diff --git a/src/mock_vws/_mock_web_services_api.py b/src/mock_vws/_mock_web_services_api.py
index 0aa8c6cbe..cb9d8f060 100644
--- a/src/mock_vws/_mock_web_services_api.py
+++ b/src/mock_vws/_mock_web_services_api.py
@@ -43,7 +43,9 @@
     validate_width,
 )
 from ._services_validators.auth_validators import (
+    validate_access_key_exists,
     validate_auth_header_exists,
+    validate_auth_header_has_signature,
     validate_authorization,
 )
 from ._services_validators.date_validators import (
@@ -222,6 +224,8 @@ def decorator(method: Callable[..., str]) -> Callable[..., str]:
             ]
 
         common_decorators = [
+            validate_access_key_exists,
+            validate_auth_header_has_signature,
             validate_auth_header_exists,
             set_content_length_header,
             update_request_count,
diff --git a/src/mock_vws/_query_validators/auth_validators.py b/src/mock_vws/_query_validators/auth_validators.py
index b2341e97f..ad3ed394e 100644
--- a/src/mock_vws/_query_validators/auth_validators.py
+++ b/src/mock_vws/_query_validators/auth_validators.py
@@ -101,7 +101,7 @@ def validate_client_key_exists(
 
     Returns:
         The result of calling the endpoint.
-        An ``UNAUTHORIZED`` FOOBAR.
+        An ``UNAUTHORIZED`` response if the client key is unknown.
     """
     request, context = args
 
diff --git a/src/mock_vws/_services_validators/auth_validators.py b/src/mock_vws/_services_validators/auth_validators.py
index 1b2f3b173..fd524294c 100644
--- a/src/mock_vws/_services_validators/auth_validators.py
+++ b/src/mock_vws/_services_validators/auth_validators.py
@@ -47,6 +47,79 @@ def validate_auth_header_exists(
     return json_dump(body)
 
 
+@wrapt.decorator
+def validate_access_key_exists(
+    wrapped: Callable[..., str],
+    instance: Any,
+    args: Tuple[_RequestObjectProxy, _Context],
+    kwargs: Dict,
+) -> str:
+    """
+    Validate the authorization header includes an access key for a database.
+
+    Args:
+        wrapped: An endpoint function for `requests_mock`.
+        instance: The class that the endpoint function is in.
+        args: The arguments given to the endpoint function.
+        kwargs: The keyword arguments given to the endpoint function.
+
+    Returns:
+        The result of calling the endpoint.
+        An ``UNAUTHORIZED`` response if the access key is unknown.
+    """
+    request, context = args
+
+    header = request.headers['Authorization']
+    first_part, _ = header.split(b':')
+    _, access_key = first_part.split(b' ')
+    for database in instance.databases:
+        if access_key == database.server_access_key:
+            return wrapped(*args, **kwargs)
+
+    context.status_code = codes.BAD_REQUEST
+
+    body = {
+        'transaction_id': uuid.uuid4().hex,
+        'result_code': ResultCodes.FAIL.value,
+    }
+    return json_dump(body)
+
+
+@wrapt.decorator
+def validate_auth_header_has_signature(
+    wrapped: Callable[..., str],
+    instance: Any,  # pylint: disable=unused-argument
+    args: Tuple[_RequestObjectProxy, _Context],
+    kwargs: Dict,
+) -> str:
+    """
+    Validate the authorization header includes a signature.
+
+    Args:
+        wrapped: An endpoint function for `requests_mock`.
+        instance: The class that the endpoint function is in.
+        args: The arguments given to the endpoint function.
+        kwargs: The keyword arguments given to the endpoint function.
+
+    Returns:
+        The result of calling the endpoint.
+        An ``UNAUTHORIZED`` response if the "Authorization" header is not as
+        expected.
+    """
+    request, context = args
+
+    header = request.headers['Authorization']
+    if header.count(b':') == 1 and header.split(b':')[1]:
+        return wrapped(*args, **kwargs)
+
+    context.status_code = codes.BAD_REQUEST
+    body = {
+        'transaction_id': uuid.uuid4().hex,
+        'result_code': ResultCodes.FAIL.value,
+    }
+    return json_dump(body)
+
+
 @wrapt.decorator
 def validate_authorization(
     wrapped: Callable[..., str],
@@ -78,9 +151,9 @@ def validate_authorization(
     if database is not None:
         return wrapped(*args, **kwargs)
 
-    context.status_code = codes.BAD_REQUEST
+    context.status_code = codes.UNAUTHORIZED
     body = {
         'transaction_id': uuid.uuid4().hex,
-        'result_code': ResultCodes.FAIL.value,
+        'result_code': ResultCodes.AUTHENTICATION_FAILURE.value,
     }
     return json_dump(body)
diff --git a/tests/mock_vws/test_authorization_header.py b/tests/mock_vws/test_authorization_header.py
index 90aa082ce..82d16d82a 100644
--- a/tests/mock_vws/test_authorization_header.py
+++ b/tests/mock_vws/test_authorization_header.py
@@ -246,6 +246,27 @@ def test_bad_access_key_query(
         )
         assert response.text == expected_text
 
+    def test_bad_secret_key_services(
+        self,
+        vuforia_database: VuforiaDatabase,
+    ) -> None:
+        """
+        If the server secret key given is incorrect, an
+        ``AuthenticationFailure`` response is returned.
+        """
+        keys = vuforia_database
+        keys.server_secret_key = b'example'
+        response = get_vws_target(
+            target_id=uuid.uuid4().hex,
+            vuforia_database=keys,
+        )
+
+        assert_vws_failure(
+            response=response,
+            status_code=codes.UNAUTHORIZED,
+            result_code=ResultCodes.AUTHENTICATION_FAILURE,
+        )
+
     def test_bad_secret_key_query(
         self,
         vuforia_database: VuforiaDatabase,
diff --git a/tests/mock_vws/test_usage.py b/tests/mock_vws/test_usage.py
index 567d99fa9..90a1cd8e5 100644
--- a/tests/mock_vws/test_usage.py
+++ b/tests/mock_vws/test_usage.py
@@ -54,7 +54,7 @@ def request_mocked_address() -> None:
         url='https://vws.vuforia.com/summary',
         headers={
             'Date': rfc_1123_date(),
-            'Authorization': 'bad_auth_token',
+            'Authorization': b'bad_auth_token',
         },
         data=b'',
     )