78,7 +71,7 @@ public:
 
    void remove_info_for_vin( const info_for_vin& obj );
 
-   std::pair<bool, input_withdrawal_info::iterator_identifier_vin> find_info_for_vin( fc::sha256 identifier );
+   fc::optional<info_for_vin> find_info_for_vin( fc::sha256 identifier );
 
    size_t size_info_for_vins() { return info_for_vins.size(); }
 
@@ -91,7 +84,7 @@ public:
 
    void remove_info_for_vout( const info_for_vout& obj );
 
-   std::pair<bool, input_withdrawal_info::iterator_id_vout> find_info_for_vout( graphene::chain::info_for_vout_id_type id );
+   fc::optional<graphene::chain::info_for_vout_object> find_info_for_vout( graphene::chain::info_for_vout_id_type id );
 
    size_t size_info_for_vouts();
 
diff --git a/libraries/sidechain/include/sidechain/thread_safe_index.hpp b/libraries/sidechain/include/sidechain/thread_safe_index.hpp
index 6c0e1d7d..4e45ebe1 100644
--- a/libraries/sidechain/include/sidechain/thread_safe_index.hpp
+++ b/libraries/sidechain/include/sidechain/thread_safe_index.hpp
@@ -1,31 +1,33 @@
 #pragma once
 
 #include <mutex>
+#include <fc/optional.hpp>
 
 namespace sidechain {
 
-struct by_identifier;
-
 template<class T1>
 class thread_safe_index {
 
 public:
 
    using iterator = typename T1::iterator;
-   using iterator_identifier = typename T1::template index<by_identifier>::type::iterator;
 
    std::pair<iterator,bool> insert( const typename T1::value_type& value ) {
       std::lock_guard<std::recursive_mutex> locker( lock );
       return data.insert( value );
    }
 
-   void modify( const typename T1::value_type& obj, const std::function<void( typename T1::value_type& e)>& func ) {
+   template<class T2, typename Key>
+   void modify( const Key _key, const std::function<void( typename T1::value_type& e)>& func ) {
       std::lock_guard<std::recursive_mutex> locker( lock );
-      data.modify( data.iterator_to(obj), [&func]( typename T1::value_type& obj ) { func(obj); } );
+      const auto& obj = *find_iterator<T2>( _key );
+      data.modify( data.iterator_to( obj ), [&func]( typename T1::value_type& obj ) { func( obj ); } );
    }
 
-   void remove( const typename T1::value_type& obj ) {
+   template<class T2, typename Key>
+   void remove( const Key _key ) {
       std::lock_guard<std::recursive_mutex> locker( lock );
+      const auto& obj = *find_iterator<T2>( _key );
       data.erase( data.iterator_to( obj ) );
    }
 
@@ -34,14 +36,15 @@ public:
       return data.size();
    }
 
-   std::pair<bool, iterator_identifier> find( fc::sha256 identifier ) {
+   template<class T2, typename Key>
+   fc::optional<typename T1::value_type> find( const Key _key ) {
       std::lock_guard<std::recursive_mutex> locker( lock );
-      auto& index = data.template get<by_identifier>();
-      auto it = index.find( identifier );
+      auto& index = data.template get<T2>();
+      auto it = index.find( _key );
       if( it != index.end() ) {
-         return std::make_pair(true, it);
+         return fc::optional<typename T1::value_type>(*it);
       }
-      return std::make_pair(false, it);
+      return fc::optional<typename T1::value_type>();
    }
 
    template<class T2>
@@ -54,6 +57,14 @@ public:
 
 private:
 
+   template<class T2, typename Key>
+   typename T1::template index<T2>::type::iterator find_iterator( const Key _key ) {
+      auto& index = data.template get<T2>();
+      auto it = index.find( _key );
+      return it;
+   }
+
+
    std::recursive_mutex lock;
    
    T1 data;
diff --git a/libraries/sidechain/input_withdrawal_info.cpp b/libraries/sidechain/input_withdrawal_info.cpp
index c839ede7..40657f52 100644
--- a/libraries/sidechain/input_withdrawal_info.cpp
+++ b/libraries/sidechain/input_withdrawal_info.cpp
@@ -40,24 +40,24 @@ void input_withdrawal_info::insert_info_for_vin( const prev_out& out, const std:
 
 void input_withdrawal_info::modify_info_for_vin( const info_for_vin& obj, const std::function<void( info_for_vin& e )>& func )
 {
-   info_for_vins.modify( obj, func );
+   info_for_vins.modify<by_identifier>( obj.identifier, func );
 }
 
 void input_withdrawal_info::mark_as_used_vin( const info_for_vin& obj )
 {
-   info_for_vins.modify( obj, [&]( info_for_vin& o ) {
+   info_for_vins.modify<by_identifier>( obj.identifier, [&]( info_for_vin& o ) {
       o.created = true;
-   } );
+   });
 }
 
 void input_withdrawal_info::remove_info_for_vin( const info_for_vin& obj )
 {
-   info_for_vins.remove( obj );
+   info_for_vins.remove<by_identifier>( obj.identifier );
 }
 
-std::pair<bool, input_withdrawal_info::iterator_identifier_vin> input_withdrawal_info::find_info_for_vin( fc::sha256 identifier )
+fc::optional<info_for_vin> input_withdrawal_info::find_info_for_vin( fc::sha256 identifier )
 { 
-   return info_for_vins.find( identifier );
+   return info_for_vins.find<by_identifier>( identifier );
 }
 
 std::vector<info_for_vin> input_withdrawal_info::get_info_for_vins()
@@ -100,21 +100,28 @@ void input_withdrawal_info::insert_info_for_vout( const graphene::chain::account
 
 void input_withdrawal_info::mark_as_used_vout( const graphene::chain::info_for_vout_object& obj )
 {
-   db.modify<graphene::chain::info_for_vout_object>( obj, [&]( graphene::chain::info_for_vout_object& o ) {
+   const auto& info_for_vout_idx = db.get_index_type<graphene::chain::info_for_vout_index>().indices().get< graphene::chain::by_id >();
+   auto itr = info_for_vout_idx.find( obj.id );
+
+   db.modify<graphene::chain::info_for_vout_object>( *itr, [&]( graphene::chain::info_for_vout_object& o ) {
       o.created = true;
    });
 }
 
 void input_withdrawal_info::remove_info_for_vout( const info_for_vout& obj )
 {
-   db.remove( obj );
+   const auto& info_for_vout_idx = db.get_index_type<graphene::chain::info_for_vout_index>().indices().get< graphene::chain::by_id >();
+   auto itr = info_for_vout_idx.find( obj.id );
+   db.remove( *itr );
 }
 
-std::pair<bool, input_withdrawal_info::iterator_id_vout> input_withdrawal_info::find_info_for_vout( graphene::chain::info_for_vout_id_type id )
+fc::optional<graphene::chain::info_for_vout_object> input_withdrawal_info::find_info_for_vout( graphene::chain::info_for_vout_id_type id )
 {
    const auto& info_for_vout_idx = db.get_index_type<graphene::chain::info_for_vout_index>().indices().get< graphene::chain::by_id >();
    auto itr = info_for_vout_idx.find( id );
-   return std::make_pair( itr != info_for_vout_idx.end(), itr );
+   if( itr != info_for_vout_idx.end() )
+      return fc::optional<graphene::chain::info_for_vout_object>( *itr );
+   return fc::optional<graphene::chain::info_for_vout_object>();
 }
 
 size_t input_withdrawal_info::size_info_for_vouts()
diff --git a/libraries/sidechain/network/sidechain_net_manager.cpp b/libraries/sidechain/network/sidechain_net_manager.cpp
index cae92489..adae9f35 100644
--- a/libraries/sidechain/network/sidechain_net_manager.cpp
+++ b/libraries/sidechain/network/sidechain_net_manager.cpp
@@ -109,6 +109,8 @@ void sidechain_net_manager::update_estimated_fee()
 
 void sidechain_net_manager::send_btc_tx( const sidechain::bitcoin_transaction& trx )
 {
+   db->bitcoin_confirmations.insert( btc_tx_confirmations( trx.get_txid() ) );
+
    FC_ASSERT( !bitcoin_client->connection_is_not_defined() );
    const auto tx_hex = fc::to_hex( pack( trx ) );
    idump((tx_hex));
diff --git a/tests/tests/input_withdrawal_info_tests.cpp b/tests/tests/input_withdrawal_info_tests.cpp
index 48ae4fe0..2f07bb16 100644
--- a/tests/tests/input_withdrawal_info_tests.cpp
+++ b/tests/tests/input_withdrawal_info_tests.cpp
@@ -37,8 +37,8 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_id_test )
       prev_out out = { std::to_string( i ), static_cast<uint32_t>( i ), static_cast< uint64_t >( i ) };
       infos.insert_info_for_vin( out, "addr" + std::to_string( i ), { 0x01, 0x02, 0x03 } );
       auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).first );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->id == i );
+      BOOST_CHECK( infos.find_info_for_vin( identifier ).valid() );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->id == i );
    }
 
    info_for_vin::count_id_info_for_vin = 0;
@@ -54,14 +54,14 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_check_data_test )
 
    for( size_t i = 0; i < 10; i++ ) {
       auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).first );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->id == i );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->out.hash_tx == std::to_string( i ) );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->out.n_vout == i );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->out.amount == i );
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->address == "addr" + std::to_string( i ) );
+      BOOST_CHECK( infos.find_info_for_vin( identifier ).valid() );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->id == i );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->out.hash_tx == std::to_string( i ) );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->out.n_vout == i );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->out.amount == i );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->address == "addr" + std::to_string( i ) );
       std::vector<char> script = { 0x01, 0x02, 0x03 };
-      BOOST_CHECK( infos.find_info_for_vin( identifier ).second->script == script );
+      BOOST_CHECK( infos.find_info_for_vin( identifier )->script == script );
    }
 
    info_for_vin::count_id_info_for_vin = 0;
@@ -79,8 +79,8 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_modify_test )
       if( i % 2 == 0 ) {
          auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
          auto iter = infos.find_info_for_vin( identifier );
-         BOOST_CHECK( iter.first );
-         infos.modify_info_for_vin( *iter.second, [&]( info_for_vin& obj ) {
+         BOOST_CHECK( iter.valid() );
+         infos.modify_info_for_vin( *iter, [&]( info_for_vin& obj ) {
             obj.out.hash_tx = std::to_string( i + 1 );
             obj.out.n_vout = i + 1;
             obj.out.amount = i + 1;
@@ -92,14 +92,14 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_modify_test )
    for( size_t i = 0; i < 10; i++ ) {
       if( i % 2 == 0 ) {
          auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).first );
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).second->id == i );
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).second->out.hash_tx == std::to_string( i + 1 ) );
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).second->out.n_vout == i + 1 );
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).second->out.amount == i + 1 );
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).second->address == "addr" + std::to_string( i ) + std::to_string( i ) );
+         BOOST_CHECK( infos.find_info_for_vin( identifier ).valid() );
+         BOOST_CHECK( infos.find_info_for_vin( identifier )->id == i );
+         BOOST_CHECK( infos.find_info_for_vin( identifier )->out.hash_tx == std::to_string( i + 1 ) );
+         BOOST_CHECK( infos.find_info_for_vin( identifier )->out.n_vout == i + 1 );
+         BOOST_CHECK( infos.find_info_for_vin( identifier )->out.amount == i + 1 );
+         BOOST_CHECK( infos.find_info_for_vin( identifier )->address == "addr" + std::to_string( i ) + std::to_string( i ) );
          std::vector<char> script = { 0x01, 0x02, 0x03 };
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).second->script == script );
+         BOOST_CHECK( infos.find_info_for_vin( identifier )->script == script );
       }
    }
 
@@ -118,17 +118,17 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_remove_vin_test )
       if( i % 2 == 0 ) {
          auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
          auto iter = infos.find_info_for_vin( identifier );
-         BOOST_CHECK( iter.first );
-         infos.remove_info_for_vin( *iter.second );
+         BOOST_CHECK( iter.valid() );
+         infos.remove_info_for_vin( *iter );
       }
    }
 
    for( size_t i = 0; i < 10; i++ ) {
       auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
       if( i % 2 == 0 ) {
-         BOOST_CHECK( !infos.find_info_for_vin( identifier ).first );
+         BOOST_CHECK( !infos.find_info_for_vin( identifier ).valid() );
       } else {
-         BOOST_CHECK( infos.find_info_for_vin( identifier ).first );
+         BOOST_CHECK( infos.find_info_for_vin( identifier ).valid() );
       }
    }
 
@@ -149,7 +149,7 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_get_info_for_vins_test )
    for( size_t i = 0; i < 7; i++ ) {
       auto identifier = fc::sha256::hash( std::to_string( i ) + std::to_string( i ) );
       auto iter = infos.find_info_for_vin( identifier );
-      infos.mark_as_used_vin( *iter.second );
+      infos.mark_as_used_vin( *iter );
    }
 
    const auto& vins2 = infos.get_info_for_vins();
@@ -184,16 +184,16 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_remove_vout_test )
    for( size_t i = 0; i < 10; i++ ) {
       if( i % 2 == 0 ) {
          auto iter = infos.find_info_for_vout( graphene::chain::info_for_vout_id_type(i) );
-         BOOST_CHECK( iter.first );
-         infos.remove_info_for_vout( *iter.second );
+         BOOST_CHECK( iter.valid() );
+         infos.remove_info_for_vout( *iter );
       }
    }
 
    for( size_t i = 0; i < 10; i++ ) {
       if( i % 2 == 0 ) {
-         BOOST_CHECK( !infos.find_info_for_vout( graphene::chain::info_for_vout_id_type(i) ).first );
+         BOOST_CHECK( !infos.find_info_for_vout( graphene::chain::info_for_vout_id_type(i) ).valid() );
       } else {
-         BOOST_CHECK( infos.find_info_for_vout( graphene::chain::info_for_vout_id_type(i) ).first );
+         BOOST_CHECK( infos.find_info_for_vout( graphene::chain::info_for_vout_id_type(i) ).valid() );
       }
    }
 }
@@ -210,7 +210,7 @@ BOOST_AUTO_TEST_CASE( input_withdrawal_info_get_info_for_vouts_test )
 
    for( size_t i = 0; i < 7; i++ ) {
       auto iter = infos.find_info_for_vout( graphene::chain::info_for_vout_id_type(i) );
-      infos.mark_as_used_vout( *iter.second );
+      infos.mark_as_used_vout( *iter );
    }
 
    const auto& vouts2 = infos.get_info_for_vouts();