diff --git a/lib/tfw/networking/server/controller_responder.py b/lib/tfw/networking/server/controller_responder.py
index 32567d7..a0924e7 100644
--- a/lib/tfw/networking/server/controller_responder.py
+++ b/lib/tfw/networking/server/controller_responder.py
@@ -5,21 +5,28 @@ from tfw.networking.serialization import deserialize_all, serialize_all
 class ControllerResponder:
     def __init__(self, fsm):
         self.fsm = fsm
+        self.token = None
         self.controller_connector = ControllerConnector()
         self.controller_connector.register_callback(self.handle_controller_request)
         self.controller_request_handlers = {
             'solution_check': self.handle_solution_check_request,
-            'test': self.handle_test_request
+            'test': self.handle_test_request,
+            'token': self.handle_token_request
         }
 
     def handle_controller_request(self, stream, msg_parts):
         key, data = deserialize_all(*msg_parts)
         response = self.controller_request_handlers[key](data)
-        stream.send_multipart(serialize_all(key, response))
+        stream.send_multipart(serialize_all(self.token, response))
 
     def handle_test_request(self, data):
         return 'OK'
 
+    def handle_token_request(self, data):
+        if self.token is None:
+            self.token = data
+        return {'token': self.token}
+
     def handle_solution_check_request(self, data):
         return {
             'solved': self.fsm.is_solved(),
diff --git a/src/controller/app.py b/src/controller/app.py
index 67b2faa..a6ae9b6 100644
--- a/src/controller/app.py
+++ b/src/controller/app.py
@@ -1,3 +1,4 @@
+import secrets
 from tornado.ioloop import IOLoop
 from tornado.web import Application
 
@@ -7,13 +8,24 @@ from handlers import SolutionCheckHandler, TestHandler
 from tfw.networking.async_solvable_connector import AsyncSolvableConnector
 
 from tfw.config.logs import logging
+
 log = logging.getLogger(__name__)
 
+
+async def setup_token(solvable_connector, token):
+    solvable_connector.send('token', token)
+    key, data = await solvable_connector.recv()
+    log.debug('Token setup is done.')
+
 if __name__ == '__main__':
-    solvable_connector = AsyncSolvableConnector()
+    kwargs = {
+        'solvable_connector': AsyncSolvableConnector(),
+        'token': secrets.token_hex(32)
+    }
+    IOLoop.instance().add_callback(setup_token, **kwargs)
     routes = [
-        (r'/{secret}/?'.format(secret=taoenv.SECRET), SolutionCheckHandler, {'solvable_connector': solvable_connector}),
-        (r'/{secret}/test/?'.format(secret=taoenv.SECRET), TestHandler, {'solvable_connector': solvable_connector})
+        (r'/{secret}/?'.format(secret=taoenv.SECRET), SolutionCheckHandler, kwargs),
+        (r'/{secret}/test/?'.format(secret=taoenv.SECRET), TestHandler, kwargs)
     ]
     app = Application(
         routes
diff --git a/src/controller/handlers/solution_check_handler.py b/src/controller/handlers/solution_check_handler.py
index cfe2c1c..e84dc80 100644
--- a/src/controller/handlers/solution_check_handler.py
+++ b/src/controller/handlers/solution_check_handler.py
@@ -1,15 +1,19 @@
-from tornado.web import RequestHandler
+import secrets
+from tornado.web import RequestHandler, HTTPError
 
 from tfw.config.logs import logging
 log = logging.getLogger(__name__)
 
 class SolutionCheckHandler(RequestHandler):
-    def initialize(self, solvable_connector):
+    def initialize(self, solvable_connector, token):
         self.solvable_connector = solvable_connector
+        self.token = token
 
     async def get(self):
         log.debug('Sending request to solvable')
         self.solvable_connector.send('solution_check', {})
-        resp_key, resp_data = await self.solvable_connector.recv()
+        resp_token, resp_data = await self.solvable_connector.recv()
+        if not secrets.compare_digest(self.token, resp_token):
+            raise HTTPError(500, 'Solvable didn\'t provide initial token.')
         log.debug('Received answer from solvable')
         self.write(resp_data)
diff --git a/src/controller/handlers/test_handler.py b/src/controller/handlers/test_handler.py
index 564bcdc..85c675c 100644
--- a/src/controller/handlers/test_handler.py
+++ b/src/controller/handlers/test_handler.py
@@ -1,11 +1,15 @@
-from tornado.web import RequestHandler
+import secrets
+from tornado.web import RequestHandler, HTTPError
 
 
 class TestHandler(RequestHandler):
-    def initialize(self, solvable_connector):
+    def initialize(self, solvable_connector, token):
         self.solvable_connector = solvable_connector
+        self.token = token
 
     async def get(self):
         self.solvable_connector.send('test', {})
-        resp_key, resp_data = await self.solvable_connector.recv()
+        resp_token, resp_data = await self.solvable_connector.recv()
+        if not secrets.compare_digest(self.token, resp_token):
+            raise HTTPError(500, 'Solvable didn\'t provide initial token.')
         self.write(resp_data)