diff --git a/pre_commit/store.py b/pre_commit/store.py
index f2a93008..38c02385 100644
--- a/pre_commit/store.py
+++ b/pre_commit/store.py
@@ -1,6 +1,5 @@
 from __future__ import unicode_literals
 
-import hashlib
 import io
 import logging
 import os
@@ -11,6 +10,7 @@ from plumbum import local
 
 from pre_commit.prefixed_command_runner import PrefixedCommandRunner
 from pre_commit.util import clean_path_on_failure
+from pre_commit.util import hex_md5
 
 
 logger = logging.getLogger('pre_commit')
@@ -75,9 +75,7 @@ class Store(object):
         self.require_created()
 
         # Check if we already exist
-        sha_path = os.path.join(
-            self.directory, sha + '_' + hashlib.md5(url).hexdigest()
-        )
+        sha_path = os.path.join(self.directory, sha + '_' + hex_md5(url))
         if os.path.exists(sha_path):
             return os.readlink(sha_path)
 
diff --git a/pre_commit/util.py b/pre_commit/util.py
index 5b9822fa..4b625c27 100644
--- a/pre_commit/util.py
+++ b/pre_commit/util.py
@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 import contextlib
 import functools
+import hashlib
 import os
 import os.path
 import shutil
@@ -56,3 +57,11 @@ def noop_context():
 
 def shell_escape(arg):
     return "'" + arg.replace("'", "'\"'\"'".strip()) + "'"
+
+
+def hex_md5(s):
+    """Hexdigest an md5 of the string.
+
+    :param text s:
+    """
+    return hashlib.md5(s.encode('utf-8')).hexdigest()
diff --git a/tests/store_test.py b/tests/store_test.py
index d93b9af8..4c767885 100644
--- a/tests/store_test.py
+++ b/tests/store_test.py
@@ -1,7 +1,6 @@
 from __future__ import absolute_import
 from __future__ import unicode_literals
 
-import hashlib
 import io
 import mock
 import os
@@ -14,6 +13,7 @@ from pre_commit import five
 from pre_commit.store import _get_default_directory
 from pre_commit.store import logger
 from pre_commit.store import Store
+from pre_commit.util import hex_md5
 from testing.fixtures import git_dir
 from testing.util import get_head_sha
 
@@ -105,9 +105,7 @@ def test_clone(store, tmpdir_factory, log_info_mock):
     assert get_head_sha(ret) == sha
 
     # Assert that we made a symlink from the sha to the repo
-    sha_path = os.path.join(
-        store.directory, sha + '_' + hashlib.md5(path).hexdigest(),
-    )
+    sha_path = os.path.join(store.directory, sha + '_' + hex_md5(path))
     assert os.path.exists(sha_path)
     assert os.path.islink(sha_path)
     assert os.readlink(sha_path) == ret
@@ -141,9 +139,7 @@ def test_clone_when_repo_already_exists(store):
     os.mkdir(repo_dir_path)
     os.symlink(
         repo_dir_path,
-        os.path.join(
-            store.directory, 'fake_sha' + '_' + hashlib.md5('url').hexdigest(),
-        ),
+        os.path.join(store.directory, 'fake_sha' + '_' + hex_md5('url')),
     )
 
     ret = store.clone('url', 'fake_sha')