diff --git a/http_client/src/vonage_http_client/auth.py b/http_client/src/vonage_http_client/auth.py
index 9c9fc641..c1125a44 100644
--- a/http_client/src/vonage_http_client/auth.py
+++ b/http_client/src/vonage_http_client/auth.py
@@ -37,10 +37,10 @@ def __init__(
         application_id: Optional[str] = None,
         private_key: Optional[str] = None,
         signature_secret: Optional[str] = None,
-        signature_method: Optional[Literal['md5', 'sha1', 'sha256', 'sha512']] = None,
+        signature_method: Optional[Literal['md5', 'sha1', 'sha256', 'sha512']] = 'md5',
     ) -> None:
         self._validate_input_combinations(
-            api_key, api_secret, application_id, private_key
+            api_key, api_secret, application_id, private_key, signature_secret
         )
 
         self._api_key = api_key
@@ -110,18 +110,27 @@ def sign_params(self, params: dict) -> dict:
 
         if self._signature_method is None:
             hasher.update(self._signature_secret.encode())
-
         return hasher.hexdigest()
 
+    def check_signature(self, params) -> bool:
+        params = dict(params)
+        signature = params.pop('sig', '').lower()
+        return hmac.compare_digest(signature, self.signature(params))
+
     def _validate_input_combinations(
-        self, api_key, api_secret, application_id, private_key
+        self, api_key, api_secret, application_id, private_key, signature_secret
     ):
-        if (api_key and not api_secret) or (not api_key and api_secret):
+        if (api_secret or signature_secret) and not api_key:
+            raise InvalidAuthError(
+                '`api_key` must be set when `api_secret` or `signature_secret` is set.'
+            )
+
+        if api_key and not (api_secret or signature_secret):
             raise InvalidAuthError(
-                'Both api_key and api_secret must be set or both must be None.'
+                'At least one of `api_secret` and `signature_secret` must be set if `api_key` is set.'
             )
 
         if (application_id and not private_key) or (not application_id and private_key):
             raise InvalidAuthError(
-                'Both application_id and private_key must be set or both must be None.'
+                'Both `application_id` and `private_key` must be set or both must be None.'
             )
diff --git a/http_client/src/vonage_http_client/http_client.py b/http_client/src/vonage_http_client/http_client.py
index 8a5d3d58..66c85807 100644
--- a/http_client/src/vonage_http_client/http_client.py
+++ b/http_client/src/vonage_http_client/http_client.py
@@ -136,6 +136,10 @@ def make_request(
             self._headers['Authorization'] = self._auth.create_basic_auth_string()
         elif auth_type == 'signature':
             params = self._auth.sign_params(params)
+
+            print(params)
+            print(self._auth.check_signature(params))
+
             with self._session.request(
                 request_type,
                 url,
@@ -161,6 +165,7 @@ def _parse_response(self, response: Response) -> Union[dict, None]:
         logger.debug(
             f'Response received from {response.url} with status code: {response.status_code}; headers: {response.headers}'
         )
+        print(response.request.headers)
         content_type = response.headers['Content-Type'].split(';', 1)[0]
         if 200 <= response.status_code < 300:
             if response.status_code == 204:
diff --git a/http_client/tests/test_auth.py b/http_client/tests/test_auth.py
index be805604..4303b469 100644
--- a/http_client/tests/test_auth.py
+++ b/http_client/tests/test_auth.py
@@ -19,6 +19,8 @@ def read_file(path):
 api_secret = '1234qwerasdfzxcv'
 application_id = 'asdfzxcv'
 private_key = read_file('data/dummy_private_key.txt')
+signature_secret = 'signature_secret'
+signature_method = 'sha256'
 
 
 def test_create_auth_class_and_get_objects():
@@ -27,6 +29,8 @@ def test_create_auth_class_and_get_objects():
         api_secret=api_secret,
         application_id=application_id,
         private_key=private_key,
+        signature_secret=signature_secret,
+        signature_method=signature_method,
     )
 
     assert auth.api_key == api_key
diff --git a/http_client/tests/test_http_client.py b/http_client/tests/test_http_client.py
index 94bcbf99..11483336 100644
--- a/http_client/tests/test_http_client.py
+++ b/http_client/tests/test_http_client.py
@@ -95,6 +95,33 @@ def test_make_post_request():
     assert loads(responses.calls[0].request.body) == params
 
 
+@responses.activate
+def test_make_post_request_with_signature():
+    build_response(
+        path, 'POST', 'https://example.com/post_signed_params', 'example_post.json'
+    )
+    client = HttpClient(
+        Auth(
+            api_key='asdfzxcv', signature_secret='qwerasdfzxcv', signature_method='sha256'
+        ),
+        http_client_options={'api_host': 'example.com'},
+    )
+    params = {
+        'test': 'post request',
+        'testing': 'http client',
+    }
+
+    res = client.post(
+        host='example.com',
+        request_path='/post_signed_params',
+        params=params,
+        auth_type='signature',
+    )
+    assert res['hello'] == 'world!'
+
+    assert loads(responses.calls[0].request.body) == params
+
+
 @responses.activate
 def test_http_response_general_error():
     build_response(path, 'GET', 'https://example.com/get_json', '400.json', 400)