diff --git a/server.py b/server.py
index ca7fee5..750d732 100644
--- a/server.py
+++ b/server.py
@@ -39,7 +39,7 @@ async def github(request):
         abort(501)
 
     # HMAC requires the key to be bytes, but data is string
-    mac = hmac.new(str(secret), msg=request.body, digestmod=hashlib.sha1)
+    mac = hmac.new(secret.encode(), msg=request.body, digestmod=hashlib.sha1)
 
     if not hmac.compare_digest(str(mac.hexdigest()), str(signature)):
         abort(403)