diff --git a/common/lib/xmodule/xmodule/vertical_block.py b/common/lib/xmodule/xmodule/vertical_block.py
index 3971154b4f..e56f00a438 100644
--- a/common/lib/xmodule/xmodule/vertical_block.py
+++ b/common/lib/xmodule/xmodule/vertical_block.py
@@ -70,7 +70,7 @@ class VerticalBlock(SequenceFields, XModuleFields, StudioEditableBlock, XmlParse
             'unit_title': self.display_name_with_default if not is_child_of_vertical else None,
             'show_bookmark_button': not is_child_of_vertical,
             'bookmarked': child_context['bookmarked'],
-            'bookmark_id': "{},{}".format(child_context['username'], unicode(self.location))
+            'bookmark_id': u"{},{}".format(child_context['username'], unicode(self.location))
         }))
 
         fragment.add_javascript_url(self.runtime.local_resource_url(self, 'public/js/vertical_student_view.js'))
diff --git a/openedx/core/djangoapps/bookmarks/models.py b/openedx/core/djangoapps/bookmarks/models.py
index cbde6bbe70..d048bb214a 100644
--- a/openedx/core/djangoapps/bookmarks/models.py
+++ b/openedx/core/djangoapps/bookmarks/models.py
@@ -98,7 +98,7 @@ class Bookmark(TimeStampedModel):
         """
         Return the resource id: {username,usage_id}.
         """
-        return "{0},{1}".format(self.user.username, self.usage_key)  # pylint: disable=no-member
+        return u"{0},{1}".format(self.user.username, self.usage_key)  # pylint: disable=no-member
 
     @property
     def display_name(self):
diff --git a/openedx/core/djangoapps/bookmarks/serializers.py b/openedx/core/djangoapps/bookmarks/serializers.py
index d06019ffa5..b7479fd1ef 100644
--- a/openedx/core/djangoapps/bookmarks/serializers.py
+++ b/openedx/core/djangoapps/bookmarks/serializers.py
@@ -51,7 +51,7 @@ class BookmarkSerializer(serializers.ModelSerializer):
         """
         Return the REST resource id: {username,usage_id}.
         """
-        return "{0},{1}".format(bookmark.user.username, bookmark.usage_key)
+        return u"{0},{1}".format(bookmark.user.username, bookmark.usage_key)
 
     def get_path(self, bookmark):
         """
diff --git a/openedx/core/djangoapps/user_api/accounts/image_helpers.py b/openedx/core/djangoapps/user_api/accounts/image_helpers.py
index 9e7eaed7f0..71f8f6be56 100644
--- a/openedx/core/djangoapps/user_api/accounts/image_helpers.py
+++ b/openedx/core/djangoapps/user_api/accounts/image_helpers.py
@@ -38,7 +38,8 @@ def _make_profile_image_name(username):
     Returns the user-specific part of the image filename, based on a hash of
     the username.
     """
-    return hashlib.md5(settings.PROFILE_IMAGE_SECRET_KEY + username).hexdigest()
+    hash_input = settings.PROFILE_IMAGE_SECRET_KEY + username
+    return hashlib.md5(hash_input.encode('utf-8')).hexdigest()
 
 
 def _get_profile_image_filename(name, size, file_extension=PROFILE_IMAGE_FILE_EXTENSION):