diff --git a/superset/db_engine_specs/base.py b/superset/db_engine_specs/base.py
index 5a8354fd78dc7..d80625dc0c385 100644
--- a/superset/db_engine_specs/base.py
+++ b/superset/db_engine_specs/base.py
@@ -1618,7 +1618,7 @@ def get_impersonation_key(cls, user: Optional[User]) -> Any:
         return user.username if user else None
 
     @classmethod
-    def mask_encrypted_extra(cls, encrypted_extra: str) -> str:
+    def mask_encrypted_extra(cls, encrypted_extra: Optional[str]) -> Optional[str]:
         """
         Mask ``encrypted_extra``.
 
@@ -1631,7 +1631,9 @@ def mask_encrypted_extra(cls, encrypted_extra: str) -> str:
 
     # pylint: disable=unused-argument
     @classmethod
-    def unmask_encrypted_extra(cls, old: str, new: str) -> str:
+    def unmask_encrypted_extra(
+        cls, old: Optional[str], new: Optional[str]
+    ) -> Optional[str]:
         """
         Remove masks from ``encrypted_extra``.
 
diff --git a/superset/db_engine_specs/bigquery.py b/superset/db_engine_specs/bigquery.py
index 4016c8f08f524..38b1f92023a10 100644
--- a/superset/db_engine_specs/bigquery.py
+++ b/superset/db_engine_specs/bigquery.py
@@ -396,10 +396,13 @@ def get_parameters_from_uri(
         raise ValidationError("Invalid service credentials")
 
     @classmethod
-    def mask_encrypted_extra(cls, encrypted_extra: str) -> str:
+    def mask_encrypted_extra(cls, encrypted_extra: Optional[str]) -> Optional[str]:
+        if encrypted_extra is None:
+            return encrypted_extra
+
         try:
             config = json.loads(encrypted_extra)
-        except json.JSONDecodeError:
+        except (json.JSONDecodeError, TypeError):
             return encrypted_extra
 
         try:
@@ -410,14 +413,19 @@ def mask_encrypted_extra(cls, encrypted_extra: str) -> str:
         return json.dumps(config)
 
     @classmethod
-    def unmask_encrypted_extra(cls, old: str, new: str) -> str:
+    def unmask_encrypted_extra(
+        cls, old: Optional[str], new: Optional[str]
+    ) -> Optional[str]:
         """
         Reuse ``private_key`` if available and unchanged.
         """
+        if old is None or new is None:
+            return new
+
         try:
             old_config = json.loads(old)
             new_config = json.loads(new)
-        except json.JSONDecodeError:
+        except (TypeError, json.JSONDecodeError):
             return new
 
         if "credentials_info" not in new_config:
diff --git a/superset/db_engine_specs/gsheets.py b/superset/db_engine_specs/gsheets.py
index 3ee284788c245..3562e0d0b1384 100644
--- a/superset/db_engine_specs/gsheets.py
+++ b/superset/db_engine_specs/gsheets.py
@@ -140,10 +140,13 @@ def get_parameters_from_uri(
         raise ValidationError("Invalid service credentials")
 
     @classmethod
-    def mask_encrypted_extra(cls, encrypted_extra: str) -> str:
+    def mask_encrypted_extra(cls, encrypted_extra: Optional[str]) -> Optional[str]:
+        if encrypted_extra is None:
+            return encrypted_extra
+
         try:
             config = json.loads(encrypted_extra)
-        except json.JSONDecodeError:
+        except (TypeError, json.JSONDecodeError):
             return encrypted_extra
 
         try:
@@ -154,14 +157,19 @@ def mask_encrypted_extra(cls, encrypted_extra: str) -> str:
         return json.dumps(config)
 
     @classmethod
-    def unmask_encrypted_extra(cls, old: str, new: str) -> str:
+    def unmask_encrypted_extra(
+        cls, old: Optional[str], new: Optional[str]
+    ) -> Optional[str]:
         """
         Reuse ``private_key`` if available and unchanged.
         """
+        if old is None or new is None:
+            return new
+
         try:
             old_config = json.loads(old)
             new_config = json.loads(new)
-        except json.JSONDecodeError:
+        except (TypeError, json.JSONDecodeError):
             return new
 
         if "service_account_info" not in new_config:
diff --git a/superset/models/core.py b/superset/models/core.py
index 8c1b58171d470..ca15137935ef9 100755
--- a/superset/models/core.py
+++ b/superset/models/core.py
@@ -248,7 +248,7 @@ def backend(self) -> str:
         return sqlalchemy_url.get_backend_name()
 
     @property
-    def masked_encrypted_extra(self) -> str:
+    def masked_encrypted_extra(self) -> Optional[str]:
         return self.db_engine_spec.mask_encrypted_extra(self.encrypted_extra)
 
     @property
@@ -261,10 +261,12 @@ def parameters(self) -> Dict[str, Any]:
         masked_encrypted_extra = db_engine_spec.mask_encrypted_extra(
             self.encrypted_extra
         )
-        try:
-            encrypted_config = json.loads(masked_encrypted_extra)
-        except (TypeError, json.JSONDecodeError):
-            encrypted_config = {}
+        encrypted_config = {}
+        if masked_encrypted_extra is not None:
+            try:
+                encrypted_config = json.loads(masked_encrypted_extra)
+            except (TypeError, json.JSONDecodeError):
+                pass
 
         try:
             # pylint: disable=useless-suppression
diff --git a/tests/unit_tests/db_engine_specs/test_bigquery.py b/tests/unit_tests/db_engine_specs/test_bigquery.py
index 13f7fd3150fc4..8c33489faf598 100644
--- a/tests/unit_tests/db_engine_specs/test_bigquery.py
+++ b/tests/unit_tests/db_engine_specs/test_bigquery.py
@@ -186,9 +186,61 @@ def test_unmask_encrypted_extra() -> None:
         }
     )
 
-    assert json.loads(BigQueryEngineSpec.unmask_encrypted_extra(old, new)) == {
+    assert json.loads(str(BigQueryEngineSpec.unmask_encrypted_extra(old, new))) == {
         "credentials_info": {
             "project_id": "yellow-unicorn-314419",
             "private_key": "SECRET",
         },
     }
+
+
+def test_unmask_encrypted_extra_when_empty() -> None:
+    """
+    Test that a None value works for ``encrypted_extra``.
+    """
+    from superset.db_engine_specs.bigquery import BigQueryEngineSpec
+
+    old = None
+    new = json.dumps(
+        {
+            "credentials_info": {
+                "project_id": "yellow-unicorn-314419",
+                "private_key": "XXXXXXXXXX",
+            },
+        }
+    )
+
+    assert json.loads(str(BigQueryEngineSpec.unmask_encrypted_extra(old, new))) == {
+        "credentials_info": {
+            "project_id": "yellow-unicorn-314419",
+            "private_key": "XXXXXXXXXX",
+        },
+    }
+
+
+def test_unmask_encrypted_extra_when_new_is_empty() -> None:
+    """
+    Test that a None value works for ``encrypted_extra``.
+    """
+    from superset.db_engine_specs.bigquery import BigQueryEngineSpec
+
+    old = json.dumps(
+        {
+            "credentials_info": {
+                "project_id": "black-sanctum-314419",
+                "private_key": "SECRET",
+            },
+        }
+    )
+    new = None
+
+    assert BigQueryEngineSpec.unmask_encrypted_extra(old, new) is None
+
+
+def test_mask_encrypted_extra_when_empty() -> None:
+    """
+    Test that the encrypted extra will return a none value if the field is empty.
+    """
+    from superset.db_engine_specs.bigquery import BigQueryEngineSpec
+
+    assert BigQueryEngineSpec.mask_encrypted_extra(None) is None
diff --git a/tests/unit_tests/db_engine_specs/test_gsheets.py b/tests/unit_tests/db_engine_specs/test_gsheets.py
index 219f259c1f39f..a226653ed57e0 100644
--- a/tests/unit_tests/db_engine_specs/test_gsheets.py
+++ b/tests/unit_tests/db_engine_specs/test_gsheets.py
@@ -228,9 +228,52 @@ def test_unmask_encrypted_extra() -> None:
         }
     )
 
-    assert json.loads(GSheetsEngineSpec.unmask_encrypted_extra(old, new)) == {
+    assert json.loads(str(GSheetsEngineSpec.unmask_encrypted_extra(old, new))) == {
         "service_account_info": {
             "project_id": "yellow-unicorn-314419",
             "private_key": "SECRET",
         },
     }
+
+
+def test_unmask_encrypted_extra_when_old_is_none() -> None:
+    """
+    Test that a None value works for ``encrypted_extra``.
+    """
+    from superset.db_engine_specs.gsheets import GSheetsEngineSpec
+
+    old = None
+    new = json.dumps(
+        {
+            "service_account_info": {
+                "project_id": "yellow-unicorn-314419",
+                "private_key": "XXXXXXXXXX",
+            },
+        }
+    )
+
+    assert json.loads(str(GSheetsEngineSpec.unmask_encrypted_extra(old, new))) == {
+        "service_account_info": {
+            "project_id": "yellow-unicorn-314419",
+            "private_key": "XXXXXXXXXX",
+        },
+    }
+
+
+def test_unmask_encrypted_extra_when_new_is_none() -> None:
+    """
+    Test that a None value works for ``encrypted_extra``.
+    """
+    from superset.db_engine_specs.gsheets import GSheetsEngineSpec
+
+    old = json.dumps(
+        {
+            "service_account_info": {
+                "project_id": "yellow-unicorn-314419",
+                "private_key": "XXXXXXXXXX",
+            },
+        }
+    )
+    new = None
+
+    assert GSheetsEngineSpec.unmask_encrypted_extra(old, new) is None