diff --git a/common/djangoapps/student/models.py b/common/djangoapps/student/models.py
index 5975853a21..2f5bc3ac04 100644
--- a/common/djangoapps/student/models.py
+++ b/common/djangoapps/student/models.py
@@ -36,7 +36,7 @@ file and check it in at the same time as your model changes. To do that,
 3. Add the migration file created in mitx/common/djangoapps/student/migrations/
 """
 from datetime import datetime
-from hashlib import sha1
+import hashlib
 import json
 import logging
 import uuid
@@ -197,14 +197,13 @@ def unique_id_for_user(user):
     """
     Return a unique id for a user, suitable for inserting into
     e.g. personalized survey links.
-
-    Currently happens to be implemented as a sha1 hash of the username
-    (and thus assumes that usernames don't change).
     """
-    # Using the user id as the salt because it's sort of random, and is already
-    # in the db.
-    salt = str(user.id)
-    return sha1(salt + user.username).hexdigest()
+    # include the secret key as a salt, and to make the ids unique accross
+    # different LMS installs.    
+    h = hashlib.md5()
+    h.update(settings.SECRET_KEY)
+    h.update(str(user.id))
+    return h.hexdigest()
 
 
 ## TODO: Should be renamed to generic UserGroup, and possibly
diff --git a/lms/djangoapps/courseware/module_render.py b/lms/djangoapps/courseware/module_render.py
index 67927c0ee7..eb7b41b1e9 100644
--- a/lms/djangoapps/courseware/module_render.py
+++ b/lms/djangoapps/courseware/module_render.py
@@ -1,4 +1,3 @@
-import hashlib
 import json
 import logging
 import pyparsing
@@ -20,6 +19,7 @@ from mitxmako.shortcuts import render_to_string
 from models import StudentModule, StudentModuleCache
 from psychometrics.psychoanalyze import make_psychometrics_data_update_handler
 from static_replace import replace_urls
+from student.models import unique_id_for_user
 from xmodule.errortracker import exc_info_to_str
 from xmodule.exceptions import NotFoundError
 from xmodule.modulestore import Location
@@ -152,12 +152,6 @@ def _get_module(user, request, location, student_module_cache, course_id, positi
     if not has_access(user, descriptor, 'load'):
         return None
 
-    # Anonymized student identifier
-    h = hashlib.md5()
-    h.update(settings.SECRET_KEY)
-    h.update(str(user.id))
-    anonymous_student_id = h.hexdigest()
-
     # Only check the cache if this module can possibly have state
     instance_module = None
     shared_module = None
@@ -230,7 +224,7 @@ def _get_module(user, request, location, student_module_cache, course_id, positi
                           # by the replace_static_urls code below
                           replace_urls=replace_urls,
                           node_path=settings.NODE_PATH,
-                          anonymous_student_id=anonymous_student_id,
+                          anonymous_student_id=unique_id_for_user(user),
                           )
     # pass position specified in URL to module through ModuleSystem
     system.set('position', position)