diff --git a/src/currency_core/blockchain_storage.cpp b/src/currency_core/blockchain_storage.cpp
index 6946bca2..3c2e6f15 100644
--- a/src/currency_core/blockchain_storage.cpp
+++ b/src/currency_core/blockchain_storage.cpp
@@ -5220,7 +5220,16 @@ bool blockchain_storage::validate_tx_for_hardfork_specific_terms(const transacti
     if (var_is_after_hardfork_4_zone && !is_allowed_after_hardfork4(el))
       return false;
   }
-    
+  
+
+  if (var_is_after_hardfork_4_zone)
+  {
+    if(!validate_inputs_sorting(tx))
+    {
+      return false;
+    }
+  }
+
 
   return true;
 }
diff --git a/src/currency_core/currency_format_utils_abstract.h b/src/currency_core/currency_format_utils_abstract.h
index 1d99fb29..9e3a134d 100644
--- a/src/currency_core/currency_format_utils_abstract.h
+++ b/src/currency_core/currency_format_utils_abstract.h
@@ -148,6 +148,96 @@ namespace currency
     }
   }
   //---------------------------------------------------------------
+  inline
+    const crypto::key_image & get_key_image_txin_v(const txin_v& in_v)
+  {
+    if (in_v.type() == typeid(txin_to_key))
+    {
+      return boost::get<txin_to_key>(in_v).k_image;
+    }
+    else if (in_v.type() == typeid(txin_htlc))
+    {
+      return boost::get<txin_htlc>(in_v).k_image;
+    }
+    else if (in_v.type() == typeid(txin_zc_input))
+    {
+      return boost::get<txin_zc_input>(in_v).k_image;
+    }
+    else
+    {
+      ASSERT_MES_AND_THROW("[get_to_key_input_from_txin_v] Wrong type " << in_v.type().name());
+    }
+  }
+
+  //, txin_htlc, txin_zc_input
+  bool compare_varian_by_types(const txin_multisig& left, typename txin_multisig& right)
+  {
+    return (left.multisig_out_id < right.multisig_out_id);
+  }
+  //---------------------------------------------------------------
+  bool compare_varian_by_types(const txin_gen& left, typename txin_gen& right)
+  {
+    //actually this should never happen, should we leave it in case it happen in unit tests? @sowle 
+    return (left.height < right.height);
+  }
+  //---------------------------------------------------------------
+  template<typename type_with_kimage_t>
+  bool compare_varian_by_types(const type_with_kimage_t& left, typename type_with_kimage_t& right)
+  {
+    return (left.k_image < right.k_image);
+  }
+  //---------------------------------------------------------------
+  template<typename t_type_left, typename t_type_right>
+  bool compare_varian_by_types(const t_type_left& left, const t_type_right& right)
+  {
+    if (typeid(t_type_left) == typeid(t_type_right))
+    {
+      ASSERT_MES_AND_THROW("[compare_varian_by_types] Left and Right types matched type " << typeid(t_type_left).name());
+    }
+    //@sowle should we use here variant index instead? (tags takes since it's ids something more "unchangebale", but we can reconsider)
+    return (variant_serialization_traits<typename binary_archive<true>, typename t_type_left>::get_tag() < variant_serialization_traits<typename binary_archive<true>, typename t_type_right>::get_tag());
+  }
+  //---------------------------------------------------------------
+  template<typename t_type_left>
+  struct right_visitor : public boost::static_visitor<bool>
+  {
+    const t_type_left& m_rleft;
+
+    right_visitor(const t_type_left& left) : m_rleft(left)
+    {}
+    
+    template<typename t_type_right>
+    bool operator()(const t_type_right& right)const
+    {
+      return compare_varian_by_types(m_rleft, right);
+    }
+  };
+
+  struct left_visitor : public boost::static_visitor<bool>
+  {
+    const txin_v& m_rright;
+
+    left_visitor(const txin_v& right) : m_rright(right)
+    {}
+    template<typename t_type_left>
+    bool operator()(const t_type_left& left)const
+    {
+      return boost::apply_visitor(right_visitor<t_type_left>(left), m_rright);
+    }
+  };
+  //---------------------------------------------------------------
+  bool less_txin_v(const txin_v& left, const txin_v& right)
+  {
+    //txin_gen, txin_to_key, txin_multisig, txin_htlc, txin_zc_input
+    if (left.type() != right.type())
+    {
+      //predefined type hierarchy based on it's tags defined in currency_basic.h, call compare_varian_by_types via 2-level visitor
+      return boost::apply_visitor(left_visitor(right), left);
+    }
+    //compare 
+    return true;//(left < right);
+  }
+  //---------------------------------------------------------------
   template<typename variant_container_t>
   bool check_allowed_types_in_variant_container(const variant_container_t& container, const std::unordered_set<std::type_index>& allowed_types, bool elements_must_be_unique = true)
   {
diff --git a/src/currency_core/currency_format_utils_transactions.cpp b/src/currency_core/currency_format_utils_transactions.cpp
index 46130401..33012294 100644
--- a/src/currency_core/currency_format_utils_transactions.cpp
+++ b/src/currency_core/currency_format_utils_transactions.cpp
@@ -275,14 +275,27 @@ namespace currency
     std::unordered_set<crypto::key_image> ki;
     BOOST_FOREACH(const auto& in, tx.vin)
     {
-      if (in.type() == typeid(txin_to_key) || in.type() == typeid(txin_htlc))
+      if (in.type() == typeid(txin_to_key) || in.type() == typeid(txin_htlc) || in.type() == typeid(txin_zc_input))
       {
          
-        if (!ki.insert(get_to_key_input_from_txin_v(in).k_image).second)
+        if (!ki.insert(get_key_image_txin_v(in)).second)
           return false;
       }
     }
     return true;
   }
-
+  //---------------------------------------------------------------
+  bool validate_inputs_sorting(const transaction& tx)
+  {
+    size_t i = 0;
+    for(; i+1 < tx.vin.size(); i++)
+    {
+      //same less_txin_v() function should be used for sorting inputs during transacction creation
+      if (less_txin_v(tx.vin[i+1], tx.vin[i]))
+      {
+        return false;
+      }
+    }
+    return true;
+  }
 }
\ No newline at end of file
diff --git a/src/currency_core/currency_format_utils_transactions.h b/src/currency_core/currency_format_utils_transactions.h
index af78a741..d678cc38 100644
--- a/src/currency_core/currency_format_utils_transactions.h
+++ b/src/currency_core/currency_format_utils_transactions.h
@@ -153,6 +153,7 @@ namespace currency
   blobdata tx_to_blob(const transaction& b);
   bool tx_to_blob(const transaction& b, blobdata& b_blob);
   bool read_keyimages_from_tx(const transaction& tx, std::list<crypto::key_image>& kil);
+  bool validate_inputs_sorting(const transaction& tx);
 
 
 }