diff -r 96380c1524b0 -r e08102f45237 web/request.py
--- a/web/request.py	Thu Oct 01 11:40:23 2015 +0200
+++ b/web/request.py	Tue Oct 13 16:57:09 2015 +0200
@@ -52,7 +52,7 @@
 _MARKER = object()
 
 def build_cb_uid(seed):
-    sha = sha1('%s%s%s' % (time.time(), seed, random.random()))
+    sha = sha1(('%s%s%s' % (time.time(), seed, random.random())).encode('ascii'))
     return 'cb_%s' % (sha.hexdigest())