diff --git a/tools/download_file.py b/tools/download_file.py
index 3e6fca947b..d4ddf1c2d6 100755
--- a/tools/download_file.py
+++ b/tools/download_file.py
@@ -77,7 +77,7 @@ def cache_entry(args):
   if args.v:
     h = args.v
   else:
-    h = sha1(args.u).hexdigest()
+    h = sha1(args.u.encode('utf-8')).hexdigest()
   name = '%s-%s' % (path.basename(args.o), h)
   return path.join(CACHE_DIR, name)