diff --git a/libraries/chain/block_database.cpp b/libraries/chain/block_database.cpp
index 95c37790..cd1f1e29 100644
--- a/libraries/chain/block_database.cpp
+++ b/libraries/chain/block_database.cpp
@@ -68,8 +68,14 @@ void block_database::flush()
   _block_num_to_pos.flush();
 }
 
-void block_database::store( const block_id_type& id, const signed_block& b )
+void block_database::store( const block_id_type& _id, const signed_block& b )
 {
+   block_id_type id = _id;
+   if( id == block_id_type() )
+   {
+      id = b.id();
+      elog( "id argument of block_database::store() was not initialized for block ${id}", ("id", id) );
+   }
    auto num = block_header::num_from_id(id);
    _block_num_to_pos.seekp( sizeof( index_entry ) * num );
    index_entry e;
@@ -103,6 +109,9 @@ void block_database::remove( const block_id_type& id )
 
 bool block_database::contains( const block_id_type& id )const
 {
+   if( id == block_id_type() )
+      return false;
+
    index_entry e;
    auto index_pos = sizeof(e)*block_header::num_from_id(id);
    _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
@@ -116,6 +125,7 @@ bool block_database::contains( const block_id_type& id )const
 
 block_id_type block_database::fetch_block_id( uint32_t block_num )const
 {
+   assert( block_num != 0 );
    index_entry e;
    auto index_pos = sizeof(e)*block_num;
    _block_num_to_pos.seekg( 0, _block_num_to_pos.end );
@@ -125,6 +135,7 @@ block_id_type block_database::fetch_block_id( uint32_t block_num )const
    _block_num_to_pos.seekg( index_pos );
    _block_num_to_pos.read( (char*)&e, sizeof(e) );
 
+   FC_ASSERT( e.block_id != block_id_type(), "Empty block_id in block_database (maybe corrupt on disk?)" );
    return e.block_id;
 }
 
diff --git a/libraries/chain/fork_database.cpp b/libraries/chain/fork_database.cpp
index 0fab49a3..7910b417 100644
--- a/libraries/chain/fork_database.cpp
+++ b/libraries/chain/fork_database.cpp
@@ -143,22 +143,30 @@ void fork_database::set_max_size( uint32_t s )
    }
 }
 
-
-
-
 bool fork_database::is_known_block(const block_id_type& id)const
 {
    auto& index = _index.get<block_id>();
    auto itr = index.find(id);
-   return itr != index.end();
+   if( itr != index.end() )
+      return true;
+   auto& unlinked_index = _unlinked_index.get<block_id>();
+   auto unlinked_itr = unlinked_index.find(id);
+   return unlinked_itr != unlinked_index.end();
 }
+
 item_ptr fork_database::fetch_block(const block_id_type& id)const
 {
-   auto itr = _index.get<block_id>().find(id);
-   if( itr != _index.get<block_id>().end() )
+   auto& index = _index.get<block_id>();
+   auto itr = index.find(id);
+   if( itr != index.end() )
       return *itr;
+   auto& unlinked_index = _unlinked_index.get<block_id>();
+   auto unlinked_itr = unlinked_index.find(id);
+   if( unlinked_itr != unlinked_index.end() )
+      return *unlinked_itr;
    return item_ptr();
 }
+
 vector<item_ptr> fork_database::fetch_block_by_number(uint32_t num)const
 {
    vector<item_ptr> result;
diff --git a/libraries/wallet/include/graphene/wallet/wallet.hpp b/libraries/wallet/include/graphene/wallet/wallet.hpp
index ac1c334b..68b191e9 100644
--- a/libraries/wallet/include/graphene/wallet/wallet.hpp
+++ b/libraries/wallet/include/graphene/wallet/wallet.hpp
@@ -356,6 +356,12 @@ class wallet_api
        */
       string                            get_wallet_filename() const;
 
+      /**
+       * Get the WIF private key corresponding to a public key.  The
+       * private key must already be in the wallet.
+       */
+      string                            get_private_key( public_key_type pubkey )const;
+
       /**
        * @ingroup Transaction Builder API
        */
@@ -1301,6 +1307,7 @@ FC_API( graphene::wallet::wallet_api,
         (get_global_properties)
         (get_dynamic_global_properties)
         (get_object)
+        (get_private_key)
         (load_wallet_file)
         (normalize_brain_key)
         (get_limit_orders)
diff --git a/libraries/wallet/wallet.cpp b/libraries/wallet/wallet.cpp
index 0eefe792..1c211d32 100644
--- a/libraries/wallet/wallet.cpp
+++ b/libraries/wallet/wallet.cpp
@@ -2800,6 +2800,11 @@ string wallet_api::get_key_label( public_key_type key )const
    return string();
 }
 
+string wallet_api::get_private_key( public_key_type pubkey )const
+{
+   return key_to_wif( my->get_private_key( pubkey ) );
+}
+
 public_key_type  wallet_api::get_public_key( string label )const
 {
    try { return fc::variant(label).as<public_key_type>(); } catch ( ... ){}