diff --git a/mia_core/digest_auth.py b/mia_core/digest_auth.py
index af34ffb..6eeaae1 100644
--- a/mia_core/digest_auth.py
+++ b/mia_core/digest_auth.py
@@ -1,11 +1,54 @@
+# The core application of the Mia project.
+#   by imacat <imacat@mail.imacat.idv.tw>, 2020/7/5
+
+#  Copyright (c) 2020 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+"""The utilities for the HTTP digest authentication.
+
+"""
 from mia_core.models import User
 
 
 class AccountBackend:
+    """The account backend for the django-digest module."""
+
     def get_partial_digest(self, username):
-        if username != "imacat":
+        """Returns the HTTP digest authentication password digest hash
+        of a user.
+
+        Args:
+            username (str): The log in user name.
+
+        Return:
+            str: The HTTP digest authentication password hash of
+            the user, or None if the user does not exist.
+        """
+        user = User.objects.filter(login_id=username).first()
+        if user is None:
             return None
-        return "5486b64881adaf7bc1485cc26e57e51e"
+        return user.password
 
     def get_user(self, username):
-        return User(username)
+        """Returns the user by her log in user name.
+
+        Args:
+            username (str): The log in user name.
+
+        Return:
+            User: The user, or None if the user does not eixst.
+        """
+        print("mia_core.digest_auth.AccountBackend.get_user(): " + str(User.objects.filter(
+            login_id=username).first()))
+        return User.objects.filter(login_id=username).first()