diff --git a/daphne/ws_protocol.py b/daphne/ws_protocol.py
index a94a466..0bf3c45 100755
--- a/daphne/ws_protocol.py
+++ b/daphne/ws_protocol.py
@@ -28,12 +28,13 @@ class WebSocketProtocol(WebSocketServerProtocol):
         self.last_data = time.time()
         try:
             # Sanitize and decode headers
-            clean_headers = {}
+            self.clean_headers = []
             for name, value in request.headers.items():
+                name = name.encode("ascii")
                 # Prevent CVE-2015-0219
-                if "_" in name:
+                if b"_" in name:
                     continue
-                clean_headers[name.lower()] = value.encode("latin1")
+                self.clean_headers.append((name.lower(), value.encode("latin1")))
             # Reconstruct query string
             # TODO: get autobahn to provide it raw
             query_string = urlencode(request.params, doseq=True).encode("ascii")
@@ -52,7 +53,7 @@ class WebSocketProtocol(WebSocketServerProtocol):
             self.path = request.path.encode("ascii")
             self.request_info = {
                 "path": self.unquote(self.path),
-                "headers": clean_headers,
+                "headers": self.clean_headers,
                 "query_string": self.unquote(query_string),
                 "client": self.client_addr,
                 "server": self.server_addr,
@@ -65,7 +66,10 @@ class WebSocketProtocol(WebSocketServerProtocol):
             logger.error(traceback.format_exc())
             raise
 
-        ws_protocol = clean_headers.get('sec-websocket-protocol')
+        ws_protocol = None
+        for header, value in self.clean_headers:
+            if header == 'sec-websocket-protocol':
+                ws_protocol = value
         if ws_protocol and ws_protocol in self.factory.protocols:
             return ws_protocol