diff --git a/libraries/chain/include/graphene/chain/protocol/sidechain_transaction.hpp b/libraries/chain/include/graphene/chain/protocol/sidechain_transaction.hpp
index dda3298f..01a4ce74 100644
--- a/libraries/chain/include/graphene/chain/protocol/sidechain_transaction.hpp
+++ b/libraries/chain/include/graphene/chain/protocol/sidechain_transaction.hpp
@@ -27,6 +27,7 @@ namespace graphene { namespace chain {
       struct fee_parameters_type { uint64_t fee = 0; };
 
       asset fee;
+      son_id_type signer;
       account_id_type payer;
 
       sidechain_transaction_id_type sidechain_transaction_id;
@@ -73,7 +74,7 @@ FC_REFLECT( graphene::chain::sidechain_transaction_create_operation, (fee)(payer
         (signers) )
 
 FC_REFLECT( graphene::chain::sidechain_transaction_sign_operation::fee_parameters_type, (fee) )
-FC_REFLECT( graphene::chain::sidechain_transaction_sign_operation, (fee)(payer)
+FC_REFLECT( graphene::chain::sidechain_transaction_sign_operation, (fee)(signer)(payer)
         (sidechain_transaction_id)
         (signature) )
 
diff --git a/libraries/chain/sidechain_transaction_evaluator.cpp b/libraries/chain/sidechain_transaction_evaluator.cpp
index 124b050d..12bf2f42 100644
--- a/libraries/chain/sidechain_transaction_evaluator.cpp
+++ b/libraries/chain/sidechain_transaction_evaluator.cpp
@@ -49,13 +49,14 @@ object_id_type sidechain_transaction_create_evaluator::do_apply(const sidechain_
 void_result sidechain_transaction_sign_evaluator::do_evaluate(const sidechain_transaction_sign_operation &op)
 { try {
    FC_ASSERT(db().head_block_time() >= HARDFORK_SON_TIME, "Not allowed until SON HARDFORK"); // can be removed after HF date pass
+   FC_ASSERT( op.payer == db().get_global_properties().parameters.son_account(), "SON paying account must be set as payer." );
 
    const auto &sto_idx = db().get_index_type<sidechain_transaction_index>().indices().get<by_id>();
    const auto &sto_obj = sto_idx.find(op.sidechain_transaction_id);
    FC_ASSERT(sto_obj != sto_idx.end(), "Sidechain transaction object not found");
 
-   const auto &son_idx = db().get_index_type<son_index>().indices().get<by_account>();
-   const auto &son_obj = son_idx.find(op.payer);
+   const auto &son_idx = db().get_index_type<son_index>().indices().get<by_id>();
+   const auto &son_obj = son_idx.find(op.signer);
    FC_ASSERT(son_obj != son_idx.end(), "SON object not found");
 
    bool expected = false;
@@ -76,8 +77,8 @@ object_id_type sidechain_transaction_sign_evaluator::do_apply(const sidechain_tr
    const auto &sto_idx = db().get_index_type<sidechain_transaction_index>().indices().get<by_id>();
    auto sto_obj = sto_idx.find(op.sidechain_transaction_id);
 
-   const auto &son_idx = db().get_index_type<son_index>().indices().get<by_account>();
-   auto son_obj = son_idx.find(op.payer);
+   const auto &son_idx = db().get_index_type<son_index>().indices().get<by_id>();
+   auto son_obj = son_idx.find(op.signer);
 
    db().modify(*sto_obj, [&](sidechain_transaction_object &sto) {
       for (size_t i = 0; i < sto.signatures.size(); i++) {
diff --git a/libraries/plugins/peerplays_sidechain/include/graphene/peerplays_sidechain/sidechain_net_handler.hpp b/libraries/plugins/peerplays_sidechain/include/graphene/peerplays_sidechain/sidechain_net_handler.hpp
index dc47beda..255aa342 100644
--- a/libraries/plugins/peerplays_sidechain/include/graphene/peerplays_sidechain/sidechain_net_handler.hpp
+++ b/libraries/plugins/peerplays_sidechain/include/graphene/peerplays_sidechain/sidechain_net_handler.hpp
@@ -25,7 +25,7 @@ public:
    std::vector<std::string> get_sidechain_withdraw_addresses();
    std::string get_private_key(std::string public_key);
 
-   bool proposal_exists(int32_t operation_tag, const object_id_type &object_id);
+   bool proposal_exists(int32_t operation_tag, const object_id_type &object_id, boost::optional<chain::operation &> proposal_op = boost::none);
    bool approve_proposal(const proposal_id_type &proposal_id, const son_id_type &son_id);
    void sidechain_event_data_received(const sidechain_event_data &sed);
 
diff --git a/libraries/plugins/peerplays_sidechain/sidechain_net_handler.cpp b/libraries/plugins/peerplays_sidechain/sidechain_net_handler.cpp
index b769ddfa..6d4f85cd 100644
--- a/libraries/plugins/peerplays_sidechain/sidechain_net_handler.cpp
+++ b/libraries/plugins/peerplays_sidechain/sidechain_net_handler.cpp
@@ -53,7 +53,7 @@ std::string sidechain_net_handler::get_private_key(std::string public_key) {
    return std::string();
 }
 
-bool sidechain_net_handler::proposal_exists(int32_t operation_tag, const object_id_type &object_id) {
+bool sidechain_net_handler::proposal_exists(int32_t operation_tag, const object_id_type &object_id, boost::optional<chain::operation &> proposal_op) {
 
    bool result = false;
 
@@ -92,6 +92,16 @@ bool sidechain_net_handler::proposal_exists(int32_t operation_tag, const object_
             break;
          }
 
+         case chain::operation::tag<chain::sidechain_transaction_sign_operation>::value: {
+            if (proposal_op) {
+               chain::operation proposal_op_obj_0 = proposal_op.get();
+               result = ((proposal_op_obj_0.get<sidechain_transaction_sign_operation>().sidechain_transaction_id == op_obj_idx_0.get<sidechain_transaction_sign_operation>().sidechain_transaction_id) &&
+                         (proposal_op_obj_0.get<sidechain_transaction_sign_operation>().signer == op_obj_idx_0.get<sidechain_transaction_sign_operation>().signer) &&
+                         (proposal_op_obj_0.get<sidechain_transaction_sign_operation>().signature == op_obj_idx_0.get<sidechain_transaction_sign_operation>().signature));
+            }
+            break;
+         }
+
          default:
             return false;
          }
@@ -296,6 +306,16 @@ void sidechain_net_handler::process_proposals() {
             break;
          }
 
+         case chain::operation::tag<chain::sidechain_transaction_sign_operation>::value: {
+            sidechain_transaction_id_type st_id = op_obj_idx_0.get<sidechain_transaction_sign_operation>().sidechain_transaction_id;
+            const auto &idx = database.get_index_type<sidechain_transaction_index>().indices().get<by_id>();
+            const auto sto = idx.find(st_id);
+            if (sto != idx.end()) {
+               should_process = ((sto->sidechain == sidechain) && (sto->status == sidechain_transaction_status::valid));
+            }
+            break;
+         }
+
          case chain::operation::tag<chain::sidechain_transaction_settle_operation>::value: {
             sidechain_transaction_id_type st_id = op_obj_idx_0.get<sidechain_transaction_settle_operation>().sidechain_transaction_id;
             const auto &idx = database.get_index_type<sidechain_transaction_index>().indices().get<by_id>();
@@ -394,12 +414,24 @@ void sidechain_net_handler::process_sidechain_transactions() {
          return;
       }
 
+      const chain::global_property_object &gpo = database.get_global_properties();
       sidechain_transaction_sign_operation sts_op;
-      sts_op.payer = plugin.get_current_son_object().son_account;
+      sts_op.signer = plugin.get_current_son_object().id;
+      sts_op.payer = gpo.parameters.son_account();
       sts_op.sidechain_transaction_id = sto.id;
       sts_op.signature = processed_sidechain_tx;
 
-      signed_transaction trx = database.create_signed_transaction(plugin.get_private_key(plugin.get_current_son_id()), sts_op);
+      proposal_create_operation proposal_op;
+      proposal_op.fee_paying_account = plugin.get_current_son_object().son_account;
+      uint32_t lifetime = (gpo.parameters.block_interval * gpo.active_witnesses.size()) * 3;
+      proposal_op.expiration_time = time_point_sec(database.head_block_time().sec_since_epoch() + lifetime);
+      proposal_op.proposed_ops.emplace_back(sts_op);
+
+      if (proposal_exists(chain::operation::tag<chain::sidechain_transaction_sign_operation>::value, sto.id, proposal_op.proposed_ops[0].op)) {
+         return;
+      }
+
+      signed_transaction trx = database.create_signed_transaction(plugin.get_private_key(plugin.get_current_son_id()), proposal_op);
       try {
          trx.validate();
          database.push_transaction(trx, database::validation_steps::skip_block_size_check);
diff --git a/libraries/plugins/peerplays_sidechain/sidechain_net_handler_bitcoin.cpp b/libraries/plugins/peerplays_sidechain/sidechain_net_handler_bitcoin.cpp
index eb7c7170..807fc0ba 100644
--- a/libraries/plugins/peerplays_sidechain/sidechain_net_handler_bitcoin.cpp
+++ b/libraries/plugins/peerplays_sidechain/sidechain_net_handler_bitcoin.cpp
@@ -1151,6 +1151,41 @@ bool sidechain_net_handler_bitcoin::process_proposal(const proposal_object &po)
       break;
    }
 
+   case chain::operation::tag<chain::sidechain_transaction_sign_operation>::value: {
+      using namespace bitcoin;
+      should_approve = true;
+      son_id_type signer = op_obj_idx_0.get<sidechain_transaction_sign_operation>().signer;
+      std::string signature = op_obj_idx_0.get<sidechain_transaction_sign_operation>().signature;
+      sidechain_transaction_id_type sidechain_transaction_id = op_obj_idx_0.get<sidechain_transaction_sign_operation>().sidechain_transaction_id;
+      std::vector<uint64_t> in_amounts;
+      std::string tx_hex;
+      std::string redeem_script;
+      const auto &st_idx = database.get_index_type<sidechain_transaction_index>().indices().get<by_id>();
+      const auto sto = st_idx.find(sidechain_transaction_id);
+      if (sto == st_idx.end()) {
+         should_approve = false;
+         break;
+      }
+
+      const auto &s_idx = database.get_index_type<son_index>().indices().get<by_id>();
+      const auto son = s_idx.find(signer);
+      if (son == s_idx.end()) {
+         should_approve = false;
+         break;
+      }
+
+      read_transaction_data(sto->transaction, tx_hex, in_amounts, redeem_script);
+      bitcoin_transaction tx = unpack(parse_hex(tx_hex));
+      bitcoin::bytes pubkey = parse_hex(son->sidechain_public_keys.at(sidechain_type::bitcoin));
+      vector<bitcoin::bytes> sigs = read_byte_arrays_from_string(signature);
+      for (size_t i = 0; i < tx.vin.size(); i++) {
+         const auto &sighash_str = get_signature_hash(tx, parse_hex(redeem_script), static_cast<int64_t>(in_amounts[i]), i, 1, true).str();
+         const bitcoin::bytes &sighash_hex = parse_hex(sighash_str);
+         should_approve = should_approve && verify_sig(sigs[i], pubkey, sighash_hex, btc_context());
+      }
+      break;
+   }
+
    case chain::operation::tag<chain::sidechain_transaction_settle_operation>::value: {
       should_approve = true;
       break;