diff --git a/lib/network.py b/lib/network.py
index 10a395f68..39b457b31 100644
--- a/lib/network.py
+++ b/lib/network.py
@@ -491,12 +491,16 @@ class Network(util.DaemonThread):
         for callback in callbacks:
             callback(response)
 
+    def get_index(self, method, params):
+        """ hashable index for subscriptions and cache"""
+        return str(method) + (':' + str(params[0]) if params  else '')
+
     def process_responses(self, interface):
         responses = interface.get_responses()
-
         for request, response in responses:
             if request:
                 method, params, message_id = request
+                k = self.get_index(method, params)
                 # client requests go through self.send() with a
                 # callback, are only sent to the current interface,
                 # and are placed in the unanswered_requests dictionary
@@ -520,16 +524,18 @@ class Network(util.DaemonThread):
                 # Rewrite response shape to match subscription request response
                 method = response.get('method')
                 params = response.get('params')
+                k = self.get_index(method, params)
                 if method == 'blockchain.headers.subscribe':
                     response['result'] = params[0]
                     response['params'] = []
                 elif method == 'blockchain.address.subscribe':
                     response['params'] = [params[0]]  # addr
                     response['result'] = params[1]
-                callbacks = self.subscriptions.get(repr((method, params)), [])
+                callbacks = self.subscriptions.get(k, [])
+
             # update cache if it's a subscription
             if method.endswith('.subscribe'):
-                self.sub_cache[repr((method, params))] = response
+                self.sub_cache[k] = response
             # Response is now in canonical form
             self.process_response(interface, response, callbacks)
 
@@ -538,7 +544,6 @@ class Network(util.DaemonThread):
         with self.lock:
             self.pending_sends.append((messages, callback))
 
-
     def process_pending_sends(self):
         # Requests needs connectivity.  If we don't have an interface,
         # we cannot process them.
@@ -551,16 +556,16 @@ class Network(util.DaemonThread):
 
         for messages, callback in sends:
             for method, params in messages:
-                k = repr((method, params))
+                r = None
                 if method.endswith('.subscribe'):
+                    k = self.get_index(method, params)
                     # add callback to list
                     l = self.subscriptions.get(k, [])
                     if callback not in l:
                         l.append(callback)
                     self.subscriptions[k] = l
-
-                # check cached response for subscriptions
-                r = self.sub_cache.get(k)
+                    # check cached response for subscriptions
+                    r = self.sub_cache.get(k)
                 if r is not None:
                     util.print_error("cache hit", k)
                     callback(r)