diff --git a/celery/security/serialization.py b/celery/security/serialization.py
index c58ef906542..937abe63c72 100644
--- a/celery/security/serialization.py
+++ b/celery/security/serialization.py
@@ -29,7 +29,8 @@ def serialize(self, data):
         assert self._cert is not None
         with reraise_errors('Unable to serialize: {0!r}', (Exception,)):
             content_type, content_encoding, body = dumps(
-                bytes_to_str(data), serializer=self._serializer)
+                data, serializer=self._serializer)
+
             # What we sign is the serialized body, not the body itself.
             # this way the receiver doesn't have to decode the contents
             # to verify the signature (and thus avoiding potential flaws
@@ -48,7 +49,7 @@ def deserialize(self, data):
                                        payload['signer'],
                                        payload['body'])
             self._cert_store[signer].verify(body, signature, self._digest)
-        return loads(bytes_to_str(body), payload['content_type'],
+        return loads(body, payload['content_type'],
                      payload['content_encoding'], force=True)
 
     def _pack(self, body, content_type, content_encoding, signer, signature,
@@ -84,7 +85,7 @@ def _unpack(self, payload, sep=str_to_bytes('\x00\x01')):
             'signature': signature,
             'content_type': bytes_to_str(v[0]),
             'content_encoding': bytes_to_str(v[1]),
-            'body': bytes_to_str(v[2]),
+            'body': v[2],
         }
 
 
diff --git a/t/unit/security/test_serialization.py b/t/unit/security/test_serialization.py
index 6caf3857b81..cb16d9f14fc 100644
--- a/t/unit/security/test_serialization.py
+++ b/t/unit/security/test_serialization.py
@@ -16,15 +16,19 @@
 
 class test_secureserializer(SecurityCase):
 
-    def _get_s(self, key, cert, certs):
+    def _get_s(self, key, cert, certs, serializer="json"):
         store = CertStore()
         for c in certs:
             store.add_cert(Certificate(c))
-        return SecureSerializer(PrivateKey(key), Certificate(cert), store)
+        return SecureSerializer(
+            PrivateKey(key), Certificate(cert), store, serializer=serializer
+        )
 
-    def test_serialize(self):
-        s = self._get_s(KEY1, CERT1, [CERT1])
-        assert s.deserialize(s.serialize('foo')) == 'foo'
+    @pytest.mark.parametrize("data", [1, "foo", b"foo", {"foo": 1}])
+    @pytest.mark.parametrize("serializer", ["json", "pickle"])
+    def test_serialize(self, data, serializer):
+        s = self._get_s(KEY1, CERT1, [CERT1], serializer=serializer)
+        assert s.deserialize(s.serialize(data)) == data
 
     def test_deserialize(self):
         s = self._get_s(KEY1, CERT1, [CERT1])