diff --git a/lib/tfw/components/fsm_managing_event_handler.py b/lib/tfw/components/fsm_managing_event_handler.py
index ee95c6f..47761a0 100644
--- a/lib/tfw/components/fsm_managing_event_handler.py
+++ b/lib/tfw/components/fsm_managing_event_handler.py
@@ -2,18 +2,19 @@
 # All Rights Reserved. See LICENSE file for details.
 
 from tfw import EventHandlerBase
-from tfw.crypto import KeyManager, sign_message
+from tfw.crypto import KeyManager, sign_message, verify_message
 from tfw.config.logs import logging
 
 LOG = logging.getLogger(__name__)
 
 
 class FSMManagingEventHandler(EventHandlerBase):
-    def __init__(self, key, fsm_type):
+    def __init__(self, key, fsm_type, require_signature=False):
         super().__init__(key)
         self.fsm = fsm_type()
         self._fsm_updater = FSMUpdater(self.fsm)
         self.auth_key = KeyManager().auth_key
+        self._require_signature = require_signature
 
         self.command_handlers = {
             'trigger': self.handle_trigger,
@@ -22,24 +23,29 @@ class FSMManagingEventHandler(EventHandlerBase):
 
     def handle_event(self, message):
         try:
-            data = message['data']
-            message['data'] = self.command_handlers[data['command']](data)
-            fsm_update_message = self._fsm_updater.generate_fsm_update()
-            sign_message(self.auth_key, message)
-            sign_message(self.auth_key, fsm_update_message)
-            self.server_connector.broadcast(fsm_update_message)
+            message = self.command_handlers[message['data']['command']](message)
+            if message:
+                fsm_update_message = self._fsm_updater.generate_fsm_update()
+                sign_message(self.auth_key, message)
+                sign_message(self.auth_key, fsm_update_message)
+                self.server_connector.broadcast(fsm_update_message)
             return message
         except KeyError:
             LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
 
-    def handle_trigger(self, data):
-        trigger = data['value']
-        self.fsm.step(trigger)
-        return data
+    def handle_trigger(self, message):
+        trigger = message['data']['value']
+        if self._require_signature:
+            if not verify_message(self.auth_key, message):
+                LOG.error('Ignoring unsigned trigger command: %s', message)
+                return None
+        if self.fsm.step(trigger):
+            return message
+        return None
 
-    def handle_update(self, data):
+    def handle_update(self, message):
         # pylint: disable=no-self-use
-        return data
+        return message
 
 
 class FSMUpdater:
diff --git a/lib/tfw/fsm_base.py b/lib/tfw/fsm_base.py
index 3cc2af5..7ae8157 100644
--- a/lib/tfw/fsm_base.py
+++ b/lib/tfw/fsm_base.py
@@ -62,5 +62,7 @@ class FSMBase(Machine, CallbackMixin):
             try:
                 self.trigger(trigger)
                 self.trigger_history.append(trigger)
+                return True
             except (AttributeError, MachineError):
                 LOG.debug('FSM failed to execute nonexistent trigger: "%s"', trigger)
+        return False
diff --git a/lib/tfw/networking/server/tfw_server.py b/lib/tfw/networking/server/tfw_server.py
index 5f297df..c0d98f5 100644
--- a/lib/tfw/networking/server/tfw_server.py
+++ b/lib/tfw/networking/server/tfw_server.py
@@ -9,6 +9,7 @@ from tornado.web import Application
 from tfw.networking.event_handlers import ServerUplinkConnector
 from tfw.networking.server import EventHandlerConnector
 from tfw.networking import MessageSender
+from tfw.crypto import KeyManager, verify_message, sign_message
 from tfw.config.logs import logging
 from .zmq_websocket_proxy import ZMQWebSocketProxy
 
@@ -24,6 +25,7 @@ class TFWServer:
     def __init__(self):
         self._event_handler_connector = EventHandlerConnector()
         self._uplink_connector = ServerUplinkConnector()
+        self._auth_key = KeyManager().auth_key
 
         self.application = Application([(
             r'/ws', ZMQWebSocketProxy, {
@@ -37,13 +39,16 @@ class TFWServer:
     def handle_trigger(self, message):
         if 'trigger' in message:
             LOG.debug('Executing handler for trigger "%s"', message.get('trigger', ''))
-            self._uplink_connector.send_to_eventhandler({
+            fsm_eh_command = {
                 'key': 'fsm',
                 'data': {
                     'command': 'trigger',
-                    'value': message.get('trigger', '')
+                    'value': message['trigger']
                 }
-            })
+            }
+            if verify_message(self._auth_key, message):
+                sign_message(self._auth_key, fsm_eh_command)
+            self._uplink_connector.send_to_eventhandler(fsm_eh_command)
 
     def handle_recover(self, message):
         if message['key'] == 'recover':