diff --git a/glance/common/crypt.py b/glance/common/crypt.py
index 74a25103..59d28eb1 100644
--- a/glance/common/crypt.py
+++ b/glance/common/crypt.py
@@ -24,6 +24,7 @@ import base64
 from Crypto.Cipher import AES
 from Crypto import Random
 from Crypto.Random import random
+from oslo_utils import encodeutils
 import six
 # NOTE(jokke): simplified transition to py3, behaves like py2 xrange
 from six.moves import range
@@ -51,10 +52,8 @@ def urlsafe_encrypt(key, plaintext, blocksize=16):
         # We use chr(0) as a delimiter between text and padding
         return text + b'\0' + pad
 
-    if isinstance(plaintext, six.text_type):
-        plaintext = plaintext.encode('utf-8')
-    if isinstance(key, six.text_type):
-        key = key.encode('utf-8')
+    plaintext = encodeutils.to_utf8(plaintext)
+    key = encodeutils.to_utf8(key)
     # random initial 16 bytes for CBC
     init_vector = Random.get_random_bytes(16)
     cypher = AES.new(key, AES.MODE_CBC, init_vector)
@@ -76,10 +75,8 @@ def urlsafe_decrypt(key, ciphertext):
     :returns: Resulting plaintext
     """
     # Cast from unicode
-    if isinstance(ciphertext, six.text_type):
-        ciphertext = ciphertext.encode('utf-8')
-    if isinstance(key, six.text_type):
-        key = key.encode('utf-8')
+    ciphertext = encodeutils.to_utf8(ciphertext)
+    key = encodeutils.to_utf8(key)
     ciphertext = base64.urlsafe_b64decode(ciphertext)
     cypher = AES.new(key, AES.MODE_CBC, ciphertext[:16])
     padded = cypher.decrypt(ciphertext[16:])
diff --git a/glance/common/signature_utils.py b/glance/common/signature_utils.py
index df5be511..3df28aa5 100644
--- a/glance/common/signature_utils.py
+++ b/glance/common/signature_utils.py
@@ -29,7 +29,6 @@ import debtcollector
 from oslo_log import log as logging
 from oslo_serialization import base64
 from oslo_utils import encodeutils
-import six
 
 from glance.common import exception
 from glance.i18n import _LE
@@ -175,8 +174,7 @@ def verify_signature(context, checksum_hash, image_properties):
             'Required image properties for signature verification do not'
             ' exist. Cannot verify signature.')
 
-    if isinstance(checksum_hash, six.text_type):
-        checksum_hash = checksum_hash.encode('utf-8')
+    checksum_hash = encodeutils.to_utf8(checksum_hash)
 
     signature = get_signature(image_properties[OLD_SIGNATURE])
     hash_method = get_hash_method(image_properties[OLD_HASH_METHOD])
diff --git a/glance/common/wsgi.py b/glance/common/wsgi.py
index 49acce8d..61e0d564 100644
--- a/glance/common/wsgi.py
+++ b/glance/common/wsgi.py
@@ -819,8 +819,7 @@ class JSONResponseSerializer(object):
     def default(self, response, result):
         response.content_type = 'application/json'
         body = self.to_json(result)
-        if isinstance(body, six.text_type):
-            body = body.encode('utf-8')
+        body = encodeutils.to_utf8(body)
         response.body = body
 
 
diff --git a/glance/tests/unit/common/test_rpc.py b/glance/tests/unit/common/test_rpc.py
index a6a83a46..6d5fc6c3 100644
--- a/glance/tests/unit/common/test_rpc.py
+++ b/glance/tests/unit/common/test_rpc.py
@@ -18,6 +18,7 @@ import datetime
 
 from oslo_config import cfg
 from oslo_serialization import jsonutils
+from oslo_utils import encodeutils
 import routes
 import six
 import webob
@@ -211,8 +212,7 @@ class TestRPCClient(base.IsolatedUnitTest):
 
     def fake_request(self, method, url, body, headers):
         req = webob.Request.blank(url.path)
-        if isinstance(body, six.text_type):
-            body = body.encode('utf-8')
+        body = encodeutils.to_utf8(body)
         req.body = body
         req.method = method
 
diff --git a/requirements.txt b/requirements.txt
index 50f0602c..034868c5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,7 +18,7 @@ oslo.config>=3.4.0 # Apache-2.0
 oslo.concurrency>=2.3.0 # Apache-2.0
 oslo.context>=0.2.0 # Apache-2.0
 oslo.service>=1.0.0 # Apache-2.0
-oslo.utils>=3.4.0 # Apache-2.0
+oslo.utils>=3.5.0 # Apache-2.0
 stevedore>=1.5.0 # Apache-2.0
 futurist>=0.11.0 # Apache-2.0
 taskflow>=1.26.0 # Apache-2.0