diff --git a/google/oauth2/_id_token_async.py b/google/oauth2/_id_token_async.py
index 20630e0d4..b90994cdc 100644
--- a/google/oauth2/_id_token_async.py
+++ b/google/oauth2/_id_token_async.py
@@ -95,7 +95,7 @@ async def _fetch_certs(request, certs_url):
 
     data = await response.data.read()
 
-    return json.loads(json.dumps(data))
+    return json.loads(data.decode("utf-8"))
 
 
 async def verify_token(
diff --git a/system_tests/secrets.tar.enc b/system_tests/secrets.tar.enc
index 9baa3acd2..31e079b4e 100644
Binary files a/system_tests/secrets.tar.enc and b/system_tests/secrets.tar.enc differ
diff --git a/tests_async/oauth2/test_id_token.py b/tests_async/oauth2/test_id_token.py
index b84e74db2..a52b8b4e0 100644
--- a/tests_async/oauth2/test_id_token.py
+++ b/tests_async/oauth2/test_id_token.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
 import os
 
 import mock
@@ -32,7 +33,9 @@ def make_request(status, data=None):
 
     if data is not None:
         response.data = mock.AsyncMock(spec=["__call__", "read"])
-        response.data.read = mock.AsyncMock(spec=["__call__"], return_value=data)
+        response.data.read = mock.AsyncMock(
+            spec=["__call__"], return_value=json.dumps(data).encode("utf-8")
+        )
 
     request = mock.AsyncMock(spec=["transport.Request"])
     request.return_value = response