diff --git a/google/cloud/secretmanager_v1/services/secret_manager_service/async_client.py b/google/cloud/secretmanager_v1/services/secret_manager_service/async_client.py
index da3b66e..c84f589 100644
--- a/google/cloud/secretmanager_v1/services/secret_manager_service/async_client.py
+++ b/google/cloud/secretmanager_v1/services/secret_manager_service/async_client.py
@@ -262,7 +262,7 @@ async def list_secrets(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent])
         if request is not None and has_flattened_params:
@@ -368,7 +368,7 @@ async def create_secret(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent, secret_id, secret])
         if request is not None and has_flattened_params:
@@ -457,7 +457,7 @@ async def add_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent, payload])
         if request is not None and has_flattened_params:
@@ -537,7 +537,7 @@ async def get_secret(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -622,7 +622,7 @@ async def update_secret(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([secret, update_mask])
         if request is not None and has_flattened_params:
@@ -692,7 +692,7 @@ async def delete_secret(
                 sent along with the request as metadata.
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -770,7 +770,7 @@ async def list_secret_versions(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent])
         if request is not None and has_flattened_params:
@@ -857,7 +857,7 @@ async def get_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -939,7 +939,7 @@ async def access_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1029,7 +1029,7 @@ async def disable_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1109,7 +1109,7 @@ async def enable_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1190,7 +1190,7 @@ async def destroy_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
diff --git a/google/cloud/secretmanager_v1/services/secret_manager_service/client.py b/google/cloud/secretmanager_v1/services/secret_manager_service/client.py
index d8dd584..bd34855 100644
--- a/google/cloud/secretmanager_v1/services/secret_manager_service/client.py
+++ b/google/cloud/secretmanager_v1/services/secret_manager_service/client.py
@@ -478,7 +478,7 @@ def list_secrets(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent])
         if request is not None and has_flattened_params:
@@ -584,7 +584,7 @@ def create_secret(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent, secret_id, secret])
         if request is not None and has_flattened_params:
@@ -673,7 +673,7 @@ def add_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent, payload])
         if request is not None and has_flattened_params:
@@ -753,7 +753,7 @@ def get_secret(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -838,7 +838,7 @@ def update_secret(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([secret, update_mask])
         if request is not None and has_flattened_params:
@@ -908,7 +908,7 @@ def delete_secret(
                 sent along with the request as metadata.
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -986,7 +986,7 @@ def list_secret_versions(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([parent])
         if request is not None and has_flattened_params:
@@ -1073,7 +1073,7 @@ def get_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1155,7 +1155,7 @@ def access_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1235,7 +1235,7 @@ def disable_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1315,7 +1315,7 @@ def enable_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
@@ -1396,7 +1396,7 @@ def destroy_secret_version(
 
         """
         # Create or coerce a protobuf request object.
-        # Sanity check: If we got a request object, we should *not* have
+        # Quick check: If we got a request object, we should *not* have
         # gotten any keyword arguments that map to the request.
         has_flattened_params = any([name])
         if request is not None and has_flattened_params:
diff --git a/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc.py b/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc.py
index 70beab4..4bfe164 100644
--- a/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc.py
+++ b/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc.py
@@ -168,8 +168,11 @@ def __init__(
         if not self._grpc_channel:
             self._grpc_channel = type(self).create_channel(
                 self._host,
+                # use the credentials which are saved
                 credentials=self._credentials,
-                credentials_file=credentials_file,
+                # Set ``credentials_file`` to ``None`` here as
+                # the credentials that we saved earlier should be used.
+                credentials_file=None,
                 scopes=self._scopes,
                 ssl_credentials=self._ssl_channel_credentials,
                 quota_project_id=quota_project_id,
diff --git a/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc_asyncio.py b/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc_asyncio.py
index 9415311..356b145 100644
--- a/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc_asyncio.py
+++ b/google/cloud/secretmanager_v1/services/secret_manager_service/transports/grpc_asyncio.py
@@ -213,8 +213,11 @@ def __init__(
         if not self._grpc_channel:
             self._grpc_channel = type(self).create_channel(
                 self._host,
+                # use the credentials which are saved
                 credentials=self._credentials,
-                credentials_file=credentials_file,
+                # Set ``credentials_file`` to ``None`` here as
+                # the credentials that we saved earlier should be used.
+                credentials_file=None,
                 scopes=self._scopes,
                 ssl_credentials=self._ssl_channel_credentials,
                 quota_project_id=quota_project_id,
diff --git a/google/cloud/secretmanager_v1/types/resources.py b/google/cloud/secretmanager_v1/types/resources.py
index 1060ad0..2c9f9e3 100644
--- a/google/cloud/secretmanager_v1/types/resources.py
+++ b/google/cloud/secretmanager_v1/types/resources.py
@@ -154,6 +154,13 @@ class SecretVersion(proto.Message):
         etag (str):
             Output only. Etag of the currently stored
             [SecretVersion][google.cloud.secretmanager.v1.SecretVersion].
+        client_specified_payload_checksum (bool):
+            Output only. True if payload checksum specified in
+            [SecretPayload][google.cloud.secretmanager.v1.SecretPayload]
+            object has been received by
+            [SecretManagerService][google.cloud.secretmanager.v1.SecretManagerService]
+            on
+            [SecretManagerService.AddSecretVersion][google.cloud.secretmanager.v1.SecretManagerService.AddSecretVersion].
     """
 
     class State(proto.Enum):
@@ -176,6 +183,7 @@ class State(proto.Enum):
         proto.MESSAGE, number=5, message="ReplicationStatus",
     )
     etag = proto.Field(proto.STRING, number=6,)
+    client_specified_payload_checksum = proto.Field(proto.BOOL, number=7,)
 
 
 class Replication(proto.Message):
@@ -281,8 +289,8 @@ class Replica(proto.Message):
 
 
 class CustomerManagedEncryption(proto.Message):
-    r"""Configuration for encrypting secret payloads using customer-
-    anaged encryption keys (CMEK).
+    r"""Configuration for encrypting secret payloads using
+    customer-managed encryption keys (CMEK).
 
     Attributes:
         kms_key_name (str):
@@ -490,9 +498,31 @@ class SecretPayload(proto.Message):
         data (bytes):
             The secret data. Must be no larger than
             64KiB.
+        data_crc32c (int):
+            Optional. If specified,
+            [SecretManagerService][google.cloud.secretmanager.v1.SecretManagerService]
+            will verify the integrity of the received
+            [data][google.cloud.secretmanager.v1.SecretPayload.data] on
+            [SecretManagerService.AddSecretVersion][google.cloud.secretmanager.v1.SecretManagerService.AddSecretVersion]
+            calls using the crc32c checksum and store it to include in
+            future
+            [SecretManagerService.AccessSecretVersion][google.cloud.secretmanager.v1.SecretManagerService.AccessSecretVersion]
+            responses. If a checksum is not provided in the
+            [SecretManagerService.AddSecretVersion][google.cloud.secretmanager.v1.SecretManagerService.AddSecretVersion]
+            request, the
+            [SecretManagerService][google.cloud.secretmanager.v1.SecretManagerService]
+            will generate and store one for you.
+
+            The CRC32C value is encoded as a Int64 for compatibility,
+            and can be safely downconverted to uint32 in languages that
+            support this type.
+            https://cloud.google.com/apis/design/design_patterns#integer_types
+
+            This field is a member of `oneof`_ ``_data_crc32c``.
     """
 
     data = proto.Field(proto.BYTES, number=1,)
+    data_crc32c = proto.Field(proto.INT64, number=2, optional=True,)
 
 
 __all__ = tuple(sorted(__protobuf__.manifest))
diff --git a/tests/unit/gapic/secretmanager_v1/test_secret_manager_service.py b/tests/unit/gapic/secretmanager_v1/test_secret_manager_service.py
index 8abcea7..fd57b41 100644
--- a/tests/unit/gapic/secretmanager_v1/test_secret_manager_service.py
+++ b/tests/unit/gapic/secretmanager_v1/test_secret_manager_service.py
@@ -539,25 +539,28 @@ def test_secret_manager_service_client_client_options_scopes(
 
 
 @pytest.mark.parametrize(
-    "client_class,transport_class,transport_name",
+    "client_class,transport_class,transport_name,grpc_helpers",
     [
         (
             SecretManagerServiceClient,
             transports.SecretManagerServiceGrpcTransport,
             "grpc",
+            grpc_helpers,
         ),
         (
             SecretManagerServiceAsyncClient,
             transports.SecretManagerServiceGrpcAsyncIOTransport,
             "grpc_asyncio",
+            grpc_helpers_async,
         ),
     ],
 )
 def test_secret_manager_service_client_client_options_credentials_file(
-    client_class, transport_class, transport_name
+    client_class, transport_class, transport_name, grpc_helpers
 ):
     # Check the case credentials file is provided.
     options = client_options.ClientOptions(credentials_file="credentials.json")
+
     with mock.patch.object(transport_class, "__init__") as patched:
         patched.return_value = None
         client = client_class(client_options=options, transport=transport_name)
@@ -593,6 +596,72 @@ def test_secret_manager_service_client_client_options_from_dict():
         )
 
 
+@pytest.mark.parametrize(
+    "client_class,transport_class,transport_name,grpc_helpers",
+    [
+        (
+            SecretManagerServiceClient,
+            transports.SecretManagerServiceGrpcTransport,
+            "grpc",
+            grpc_helpers,
+        ),
+        (
+            SecretManagerServiceAsyncClient,
+            transports.SecretManagerServiceGrpcAsyncIOTransport,
+            "grpc_asyncio",
+            grpc_helpers_async,
+        ),
+    ],
+)
+def test_secret_manager_service_client_create_channel_credentials_file(
+    client_class, transport_class, transport_name, grpc_helpers
+):
+    # Check the case credentials file is provided.
+    options = client_options.ClientOptions(credentials_file="credentials.json")
+
+    with mock.patch.object(transport_class, "__init__") as patched:
+        patched.return_value = None
+        client = client_class(client_options=options, transport=transport_name)
+        patched.assert_called_once_with(
+            credentials=None,
+            credentials_file="credentials.json",
+            host=client.DEFAULT_ENDPOINT,
+            scopes=None,
+            client_cert_source_for_mtls=None,
+            quota_project_id=None,
+            client_info=transports.base.DEFAULT_CLIENT_INFO,
+            always_use_jwt_access=True,
+        )
+
+    # test that the credentials from file are saved and used as the credentials.
+    with mock.patch.object(
+        google.auth, "load_credentials_from_file", autospec=True
+    ) as load_creds, mock.patch.object(
+        google.auth, "default", autospec=True
+    ) as adc, mock.patch.object(
+        grpc_helpers, "create_channel"
+    ) as create_channel:
+        creds = ga_credentials.AnonymousCredentials()
+        file_creds = ga_credentials.AnonymousCredentials()
+        load_creds.return_value = (file_creds, None)
+        adc.return_value = (creds, None)
+        client = client_class(client_options=options, transport=transport_name)
+        create_channel.assert_called_with(
+            "secretmanager.googleapis.com:443",
+            credentials=file_creds,
+            credentials_file=None,
+            quota_project_id=None,
+            default_scopes=("https://www.googleapis.com/auth/cloud-platform",),
+            scopes=None,
+            default_host="secretmanager.googleapis.com",
+            ssl_credentials=None,
+            options=[
+                ("grpc.max_send_message_length", -1),
+                ("grpc.max_receive_message_length", -1),
+            ],
+        )
+
+
 @pytest.mark.parametrize("request_type", [service.ListSecretsRequest, dict,])
 def test_list_secrets(request_type, transport: str = "grpc"):
     client = SecretManagerServiceClient(
@@ -1190,6 +1259,7 @@ def test_add_secret_version(request_type, transport: str = "grpc"):
             name="name_value",
             state=resources.SecretVersion.State.ENABLED,
             etag="etag_value",
+            client_specified_payload_checksum=True,
         )
         response = client.add_secret_version(request)
 
@@ -1203,6 +1273,7 @@ def test_add_secret_version(request_type, transport: str = "grpc"):
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 def test_add_secret_version_empty_call():
@@ -1244,6 +1315,7 @@ async def test_add_secret_version_async(
                 name="name_value",
                 state=resources.SecretVersion.State.ENABLED,
                 etag="etag_value",
+                client_specified_payload_checksum=True,
             )
         )
         response = await client.add_secret_version(request)
@@ -1258,6 +1330,7 @@ async def test_add_secret_version_async(
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 @pytest.mark.asyncio
@@ -2451,6 +2524,7 @@ def test_get_secret_version(request_type, transport: str = "grpc"):
             name="name_value",
             state=resources.SecretVersion.State.ENABLED,
             etag="etag_value",
+            client_specified_payload_checksum=True,
         )
         response = client.get_secret_version(request)
 
@@ -2464,6 +2538,7 @@ def test_get_secret_version(request_type, transport: str = "grpc"):
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 def test_get_secret_version_empty_call():
@@ -2505,6 +2580,7 @@ async def test_get_secret_version_async(
                 name="name_value",
                 state=resources.SecretVersion.State.ENABLED,
                 etag="etag_value",
+                client_specified_payload_checksum=True,
             )
         )
         response = await client.get_secret_version(request)
@@ -2519,6 +2595,7 @@ async def test_get_secret_version_async(
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 @pytest.mark.asyncio
@@ -2905,6 +2982,7 @@ def test_disable_secret_version(request_type, transport: str = "grpc"):
             name="name_value",
             state=resources.SecretVersion.State.ENABLED,
             etag="etag_value",
+            client_specified_payload_checksum=True,
         )
         response = client.disable_secret_version(request)
 
@@ -2918,6 +2996,7 @@ def test_disable_secret_version(request_type, transport: str = "grpc"):
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 def test_disable_secret_version_empty_call():
@@ -2959,6 +3038,7 @@ async def test_disable_secret_version_async(
                 name="name_value",
                 state=resources.SecretVersion.State.ENABLED,
                 etag="etag_value",
+                client_specified_payload_checksum=True,
             )
         )
         response = await client.disable_secret_version(request)
@@ -2973,6 +3053,7 @@ async def test_disable_secret_version_async(
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 @pytest.mark.asyncio
@@ -3138,6 +3219,7 @@ def test_enable_secret_version(request_type, transport: str = "grpc"):
             name="name_value",
             state=resources.SecretVersion.State.ENABLED,
             etag="etag_value",
+            client_specified_payload_checksum=True,
         )
         response = client.enable_secret_version(request)
 
@@ -3151,6 +3233,7 @@ def test_enable_secret_version(request_type, transport: str = "grpc"):
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 def test_enable_secret_version_empty_call():
@@ -3192,6 +3275,7 @@ async def test_enable_secret_version_async(
                 name="name_value",
                 state=resources.SecretVersion.State.ENABLED,
                 etag="etag_value",
+                client_specified_payload_checksum=True,
             )
         )
         response = await client.enable_secret_version(request)
@@ -3206,6 +3290,7 @@ async def test_enable_secret_version_async(
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 @pytest.mark.asyncio
@@ -3371,6 +3456,7 @@ def test_destroy_secret_version(request_type, transport: str = "grpc"):
             name="name_value",
             state=resources.SecretVersion.State.ENABLED,
             etag="etag_value",
+            client_specified_payload_checksum=True,
         )
         response = client.destroy_secret_version(request)
 
@@ -3384,6 +3470,7 @@ def test_destroy_secret_version(request_type, transport: str = "grpc"):
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 def test_destroy_secret_version_empty_call():
@@ -3425,6 +3512,7 @@ async def test_destroy_secret_version_async(
                 name="name_value",
                 state=resources.SecretVersion.State.ENABLED,
                 etag="etag_value",
+                client_specified_payload_checksum=True,
             )
         )
         response = await client.destroy_secret_version(request)
@@ -3439,6 +3527,7 @@ async def test_destroy_secret_version_async(
     assert response.name == "name_value"
     assert response.state == resources.SecretVersion.State.ENABLED
     assert response.etag == "etag_value"
+    assert response.client_specified_payload_checksum is True
 
 
 @pytest.mark.asyncio