diff --git a/atreal_openads/utils.py b/atreal_openads/utils.py
index f8c3059..ccd6828 100644
--- a/atreal_openads/utils.py
+++ b/atreal_openads/utils.py
@@ -94,7 +94,7 @@ def normalize(value):
 
 def get_file_data(path, b64=True):
     """Return the content of a file as a string, in base64 if specified."""
-    with open(path, 'r') as file_pt:
+    with open(path, 'rb') as file_pt:
         if b64:
             return base64.b64encode(file_pt.read())
         return file_pt.read()